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Reading Material 15阅读材料15Chemical Industry and Environmental Protection化学工业与环境保护How can we reduce the amount of waste that is produced? And how we close the loop by redirecting spent materials and products into programs of recycling? All of these questions must be answered through careful research in the coming years as we strive to keep civilization in balance with nature.我们怎么样才能够减少化学工业产生的污染物的排放，怎么才能够使材料的产品更好地循环利用，为了自然生态的平衡，所有这些问题都是下来我们必须通过认真的研究和探索来解决的问题。
1. Life Cycle Analysis1.生命循环的分析Every stage of a product’s life cycle has an environmental impact, starting extraction of raw materials, continuing through processing, manufacturing, and transportation, and concluding with consumption and disposal or recovery. Technology and chemical science are challenged at every stage. Redesigning products and processes to minimize environmental impact requires a new philosophy of production and a different level of understanding of chemical transformations. Environment friendly products require novel materials that are reusable, recyclable, or biodegradable; properties of the materials are determined by the chemical composition and structure. To minimize waste and polluting by-products, new kinds of chemical process schemes will have to be developed. Improved chemical separation techniques are needed to enhance efficiency and remove residual pollutants, which in turn will require new chemical treatment methods in order to render them harmless. Pollutants such as radioactive elements and toxic heavy metals that cannot be readily converted into harmless materials will need to be immobilized in inert materials so that can be safely stored. Finally, the leftover pollution of an earlier, less environmentally aware era demands improved chemical and biological remediation techniques.每一个时代的产品的循环利用对环境都有着重大的影响，力争选用天然的材料，继续通过加工，制造，运输，总结与消费和处置或回收。
高三英语科学前沿动态单选题30题1. The new scientific discovery has opened up ______ possibilities for future research.A. numerousB. rareC. fewD. single答案：A。
本题主要考查词汇的含义。
A 选项“numerous”意思是“众多的，许多的”，符合语境，新的科学发现为未来研究开辟了许多可能性。
B 选项“rare”表示“罕见的，稀有的”；C 选项“few”表示“很少的，几乎没有”，与语境不符；D 选项“single”意思是“单一的”，也不符合“开辟多种可能性”的语境。
2. The latest space exploration mission requires ______ technology and advanced equipment.A. complexB. simpleC. ancientD. common答案：A。
本题考查词汇理解。
A 选项“complex”意为“复杂的”，最新的太空探索任务需要复杂的技术和先进的设备，符合逻辑。
B 选项“simple”表示“简单的”；C 选项“ancient”是“古老的”；D 选项“common”为“普通的”，都不符合太空探索任务对技术和设备的要求。
3. Scientists are working hard to find a ______ to the global warming problem.A. solutionB. questionC. causeD. result答案：A。
“solution”有“解决办法”的意思。
科学家努力工作是为了找到全球变暖问题的解决办法，A 选项符合。
B 选项“question”是“问题”；C 选项“cause”指“原因”；D 选项“result”意为“结果”，均不符合题意。
4. The breakthrough in artificial intelligence has brought ______ changes to our daily lives.A. slightB. hugeC. tinyD. minor答案：B。
2018年第37卷第1期 CHEMICAL INDUSTRY AND ENGINEERING PROGRESS·301·化 工 进展HCN 、COS 和CS 2催化水解及其水解产物协同净化的研究进展刘娜1，宁平1，李凯1，梅毅2，王驰2，孙鑫1，汤立红1，宋辛1，唐勰1（1昆明理工大学环境科学与工程学院，云南 昆明650500；2昆明理工大学化学工程学院，云南 昆明 650500） 摘要：氰化氢（HCN ）、羰基硫（COS ）、二硫化碳（CS 2）广泛共存于黄磷尾气、焦炉煤气、碳一化工等化工行业废气中，目前大多数研究局限于3种气体的单独脱除，3种气体同时脱除的研究鲜有报道，而3种气体的协同脱除势在必行。
催化水解法能够将HCN 转化成NH 3，COS 和CS 2水解成H 2S 。
NH 3和H 2S 可以分别被催化氧化为N 2及S ，S 可以回收利用。
一步法实现HCN 、COS 和CS 2的水解及水解产物NH 3和H 2S 的催化氧化的催化剂开发是该技术的核心问题，本文针对近几年3种气体水解催化剂的相关研究成果进行了综述，包括负载型催化剂和非负载型催化剂，与此同时，针对水解产物NH 3和H 2S 的催化氧化的协同净化技术进行了分析，旨在为后续3种气体同时催化水解及协同净化其水解产物催化剂的开发提供理论指导，为低温环境下协同催化水解HCN 、COS 和CS 2，并利用原料气中的氧一步法净化水解产物技术的未来发展及应用提供参考。
关键词：催化；水解；催化剂载体；氰化氢；羰基硫；二硫化碳；水解产物；协同净化 中图分类号：X511 文献标志码：A 文章编号：1000–6613（2018）01–0301–10 DOI ：10.16085/j.issn.1000-6613.2017-0835Research progress in catalytic hydrolysis of HCN ，COS and CS 2 andsynergetic purification of hydrolysatesLIU Na 1，NING Ping 1，LI Kai 1，MEI Yi 2，WANG Chi 2，SUN Xin 1，TANG Lihong 1，SONG Xin 1，TANG Xie 1（1College of Enviromental Science and Engineering ，Kunming University of Science and Technology ，Kunming 650500，Yunnan ，China ；2 College of Chemistry and Engineering ，Kunming University of Science and Technology ，Kunming 650500，Yunnan ，China ）Abstract ：HCN （hydrogen cyanide ），COS （carbonyl sulfide ）and CS 2（carbon disulfide ） are widely coexisted in the chemical industry tail gas ，for example ，yellow phosphorus tail gas ，coke oven gas and C1 chemical industry. At present ，there are many studies on the single removal of the three gases ，and the research on the simultaneous removal of the three gases is rarely reported. So simultaneous removing of three gases is necessary. HCN can be converted into NH 3，and COS/CS 2 can be converted into H 2S during the catalysis hydrolysis process. NH 3 and H 2S can be catalytic oxidized to N 2 and S respectively ，and S can be recycled. The development of catalysts for the simultaneous catalytic hydrolysis of HCN ，COS and CS 2 and oxidation of NH 3 and H 2S in one step is the key problem of this technology. In this paper ，the related research achievements of catalysts for hydrolysis of three gas were reviewed both in supported catalyst and unsupported catalyst. Meanwhile ，the synergetic purification technology of hydrolysates （NH 3 and H 2S ）was analyzed. This paper provides a reference to the development and application of the way that catalytic hydrolysis of HCN/COS/CS 2 and synergistic控制。
过硫酸盐活化技术降解污染物的研究进展徐文思;彭伟;张星;李晨旭;刘杰【摘要】We briefly introduce physical and chemical properties of persulfate(PS),and emphasize the PS ac-tivation technology,including transition metal ions activation,transition metal activation,carbon activation,and thermal activation,etc.Meanwhile,we summarize the activation mechanism and the application of activated PS in the degradation of organic matter,and propose the main research directions and the technical improvement di-rections of PS activation technology in the future.%简单介绍了过硫酸盐的物理和化学性质,重点介绍了过硫酸盐的活化技术,如过渡金属离子活化、过渡金属活化、碳活化、热活化等,并对活化机理及活化过硫酸盐在有机物降解中的应用进行了简述,提出了过硫酸盐活化技术未来的主要研究方向以及技术改进方向.【期刊名称】《化学与生物工程》【年(卷),期】2018(035)006【总页数】5页(P14-18)【关键词】过硫酸盐;硫酸根自由基;活化;污染物;过渡金属【作者】徐文思;彭伟;张星;李晨旭;刘杰【作者单位】陆军勤务学院军事设施系,重庆 401331;陆军勤务学院军事设施系,重庆 401331;陆军勤务学院军事设施系,重庆 401331;陆军勤务学院军事设施系,重庆401331;陆军勤务学院军事设施系,重庆 401331【正文语种】中文【中图分类】X703.1无处不在的无机物和有机物导致的全球污染越来越严重，致使全球约超过25%的人口遭受水污染带来的健康和卫生问题[1]，尤其是在人类发展指数(HDI)较低的许多非洲和亚洲国家，地表水和地下水的污染直接导致缺水。
单分散气溶胶的声波团聚实验周栋;骆仲泱;鲁梦诗;赫明春;陈浩;方梦祥【摘要】针对在声波团聚研究中最佳声波参数与气溶胶粒径分布情况之间的关系尚不明确的问题,提出采用单分散气溶胶作为颗粒源,研究不同粒径的单分散气溶胶对最佳声波团聚参数影响的方法.采用单分散癸二酸二异辛酯(DEHs)气溶胶作为颗粒源,研究在不同声场作用下,不同粒径、不同频率对单分散气溶胶数目浓度的影响.颗粒物数目浓度减少率越大,声波团聚的效果越好.结果表明,在选取的1 000~2 200 Hz频率段,大粒径的2 μm颗粒物声波团聚效果好于小粒径的0.2和0.5 μm的情况,而2 μm颗粒物较优的声波团聚频率略低于0.2和0.5 μm的颗粒物.%Taking monodispersed aerosols as particle sources, the influence of that with different particle sizes on optimal acoustic agglomeration parameters was investigated to figure out the relationship between optimal sound parameters and particle size distributions of different aerosols in acoustic agglomeration.Monodispersed DEHs (diethylhexylsebacate) aerosol was used as the particle source.The effect of particle size and sound frequency on the number concentration of monodispersed aerosol under different sound conditions was analyzed.A higher decrement rate of particle number concentration means a better effect of sound wave.It is found that when the sound frequency ranges from 1 000 to 2 200 Hz, the acoustic agglomeration of 2 μm particle is more effective than that of 0.2 μm and 0.5 μm.The optimum frequency for 2 μm particle is a bit lower.【期刊名称】《浙江大学学报（工学版）》【年(卷),期】2017(051)002【总页数】6页(P358-362,369)【关键词】单分散气溶胶;PM2.5;DEHs;声波团聚;声波频率【作者】周栋;骆仲泱;鲁梦诗;赫明春;陈浩;方梦祥【作者单位】浙江大学能源清洁利用国家重点实验室,浙江杭州 310027;浙江大学能源清洁利用国家重点实验室,浙江杭州 310027;浙江大学能源清洁利用国家重点实验室,浙江杭州 310027;浙江大学能源清洁利用国家重点实验室,浙江杭州310027;浙江大学能源清洁利用国家重点实验室,浙江杭州 310027;浙江大学能源清洁利用国家重点实验室,浙江杭州 310027【正文语种】中文【中图分类】X51随着我国社会经济持续高速增长,大量的能源消耗所引起的雾霾问题越来越严重[1].颗粒物已经成为大城市中空气污染的主要因素,而其中PM2.5由于体积小,比表面积大,易携带大量有毒物质,能进入人体肺部造成巨大危害[2].而传统除尘设备如旋风分离器、静电除尘器等对PM2.5的脱除效率不高,因此研究细颗粒物的预处理技术显得尤为重要[3].细颗粒物的预处理技术包括声波团聚[4-9]、电团聚[10]、化学团聚[11]、核化凝结长大[12]、磁团聚[13]等.声波团聚技术是利用高强声波对气溶胶进行作用,使得其中颗粒物通过不同的振动和相互作用而发生碰撞团聚,成为粒径更大的颗粒物,从而提高后续除尘设备的脱除效果[14].声波团聚的效果与声波频率、声压级、颗粒物粒径分布、声波作用时间等因素有关[15-18].声波团聚主要是基于声波对颗粒物的携带作用,声波的振动带动介质振动,介质又通过黏性力带动其中的颗粒物振动.不同频率的声波对不同粒径的颗粒物具有的携带能力不一样,称为为携带系数[7].由于颗粒物具有惯性,在介质中的振动滞后于介质本身的振动,颗粒越大惯性越大,滞后性也就越强,因而粒径的变化对颗粒物在声场中的振动情况有显著影响.王洁等[19]通过研究高频20 kHz声波和低频1 400 Hz声波对燃煤电厂颗粒物作用的对比,发现低频1 400 Hz更适合于燃煤电厂颗粒物,而高频20 kHz的效果并不好,对极细颗粒物(纳米级)的颗粒物作用优于微米级的颗粒物.针对不同的颗粒源,采用合适的声波频率,最大化声波团聚的作用,是实现声波团聚实际应用的重要研究内容.在声波团聚的相关研究中,采用的颗粒源不尽相同,最后得到的最佳声波团聚参数也没有一致的结论,关于粒径的对声波团聚效果影响的研究内容也较少.本文通过研究单分散气溶胶的声波团聚,探讨了不同粒径的单分散气溶胶声波团聚的最佳参数,颗粒粒径对声波最佳作用频率的选择性等问题,分析了粒径分布和声波频率对声波团聚的影响,为工业应用中多分散气溶胶的声波团聚提供实验基础.本文采用的实验装置流程图如图1所示.颗粒发生源选择的是癸二酸二辛脂(dioctyl sebacte, PALAS)凝聚式单分散气溶胶发生器,使用的颗粒为单分散癸二酸二异辛酯(DEHs)液滴颗粒物.声源系统中使用SFG-1013信号发生器和QSC-RMX2450功率放大器来驱动YF-513压缩式驱动器.团聚室采用的是6 cm×6 cm的方管,长28 cm.测量采用低压电称冲击器(electrical low pressure impactor,ELPI)进行采样测量,其进气量约为10 L/min.团聚室内气体流速约为4.63 cm/s,停留时间约为6 s. 