investigation of material for bear spring using in stirlong

小学上册英语第2单元测验卷(有答案)考试时间：80分钟（总分:140）B卷一、综合题(共计100题共100分)1. 填空题：I can fold my ________ (玩具) into different shapes.2. 听力题：A _______ is a large area of land that is covered with trees.3. 选择题：What is the name of the famous river that runs through Egypt?A. AmazonB. NileC. YangtzeD. Mississippi答案:B4. 听力题：The cake is ___ (decorated) beautifully.5. 填空题：A wildcat is a small ________________ (猫).6. 选择题：What do we call the process of plants making their own food?A. PhotosynthesisB. RespirationC. TranspirationD. Germination7. 选择题：What is the main ingredient in a traditional hamburger?A. ChickenB. BeefC. PorkD. Fish答案:B8. 填空题：The __________ was a significant event in the fight for civil rights in America. (黑人民权运动)9. 填空题：The ________ (潮汐) affects the oceans.10. 填空题：A ______ (花坛) adds beauty to a yard.11. 听力题：I like to _____ my favorite songs. (sing)12. 填空题：The ________ (国家公园管理) preserves nature.13. 选择题：How many colors are in a rainbow?A. 5B. 6C. 7D. 814. 选择题：Which animal is famous for its ability to change colors?A. ChameleonB. LizardC. FrogD. Snake15. 选择题：What do we call a story that is not real?A. FictionB. Non-fictionC. BiographyD. History16. 听力题：The bear searches for food in the ____.17. 填空题：He is a scientist, ______ (他是一名科学家), studying the human body.My uncle has a farm with many ______ (动物).19. 听力题：A catalyst is not consumed in a ______.20. 选择题：How do you say "dog" in Spanish?A. PerroB. ChienC. HundD. Cane21. 填空题：A _____ (植物艺术项目) can beautify public spaces.22. 选择题：What is the color of the sky on a clear day?A. GreenB. BlueC. RedD. Yellow23. 听力题：A solution that contains a high concentration of ions is called a ______ solution.24. 听力题：The chemical symbol for silver is ____.25. 听力题：The ______ is a popular author.26. 填空题：We visit ______ (亲戚) during the holidays.27. 选择题：What is the capital of Zambia?A. LusakaB. NdolaC. KitweD. Livingstone答案:A28. 听力题：A __________ is a natural formation created by erosion and deposition.The pig loves to roll in the ______.30. 选择题：What is the sound a dog makes?A. MeowB. BarkC. QuackD. Moo答案:B31. 填空题：She is _______ (聪明的) and kind.32. 听力题：I play _____ (视频游戏) after homework.33. 听力题：I see ___ (stars/clouds) in the sky.34. 填空题：In _____ (98), there are many castles.35. 选择题：What is the main ingredient in bread?A. RiceB. WheatC. CornD. Oats答案: B36. 听力题：My ______ enjoys playing with his friends.37. 听力题：The ______ protects the inner parts of the plant.38. 填空题：The cat is very _________ (可爱).39. 听力题：An acid has a sour taste and can turn __________ paper red.40. 填空题：The __________ (历史的教育意义) shapes perspectives.A cow's milk is an important source of ________________ (营养).42. 填空题：The __________ (植物的生长) depends on many factors.43. 选择题：Which planet is known as the Blue Planet?A. MarsB. EarthC. VenusD. Jupiter答案: B44. 选择题：What is the name of the toy that spins on the ground?A. FrisbeeB. TopC. Yo-yoD. Kite45. 选择题：What do you call the study of ancient civilizations?A. AnthropologyB. ArchaeologyC. HistoryD. Sociology答案:B46. 选择题：What is the opposite of slow?A. QuickB. FastC. RapidD. Swift答案:B47. 填空题：I wish I had a ________ (遥控飞机) to fly on sunny days.48. 听力题：We go _____ (swimming) in the lake.49. 听力题：I enjoy ______ with my family. (traveling)The pancakes are _______ (fluffy).51. (22) Ocean is the largest ocean. 填空题：The ____52. 选择题：Which fruit is red and often used to make juice?A. BananaB. AppleC. GrapeD. Orange53. 填空题：The woodpecker pecks on ______ (树木).54. 填空题：_____ (vines) can cover fences and walls.55. 选择题：What is the longest river in the world?A. AmazonB. NileC. MississippiD. Yangtze56. 选择题：What do you call the light produced by the sun?A. Natural lightB. Artificial lightC. Reflective lightD. Incandescent light答案: A. Natural light57. 选择题：What do we call the part of a flower that produces pollen?A. StamenB. PistilC. SepalD. Petal答案:A58. 听力题：The stars are _____ in the night sky. (shining)The _____ (相机) captures memories.60. 填空题：My friend loves __________ (野外探险).61. 填空题：A _______ (鸟) sings sweet melodies.62. 听力题：Geothermal energy comes from the heat within the ______.63. 选择题：What is the name of the famous waterfall located on the border between the U.S. and Canada?A. Angel FallsB. Victoria FallsC. Niagara FallsD. Iguazu Falls答案: C64. 听力题：The biosphere interacts with the ______ and geosphere.65. 选择题：How many strings does a standard guitar have?A. 4B. 5C. 6D. 7答案: C66. 选择题：Which fruit is orange?A. BananaB. AppleC. OrangeD. Grape答案:C67. 填空题：The capital of the Dominican Republic is ________ (圣多明各).68. 填空题：I love to listen to ______ on my way to school.Solar systems are made up of a star and all the objects that orbit it, including ______.70. 听力题：The chemical symbol for sodium is _______.71. 填空题：I found a ________ in the garden.72. 选择题：How many legs does a spider have?A. SixB. EightC. FourD. Ten答案:B73. 听力题：Acid rain is caused by pollution from ______.74. 听力题：The ancient Romans built _______ to carry water.75. 听力题：A solar flare is a sudden eruption of energy on the sun’s ______.76. 填空题：My dad, ______ (我爸爸), enjoys fishing and camping.77. 听力题：He is ___ to the music. (dancing)78. 听力题：A toy car moves when we _______ it.79. 选择题：Which shape has three sides?A. SquareB. CircleC. TriangleD. Rectangle答案:C80. 填空题：My best friend’s name is ________ (小明), and we play together.My sister is very ________.82. 选择题：What is the capital of Egypt?A. CairoB. AlexandriaC. LuxorD. Aswan答案:A83. 填空题：The _____ (布娃娃) is very soft and cuddly.84. 听力题：I like _____ (to cook/to eat).85. 选择题：What is the name of the fictional bear created by A.A. Milne?A. PaddingtonB. Winnie the PoohC. BalooD. Yogi答案: B86. 选择题：What is 5 2?A. 3B. 4C. 5D. 6答案:A87. 听力题：A _______ can be a solid, liquid, or gas.88. 听力题：A _______ reaction is when energy is absorbed.89. 听力题：The sun sets in the ________.90. 听力题：The flowers are _____ (beautiful/ugly).The seal barks loudly on the _________. (岩石)92. 听力题：The boy has a cool ________.93. 听力题：The chemical structure of a compound determines its ______.94. 选择题：What do we call the system of lines on a map?A. ScaleB. GridC. LegendD. Compass95. 选择题：What is the name of the famous ancient site in Egypt?A. Great PyramidB. ColosseumC. Taj MahalD. Stonehenge答案: A96. 选择题：What is the main ingredient in pizza?A. RiceB. DoughC. CheeseD. Both B and C答案:D97. 填空题：Playing with my ________ (玩具名) helps me relax after a long day at school. It’s my favorite way to unwind.98. 选择题：What do bees produce?A. MilkB. HoneyC. SilkD. Wool答案: B99. 听力题：The bat flies at _____.100. 选择题：What do you call the study of the Earth's atmosphere?A. MeteorologyB. GeologyC. AstronomyD. Ecology。