单分散气溶胶发生器发生的DEHs颗粒物粒径大小是由控制DEHs蒸发量的温度决定的.改变温度可以调节DEHs颗粒粒径的大小.分别调节温度至115、155、215 ℃,得到粒径分别为0.2、0.5、2 μm的单分散气溶胶进行声波团聚实验.用ELPI测得这3个工况下初始气溶胶粒径分布情况如图2所示.其中,d为颗粒粒径,c为不同粒径段颗粒物的数目浓度.从图2中可以看出,粒径分布基本满足单分散的条件.由于温度不同,DEHs的蒸发量有所区别,而颗粒粒径不同,同样的蒸发量能形成的颗粒物也不同,因而3种温度条件下颗粒物的浓度有所区别.虽然浓度对声波团聚的效果有影响,但是根据Wang等[15]的研究结果,浓度并不影响颗粒物对最佳声波团聚频率的选择性.因此,这3种工况下产生的颗粒物可以用来进行单分散气溶胶的声波团聚实验.实验中,先打开单分散气溶胶发生器,然后打开ELPI进行粒径测量,通过改变声波的频率、声压级等,测量在不同声场条件下,单分散气溶胶团聚后的粒径分布情况.当DEHs气溶胶粒径为0.2 μm时,在不同声波频率条件下,声压级Lp对声波团聚的影响如图3所示.f为声波频率.从图3中可以看出,初始状态为没有声波作用时DEHs颗粒物的数目浓度分布.随着声压级越来越大,数目浓度逐渐变小,可见声压级越大,越有利于声波团聚.但是减小的趋势并不明显,只有在1 400 Hz的条件下有明显的降低.效果最好的工况出现在1 400 Hz,142 dB条件下,颗粒数目浓度减少了31.5%.当气溶胶粒径改为0.5 μm时,不同频率条件下声压级的影响如图4所示.从图4中可以看出,声压级越大,颗粒物数目浓度减少的规律一致,但是效率并不高,最佳工况一样也是在1 400 Hz,150 dB条件下,颗粒物数目浓度减少了37.8%.气溶胶粒径为2 μm时,不同频率条件下声压级的影响如图5所示,从图5中可以看出,与前2种粒径相比,声波的作用明显了很多,在大多数频率作用下,颗粒物数目浓度都有非常明显的降低,可见有效的声波作用频率段变宽了,效果好的工况比较多,颗粒物数目浓度最多减少了65%～70%.用颗粒物的数目浓度的减少率来衡量声波团聚的效果,它表示声波作用后颗粒物数目的减少量与声波作用前数目浓度的比值.0.2 μm的单分散气溶胶的颗粒减少率在不同声压级条件下随着频率变化的曲线如图6所示,其中η为颗粒减少率.从图6中可以看到声压级越大,颗粒减少得越多.声压级的增加主要增大气体介质以及颗粒的振幅,振幅增大,单个颗粒运动的范围增大,颗粒之间的相对运动也变大,从而碰撞的几率增加.1 400 Hz为所选频率段中0.2 μm气溶胶声波团聚的最佳频率.0.5 μm的单分散气溶胶的颗粒减少率在不同声压级条件下随着频率变化的曲线如图7所示,从图7中可以看出,0.5 μm的气溶胶,1 000 Hz的声波作用有所提升,而在142 dB 的较高声压级条件下,1 400 Hz依旧是最佳频率.2 μm的单分散气溶胶的颗粒减少率在不同声压级条件下随着频率变化的曲线如图8所示,从图8中可以看出,1 000 Hz已经成为最佳的声波团聚频率,说明大粒径的颗粒物最佳声波团聚频率比小粒径颗粒物要低一些.通过比较3种粒径的声波团聚结果,可以看出在选择的1 000～2 200 Hz频率段,2 μm的颗粒物在声场作用下团聚作用更明显.有学者实验研究发现,颗粒物数目浓度越大,声波团聚的效果越好[15].由于单分散气溶胶发生器中DEHs的蒸发量有限,当生成2 μm颗粒物时,数目浓度偏低,仅为0.2和0.5 μm条件下数目浓度的1/3,但是声波团聚的效果还是远远好于这2种小粒径的情况,可见颗粒物的粒径分布对声波团聚的影响远远大于数目浓度带来的影响.根据声波团聚机理中最主要的同向团聚机理[19-20],声波团聚主要是基于声波对颗粒物的携带作用,颗粒跟随声波的振动产生了团聚体积和颗粒间的相对运动,如果颗粒过小,那么能完全携带颗粒的声波频率则会偏高,且亚微米颗粒物的体积非常小,其运动范围也会很小,导致颗粒间的碰撞变得更少.本文使用单分散气溶胶发生器分别产生0.2、0.5、2 μm的单分散DEHs气溶胶,将其通过不同条件的声场左右,用ELPI对其数目浓度进行在线检测,分析比较了声波团聚效果的变化,得到以下结论：(1)声压级越大,单分散气溶胶的团聚效果越好.但在实际应用中,声压级本身受到能耗和声源工作能力的限制,并不是越大越好.(2)大粒径的2 μm气溶胶在选取的1 000～2 200 Hz频率段的声波团聚效果远远好于0.2和0.5 μm,粒径增大,声波团聚后颗粒的数目浓度减少率也增大.(3)不同频率对不同粒径的颗粒物的携带能力不同,低频声波能携带更大粒径的颗粒物,而高频能携带颗粒物的粒径偏小,实验结果显示2 μm的颗粒物较优的声波团聚频率为1 000 Hz,略低于0.2和0.5 μm的1 400 Hz.【相关文献】[1] 吴兑.近十年中国灰霾天气研究综述[J].环境科学学报.2012(02): 257-269. WU Dui. Hazy weather research in China in the last decade: A review [J]. Acta Scientiae Circumstantiae, 2012, 32(2): 257-269.[2] KIM OANH N T, UPADHYAY N, ZHUANG Y H, et al. Particulate air pollution in six Asian cities: Spatial and temporal distributions, and associated sources [J]. Atmospheric Environment, 2006, 40(18): 3367-3380.[3] HEIDENREICH S, EBERT F. Condensational droplet growth as a preconditioning technique for the separation of submicron particles from gases [J]. Chemical Engineering and Processing, 1995, 34(3): 235-244.[4] 凡凤仙.外加条件作用下可吸入颗粒物长大机理研究[D].南京:东南大学, 2008. FAN Feng-xian. Mechanism study of particle growth with additional effects [D]. Nanjing: Southeast University. 2008.[5] 赵兵.利用声波团聚增强燃烧源可吸入颗粒物脱除的研究[D].南京: 东南大学, 2008. ZHAO Bing. Using acoustic agglomeration to enhance the removal efficiency of particles in combustion source. [D]. Nanjing: Southeast University. 2008.[6] 陈厚涛.声波团聚增强燃烧源细颗粒物排放控制的研究[D].南京:东南大学, 2009. CHEN Hou-tao. The study of using acoustic agglomeration to enhance the control of fine particle emission [D]. Nanjing: Southeast University. 2009.[7] PATEL S N. Low intensity (<155dB) acoustic agglomeration-bench-scale experiments[D]. Buffalo: State University of New York at Bffalo, 1981.[8] 王洁.声波团聚及联合其他方法脱除燃煤飞灰细颗粒的研究[D].杭州：浙江大学, 2012. WANG Jie. Study of combined acoustic agglomeration with other means to remove coal-fired fine particles [D]. Hangzhou: Zhejiang University. 2012.[9] 张光学.燃煤飞灰气溶胶声波团聚的理论和实验研究[D].杭州：浙江大学, 2010. ZHANGGuang-xue. Experimental and theoretical studies on acoustic agglomeration of coal-fired fly ash [D]. Hangzhou: Zhejiang University. 2010.[10] 赵磊.脉冲电晕放电烟气中细微颗粒物协同氮氧化物脱除研究[D].杭州：浙江大学, 2013. ZHAO Lei. Research on simultaneous removal of PM2.5and NOx from flue gas by pulsed corona discharge [D]. Hangzhou: Zhejiang University. 2013.[11] 赵汶,刘勇,鲍静静,等.化学团聚促进燃煤细颗粒物脱除的试验研究[J].中国电机工程学报.2013(20): 52-58. ZHAO Wen, LIU Yong, BAO Jing-jing, et al. Experimental research on fine particles removal from flue gas by chemical agglomeration [J]. Proceedings of the CSEE, 2013(20): 52-58.[12] 徐俊超.细颗粒核化凝结长大实验平台设计及特性研究[D].南京:东南大学, 2014. XU Jun-chao. Fine particle growth by nucleation and condensation experiment system design and characteristic research [D]. Nan jing: Southeast University.2014.[13] 林潮,孙传尧,徐建民.强磁性粒子间磁团聚力的研究[J].矿冶.2000(01): 25-30. LIN Chao, SUN Chuan-yao, XU Jian-min. Study on magnetic agglomeration force of ferromagnetic particles [J]. Mining and Metallurgy, 2000(01): 25-30.[14] REETHOF G. Acoustic agglomeration of power-plant fly-ash for environmental and hot gas cleanup [J]. Journal of Vibration Acoustic Stress and Reliability in Design-Transactions of The ASME, 1988, 110(4):552-556.[15] WANG J, LIU J, ZHANG G, et al. Orthogonal design process optimization and single factor analysis for bimodal acoustic agglomeration [J]. Powder Technology, 2011, 210(3): 315-322.[16] LIU J, ZHANG G, ZHOU J, et al. Experimental study of acoustic agglomeration of coal-fired fly ash particles at low frequencies[J]. Powder Technology, 2009, 193(1): 20-25. [17] RIERA-FRANCO DE SARABIA E, EIVIRA-SEGURA L, GONZLEZ-GóMEZ I, et al. Investigation of the influence of humidity on the ultrasonic agglomeration of submicron particles in diesel exhausts[J]. Ultrasonics, 2003, 41(4): 277-281.[18] GONZLEZ I A, HOFFMANN T L, GALLEGO J A. Precise measurements of particle entrainment in a standing-wave acoustic filed between 20 and 3500Hz[J]. Journal of Aerosol Science, 2000, 31(12):1461-1468.[19] LIU J, WANG J, ZHANG G, et al. Frequency comparative study of coal-fired fly ash acoustic agglomeration [J]. Journal of Environment Science, 2011, 23(11): 1845-1851. [20] HOFFMANN T L, KOOPMANN G H. Visualization of acoustic particle interaction and agglomeration: Theory and experiments [J]. Journal of the Acoustical Society of America, 1996, 99(41): 2130-2141.。
科技英语翻译6.1 介词的一般译法第1节翻译练习1In general, man serves as the source of infection while animals act as such only occasionally.An industrial robot shares many attributes in common with a numerical control machine tool.一般来说，人可作为感染源，而动物只是偶然如此。
工业用机器人与数控机床有许多共同的特性。
第1节翻译练习2With non-changeover control both the boiler plant and the chiller plant operate to provide simultaneous heating and cooling throughout the year.The online service delivers substantially more value to our global audience of e-business professionals in the chemical, plastics and allied industries.This device can mimic photosynthesis to produce usable energy from sunlight.采用非转换控制，锅炉设备和制冷装置都在运行，全年可同时供暖和制冷。
该网络服务主要向全球从事化学、塑料及相关工业的专业电子商务用户提供更有价值的服务。
这种装置能够模拟光合作用，利用阳光产生可用的能源。
第1节翻译练习3The longitudinal axis of the turbine generator is perpendicular to the axis of the steam generator. In the right conditions, membranes are self-assembling.Winding of the spring induces residual stresses through bending.汽轮发电机的纵轴与锅炉轴线垂直。
基于电解法的模拟船舶柴油机废气脱硝实验研究于景奇;韩志涛;杨少龙;季向赟;郑子升;潘新祥【摘要】采用离子膜电解槽电解NaCl溶液,研究制备阳极酸性氧化溶液及其对模拟烟气中NO的脱除效果.分别研究了电流密度、电解时间、NaCl浓度等因素对阳极酸性氧化溶液理化性能(TOS浓度、pH)的影响.结果表明:随着电流密度、电解时间、NaCl浓度的增加,阳极酸性氧化溶液中TOS浓度近乎呈线性增加.但随着电解时间增加,pH却迅速降低,并趋于稳定(1.5 ～2).随着阳极酸性氧化溶液中TOS浓度的增加,NO脱除率明显提高;当TOS浓度为700 mg· L-1时,NO脱除率达到50.4％.随着阳极氧化溶液初始pH的降低,NO脱除率明显增加,当pH为6时,NO 脱除率为38％.%The experiments were carried out using the ion-exchange membrane electrolysis cell with NaCl solution.The effects of various electrolytic conditions (current density,electrolysis time and the concentration of NaCl) on the properties of the anodic acid oxidation solution were investigated.As a strong oxidant,the anodic acid oxidation solution was used to remove NO from simulated flue gas.The effects of the properties of the anodic acid oxidation solution on the removal efficiency of NO were studied based on a scrubbing reactor.The results show that,the concentration of TOS in the anode acidic solution increases linearly with the increase of any electrolytic conditions,while the pH of the anodic acid oxidation solution decreases apparently at the beginning and then stabilizes.When increases the TOS concentration of the anode acidic solution,the NO removal efficiency is improved obviously.When the TOSc oncentration is 700 mg · L-1,the NO removal efficiency is50.4％.Increasing the pH of the anodic acid oxidation solution leads to a high NO removal efficiency.When the pH is 6,the NO removal efficiency is 38％.【期刊名称】《科学技术与工程》【年(卷),期】2017(017)013【总页数】6页(P91-96)【关键词】电解;电流效率;废气;脱硝【作者】于景奇;韩志涛;杨少龙;季向赟;郑子升;潘新祥【作者单位】大连海事大学轮机工程学院,大连116026;大连海事大学轮机工程学院,大连116026;大连海事大学轮机工程学院,大连116026;大连海事大学轮机工程学院,大连116026;大连海事大学轮机工程学院,大连116026;大连海事大学轮机工程学院,大连116026【正文语种】中文【中图分类】X701近年来，随着人们环保意识的增强，船舶废气中的NOx对大气环境的污染也引起了人们的高度重视。
第51卷第7期 辽 宁 化 工 Vol.51，No. 7 2022年7月 Liaoning Chemical Industry July，2022收稿日期： 2022-02-10 硫自养反硝化的研究进展周小翔，律泽（沈阳建筑大学， 辽宁 沈阳 110000）摘 要：硫光合自养反硝化技术是一个应用于处理氮氧化物和硫污染废物, 而不需另外加入有机碳源的工艺技术, 成为一种可行性非常高的工艺技术。
在硫光合自养反硝化的过程中, 会受不同的电子供体、pH、温度、DO、HRT值等各种因素的影响。
为此, 对上述各种的影响原因做出了比较细致的解析,并总结了主要工艺参数对硫光合自养反硝化过程的调控影响规律, 经过对比分析, 总结了主要工艺参数对硫自养反硝化的调控影响规律，通过比较分析，认识到当前的挑战和未来可行应用的需求，扩大其应用范围。
关 键 词：硫自养反硝化； 工艺参数； 脱氮除硫； NO2-中图分类号：X703.1 文献标识码： A 文章编号： 1004-0935（2022）07-1013-03随着时代的变迁，硫自养反硝化技术的种种优势，伴随着科技的发展而越来越具有代表性，得到了充分的展现。
且硫自养反硝化工艺不需外加碳源，避免了二次污染、产泥量少、降低了运行费用等特点而更有优势。
因此，硫自养反硝化工艺相比较其他工艺具有操作简单、应用广泛等特点。
本文通过总结国内外学者对硫自养反硝化技术的研究，通过比较分析，从而完善硫自养反硝化的进程，扩大其应用范围。
1 硫自养反硝化原理硫自养反硝化技术是指将无机化能营养型、光能营养型的硫氧化细菌保持在缺氧或厌氧条件下，同时将还原硫（S0、S2-、S2O32-）和硝酸盐作为电子供体和电子受体后，既可以将其还原为氮气，也能够去除含硫化合物，完成自养反硝化过程。
以下为单质硫、硫化物以及含硫化合物为电子供体完成硫自养反硝化过程，如式：1.10S+NO3-+0.76H20+0.40CO2+0.08NH4+→0.08C5H702N+0.50N2+1.10SO42-+1.28H+。
摘要随着社会经济的迅速发展，制药和石油化工等行业的工业废水排放量逐年增加。
含硫、含氮和高浓度化学需氧量（COD）是工业废水污染物组成的典型特征。
这类废水未达标排放到环境中会引起富营养化等问题。
碳氮硫共脱除工艺包含硫酸盐-有机物去除单元，反硝化脱硫单元，生物硫回收单元和硝化单元。
此工艺将硫酸盐还原与反硝化脱硫过程耦合，实现有机物、硫酸盐和氮氧化物的高效去除。
然而此工艺存在污染物去除和资源化效率易受进水负荷干扰，活性污泥中微生物群落功能机制不明确和单质硫产率较低的问题。
本研究在碳氮硫共脱除反应器中分离出一株能够在厌氧条件下同时代谢COD、硫化物和氮氧化物的功能菌株X2。
基于16S rRNA基因的系统进化分析表明菌株X2属于Pseudomonadaceae科，与Pseudomonas caeni有较近的亲缘关系。
它们在系统进化树中与Pseudomonadaceae科其他近缘物种明显分离，形成一个新的进化单元。
采用Pseudomonas caeni作为参考菌株，利用多相分类的方法对菌株X2进行鉴定，结果表明：与Pseudomonas caeni相比较，菌株X2X2代表Pseudomonadaceae科中一个新属的模式种。
依据其硫氧化和反硝化的生理特性命名为Thiopseudomonas denitrificans X2。
根据能量和营养来源差异，设置不同的条件分析菌株X2的代谢特征。
菌株X2可以分别在异养反硝化、混养硫氧化-反硝化和自养硫氧化-反硝化条件下生长代谢。
它可以利用有机或者无机碳作为营养来源，也可以利用硫化物或有机物氧化作为能量来源，属于兼性化能无机营养型硫细菌。
在菌株X2代谢过程中，高浓度电子受体存在的条件下，硫化物不发生过度氧化。
氧化反应的主要产物为颗粒状单质硫。
功能基因表达分析表明硫氧化基因fccAB和反硝化基因nirS都是不受底物诱导的持家基因。
在混养硫氧化-反硝化条件下，这两种基因的表达量都显著低于反硝化条件。
第４８卷２０２０年７月第７期第２４－３５页材 料 工 程ＪｏｕｒｎａｌｏｆＭａｔｅｒｉａｌｓＥｎｇｉｎｅｅｒｉｎｇＶｏｌ．４８Ｊｕｌ．２０２０Ｎｏ．７ｐｐ．２４－３５氧化石墨烯的化学还原方法与机理研究进展Ｒｅｓｅａｒｃｈｐｒｏｇｒｅｓｓｉｎｍｅｔｈｏｄｓａｎｄｍｅｃｈａｎｉｓｍｓｏｆｃｈｅｍｉｃａｌｒｅｄｕｃｔｉｏｎｇｒａｐｈｅｎｅｏｘｉｄｅ郭建强１，２，３，李炯利１，２，３，梁佳丰１，２，李 岳１，２，朱巧思１，２，王旭东１，２，３（１中国航发北京航空材料研究院，北京１０００９５；２北京石墨烯技术研究院有限公司，北京１０００９４；３北京市石墨烯及应用工程技术研究中心，北京１０００９５）ＧＵＯＪｉａｎ ｑｉａｎｇ１，２，３，ＬＩＪｉｏｎｇ ｌｉ１，２，３，ＬＩＡＮＧＪｉａ ｆｅｎｇ１，２，ＬＩＹｕｅ１，２，ＺＨＵＱｉａｏ ｓｉ１，２，ＷＡＮＧＸｕ ｄｏｎｇ１，２，３（１ＡＥＣＣＢｅｉｊｉｎｇＩｎｓｔｉｔｕｔｅｏｆＡｅｒｏｎａｕｔｉｃａｌＭａｔｅｒｉａｌｓ，Ｂｅｉｊｉｎｇ１０００９５，Ｃｈｉｎａ；２ＢｅｉｊｉｎｇＩｎｓｔｉｔｕｔｅｏｆＧｒａｐｈｅｎｅＴｅｃｈｎｏｌｏｇｙ，Ｂｅｉｊｉｎｇ１０００９４，Ｃｈｉｎａ；３ＢｅｉｊｉｎｇＥｎｇｉｎｅｅｒｉｎｇＲｅｓｅａｒｃｈＣｅｎｔｒｅｏｆＧｒａｐｈｅｎｅＡｐｐｌｉｃａｔｉｏｎ，Ｂｅｉｊｉｎｇ１０００９５，Ｃｈｉｎａ）摘要：石墨烯物理性能优异，自被发现以来迅速引起了国内外研究者的广泛关注。
石墨烯的批量生产是实现石墨烯材料应用的前提，由于氧化石墨烯具有丰富的含氧官能团，便于化学改性，生产成本低、可规模化生产，化学还原氧化石墨烯成为目前大批量制备石墨烯材料最常用的方法之一。
至今已经有数十种化学还原氧化石墨烯的方法被报道，还原效果千差万别，还原机理也尚未定论。
本文梳理了氧化石墨烯的主要化学还原方法，从关键反应基团的角度进行了归纳总结，论述了它们的优缺点；分析了多种氧化石墨烯的还原机理，提出氧化石墨烯化学还原的本质是羟基还原同时形成碳碳双键的过程。
Simultaneous removal of SO 2and NO x by microwave with potassium permanganate over zeoliteZai-shan Wei ⁎,He-jingying Niu,Yong-feng JiSchool of Environmental Science and Engineering,Sun Yat-sen University,Guangzhou 510275,People's Republic of ChinaA R T I C L E D A T AA B S T R A C TArticle history:Received 11December 2007Received in revised form 8June 2008Accepted 11September 2008Simultaneous sulfur dioxide (SO 2)and nitrogen oxides (NO x )removal from flue gas can be achieved with high efficiency by microwave with potassium permanganate (KMnO 4)over zeolite.The experimental results showed that the microwave reactor could be used to oxidation of SO 2to sulfate with the best desulfurization efficiency of 96.8%and oxidize NO x to nitrates with the best NO x removal efficiency of 98.4%.Microwave accentuates catalytic oxidation treatment,and microwave addition can increase the SO 2and NO x removal efficiency by 7.2%and 12.2%separately.The addition of zeolite to microwave potassium permanganate increases from 16.5%to 43.5%the microwave removal efficiency for SO 2,and the NO x removal efficiency from 85.6%to 98.2%.The additional use of potassium permanganate to the microwave zeolite leads to the enhancement of SO 2removal efficiency up from 53.9%to 95%,and denitrification efficiency up from 85.6%to 98.2%.The optimal microwave power and empty bed residence time (EBRT)on simultaneous desulfurization and denitrification are 259W and 0.357s,respectively.SO 2and NO x were rapidly oxidized in microwave induced catalytic oxidation reaction using potassium permanganate with zeolite being the catalyst and microwave absorbent.©2008Elsevier B.V.All rights reserved.Keywords:Simultaneous desulfurization and denitrification ZeolitePotassium permanganate (KMnO 4)Microwave induced catalytic reaction1.IntroductionSulfur dioxide (SO 2)and nitrogen oxides (NO x ),mainly emitted from fossil fuel combustion,are major air pollutants.Sulfur dioxide is generally accepted to be the most important pre-cursor to acid rain [1].Nitrogen oxides contribute a lot to photochemical smog,acid rain,ozone depletion and green-house effect [2,3].China produces about 24million tons SO 2and 7.7million tons NO x per year,which leads to more than 13.3billion dollars loss [4].The new policy against pollution further appeals to the desulfurization and denitrification of flue gas.Therefore,desulfurization and denitrification of flue gas attracted much more attention.Many technologies have been developed to remove SO 2and NO x from flue gas.Among them,flue gas desulfurization (FGD)and selective catalytic reduction (SCR)are most effective for SO 2and NO x removal pared to the individual control techniques,simultaneous desulfurization and denitri-fication is advantageous due to less equipment demanded.Simultaneous SO 2and NO x removal from stationary sources can be achieved with high efficiency using copper on alumina catalyst sorbents (CuO/Al 2O 3)[5].SO 2and NO x from flue gas are simultaneously removed by a dual bed of potassium-contain-ing coal-pellets and calcium-containing pellets [6].Microwave has been widely used in environment protection [7].Micro-wave is also applied to a pyrolytic carbon such as activated carbon and char,enhancing the reaction of sulfur dioxide (SO 2)and nitrogen oxides (NO)with carbon [8].The simultaneous treatment with the accelerated electronic beams and the microwaves can increase the removal efficiency of NO x and SO 2,about 80%of NO x and more than 95%of SO 2were removed by precipitation with ammonia [9].It was reported that the reaction efficiency of microwave reduction of NO x could be up to 98%when microwave energy was applied continuously [10].F U E L P R O C E S S I NG T E CH N O L O G Y 90(2009)324–329⁎Corresponding author.Tel.:+862084037096;fax:+862084115065.E-mail address:weizaishan98@ (Z.-Wei).0378-3820/$–see front matter ©2008Elsevier B.V.All rights reserved.doi:10.1016/j.fuproc.2008.09.005ava i l a b l e a t w w w.s c i e n c e d i r e c t.c o mw w w.e l s ev i e r.c o m /l o c a t e /f u p r o cSO 2and NO x emissions from coal combustion were simulta-neously reduced by calcium magnesium acetate [11].In this study,experimental investigations were conducted to simultaneous desulfurization and denitrification from stimu-lated flue gas by the novel microwave reactor with potassium permanganate and zeolite.The study evaluates the influence of microwave power,empty bed residence time (EBRT),inlet con-centration,microwave and catalyst on the performance of the microwave reaction system,and the mechanism for microwave induced catalytic SO 2and NO x oxidation was elicited.An under-standing of the role of microwave and catalyst on simultaneous desulfurization and denitrification can help evaluate the po-tential of applying this novel method as an effective SO 2and NO x emission control strategy for the flue gas cleaning.2.Experimental2.1.Microwave reaction systemThe experimental flow loop used in the study was shown schematically in Fig.1A constant input power of 119–280W was used and the microwave frequency was 2450MHz.The microwave reactor consisted of quartz tube (o.d.25mm and 85mm long)with the potassium permanganate (KMnO 4)and zeolite was set up to study the removal of SO 2and NO x from waste gas.The SO 2and NO x supplied from the compressed-gas steel cylinders,was first diluted with the air from a com-pressor,passed through air mixture bottle and flowed up-wards through the microwave reactor.The flow meter and the valve were used to monitor the gas flow through the reactor.The SO 2and NO x concentrations were monitored by the analysis device of S2000flue gas,and the rate of the gas flow was monitored by the rotameters and the mass flow con-trollers.In the process of the experiments,the simulated SO 2and NO x -containing flue gas were supplied to the microwave reactor,at a flow rate of 200–500l.h −1(empty bed residence time (EBRT),0.214–0.536s).2.2.Measurement methodsThe periodic measurements of the gas concentration from sampling ports in the quartz tube and the gas flow of thequartz tube in the microwave reaction system were car-ried out by using the following devices.S2000flue gas device was used for the analysis of sulfur dioxide (SO 2)and nitrogen oxides (NO x ).The rate of the gas flow was measured by ‘Model LZB-1’flow meters with the units of 0.01m 3h −1.Fig.1–Experimental flow loop of microwave induced catalysis oxidation of SO 2and NO x with potassium permanganateover catalyst zeolite.