表面等离子体共振在研究中的应用摘要：表面等离子共振（SPR）近年来迅速发展为用于分析生物分子相互作用的一种新的光学检测技术。

应用SPR原理可检测生物传感芯片上配位体与分析物之间的相互作用情况，在生命科学、医疗检测、药物筛选、食品检测及环境监测等领域具有广泛的应用需求。

该技术无需标记、特异性强、灵敏度高、样品用量小，可实现在线连续实时检测。

本文阐述了基于表面等离子共振技术生物传感器的基本原理，综述了SPR在蛋白质、水质、有毒气体检测及疾病诊断中的应用，以及利用SPR分析蛋白质—蛋白质相互作用中的主要研究方向，并对其发展趋势进行了展望。

关键词：表面等离子体共振；蛋白质；水质检测；有毒气体检测；疾病诊断Application in the Scientific Research ofSurface Plasmon ResonanceAbstract:The optical technique of surface plasmon resonance(SPR)has been rapidly developed to investigate the interactions of biomolecules in recent years, it can be applied for monitoring of interaction between ligand and analyte on a sensor chip. Thus, it has been largely demanded in the field of life science, medical testing, drug screening, food and environmental monitoring, and so on.SPR technique has many advantages,such as label-free,specificity,sensitivity, sample dosage, real-time and online detection.In this paper, the principle of biosensor chip technology of SPR biosensors was briefly described, its application on protein, water quality, toxic gas investigations and disease diagnosis were reviewed, and the mainly research fields of using SPR analyse interaction between protein and protein were stated. Furthermore，the trend of its development in near future has been prospected．Key words: surface plasmon resonance; protein; immunosensor; water quality investigation; toxic gas investigation表面等离子体子共振(surface plasmon resonance，SPR)是一种利用金属薄膜的光学耦合产生的物理光学现象。

RPMI-1640 MEDIUMWith L-Glutamine and Without Sodium Bicarbonate Product Number R6504Product DescriptionRPMI-1640 medium was developed by Moore et al., at Roswell Park Memorial Institute, hence the acronym RPMI. RPMI-1640 medium has been used for the culture of normal and neoplastic leukocytesComponents g/L L-Arginine [Free Base] 0.2L-Asparagine [Anhydrous] 0.05L-Aspartic Acid 0.02L-Cystine •2HCl 0.0652L-Glutamic Acid 0.02L-Glutamine 0.3Glycine 0.01L-Histidine [Free Base] 0.015Hydroxy-L-Proline 0.02L-Isoleucine 0.05L-Leucine 0.05 L-Lysine •HCl 0.04 L-Methionine 0.015 L-Phenylalanine 0.015L-Proline 0.02L-Serine 0.03L-Threonine 0.02L-Tryptophan 0.005L-Tyrosine •2Na •2H 2O 0.02883L-Valine 0.02Biotin 0.0002Choline Chloride 0.003Folic Acid 0.001myo-Inositol 0.035Niacinamide 0.001D-Pantothenic Acid Hemicalcium 0.00025PABA 0.001Pyridoxine •HCl 0.001 Riboflavin 0.0002Thiamine •HCl 0.001Vitamin B12 0.000005Calcium Nitrate •4 H 2O 0.1Magnesium Sulfate [Anhydrous] 0.04884Potassium Chloride 0.4Sodium Chloride 6.0Sodium Phosphate Dibasic [Anhydrous] 0.8D-Glucose 2.0Glutathione, Reduced 0.001Phenol Red •Na 0.0053Precautions and Disclaimer REAGENTFor R&D use only. Not for drug, household or other uses.Preparation InstructionsPowdered media are hygroscopic and should be protected from moisture. The entire contents of each package should be used after opening. Preparing a concentrated solution of medium is not recommended as precipitates may form. Supplements can be added prior to filtration or introduced aseptically to sterile medium.1.Measure out 90% of final required volume of water.Water temperature should be 15-20 °C.2.While gently stirring the water, add the powderedmedium. Stir until dissolved. Do NOT heat.3.Rinse original package with a small amount of water toremove all traces of powder. Add to solution in step 2.NOTE: It may be necessary to lower the pH to 4.0 with 1N HCl to completely dissolve this product. After it has dissolved completely, the pH can be raised to 7.2 with 1N NaOH prior to the addition of sodium bicarbonate.4.To the solution in step 3, add 2.0 g sodium bicarbonateor 26.7 ml of sodium bicarbonate solution [7.5%w/v] for each liter of final volume of medium being prepared. Stir until dissolved.5.While stirring, adjust the pH of the medium to 0.1-0.3 pHunits below the desired pH since it may rise during filtration. The use of 1N HCl or 1N NaOH is recommended.6.Add additional water to bring the solution to finalvolume.7.Sterilize immediately by filtration using a membrane witha porosity of 0.22 microns.8.Aseptically dispense medium into sterile container. Storage and StabilityStore the dry powdered medium at 2-8 °C under dry conditions and liquid medium at 2-8 °C in the dark.Deterioration of the powdered medium may be recognized by any or all of the following: [1] color change, [2]granulation/clumping, [3] insolubility. Deterioration of the liquid medium may be recognized by any or all of thefollowing: [1] pH change, [2] precipitate or particulates, [3] cloudy appearance [4] color change. The nature ofsupplements added may affect storage conditions and shelf life of the medium. Product label bears expiration date.ProcedureMATERIALS REQUIRED BUT NOT PROVIDED Water for tissue culture use [W3500]Sodium Bicarbonate [S5761] orSodium Bicarbonate Solution, 7.5% [S8761]1N Hydrochloric Acid [H9892]1N Sodium Hydroxide [S2770]Medium additives as requiredReferences1.Moore, G.E., Gerner, R.E. and Franklin, H.A., (1967).Culture of Normal Human Leukocytes. JAMA. 199, 519-524.Revised: May 2007Sigma-Aldrich, I nc. warrants that its products conform to theinformation contained in this and other Sigma-Aldrich publications.Purchaser must determine the suitability of the product(s) for theirparticular use. Additional terms and conditions may apply. Pleasesee reverse side of the invoice or packing slip.Sigma-Aldrich Inc.3050 Spruce St. St. Louis, MO 63103USA 314-771-5765Technical Service: 800-325-5832 or call collect 314-771-5765Or e-mail at *****************To order: 800-325-3010 or call collect 314-771-5750。