(1)SO 2gas cylinder,(2)air compressor,(3)NO x gas cylinder,(4)the bottle of gas mixture,(5)flow meter,(7)quartz tube,(7)microwave reactor,(8)outlet port,(G)samplingport.Fig.2–a Influence of concentration of SO 2in inlet ondesulfurization (reaction conditions:gas flow=0.4m 3h −1;inlet concentration of NO x =180mg m −3).b Influence of concentration of NO x in inlet on denitrification (reaction conditions:gas flow=0.4m 3h −1;inlet concentration of SO 2=600mg m −3).325F U E L P R O C E S S I NG T E CH N O L O G Y 90(2009)324–3293.Results and discussion3.1.The influence of concentration of SO2in inlet on desulfurizationFig.2a shows the effect of concentration of SO2in inlet on desulfurization using potassium permanganate(KMnO4)or zeolite.The“PP”,“Z”and“PPZ”profile are represented by potassium permanganate,zeolite,potassium permanganate and zeolite respectively.Fig.2a indicates the purifying ef-ficiency of SO2is gradually decreased when the concentration of SO2in inlet is increased,the effect of desulfurization using Potassium permanganate(KMnO4)only is very low.Potas-sium permanganate(KMnO4)addition to zeolite increased the SO2removal efficiency about10%.The possible reason for the shape of the curve“PPZ”could be that high humidity in sti-mulated flue gas increased the SO2removal efficiency in the inlet concentration of SO2at1000mg m−3,1230mg m−3.For comparison,the desulfurization effect using potassium per-manganate and zeolite together are higher than that using potassium permanganate or the zeolite only.Zeolite could adsorptive SO2potassium permanganate could oxidative SO2 to sulfate.The use of both zeolite and potassium perman-ganate would induce SO2oxidizing catalyst reaction using zeolite as catalyst.3.2.The influence of concentration of NO x in inlet on denitrificationFig.2b shows the effect of concentration of NO x in inlet on denitrification using potassium permanganate(KMnO4)or zeolite.Denitrification is generally in the order:(PPZ)N(PP)N (Z).It has no effect of the denitrification with zeolite only,the possible explanation for this is that the zeolite is not adsorp-tive NO x.Fig.2b indicates the effect of denitrification using potassium permanganate is very low but not more than10%. When potassium permanganate and zeolite are added toreactor simultaneously,NO x removal efficiency increases from57%to87%,reaching from66.7%to90.3%.The possible reason for this could be that the use of both zeolite and po-tassium permanganate would induce NO x oxidizing catalyst reaction to nitrates using zeolite as catalyst under our expe-rimental conditions.3.3.The influence of microwave power on simultaneous desulfurization and denitrification with potassium permanganate(KMnO4)and zeoliteFig.3a and b shows the effect of simultaneous desulfuriza-tion and denitrification by microwave reactor with dif-ferent microwave power using potassium permanganate (KMnO4)as oxidizing agent and zeolite as catalyst.The“PP–MW”,“Z–MW”and“PPZ–MW”profile are represented by potassium permanganate,zeolite,potassium permanganate and zeolite under the microwave respectively.The conver-sion of desulfurization purifying efficiency increases from 33.3%with119W microwave power to95%with280W,and the conversion of denitrification increases from85.6%with 119W to98.2%with280W,showing excellent desulfurization and denitrification effect of the microwave power with the potassium permanganate and zeolite.The reason for over 259W microwave power the shape of the“PPZ-MW”increases could be that high temperature keeps the catalytic surface reaction of microwave desulfurization and leads to the enhancement of SO2removal efficiency up0.7%.The experi-mental results showed that the optimum microwave power on desulfurization and denitrification is supposed to be 259W.Compare Fig.3a with Fig.2a,and compare Fig.3b with Fig.2b,in the presence of Potassium permanganate(KMnO4) and zeolite,SO2and NO x removal efficiency,with/without microwave irradiation in flue gas treatment process,in-creased by7.2%and12.2%under the conditions of microwave power of259W,inlet concentration of800mg m−3SO2,and inlet concentration of NO x180mg m−3,and more than94%of SO2,97%of NO x was oxidized at microwave power of259W. The additional use of microwave energy to Potassium per-manganate(KMnO4)and zeolite is very effective in the pol-lutants oxidation.For comparison,the microwave desulfurization and deni-trification effect using potassium permanganate andzeolite Fig.3–a Influence of microwave power on desulfurization (reaction conditions:gas flow=0.4m3h−1;inlet concentration of SO2=600mg m−3;inlet concentration of NO x=180mg m−3).b Influence of microwave power on denitrification(reaction conditions:gas flow=0.4m3h−1;inlet concentration ofSO2=600mg m−3;inlet concentration of NO x=180mg m−3).326F U E L P R O C E S S I N G T E C H N O L O G Y90(2009)324–329together are much higher than that using potassium per-manganate or the zeolites only,which are generally in the order:PPZ ÀMW ðÞN PP ÀMW ðÞN Z ÀMW ðÞAs are shown in Fig.3a and b,the simultaneous presence of microwave potassium permanganate and zeolite increases from 16.5%to 43.5%the microwave removal efficiency for SO 2,and the NO x removal efficiency from 85.6%to 98.2%than the microwave potassium permanganate only.The addi-tional use of potassium permanganate to the microwave zeolite leads to the enhancement of SO 2removal efficiency up from 53.9%to 95%,and denitrification efficiency up from 85.6%to 98.2%.Based on the experiments as above,we assumed that SO 2and NO x from flue gas can react with potassium permanga-nate to produce SO 42−,NO 3−when potassium permanganate and zeolite are used together under microwave,which is critical to desulfurization and denitrification.The potassium perman-ganate does not absorb microwave energy and hence micro-wave would not induce SO 2and NO x oxidation without microwave absorbent such as zeolite [12].Zeolite does absorb microwave energy but require the oxidizing agent such as potassium permanganate.The use of both zeolite and potas-sium permanganate combined with microwave energy would induce SO 2and NO x oxidizing catalyst reaction significantly.Significant synergetic effects of microwave and catalyst treat-ment were observed.We could speculate that microwave accentuates catalyst treatment,and increases the removal efficiency of SO 2and NO x [8–13].Zhang [1]verified on the existence of hot spots in the catalysts heated by microwave irradiation.Thus,a major mechanism for microwave-induced SO 2and NO x oxidation can be described as the microwave induced oxidizing catalyst reaction between SO 2and NO x and potassium permanganate with zeolite being the catalyst and microwave absorbent.The microwave induced catalytic oxidation reaction be-tween SO 2and NO x from the flue gas and potassium perman-ganate can also proceed in a different way,giving rise to the product sulfate,nitrates with zeolite acting as catalyst.There-fore,we assumed that the mechanism of the reactions might be followed as below:KMnO 4þNO →KNO 3þMnO 2ð1Þ2KMnO 4þ3SO 2þ2H 2O →K 2SO 4þ2H 2SO 4þ2MnO 2ð2Þ2KMnO 4→K 2MnO 4þMnO 2þO 2↑ð3Þ2SO 2þO 2→2SO 3→SO 2−4ð4Þ2NO þO 2→2NO 2→NO −3ð5Þ3.4.The influence of empty bed residence time (EBRT)on simultaneous desulfurization and denitrificationThe effect of empty bed residence time (EBRT)on simulta-neous desulfurization and denitrification is presented in Fig.4,under the conditions of microwave power of 259W,inlet con-centration of 800mg m −3SO 2and inlet concentration of NO x 180mg m −3with potassium permanganate and zeolite.As keeping the inlet concentration of SO 2and NO x at 800mg m −3,180mg m −3respectively,the flow meter in the process should be changed step by step to make the mass loading of SO 2and NO x changed proportionally,and the system should be stabi-lized for 3min after every adjustment.In our experiment,6-step adjustment was conducted to increase the empty bed residence time (EBRT)from 0.214s at 0.5m 3h −1air flow rate to 0.536s at 0.2m 3h −1air flow rate.Fig.4shows that the desulfurization efficiency increases from 86.5%to 96.8%,whereas the NO x removal efficiency increases from 93.2%to 98.4%with empty bed residence time (EBRT)increasing.Fig.4demonstrates that SO 2and NO x were rapidly oxidized at microwave power of 259W,when potas-sium permanganate and zeolite are added simultaneously.SO 2was oxidation to sulfate and NO x was oxidation to nitrates rapidly by potassium permanganate under microwave irra-diation.This indicates the longer residence time benefitsonFig.4–Influence of empty bed residence time (EBRT)ondesulfurization and denitrification (reaction conditions:the microwave power=259W;inlet concentration ofSO 2=800mg m −3;inlet concentration of NO x =180mg m −3).Fig.5–Influence of concentration of SO 2in inlet ondesulfurization and denitrification (reaction conditions:gas flow=0.5m 3h −1;the microwave power=259W;the empty bed residence time (EBRT)=0.282s).327F U E L P R O C E S S I NG T E CH N O L O G Y 90(2009)324–329the removal of SO 2and NO x ,in case the residence time is too short to oxidize SO 2or NO x to sulfate or nitrates before release.The type of zeolites and the length of the quartz tube with catalyst and oxidizing agent are the key elements.From Fig.4,in our experimental conditions,we can assume the optimum empty bed residence time (EBRT)is 0.357s in the desulfurization and denitrification system,and about 95.2%sulfur dioxide or 98.1%nitric oxide in the gas stream is converted.3.5.The influence of SO 2and NO x concentration on simultaneous desulfurization and denitrificationKeeping the microwave power (259W)and the empty bed residence time (EBRT)(0.357s)fixed,the influence of concen-tration of SO 2and NO x in inlet on simultaneous desulfurization and denitrification with potassium permanganate and zeolite are presented in Figs.5and 6separately.Figs.5and 6show that the conversion of desulfurization reduces from 99.5%with 200mg m −3to 82.8%with 4400mg m −3SO 2concentration,whereas the denitrification increases from 40%to 96.3%within the increasing inlet concentration of NO x from 30mg m −3to 270mg m −3.SO 2removal efficiency decreased with increased SO 2concentration,while the NO x removal efficiency increased with NO x concentration increasing,the possible explanation for this is that those denitrification reactions are involved in the NO x surface absorption catalytic oxidation by using micro-wave in the presence of potassium permanganate with zeolite as catalyst.More than 92%SO 2was oxidized at 259W for less than the initial concentration of 1000mg m −3SO 2.The high rate of SO 2oxidation is also achieved when the concentration of SO 2further increases.This experimental result is because sulfur dioxide (SO 2)is oxidized to sulfate by potassium per-manganate with zeolite as catalyst under microwave irradia-tion.Part of NO was oxidized to NO 2below 130mg m −3NO x .NO x removal efficiency reached 96.3%at 270mg m −3NO x (see Fig.6).This illustrates that the microwave reactor is efficient in purifying the waste gas whose SO 2concentration is between200mg m −3and 4400mg m −3and whose NO x concentration is between 30mg m −3and 270mg m −3.When microwave power of 259W,SO 2and NO x concentra-tion in inlet gas were 600mg m −3,170mg m −3separately and the empty bed residence time (EBRT)was 0.214s,the puri-fication efficiency of SO 2and NO x could reach 96.2%and 93.6%respectively.The use of microwave induce catalytic oxidation proves to be an efficient way to achieve desulfurization and denitrification.4.ConclusionsThis work has demonstrated that the microwave reactor with potassium permanganate and zeolite can be used for simulta-neous removal of sulfur dioxide (SO 2)and nitrogen oxides (NO x )from flue gas.Microwave accentuates catalyst treatment,and microwave addition can increase the SO 2and NO x removal efficiency.The microwave desulfurization and denitrification effect using potassium permanganate and zeolite together are much higher than that using potassium permanganate or the zeolite only.The mechanism for microwave-induced SO 2and NO x oxidation can be described as the microwave induced cata-lytic reaction between SO 2and NO x and potassium permanga-nate with zeolites being the catalyst and microwave absorbent.Microwave induced catalytic technology is a viable and pro-mising method for flue gas cleaning in view of the reduction of power consumption of the gas treatment process.AcknowledgementThe authors gratefully acknowledge the financial support from the Guangdong Natural Science Foundation (04300554).R E F E R E N C E S[1]X.L.Zhang,O.H.David,L.D.Colleen,P.M.Michael,Microwaveassisted catalytic reduction of sulfur dioxide with methane over MoS 2catalysts,Appl.Catal.,B 33(2001)137–148.[2]B.Hans,B.Annemie,E.Gerd,S.Ruud,R.H.R.Julian,Lithium –Vanadium bronzes as model catalysts for the selective reduction of nitric oxide,Catal.Today 4(1989)139–154.[3]S.E.Vicente,M.Tania,B.Guido,Low temperature selectivecatalytic reduction of NO x by ammonia over H-ZSM-5:an IR study,Appl.Catal.B 58(2005)19–231.[4]Q.F.Tang,K.Tao,The technical advance in simultaneousdesulfurization and denitrification of the power plant and study on comprehensive countermeasure,J.Chem.(2005)19–22(in Chinese).[5]G.Y.Xie,Z.Y.Liu,Z.P.Zhu,et al.,Simultaneous removal of SO 2and NO x from flue gas using a CuO/Al 2O 3catalyst sorbent II:promotion of SCR activity by SO 2at high temperatures,J.Catal.224(2004)42–49.[6]L.A.Bueno,G.A.García,Combined SO 2and NO x removal atmoderate temperature by a dual bed of potassium-containing coal-pellets and calcium-containing pellets,Fuel Process.Technol.86(2005)1745–1759.[7]D.A.Jones,T.P.Lelyveld,S.D.Mavrofidis,et al.,Microwaveheating applications in environmental engineering —a review,Resour.Conserv.Recycl.34(2002)75–90.Fig.6–Influence of concentration of NO x in inlet ondesulfurization and denitrification (reaction conditions:gas flow=0.5m 3h −1;the microwave power=259W;the empty bed residence time (EBRT)=0.282s).328F U E L P R O C E S S I NG T E CH N O L O G Y 90(2009)324–329[8]Y.C.Chang,S.K.Dong,Microwave induced reactions of sulfurdioxide and nitrogen oxides in char and anthracite bed,Carbon39(2001)1159–1166.[9]T.R.Marilena,I.M.Diana,C.Ioan,Emission control of SO2andNO x by irradiation methods,J.Hazard.Mater.97(2003)145–158.[10]D.X.Zang,A.M.Yu,Q.H.Jin,Studies on microwave-carbonreduction method for the treatment of nitric oxide,Chem.J.Chin.Univ.18(1997)1271–1274.[11]W.Nimmo,A.A.Patsias,E.Hampartsoumian,et al.,Simultaneous reduction of NO x and SO2emissions from coalcombustion by calcium magnesium acetate,Fuel83(2004)149–155.[12]Z.S.Wei,Z.Y.Du,Z.H.Lin,H.M.He,R.L.Qiu,Removal of NO xby microwave reactor with ammonium bicarbonate andGa-A zeolites at low temperature,Energy32(2007)1455–1459.[13]M.T.Radoiu,D.Martin,I.Calinescu,Emission control of SO2and NO x by irradiation methods,J.Hazard.Mater.B97(2003) 145–158.329F U E L P R O C E S S I NG T E CH N O L O G Y90(2009)324–329。
响[J ].安全与环境学报,2004,4(6):43-45.[7]兰善红,李慧洁,王传路,等.Fe 3+对好氧活性污泥理化特性的影响[J ].中国造纸学报,2015,30(4):18-21.[8]Zhang Wen ,Chen Ling ,Chen Hao ,et al.The effect of Fe 0/Fe 2+/Fe 3+onnitrobenzene degradation in the anaerobic sludge [J ].Journal of Ha ⁃zardous Materials ,2007,143(1/2):57-64.[9]谢芹,江敏,胡成枫,等.罗氏沼虾亲虾越冬池中不同基质上微生物群落多样性分析[J ].微生物学通报,2017,44(2):336-347.[10]Sun Li ,Zuo Wei ,Tian Yu ,et al.Performance and microbial commu ⁃nity analysis of an algal-activated sludge symbiotic system :Effectof activated sludge concentration [J ].Journal of Environmental Sci ⁃ences ,2019,76(2):121-132.[11]王祖忠,王朝阳,张迪骏,等.宁波沿海陆源排污口弓形杆菌属(Arobacter sp.)和梭菌属(Clostridium sp.)的分布特点[J ].海洋与湖沼,2016,47(4):862-868.[12]辛玉峰,曲晓华,袁梦冬,等.一株异养硝化-反硝化不动杆菌的分离鉴定及脱氮活性[J ].微生物学报,2011,51(12):1646-1654.[13]丁炜,朱亮,徐京,等.好氧反硝化菌及其在生物处理与修复中的应用研究进展[J ].应用与环境生物学报,2011,17(6):923-929.[14]赵燕,薛林贵,李琳,等.丛毛单胞菌在环境污染物降解方面的研究进展[J ].微生物学通报,2012,39(10):1471-1478.[15]罗晓,郑向阳,赵丛丛,等.A/O 工艺中污泥浓度对微生物群落结构的影响[J ].中国环境科学,2018,38(1):275-283.———————————[作者简介]严子春(1970—),博士,教授。
CaCl2与纳米SiO2-聚硅酸铝铁复合混凝剂处理高氟废水许德超;衷从强;朱婷婷;尹魁浩;彭盛华;阳立平【摘要】采用CaCl2和纳米SiO2-聚硅酸铝铁复合混凝剂对含氟废水进行两步除氟.实验结果表明:ρ(F-)为420.0 mg/L、pH为8.5的含氟废水经CaCl2处理后ρ(F-)降至26.5 mg/L;在二级除氟pH为11.5、复合混凝剂加入量(复合混凝剂与废水体积比)为0.50％的最佳条件下处理60 min后废水中ρ(F-)降至5.7 mg/L,而采用聚合氯化铝(PAC)进行二级除氟时,ρ(F-)可降至8.7 mg/L,表明复合混凝剂比PAC的除氟效果更佳.复合混凝剂中自由离子和单体羟基配合物形态Al和Fe的含量相对较高,分别占76.5％和92.5％,而低聚合度的多核羟基配合物及高聚物形态Al和Fe的含量相对较低.【期刊名称】《化工环保》【年(卷),期】2018(038)006【总页数】5页(P641-645)【关键词】SiO2-聚硅酸铝铁复合混凝剂;氯化钙;聚合氯化铝;除氟【作者】许德超;衷从强;朱婷婷;尹魁浩;彭盛华;阳立平【作者单位】深圳市环境科学研究院,广东深圳 518001;国家环境保护饮用水水源地管理技术重点实验室(深圳),广东深圳 518001;深圳市水环境中新型污染物检测与控制重点实验室,广东深圳 518001;深圳市环境科学研究院,广东深圳 518001;国家环境保护饮用水水源地管理技术重点实验室(深圳),广东深圳 518001;深圳市水环境中新型污染物检测与控制重点实验室,广东深圳 518001;深圳市环境科学研究院,广东深圳 518001;国家环境保护饮用水水源地管理技术重点实验室(深圳),广东深圳 518001;深圳市水环境中新型污染物检测与控制重点实验室,广东深圳518001;深圳市环境科学研究院,广东深圳 518001;国家环境保护饮用水水源地管理技术重点实验室(深圳),广东深圳 518001;深圳市水环境中新型污染物检测与控制重点实验室,广东深圳 518001;深圳市环境科学研究院,广东深圳 518001;国家环境保护饮用水水源地管理技术重点实验室(深圳),广东深圳 518001;深圳市水环境中新型污染物检测与控制重点实验室,广东深圳 518001;深圳市环境科学研究院,广东深圳 518001【正文语种】中文【中图分类】X703集成电路企业在生产过程中会产生大量的含氟废水，排入水体会对生态环境造成极大的危害，人体过量摄入氟会引起氟斑牙、氟骨症等，严重者还会引起急性氟中毒［1］，因此必须对含氟废水进行处理，达标排放。
第52卷第7期 辽 宁 化 工 Vol.52，No. 7 2023年7月 Liaoning Chemical Industry July，2023生物炭在厌氧氨氧化反应中应用的研究进展姜 琦（沈阳建筑大学 市政与环境工程学院，辽宁 沈阳 110168）摘 要： 厌氧氨氧化技术因其高效和低能耗等优点被认为是替代常规生物脱氮的主要工艺之一。
但是厌氧氨氧化技术在处理主流城市污水方面仍然存在一些问题，如启动时间较长，颗粒污泥稳定性较差等。
生物炭因其具有廉价易得、环境友好的特点，成为近些年来环境领域的研究热点材料，越来越受到人们的关注。
综述了生物炭在厌氧氨氧化领域的应用，为厌氧氨氧化技术存在的部分问题提供更经济环保的解决措施，旨在推动厌氧氨氧化反应的同时促进环境的友好发展。
关 键 词：生物炭； 厌氧氨氧化； 工艺强化中图分类号：TQ085+.4 文献标识码： A 文章编号： 1004-0935（2023）07-1047-04厌氧氨氧化工艺（Anaerobic ammonium oxidation, Anammox）是以NH4+-N为电子供体，NO2--N为电子受体将NH4+-N转化为N2的过程[1]。