国际机构组织缩写大全顺序版文稿归稿存档编号：[KKUY-KKIO69-OTM243-OLUI129-G00I-FDQS58-世界机构组织联盟协会缩写全称AAPP（Association of Asian Parliaments for Peace）亚洲议会和平协会ACS（Association of Caribbean States）加勒比国家联盟ACWW（Associated Country Women of the World）世界乡村妇女协会ADB（Asian Development Bank）亚洲开发银行AI（Amnesty International）大赦国际AIE（Association of International Education）国际教育协会ANRPC（Association of Natrual Rubber Producing Countries）天然橡胶生产国协会APA（Asian Parliamentary Assembly）亚洲议会大会APSCO（Asia-Pacific Space Cooperation Organization）亚太空间合作组织ASEAN（Association of Southeast Asian Nations）东南亚国家联盟ATP（Association of Tennis Professional）国际网球联合会BIE（International Exhibitions Bureau）国际展览局BJS（Bureau of Justice Statistics）美国司法统计局BSR（Business for Social Responsibility）商务社会国际责任协会CARICOM（Caribbean Community and Common Market）加勒比共同体和共同市场CBA（Continental Basketball Association）国际篮球协会CBDA（China Building Decoration Association）中国建筑装饰协会CBSS（Council of the Baltic Sea States）波罗的海国家理事会CCA（Chinese Chess Association）中国象棋协会CDB（Caribbean Development Bank）加勒比开发银行CIA（Central Intelligence Agency) 美国中央情报局CIECA（China International E-Commerce Association）中国国际电子商务协会CIS（Commonwealth of Independent States）独立国家联合体CSBA（Chinese Billiards & Snooker Association）中国台球协会CTTA（Chinese Table Tennis Association）中国乒乓球协会DHS（United States Department of Homeland Security）美国国土安全局DOD（Department of Defense）美国国家防御部ECB（European Central Bank）欧洲中央银行ECOWAS（Economic Community of West African States）西非国家经济共同体EEC（European Economic Communities）欧洲经济共同体EFTA（European Free Trade Association）欧洲自由贸易联盟ERRI（European Rail Research Institute）欧洲铁道研究所EU（the European Union）欧洲联盟Expo（World Exposition）世界博览会FATF（Financial Action Task Force on Money Laundering）反洗钱金融行动特别工作组FBI（Federal Bureau of Investigation) 美国联邦调查局FIAB（International Volleyball Federation）国际排球协会FIFA（International Federation of Association Football）国际足球协会IAEA（International Atomic Energy Agency）国际原子能机构IAEE（International Association of Exhibitions and Events）国际展览与项目协会IASA（International Association for Sports Information）国际体育信息协会IATA（International Air Transport Association）国际航空运输协会IAU（International Association of Universities）国际大学协会IBF（International Badminton Federation）国际羽毛球联合会IBRD（International Bank for Reconstruction and Development）国际复兴开发银行ICA（International Council on Archives）国际档案理事会ICAA（International Children's Art Association）国际少儿美术协会ICAO（International Civil Aviation Organization）国际民用航空组织ICC（International Chamber of Commerce）国际商会ICFTU（International Confederation of Free Trade Unions）国际自由工会联合会ICLTA（International Chinese Language Teachers Association）国际汉语教师协会ICOMOS（International Council on Monuments and Sites）国际古遗址理事会ICPO（International Criminal Police Organization）国际刑警组织ICRC（International Committee of the Red Cross）国际红十字委员会ICSID（International Centre for Settlement of Investment Disputes）国际投资争端中心ICSU（International Council for Science）国际科学理事会IDA（International Development Association）国际开发组织IEA（International Energy Agency）国际能源组织IEERA（International English Education Research Association）国际英语教育研究协会IEPCA（International education Profession Certification Association）国际教育认证协会IFAC（International Federation of Accountants）国际会计师联合会IFAD（International Fund for Agriculture Development）国际农业发展基金IFC（International Finance Centre）国际金融中心IFIP（International Federation for Information Processing）国际信息处理联合会IFLA（International Federation of Landscape Architects）国际风景师联合会IFLA（International Federation of Library Associations and Institutions）国际图书馆协会IGAD（Intergovernmental Authority on Development）政府间发展组织IGEA（International Green Economic Association）国际绿色经济协会IIA（Institute of Internal Auditors）国际内部审计师协会IIF（Institute of International Finance）国际金融协会IISS（International Institute for Strategic Studies）国际战略研究所ILO（International Labour Organization）国际劳工组织IMCPI（International Mandarin Chinese Promotion Institute）国际汉语推广协会IMF（International Monetary Fund）国际货币基金组织IMO（International Maritime Organization）国际海事组织INNA（International Newsreel and News Film Association）国际新闻电影协会INTA（International Trademark Association）国际商标协会INTELSAT（International Telecommunications Satellites）国际通信卫星机构IOC（International Olympic Committee）国际奥林匹克委员会IOM（International Organization of Migration）国际移民组织IOR（Indian Ocean Rim Association for Regional Cooperation）环印度洋地区合作联盟IPA（International Photography Association）国际摄影协会IPA（International Profession Certification Association）国际认证协会IPI（International Press Institute）国际新闻协会IPU（Inter-Parliamentary Union）各国议会联盟IRTO（International Radio and Television Organization）国际广播电视组织ISO（International Standard Organization）国际标准化组织ISOC（Internet Society）国际互联网协会ITTF（International Table Tennis Federation）国际乒乓球协会ITU（International Telecommunication Union）国际电信联盟IVHQ（International Volunteer Organization）国际志愿者组织LAES（Latin American Economic System）拉美经济体系LI（Liberal International）自由进步党国际MAA（Mathematical Association of America）美国数学协会MIGA（Multinational Investment Guarantee Agency）多边投资担保机构MSF（Medicins Sans Frontieres）无国界医生NALCA（North American Language & Culture Association）北美语言文化协会NASA（National Aeronautics and Space Administration）美国国家航空航天局NATO（North Atlantic Treaty Organization）北大西洋公约组织NBA（National Basketball Association）美国篮球职业联赛NEPAD（the New Partnership for Africa's Development）非洲发展新伙伴计划NRO（National Reconnaissance Office）美国国家侦查局NSA（National Security Agency）美国国家安全局NSF（National Sanitation Foundation）美国国家卫生基金会OAU（Organization of African Unity）非洲统一组织）OEEC（Organization of European Economic Cooperation）欧洲经济合作组织OIE（Office International Des Epizooties）世界动物卫生组织OPCW（Organization for the Prohibition of Chemical Weapons）禁止化学武器组织OPEC（Organization of Petroleum Exporting Countries）石油输出国组织ORBIS（Project Orbis）国际奥比斯组织OSCE（Organization of Security and Cooperation in Europe）欧洲安全与合作组织PGI（Platinum Guide International）国际铂金协会SISO（The Society of Independent Show Organizers）独立组展商协会SNIA（Storage Network Industry Association）全球储存网络工业协会SPR（Society for Psychical Research）英国心灵研究协会TWAS（the Third World Academy of Sciences）第三世界科学院UEA（Universal Esperanto Association）国际世界语言协会UEB（Union Economic Benelux）比荷卢经济联盟UFI（The Global Association of the Exhibition Industry）全球展览业协会UMA（Union of the Arab Maghreb）阿拉伯巴格里布联盟UN（the United Nations）联合国UNCTAD（United Nations Conference on Trade and Development）联合国贸易发展会议UNDP（The United Nations Development Programme）联合国开发计划署UNECA（United Nations Economic Commission for Africa）联合国非洲经济委员会UNEP（United Nations Environment Programme）联合国环境规划署UNFPA（United Nations Population Fund）联合国人口基金UNICEF（United Nations International Children's Emergency Fund）联合国儿童基金会UNIDO（United Nations Industrial Development Organization）联合国工业发展组织UPU（Universal Postal Union）万国邮政联盟USSS（United States Secret Service）美国特勤局WACF（World Architecture Construction Federation）国际建筑协会WBG（World Bank）世界银行WBU（World Blind Union）世界盲人联盟WCIP（World Council of Indigenous Peoples）世界土着人理事会WFB（World Fellowship of Buddhists）世界佛教徒联谊会WHO (World Health Organization) 世界卫生组织WIPO（WorldIntellectual Property Organization）世界知识产权组织WMC（World Muslim Congress）世界穆斯林大会WMO（World Meteorological Organization）世界气象组织WPC（World Peace Council）世界和平理事会WTA（World Technoplis Association）世界科技城市联盟WTO（World Toilet Organization）世界厕所组织WTO（World Tourism Organization）世界旅游组织WTO（World Trade Organization）世界贸易组织。