与传统生物脱氮工艺相比具有无需额外碳源、运行成本低、占地小的优点，因此，Anammox工艺被称为是最具有前景的新型脱氮技术[2]。
但是厌氧氨氧化菌具有倍增时间长、生物保留量差、环境敏感性等缺点，在污水处理厂的实际应用中仍存在限制[3-4]。
为了解决这些问题，研究者们进行了诸多尝试，如：换用不同的反应器（如：上流式厌氧污泥床（UASB）、膜生物反应器（MBR）、序批式反应器（SBR））；添加特定金属离子（如：Fe2+、Mn2+、Cu2+、Zn2+等）和中间肼来缩短其启动时间，稳定其脱氮效果和增加颗粒稳定性。
然而，在实际操作中，考虑到成本和实际性，寻找一种更可靠的材料是更有意义的。
生物炭（Biochar）是生物质（如，秸秆、畜禽粪便等农林废弃物）在限氧条件下通过热化学转化得到的一种固体富碳产物。
废水中硫化物的去除技术陶寅（宁波市环境保护科学研究设计院，浙江宁波315010）摘要含硫化物的废水常见于染料、医药、农药以及石油化工的生产过程中，对环境影响很大，必须经处理达标才能排放。
介绍回收利用法、汽提法、混凝沉淀法、氧化法、生化法和树脂法等六种去除废水中硫化物技术的特点、原理以及局限性，可根据具体废水水质状况选用。
关键词硫化物废水在染料、医药、农药以及石油化工等行业中常有含硫化物的废水排出，主要为硫化氢等。
硫化氢毒性较大，对水生生物具有较强的杀生能力。
在通风条件不充分的情况下，当其集聚到一定浓度时，会对操作人员产生毒害作用。
此外，当含有硫化物的废水排放到水体中后，会与水体中的铁类金属反应，使水体发臭发黑，因此国家对含硫废水有严格的排放标准。
生产、生活中的含硫化物废水必须加以处理，不同行业排出的废水硫化物组分相差很大，处理的方法也有所不同。
1回收利用法该法主要用于高浓度废水的处理，先用无机酸酸化，使硫化氢析出，再经15% ～30% 的液碱吸收成硫化钠溶液回用。
残液可用铁屑处理成硫化铁回收［1］。
这种方法是国内较早采用的去除废水中硫化物的方法，由于其产生的硫化钠溶液可以直接重复利用，在造纸行业使用较多［2］，但是该方法会产生硫化氢气体，因此对设备的密封性、耐腐蚀性要求较高，同时该方法对硫化物的去除效率不高，不能单独使用，需要和其他的处理方法联合使用。
此外，在石化、化工等行业的高浓度含硫废水通过空气氧化后可以回收硫或硫代硫酸钠。
2汽提法利用水蒸气在汽提塔中将废水中的硫化氢、氨气、挥发酚等可挥发组份进行分离，目前主要用于石油炼制废水的预处理。
该方法去除率较高，处理工艺成熟，但能耗和设备投资都较大，适用于水量大、浓度高的含硫废水的处理，对水量小的废水不适合。
目前，国内外的生产企业主要对高浓度的含硫废水进行预处理，然后再将处理后的废水送入污水处理厂。
新建炼油厂一般采用双塔蒸气汽提法回收硫化氢和氨气，汽提出来的硫化氢目前绝大部分用来生产硫黄，少量生产硫化钠和硫酸等其他产品。
三价铁双水解1. 引言三价铁是一种常见的金属离子，广泛应用于化学、医药和环境领域。
其中，三价铁的双水解反应是一项重要的化学反应，具有广泛的应用前景。
本文将对三价铁双水解进行全面详细、完整且深入的介绍。
2. 三价铁双水解反应简介三价铁双水解是指在适当条件下，三价铁离子（Fe(III)）与水（H2O）发生反应生成氢氧根离子（OH-）和亚铁离子（Fe(II)）的过程。
该反应可用以下方程式表示：Fe(III) + H2O → Fe(II) + OH-该反应需要在碱性条件下进行，通常需要加入碳酸氢钠或氢氧化钠等碱性物质作为催化剂。
3. 反应机理在三价铁双水解反应中，首先发生了电荷转移过程。
三价铁离子失去一个电子成为二价亚铁离子。
此时，在碱性条件下，OH-与H+结合生成H2O，并参与到反应中去：Fe(III) + e- → Fe(II) OH- + H+ → H2O整个反应过程可以用以下步骤描述： 1. 三价铁离子与水分子发生配位作用，生成配合物； 2. 配合物中的水分子失去一个质子成为氢氧根离子； 3. 配合物中的三价铁离子失去一个电子成为二价亚铁离子； 4. 氢氧根离子和二价亚铁离子结合生成水。
4. 影响因素三价铁双水解反应受到多种因素的影响，主要包括以下几个方面：4.1 pH值pH值是指溶液的酸碱程度，对于三价铁双水解反应而言，适宜的碱性条件是其发生的前提。
通常情况下，pH值在8-10之间时反应效果最佳。
4.2 温度温度对于反应速率有显著影响。
在适宜的温度范围内，反应速率随温度升高而增加。
但过高的温度可能会导致副反应的发生，降低产物纯度。
4.3 反应时间反应时间也是影响反应效果的重要因素。
在适宜的反应时间内，三价铁离子能够充分与水反应生成亚铁离子和氢氧根离子。
4.4 水解剂浓度水解剂的浓度直接影响反应速率和产物的生成量。
适宜的水解剂浓度可以提高反应效率。
5. 应用领域三价铁双水解反应在许多领域都有广泛的应用，主要包括以下几个方面：5.1 水处理三价铁双水解反应可以将含有重金属离子的废水中的有害物质转化为较为安全的产物，达到净化水质的目的。
水环境中硝酸根离子的特性研究与应用管凯;申婷婷;孙静;王晨;王西奎【摘要】硝酸根离子(NO-3)在自然界中的存在非常广泛,是氮元素在环境中的重要存在形式之一。
随着水环境体系富营养化及污染的不断加剧,NO3-的研究倍受关注。
本文从NO-3的性质、NO-3的催化去除以及NO-3的催化利用三个方面进行综述,旨在探索水环境中NO3-的迁移、转化及光催化作用机理;为NO-3的有效利用及新型光催化技术的研究提供参考,以期将其机制引入水环境中有机污染物的治理过程中,达到以废治废的目的。
【期刊名称】《齐鲁工业大学学报：自然科学版》【年(卷),期】2019(033)001【总页数】5页(P48-52)【关键词】水环境;NO-3;特性;作用机理;光催化【作者】管凯;申婷婷;孙静;王晨;王西奎【作者单位】[1]齐鲁工业大学(山东省科学院)环境科学与工程学院,济南250353;[1]齐鲁工业大学(山东省科学院)环境科学与工程学院,济南250353;[1]齐鲁工业大学(山东省科学院)环境科学与工程学院,济南250353;[1]齐鲁工业大学(山东省科学院)环境科学与工程学院,济南250353;[1]齐鲁工业大学(山东省科学院)环境科学与工程学院,济南250353;[2]山东农业工程学院,济南250100;【正文语种】中文【中图分类】X131.2近年来,氨氮化肥用量持续增长,化肥生产、焦化、冶炼、石油化工、制药过程中的工业废水、废渣等大量排放[1-4],以及生活废水的不当处理,导致地表水及地下水硝酸盐浓度不断上升[5],对水环境造成严重污染,甚至威胁水生生物的生存和人类健康[6-7]。
目前,在国内外各类水体中经常能检出μM至mM污染级别的N残留[1-2],因此,N的研究已经成为国际环保领域的热点[8-10]。
本研究从N的性质、N的催化去除以及N的催化利用三个方面进行综述,旨在探索水环境中N的迁移、转化及光催化作用机理,为N的有效利用及新型光催化技术的研究提供参考。
Studies on the simultaneous removal of dissolved DBP and TBP as well as uranyl ions from aqueous solutions by using Micellar-Enhanced Ultra filtration TechniqueS.K.Misra ⁎,A.K.Mahatele,S.C.Tripathi,A.DakshinamoorthyFuel Reprocessing Division,Bhabha Atomic Research Centre,Trombay,Mumbai-400094,Indiaa b s t r a c ta r t i c l e i n f o Article history:Received 26March 2008Received in revised form 16July 2008Accepted 28July 2008Available online 5August 2008Keywords:Di-butyl phosphate Tri-butyl phosphate UraniumMicellar-Enhanced Ultra filtration and Sodium Dodecyl SulphateStudies were carried out for the simultaneous removal of dissolved organic namely di-butyl phosphate (DBP)and tri-butyl phosphate (TBP)as well as uranyl ions from aqueous solutions by using Micellar-Enhanced Ultra filtration Technique (MEUF).Ultra filtration (UF),a comparatively low pressure driven membrane separation technique,offers great potential for the separation/recovery/removal of dissolved organic and metal contaminants at low concentration and from large volume of aqueous waste solutions.Throughout the study Sodium Dodecyl Sulphate (SDS),an anionic surfactant was used.The 47mm diameter Millipore ultra filtration membranes of 3000,5000and 10,000MWCO pore sizes were used and the pressure of the ultra filtration cell was kept at 1.7bar for all the experiments.To optimise the parameters,the effects of membrane pore size,DBP concentration in feed and feed acidity on the recovery/separation of DBP were studied.More than 90%removal of DBP from aqueous solution was achieved while keeping the feed acidity at 0.5M HNO 3,the DBP concentration in feed solution was kept at 720ppm and by using 3000MWCO pore size membrane.The interferences from other dissolved organic such as TBP and metal ions like uranium were also studied.The results showed that the technique can be effectively employed for the simultaneous removal of dissolved organic (DBP and TBP)and metal ions (uranium)from the aqueous ef fluent streams.©2008Elsevier B.V.All rights reserved.1.IntroductionPUREX and THOREX processes aim at complete recovery of uranium,plutonium and thorium from fission products present in the spent nuclear fuel of the reactor.In these processes,a mixture of 5%to 40%TBP-n -dodecane (hydrocarbon diluent)is used for coextraction of uranium,thorium and plutonium leaving behind a number of radioactive fission products in the aqueous raf finate.Tri-butyl phosphate (TBP),though very stable,is prone to hydrolysis or de-alkylation leading to the formation of di-butyl phosphate (DBP),monobutyl phosphate (MBP)and phosphoric acid (Blake,1968;Nowak,1973;Tripathi et al.,2001).TBP also reacts with nitric acid to give DBP and butyl nitrate.Presence of these organic,in aqueous streams,leads to the formation of heavy organic due to the concentration by evaporation in the evaporator leading to red oil formation which is explosive in nature.Hence the process waste stream that contains the dissolved organic like TBP and DBP along with minor quantities of metal ions like uranium and plutonium should be removed from these aqueous waste stream prior to their disposal.For the simultaneous recovery of dissolved organic and metal ions,no single technique or procedure is available.Membrane filtration has shown promise as a separation technique which is competitive to the conventional separation techniques such as distilla-tion,adsorption,absorption,extraction etc.The major component in membrane separation processes is the membrane.Membrane is a thin barrier between two bulk phases that permits transport of components of interest retaining others.A mass transport across the membrane requires a driving force.Ultra filtration (UF),a comparatively low pressure driven membrane separation technique,offers great potential for the separation/recovery/removal of metal contaminants at low concentration and large volume of aqueous waste solutions (Scamehorn et al.,1989;Chaufer et al.,1988;Geckeler et al.,1996).The separation is based on the size fractionation,using UF membranes as sieve and the driving force is transmembrane pressure gradient.Because of low pore size,the technique poses the problem of fouling of membrane.To overcome this problem micelle enhanced ultra filtration technique is a better alternative (Klepac et al.,1991;Volchek et al.,1993;Akita et al.,1997).Micellar-Enhanced Ultra filtration involves the addition of a surfactant above its critical micellar concentration (CMC)in order to entrap the ionic solute in solution (Gzara et al.,2001;Tangvijitsri et al.,2002;Kryvoruchko et al.,2002).The increased hydrodynamic size of the solutes enables their rejection by polymeric ultra filtration membranes.The surfactant forms micelles,(surfactant aggregates that contain about 50–100surfactant molecules),above its CMC.The micelles are having cationic or anionic heads which bind the metal anions/cations whereas the tails of the micelles will absorb the dissolved organic or non-polar organic matter present in the aqueous solutions.This solution is then passed through an ultra filtrationHydrometallurgy 96(2009)47–51⁎Corresponding author.Tel.:+912225591203;fax:+912225505151.E-mail address:skmisra@.in (S.K.Misra).0304-386X/$–see front matter ©2008Elsevier B.V.All rights reserved.doi:10.1016/j.hydromet.2008.07.013Contents lists available at ScienceDirectHydrometallurgyj o u r n a l h o me pa g e :w w w.e l s ev i e r.c o m/l o c a t e /hyd ro m e tmembrane with pore sizes small enough to block the passage of micelles.This technique has several advantages over other membrane process due to their low operation cost and simplicity.In this study,simultaneous removal of dissolved TBP,DBP and uranium from the aqueous medium under different experimental conditions was investigated by Micellar-Enhanced Ultrafiltration using Sodium Dodecyl Sulphate(SDS),as an anionic surfactant and the results are reported.2.Experimental2.1.MaterialsAll the reagents used in this study were of analytical grade.SDS,an anionic surfactant,was obtained from M/s Lancaster Synthetic Ltd., England.TBP and DBP were procured from MERCK—Schuchardt, Germany and Fluka AG,Switzerland respectively.Uranium solution of different concentrations were prepared by dissolving weighed amounts of UO2(NO3)2.6H2O(B.D.H.)in nitric acid.UF membranes (MWCO of3000to10,000and47mm in diameter)supplied by M/s Millipore were used.The uranyl concentrations in the feed and permeate were determined by spectrophotometric method described elsewhere(Das et al.,1991).All the experiments were done in duplicate and the material balance in these studies was found to be within±5%.2.2.Ultrafiltration cellExperiments were performed at room temperature using an indigenously developed cell that was stirred constantly by a magnetic motor.The cell capacity was80ml and having50ml processed capacity.The cell had the membrane of diameter47mm.The liquid phase in the cell was stirred at a speed of approximately200rpm under controlled pressure.2.3.Analytical methodsThe Shimadzu GC-9A,gas chromatograph using thermal conduc-tivity detector was used for the measurement of TBP and DBP concentration in the feed and permeate.10%XE-60column (1.5m×0.32cm was used with heating rate as specified below along with other operating parameters.Initial column temperature of170°C was maintained for1min.The heating rate of10°C/min was given to the column till thefinal temperature of column was reached to230°C which was maintained for10min.Throughout the study,the injection port temperature and carrier gas(He)flow were maintained at240°C and40ml/min respectively.The concentration of DBP in30%TBP-n-dodecane mixture was estimated by esterifying the DBP with ether solution of diazomethane into volatile methyldibutyl phosphate(MDBP)prior to its gas chromatographic assay.The quantification of DBP was made by using a calibration plot(Tripathi et al.,1989).The diazomethane was prepared by treating p-tolylsulphonyl methylnitrosamide with alco-holic potassium hydroxide(Kibkey et al.,1968).The feed solutions(50ml)were prepared by dissolving the appropriate quantity of TBP and DBP.Acidity of the feed solution was adjusted using dilute HNO3/NaOH.Then the surfactant was added in the feed and the solution was stirred for30min followed byfiltration. The permeate solutions(filtrate)were then collected atregularFig.1.Simultaneous removal of dissolved organic(DBP and TBP)and divalent heavy metal cation(uranyl ion)from aqueous solution using Micellar-Enhanced Ultrafiltration(MEUF) and schematic diagram of anionic surfactant(SDS)micelle.48S.K.Misra et al./Hydrometallurgy96(2009)47–51intervals to calculate the rejection (Sancho et al.,2006)of uranium,TBP and DBP using the formula:R ¼1−C ½ P =C ½ F ÀÁÂ100where [C ]P and [C ]F denote the uranium/TBP/DBP concentration in the permeate and feed respectively.Commonly used pore models assume that the pores of the membranes are of the same size.If we consider the membrane pores as parallel capillaries,the permeate flux can be calculated from the following equation (Katarina et al.,2006)J ¼V =t ÃAwhere V is the volume passed through the membrane at time t and A is the area of the membrane.2.4.MechanismFig.1shows the schematic diagram of MEUF technique which can be used to remove dissolved organic and metal ions simultaneously.SDS,an anionic surfactant,was added to the solution at a concentra-tion well above its critical micelle concentration so that most of the surfactant remains in micellar form.The dissolved organic solutes get solubilised within the tail of the micelles and metal cation forms a bond with the head of the micelles surface which is oppositely charged as shown in Fig.1.The solution containing the surfactant was then passed through the ultra filtration membrane of pore size small enough to reject or retain the micelles.Unsolubilised organic,unadsorbed metal cations and surfactant monomers will pass through the membrane.The following reaction can be proposed for the cationadsorption,3.Results and discussion3.1.Effect of acidity on the rejection of DBPTo find out the effect of feed acidity on the recovery of DBP by Micellar-Enhanced Ultra filtration Technique,using SDS as surfactant,acidity of the feed solution was varied from pH 8to1.0M HNO 3.In the feed,DBP concentration was kept at 2600ppm along with 100mM ofSDS in all the experiments.UF membranes,MWCO of 3000and 47mm in diameter supplied by M/s Millipore were used as filter.During all the experiments,the pressure of 1.7bar was applied to the cell.Table 1shows the result of the experiments carried out for pure DBP separation from solutions of different acidity.The results indicate that more than 90%DBP could be recovered from all the acidity of the solutions studied.The near quantitative recovery of DBP indicated that DBP in both the conditions i.e.acidic and alkaline is attached or solubilised in the tail of the SDS surfactant and SDS makes suf ficiently bigger micelles which could easily be retained by 3000MWCO membrane.3.2.Effect of surfactant concentration on rejection of DBPTo find out the optimum concentration of SDS required for the quantitative recovery of DBP,the concentration of SDS in the feed was varied from 8mM to 100mM while keeping the DBP concentration constant at 720ppm in the feed.The effect of varying the SDS concentration at constant retentate DBP concentration can be seen from Table 2.At less than its CMC value most of the surfactant should be present in monomers and practically no retention of the metal ions should take place.To see the effect of CMC on rejection experiments were performed at lower concentration (i.e.8mM SDS)that is below the CMC of SDS.At concentration lower than the CMC value,no micelles are present in the bulk solution and hence no rejection of the metal ions should take place.However,24%of the DBP rejection was observed,not 0%as expected.The probable cause for this rejection is the built up of the gel layer at the membrane/bulk solution interface due to the concentration polarisation effects.The concentration of SDS in this gel layer,may well exceed the CMC value whereas the rest of the bulk solution is free from micelles and thus was able to reject some of the DBP.The rejection of DBP was observed 55%while using 25mM SDS in feed.Though this concentration was far more than its CMC value but the micelles formed with 25mM SDS may not be suf ficiently bigger to be cut off by 3000MWCO membrane.When the SDS concentration was kept at 50mM or higher it was observed that more than 90%of DBP was retained.Hence for quantitative recovery of DBP,SDS concentration in the feed should be 50mM or higher.3.3.Effect of membrane pore size on percentage rejection and flux of DBP In order to see the effect of pore size,UF membranes of 3000MWCO,5000MWCO and 10,000MWCO were used.The feed solution was adjusted to 0.5M HNO 3and the concentration of SDS was fixed at 50mM.The concentration of DBP was kept around 710ppm in the feed.The results are summarised in Table 3.For the membranes of 3000and 5000MWCO the rejection of DBP was around 93%but the rejection of DBP decreased when membrane pore size was increased above 5000MWCO.Hence,it was clear from the experiments that the size of micelles formed in the system was such that they can be rejected by UF membranes having pore size 5000MWCO or less.Table 1Effect of feed acidity on the retention of DBP Feed acidity DBP in feed (ppm)DBP in raf finate (ppm)DBP rejection (%)pH 8261016693.6pH 2234014094.00.5M HNO 3298025291.51.0M HNO 3253022291.2Concentration of SDS in feed:100mM.Pore size of membrane:3000MWCO.Initial feed volume:50ml.Final volume of feed after filtration:10ml.Applied pressure:1.7bar.Table 2Effect of the surfactant (SDS)concentration in feed on the recovery of DBP SDS in feed (mM)DBP in feed (ppm)DBP in raf finate (ppm)DBP rejection (%)1007205093.1507205692.12572031755.6872054823.9Pore size of membrane:3000MWCO.Feed acidity:0.5M HNO 3.Initial feed volume:50ml.Final volume of feed after filtration:10ml.Applied pressure:1.7bar.49S.K.Misra et al./Hydrometallurgy 96(2009)47–51Table 3shows that the flux increased almost three times from 11.65dm 3m −2h −1to 36.13dm 3m −2h −1while increasing the pore size from 3000MWCO to 10,000MWCO.The flux of the system increases as the pore size of the membrane increases.It can be explained by the Hagen –Poiseuille equation (Mulder,1991)J ¼n πr 4ΔP ÀÁ=8ητΔx ðÞ(assuming a capillary pore shape)where J =volumetric flux,n =no.of pores/unit area,r =pore size,ΔP =transmembrane pressure,η=liquid viscosity,τ=tortuosity of membrane and Δx =thickness of the membrane.From the above equation,it is clear that