宁恒，马森，李力. 麦麸膳食纤维对发酵挂面品质的影响[J]. 食品工业科技，2023，44（18）：115−122. doi: 10.13386/j.issn1002-0306.2022120118NING Heng, MA Sen, LI Li. Study on the Effects of Wheat Bran Dietary Fiber on Quality of Fermented Dried Noodles[J]. Science and Technology of Food Industry, 2023, 44(18): 115−122. (in Chinese with English abstract). doi: 10.13386/j.issn1002-0306.2022120118· 研究与探讨 ·麦麸膳食纤维对发酵挂面品质的影响宁　恒，马　森*，李　力*（河南工业大学粮油食品学院，河南郑州 450001）摘　要：发酵挂面是近年来市场上盛行的新型营养面制食品，麦麸膳食纤维的添加可以提高发酵挂面的营养价值，但也会对其品质特性造成影响。

本文通过单因素实验，研究了不同麦麸膳食纤维添加量对发酵挂面蒸煮特性、质构特性以及孔隙率的影响，并对麦麸膳食纤维添加量和发酵挂面品质进行了相关性分析。

结果表明：随着麦麸膳食纤维添加量增加，挂面的孔隙率、抗断裂强度、吸水率、最佳蒸煮时间、内聚性、回复性、拉伸距离显著降低（P <0.05），柔韧性、蒸煮损失率、硬度、胶黏性、咀嚼性、拉伸阻力显著提高（P <0.05），感官评价得分下降。

在添加量为2%的情况下，麦麸膳食纤维对发酵挂面的蒸煮和质构特性，及感官评价得分影响较小。

本文为提高发酵挂面品质的相关研究提供了理论指导。

关键词：发酵挂面，麦麸膳食纤维，质构特性，蒸煮特性，孔隙率本文网刊:中图分类号：TS213.2 文献标识码：A 文章编号：1002−0306（2023）18−0115−08DOI: 10.13386/j.issn1002-0306.2022120118Study on the Effects of Wheat Bran Dietary Fiber on Qualityof Fermented Dried NoodlesNING Heng ，MA Sen *，LI Li *（College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China ）Abstract ：Fermented dried noodles are a popular nutritional noodle flour product in current market. Wheat bran dietary fiber (WBDF) can improve the nutritional value of fermented dried noodles, but also affect the quality characteristics of fermented dried noodles. In this paper, the effects of WBDF content on the cooking characteristics, texture characteristics and porosity of fermented dried noodles were investigated by single factor experiments, and the correlation analysis for WBDF content and the quality characteristics of fermented dried noodles was taken. The results showed that the porosity,breaking strength, water absorption, optimal cooking time, cohesiveness, resilience and tensile distance decreased significantly with the increase of bran dietary fiber addition (P <0.05), while the flexibility, rate of cooking loss, hardness,adhesiveness, chewiness and tensile resistance increased significantly (P <0.05) and the sensory evaluation score decreased.Adding 2% wheat bran dietary fiber had weaker influence on the cooking characteristics, texture characteristics and sensory evaluation score of fermented dried noodles. The research could lay a theoretic basis for the investigation of dietary fiber fermented dried noodles.Key words ：fermented dried noodles ；wheat bran dietary fiber ；texture characteristics ；cooking characteristics ；porosity发酵挂面又名空心挂面，其拥有悠久的历史，外观平滑无凹陷，内部有诸多细孔、味皆可入面，老少皆宜，营养价值极其丰富，在我国具有巨大的市场潜力[1]。

三只松鼠原材料风险应对措施英文回答：Risk Management Measures for Raw Materials by Three Squirrels.Three Squirrels, a leading Chinese snack food company, understands the paramount importance of ensuring the safety and quality of its products. As such, the company has implemented a comprehensive set of risk management measures to mitigate potential risks associated with its raw materials.Supplier Management:Three Squirrels maintains rigorous supplier selection criteria to ensure that only reputable and reliable suppliers are utilized.The company conducts thorough supplier audits toevaluate their capabilities, quality control systems, and adherence to ethical and environmental standards.Regular supplier assessments are conducted to monitor performance and identify areas for improvement.Raw Material Inspection:Incoming raw materials undergo stringent inspection and testing to verify their compliance with ThreeSquirrels' specifications.The company employs advanced laboratory equipment and analytical techniques to assess the quality and safety of ingredients.Non-conforming materials are rejected and returned to suppliers.Traceability:Three Squirrels implements a robust traceabilitysystem to track the movement of raw materials from origin to finished product.This system allows the company to quickly identify and isolate any potential food safety issues.The traceability data is regularly reviewed to detect patterns and trends that may indicate potential risks.Quality Control:Throughout the production process, Three Squirrels employs a comprehensive quality control system to ensure the safety and quality of its products.The company follows Good Manufacturing Practices (GMP) and Hazard Analysis and Critical Control Points (HACCP) principles.Regular quality audits are conducted to verify compliance with established standards.Risk Assessment and Mitigation:Three Squirrels conducts regular risk assessments to identify potential threats to its raw material supply chain.Based on these assessments, the company develops mitigation strategies to address and minimize theidentified risks.Contingency plans are in place to respond effectivelyto potential emergencies or supply disruptions.Sustainability and Ethical Sourcing:Three Squirrels recognizes the importance of sustainable and ethical sourcing practices.The company works closely with suppliers to ensurethat raw materials are procured responsibly and in accordance with environmental and social standards.Three Squirrels promotes fair trade and supports localfarmers whenever possible.Continuous Improvement:Three Squirrels is committed to continuous improvement in its risk management processes.The company regularly reviews and updates its strategies based on new information and industry best practices.Feedback from customers, suppliers, and regulatory agencies is taken into account to enhance the effectiveness of risk mitigation measures.中文回答：三只松鼠原材料风险应对措施。

第43卷第1期2024年1月硅㊀酸㊀盐㊀通㊀报BULLETIN OF THE CHINESE CERAMIC SOCIETY Vol.43㊀No.1January,2024EDTA-LDH /zeolite 制备及其对重金属离子的吸附谢修鑫1,2,廖立兵1,2,雷馨宇1,2,王丽娟1,2,唐晓尉1,2(1.中国地质大学(北京)材料科学与工程学院,非金属矿物与固废资源材料化利用北京市重点实验室,北京㊀100083;2.中国地质大学(北京)材料科学与工程学院,地质碳储与资源低碳利用教育部工程研究中心,北京㊀100083)摘要:用水热法和焙烧还原法两步合成了乙二胺四乙酸-水滑石/沸石(EDTA-LDH /zeolite)复合材料,并将其用于去除水溶液中的Cd 2+㊁Pb 2+㊁Cu 2+,系统研究不同条件下EDTA-LDH /zeolite 对单一及混合重金属离子溶液中Cd 2+㊁Pb 2+㊁Cu 2+的吸附效果与吸附机制㊂结果表明,当EDTA-LDH /zeolite 投加量为0.05g㊁重金属离子浓度为1500mg /L㊁pH 值为6.5㊁吸附时间为24h 时,EDTA-LDH /zeolite 吸附性能最佳㊂重金属离子间存在竞争吸附,EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+㊁Cu 2+的最大吸附容量分别为65.33㊁98.35和108.51mg /g㊂去除过程中沉淀作用㊁表面络合㊁螯合反应等多种机制协同作用,去除行为均符合Langmuir 等温模型与拟二阶动力学模型㊂关键词:LDH;沸石;EDTA;重金属离子;吸附性能中图分类号:O647.3㊀㊀文献标志码:A ㊀㊀文章编号:1001-1625(2024)01-0370-13Preparation of EDTA-LDH /Zeolite and Its Adsorption of Heavy Metal IonsXIE Xiuxin 1,2,LIAO Libing 1,2,LEI Xinyu 1,2,WANG Lijuan 1,2,TANG Xiaowei 1,2(1.Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes,School of Materials Science and Technology,China University of Geosciences (Beijing),Beijing 100083,China;2.Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources,School of Materials Science and Technology,China University of Geosciences (Beijing),Beijing 100083,China)Abstract :EDTA-LDH /zeolite composite material was synthesized in two steps by hydrothermal and reconstruction method and used for the removal of Cd 2+,Pb 2+,and Cu 2+from aqueous solution.The adsorption effect and mechanism of EDTA-LDH /zeolite on Cd 2+,Pb 2+and Cu 2+in single and mixed heavy metal ion solutions under different conditions were systematically investigated.The results show that the best adsorption performance of EDTA-LDH /zeolite is achieved when the dosage of EDTA-LDH /zeolite is 0.05g,the concentration of heavy metal ions is 1500mg /L,the pH value is 6.5,and the adsorption time is peting adsorption between heavy metal ions,the maximum adsorption capacities of EDTA-LDH /zeolite for Cd 2+,Pb 2+,and Cu 2+are 65.33,98.35,and 108.51mg /g,respectively.During the removal process,various mechanisms such as precipitation,surface complexation,and chelation work synergistically.The removal behavior of EDTA-LDH /zeolite are all consistent with Langmuir isotherm model and pseudo second-order kinetic model.Key words :LDH;zeolite;EDTA;heavy metal ion;adsorption performance 收稿日期:2023-07-24;修订日期:2023-09-10基金项目:国家自然科学基金重点项目(41831288)作者简介:谢修鑫(1998 ),男,硕士研究生㊂主要从事黏土矿物的研究㊂E-mail:xiexiuxin19@通信作者:廖立兵,博士,教授㊂E-mail:clayl@㊂0㊀引㊀言水体中的重金属污染问题一直受到广泛的关注,重金属具有生物累积性和毒性,不仅会对水体环境造成严重破坏[1],还会危害人体健康㊂其中,镉㊁铅㊁铜污染程度较重,对环境影响更大,通过多种途径被人体摄入后,轻则引起关节痛等症状,重则引起肝肾功能异常㊁癌症㊁精神疾病等[2-4]㊂重金属污染已成为严重的环境问题㊂去除水体中重金属的方法主要包括化学沉淀㊁离子交换㊁膜过滤㊁电化学方法㊁吸附法等[5]㊂化学沉淀法会消耗大量化学试剂,后续处理成本高昂[5];离子交换法无法应用于高浓度的污水,离子交换材料容易污㊀第1期谢修鑫等:EDTA-LDH/zeolite制备及其对重金属离子的吸附371染溶液[6];膜过滤方法需定期维护更换过滤膜,并且过滤膜造价较高,易受污染[7];电化学方法能耗较高,不适用于大规模废水处理㊂吸附法具有多功能性㊁高效性㊁操作简单和成本低廉的优点,因而被广泛应用[8]㊂常用的吸附剂有天然材料及其衍生物㊁碳吸附剂㊁介孔硅基材料等[9]㊂由于吸附场景的复杂性,许多吸附剂的吸附能力㊁生产成本等方面不能满足需求,因此需要开发新型吸附材料,以满足不同的需求㊂水滑石类材料是一类阴离子型层状化合物,也被称为层状双金属氢氧化物(layered