the flux is proportional to the fourth power of nominal pore size of the membrane.Hence increasing the pore size of the membrane had an increasing effect on the flux.3.4.Effect of DBP concentration in the feedTable 4shows the effect of DBP concentration in feed on the rejection.The feed solution was adjusted to 0.5M (nitric acid)and throughout the experiments the concentration of SDS was kept constant at 50mM.During all the experiments,pore size of the membranes was fixed at 3000MWCO and the pressure of 1.7bar was applied to the cell.These experiments were carried out by varying DBP concentration in the feed from 720ppm to 3880ppm.The result of these experiments showed that the rejection of DBP decreased with its increasing concentration of DBP in the feed.It decreased from 93%at 720ppm to 85%at 3880ppm.The results indicated that at higher concentration of DBP beyond 3000ppm in feed,DBP molecules are not fully solubilised in the micelles.The decrease in the rejection may also be due to complete loading of SDS with DBP (as only 50mM of SDS was used for all these experiments).The flux also decreased as the concentration of DBP was increased in the feed from 11.66dm 3m −2h −1for 720ppm to 7.58dm 3m −2h −1for 3880ppm.The reduction in flux for higher concentration of DBP is due to the early gel layer formation near the membrane.To understand the formation of gel layer,when we plotted DBP flux versus concentration of DBP in feed,alinear plot was observed (Fig.2).By extrapolating this graph,we found that the flux became zero when the DBP concentration in feed reached to nearly 10,000ppm.It con firms the formation of gel layer near the membrane.3.5.Simultaneous removal of organic and metal solutesInitially DBP/SDS system was studied to optimise the parameters for the separation of dissolved DBP,from aqueous solutions.The optimum parameters (feed adjusted to 0.5M nitric acid,concentration of SDS:50mM,pore size of the membrane:3000MWCO)were applied for simultaneous separation of DBP,TBP and uranium from aqueous solution.Experiments were carried out to see the effect of other dissolved organic,TBP,on the recovery/rejection of DBP.The feed containing 300ppm of TBP along with the 720ppm of DBP was subjected to filtration.No signi ficant change in the recovery of DBP is observed whereas almost 99%TBP was rejected along with DBP as shown in Table 5.In order to investigate the performance of the system for the simultaneous removal of metal ion and organic solute,the experiments were carried out to remove the UO 2++ions,TBP and DBP simultaneously.The results are shown in Table 5.The removal of metal ions depends on the electrostatic attraction between the metal ions and the charged micelles whereas removal of non-ionic organic molecules depends on the solubilisation of its molecules in the interior of the micelles.Hence both of them can be removed simultaneously.To find out theTable 4Effect of DBP concentration in feed on its rejection and flux DBP in feed (ppm)DBP in raf finate (ppm)DBP rejection (%)Average flux (dm 3m −2h −1)7105093.111.66150010093.311.06298025291.59.43388064583.47.58Concentration of SDS in feed:50mM.Pore size of membrane:3000MWCO.Feed acidity:0.5M HNO 3.Initial feed volume:50ml.Final volume of feed after filtration:20ml.Applied pressure:1.7bar.Fig.2.Plot of DBP flux versus concentration of DBP in feed.Concentration of SDS in feed:50mM.Pore size of membrane:3000MWCO.Feed acidity:0.5M HNO 3.Initial feed volume:50ml.Final volume of feed after filtration:20ml.Applied pressure:1.7bar.Table 5Effect of uranium and TBP on the rejection of DBPUraniumTBP DBP Without uraniumWith uranium Without uranium With uranium Feed (ppm)–65.83003007201340Filtrate (ppm)–13.1b 5b 543.256.5Rejection (%)–80.1999994.095.8Concentration of SDS in feed:50mM.Pore size of membrane:3000MWCO.Feed acidity:0.5M HNO 3.Initial feed volume:50ml.Final volume of feed after filtration:10ml.Applied pressure:1.7bar.Table 3Effect of the membrane pore size on DBP rejection and flux Pore size ofmembranes (MWCO)DBP in feed (ppm)DBP in raf finate (ppm)DBP rejection (%)Average flux (dm 3m −2h −1)30007105093.111.6550007105192.812.9010,00071029458.636.13Concentration of SDS in feed:50mM.Feed acidity:0.5M HNO 3.Initial feed volume:50ml.Final volume of feed after filtration:20ml.Applied pressure:1.7bar.50S.K.Misra et al./Hydrometallurgy 96(2009)47–51interference of metal ion on the separation of dissolved TBP and DBP, feed solution containing300ppm of TBP and1340ppm of DBP along with67ppm of uranium was subjected tofiltration.The results indicate that no significant effect was observed on the rejection of DBP in the presence of UO2++and TBP.More than80%uranium was also rejected along with TBP and DBP.4.ConclusionMore than90%of DBP was rejected by using3000MWCO pore size UF membrane from aqueous solution while keeping the feed acidity at 0.5M HNO3and using50mM of SDS as the anionic surfactant and applying1.7bar pressure to the UF cell.No change in the rejection of DBP was found by varying the concentration of DBP in feed from 720ppm to3000ppm.Membrane pore diameter of5000MWCO or less should be used for more than90%rejection of DBP.TBP and uranium metal ion were found to have no interference for the recovery of DBP.Near quantitative amount of TBP and more than80%of uranyl ions were also recovered along with DBP.Thus the above studies clearly indicate that MEUF technique is feasible for the simultaneous separation of dissolved organic as well as metal ions from the aqueous streams.AcknowledgementThe authors wish to thank Mr.S.D.Misra,Director,Nuclear recycle group,Mr.P.K.Dey,Head Fuel reprocessing Division,Mr.S.K.Munshi Chief Superintendent Reprocessing Facilities Bhabha Atomic Research centre,Trombay,Mumbai for their keen interest and for their constant encouragement during the course of the work.The authors also wish to thank Dr.R.Kannan,Mr.S.D.Chaudhari and Mrs.M.Bindu for their kind help and support during the course of the study.ReferencesAkita,S.,Yang,L.,Takenchi,H.,1997.Micellar-enhanced ultrafiltration of gold(III)with nonionic surfactant.J.Membr.Sci.133,189.Blake Jr.,C.A.,1968.Solvent stability in nuclear fuel processing—Evaluation of the literature,calculation of radiation dose and effects of iodine and plutonium,ORNL-4212.Oak Ridge National Laboratory.Chaufer,B.,Deratami,A.,1988.Removal of metals by complexation ultrafiltration using water-soluble macromolecules:perspective of application to wastewater treatment.Nucl.Chem.Waste Manag.8,175.Das,S.K.,Rege,S.G.,Mukherjee,A.,Ramanujam,A.,Dhumwad,R.K.,1991.BARC Report, p.1139.Geckeler,K.E.,Volchek,K.,1996.Removal of hazardous substances from water using ultrafiltration in conjunction with soluble polymers.Environ.Sci.Technol.30,725. Gzara,L.,Dhahbi,M.,2001.Removal of chromate anions by micellar-enhanced ultrafiltration using cationic surfactants.Desalination137,241.Katarina,T.,Slavica,S.,2006.Removal of heavy metal ions from water by complexation-assisted ultrafiltration.Chemosphere64,486.Kibkey,A.H.,Davis Jr.,W.,AEC Report ORNL-TM-2289.Klepac,J.,Simmons,D.L.,Taylor,R.W.,Scamehorn,J.F.,Christian,S.D.,e of ligand-modified micellar-enhanced ultrafiltration in the selective removal of metal ions from water.Sep.Sci.Technol.26,165.Kryvoruchko,A.,Yurlova,A.L.,Kornilovich,B.,2002.Purification of water containing heavy metals by chelating-enhanced ultrafiltration.Desalination144,243. Mulder,M.H.V.,1991.Basic principles of membrane technology.Kluwer Academic Publishers,Dordrecht.Nowak,Z.,1973.Radiative and thermal variations on the dodecane-30%TBP-HNO3 system.Nukleonika18,447–454.Sancho,M.,Arnal,J.M.,Verdú,G.,Lora,J.,Villaescusa,J.I.,2006.Ultrafiltration and reverse osmosis performance in the treatment of radioimmunoassay liquid wastes.Desalination201,207–215.Scamehorn,J.F.,Christian,S.D.,Elington,R.T.,e of micellar-enhanced ultrafiltration to remove multivalent metal ions from aqueous streams,in surfactant-based separation processes.Surfactant Science Series,33.Dekker,New York,pp.29–51. Tangvijitsri,S.,Saiwan,C.,Soponvuttikul,C.,Scamehorn,J.F.,2002.Polyelectrolyte-enhanced ultrafiltration of chromate,sulfate,and nitrate.Sep.Sci.Technol.37,993. Tripathi,S.C.,Misra,S.K.,Ramanujam,A.,1989.Proceedings of ISAS1st National Symp.On Recent Trends in Chromatographic Techniques,Dec15–17,University of Madras. Tripathi,S.C.,Ramanujam,A.,Gupta,K.K.,Bindu,P.,2001.Studies on the identification of harmful radiolytic products of30%TBP-n-dodecane-HNO3by gas-chromatography, part II:formation of high molecular weight organophosphates.Sep.Sci.Technol.36, 2863–2883.Volchek,K.,Krentsel,E.,Zhilin,Y.u.,Shtereva,G.,Dytnersky,Y.u.,1993.Polymer binding/ ultrafiltration as a method for concentration and separation of metals.J.Membr.Sci.79,253.51S.K.Misra et al./Hydrometallurgy96(2009)47–51。