double hydroxide, LDH),由带负电荷的层间阴离子和带正电荷的金属氢氧化物层板构成[10]㊂LDH的结构式为[M2+1-x㊃M3+x㊃(OH)x-2(A n-)x/n]㊃m H2O,其中M2+为二价金属阳离子,M3+为三价金属阳离子,A n-表示层间阴离子,x表示M3+/(M2++M3+)的摩尔比,范围为0.17<x<0.33,m表示层间水分子数㊂化合物中的M2+和M3+可以被其他具有相同价态和相似半径的金属阳离子取代,形成不同的LDH[11]㊂主层板基本单元为金属(氢)氧八面体,具体为M2+或M3+位于八面体中心,羟基位于八面体的六个顶点上,相邻两个八面体之间通过共边相互联结成层,层与层之间通过氢键结合[12]㊂LDH由于其板层离子的可调控性与层间阴离子的可变性,因而具有一些独特的性质(酸碱性㊁结构记忆效应㊁高比表面积㊁层间阴离子交换能力等),尤其在吸附方面,水滑石表现出巨大的潜力[13]㊂LDH常被用于吸附阴离子污染物,但原始LDH对重金属的吸附能力较弱㊂为了解决这一问题,可以在LDH层间引入具有特定功能的基团㊂通常采用有机阴离子(如乙二胺四乙酸㊁己二酸㊁琥珀酸㊁酒石酸盐㊁腐殖酸㊁柠檬酸盐)插层LDH,提高水滑石的吸附能力[14-17]㊂这些有机阴离子的官能团(如 SH㊁ COOH和 NH2)含有许多配位原子,可以提供电子对,使有机阴离子与重金属离子反应形成配合物[18]㊂乙二胺四乙酸(EDTA)含有羟基㊁羧基和氨基官能团,可与Cu2+㊁Cd2+㊁Pb2+㊁Ca2+㊁Mn2+等多种重金属螯合,形成金属-EDTA稳定配合物,因而常被用作吸附剂的改性材料[19]㊂Kameda等[20]将CuAl-CO3-LDH煅烧得到CuAl氧化物,然后在EDTA溶液中重构得到CuAl-EDTA-LDH,发现其对溶液中Y3+的吸附能力较好,吸附迅速,吸附机制包括EDTA的螯合作用等㊂此外,Kameda等[21]用共沉淀法制备了EDTA和TTHA插层的LiAl-LDH (EDTA-LDH㊁TTHA-LDH),并研究了其对水溶液中Nd3+和Sr2+的吸附能力与吸附机制㊂但合成的插层LDH材料容易团聚,从而降低了对重金属的吸附能力㊂将LDH生长在基体上可以阻碍LDH的聚集,提高LDH的分散性,增加吸收位点,提高LDH的吸附能力[22],但目前关于此类材料的研究较少,而且已制备的此类材料对重金属的吸附能力有待进一步提高㊂沸石是一种成本低廉的天然矿物,离子交换能力强,比表面积大,可以作为LDH的生长基体,充分分散LDH㊂本文用水热法将LDH负载于沸石基体上合成LDH/zeolite材料,通过焙烧还原法将EDTA引入LDH/ zeolite中,制备EDTA-LDH/zeolite复合材料并系统研究其对水中Cd2+㊁Pb2+㊁Cu2+单一污染物以及三者混合污染物的吸附能力及吸附机理㊂1㊀实㊀验1.1㊀原材料原材料包括:六水硝酸镁㊁九水硝酸铝㊁碳酸钠㊁尿素㊁EDTA-2Na㊁氢氧化钠㊁盐酸㊁四水硝酸镉㊁硝酸铅㊁三水硝酸铜㊂所有试剂均是分析纯,并且在没有进一步纯化的情况下使用㊂沸石产自河北围场,为钙型斜发沸石(见图1(a)),粒径为200目(74μm)左右㊂1.2㊀LDH的制备将7.2mmol Mg(NO3)2㊃6H2O㊁3.6mmol Al(NO3)3㊃9H2O在蒸馏水中混合,得到溶液A,将NaOH和Na2CO3按一定的比例配制成混合碱液,得到溶液B㊂将溶液A与B按一定的滴速同时滴入三口烧瓶中,在ZNCL-BS型磁力加热板中剧烈搅拌,控制体系pH值恒定㊂完成滴定后,持续搅拌陈化[23]㊂用蒸馏水洗至中性后在烘箱中烘干,磨细,获得层间为碳酸根的MgAl-CO2-3-LDH,样品记为LDH㊂1.3㊀EDTA-LDH/zeolite的制备将2g沸石置于蒸馏水中搅拌,得到溶液C;将14.4mmol的Mg(NO3)2㊃6H2O㊁7.2mmol的Al(NO3)3㊃9H2O溶解于蒸馏水得到溶液D;将100mmol尿素溶解于蒸馏水,得到溶液E㊂室温条件下将溶372㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第43卷液C㊁D㊁E 混合,充分搅拌后,将混合溶液移入水热反应釜内,在110ħ下反应6h㊂冷却至室温后取出,用蒸馏水冲洗2~3次,干燥,研磨,得到的样品记为LDH /zeolite㊂LDH /沸石对Cd 2+㊁Pb 2+㊁Cu 2+的吸附量为22.18㊁34.24和27.67mg /g㊂在马弗炉中400ħ条件下焙烧LDH /zeolite 4h,所得焙烧产物记作LDO /zeolite,将3g LDO /zeolite 置于0.02mol /L 的EDTA-2Na 溶液中,在80ħ下水浴加热并搅拌4h,停止搅拌后陈化2h㊂用蒸馏水将样品洗至中性,在烘箱中烘干,磨细,所得样品记作EDTA-LDH /zeolite㊂1.4㊀吸附试验1)pH 值对吸附的影响配制浓度为100mg /L 的Cd 2+㊁Pb 2+㊁Cu 2+单一溶液及三者的混合溶液,每种溶液各移取20mL 于离心管内,分别称取0.05g LDH 和EDTA-LDH /zeolite 加入其中,调控pH 值为4.0~6.5,在室温下震荡24h,取出样品过0.22μm 滤膜,测试吸附后溶液的重金属离子浓度㊂2)初始重金属离子浓度对吸附的影响移取20mL 不同重金属离子溶液于离心管中,分别称取0.05g LDH 和EDTA-LDH /zeolite 加入其中,调节pH 值为5.5,在室温下震荡24h,过0.22μm 滤膜,测试吸附后滤液中重金属离子浓度㊂3)接触时间对吸附的影响移取20mL 浓度为100mg /L 的重金属离子溶液于离心管中,分别称取0.05g LDH 和EDTA-LDH /zeolite 加入其中,调控pH 值为5.5,在室温下分别震荡不同时间后取出,取出样品过0.22μm 滤膜,测试吸附后溶液的重金属离子浓度㊂用ICP 测定吸附后溶液的残留重金属含量㊂根据式(1)㊁(2)计算吸附量与去除率㊂q e =(C 0-C e )ˑV m (1)η=C 0-C e C 0ˑ100%(2)式中:q e 为吸附平衡时的吸附量,mg /g;C 0为Cd 2+㊁Pb 2+㊁Cu 2+的初始浓度,mg /L;C e 为吸附平衡时溶液中Cd 2+㊁Pb 2+㊁Cu 2+的浓度,mg /L;V 为溶液体积,L;m 为吸附剂质量,g;η为吸附剂的去除效率,%㊂Freundlich 和Langmuir 模型是描述吸附等温线行为最常用的模型㊂Langmuir 模型方程如式(3)所示,Freundlich 模型方程如式(4)所示㊂C e q e =1bq m +C e q m(3)ln q e =ln K F +ln C e n (4)式中:b 为Langmuir 模型常数,L /mg;q m 为最大吸附容量,mg /g;K F 为Freundlich 吸附系数;n 为Freundlich 吸附常数㊂吸附动力学可以为工艺设计提供必要的参数,有助于理解动态吸附平衡㊂拟一阶动力学模型方程如式(5)所示,拟二阶动力学模型如式(6)所示㊂ln(q e -q t )=ln q e -k 1t(5)t q t =1k 2q 2e +t q e (6)式中:q t 为t 时刻的吸附量,mg /g;t 为反应时间,min;k 1为拟一阶反应速率常数,min -1;k 2为拟二阶反应速率常数,min -1㊂1.5㊀表㊀征采用D8Advances 型X 射线衍射仪分析样品的物相组成以及结晶程度,测试条件:加速电压40kV,扫描范围2θ=5~80ʎ㊂采用MERLIN Compact 型扫描电子显微镜观察样品的形貌和分析样品的表面元素种类,测试条件:加速电压为0.2~30.0kV㊂采用NICOLET iS20型红外吸收光谱仪分析样品官能团,测试条件:㊀第1期谢修鑫等:EDTA-LDH/zeolite制备及其对重金属离子的吸附373扫描次数为64,分辨率为4.0,波长范围为400~4000cm-1,数据间隔为0.482cm-1㊂用ICAP-7600型电感耦合等离子体发射光谱仪测定吸附后溶液的残留重金属含量,测试条件:RF功率为1150W,辅助气流量为0.5L/min,雾化器流量为0.7L/min㊂2㊀结果与讨论2.1㊀XRD、FT-IR分析图1(a)为LDH㊁沸石㊁LDH/zeolite和EDTA-LDH/zeolite复合材料的XRD谱及与钙型斜发沸石㊁MgAl-CO2-3-LDH标准卡的对比,可以明显看出沸石原料为钙型斜发沸石,LDH的衍射峰与标准卡吻合,衍射峰尖锐说明样品结晶度较高㊂XRD谱中未检测到AlOOH㊁MgOOH等杂相,但有少量弱杂峰㊂与沸石的XRD 谱相比,LDH/zeolite和EDTA-LDH/zeolite的XRD谱在2θ=11.78ʎ㊁23.63ʎ㊁35.02ʎ㊁62.21ʎ和65.08ʎ处分别出现了新的衍射峰,与LDH的衍射峰位置相同,说明LDH㊁EDTA-LDH成功地生长在沸石上㊂图1(b)和图1(c)分别为LDH㊁沸石㊁LDH/zeolite和EDTA-LDH/zeolite复合材料的FT-IR谱和400~ 1500cm-1的局部FT-IR谱㊂可以看出,EDTA-LDH/zeolite的谱图上同时存在沸石和EDTA-LDH的特征振动峰,520cm-1属于沸石的Al O Si弯曲振动,1011cm-1属于沸石的Si O弯曲振动,3403cm-1处宽而强的吸收带归属于LDH层内羟基和水分子的拉伸振动,1568cm-1处的吸收带为C O的拉伸振动, 1359cm-1附近的强吸收带是LDH中CO2-3的C O拉伸振动,937cm-1处是Al OH键的振动,549~ 765cm-1附近的宽吸收带对应于Mg O键和Al O键的拉伸振动㊂EDTA-LDH/zeolite1359cm-1处的吸收峰基本消失,而1606和1413cm-1处出现COOH对称和不对称拉伸振动峰,说明EDTA进入LDH层间或吸附于LDH表面[24]㊂图1㊀LDH㊁沸石㊁LDH/zeolite和EDTA-LDH/zeolite的XRD谱㊁FT-IR谱(4000~400cm-1)和FT-IR放大谱(1500~400cm-1)Fig.1㊀XRD patterns,FT-IR spectra(4000~400cm-1)and FT-IR(1500~400cm-1)amplified spectra of LDH,zeolite,LDH/zeolite and EDTA-LDH/zeoliteLDH㊁沸石㊁LDH/zeolite和EDTA-LDH/zeolite的SEM照片如图2所示㊂从图2(a)可以看出LDH为几十到几百纳米的纳米片,形状不规则,松散堆叠在一起㊂图2(b)显示沸石呈不规则块状,表面有不规则的细小颗粒㊂从图2(c)可以看出,LDH/zeolite表面呈花状结构,LDH片垂直沸石表面生长,形成松散的花状团聚体㊂除花状结构外,可见六边形片状LDH晶体,大小为2~5μm,说明LDH结晶性较好㊂EDTA-LDH/ zeolite(图2(d))与LDH/zeolite相比,表面的花状结构消失,LDH片方向也由垂直沸石表面变为平行于沸石表面,这可能是由于焙烧过程中LDH的层状结构坍塌,还原过程中LDH的晶片方向发生改变㊂2.2㊀对单一金属离子的吸附2.2.1㊀pH值对吸附的影响LDH在溶液pH值低于4时会溶解,Cd2+在较高pH条件下会生成沉淀,因此确定试验pH值为4.0~ 6.5㊂图3为LDH和EDTA-LDH/zeolite复合材料分别对Cd2+㊁Pb2+㊁Cu2+的吸附图㊂可以看出,在单一重金374㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第43卷属离子体系中,LDH与EDTA-LDH/zeolite对Cd2+㊁Pb2+㊁Cu2+的吸附量均随着pH值的增加而增加㊂pH值较低时,LDH和EDTA-LDH/zeolite对重金属离子的吸附量较低,这是由于较强酸性条件下,溶液中存在大量H+,使LDH表面出现质子化反应,并产生强烈的静电斥力,使吸附量相对较低[25]㊂EDTA以H4Y的形态存在,对重金属离子的螯合作用较弱[26]㊂随着溶液pH值的增加,H+含量降低,由于强的表面配位㊁静电力作用和螯合作用,LDH和EDTA-LDH/zeolite的吸附量迅速上升,在pH=6.5时达到最大,此时LDH对Cd2+㊁Pb2+㊁Cu2+的吸附量分别为23.1㊁39.75和27.25mg/g,EDTA-LDH/zeolite对Cd2+㊁Pb2+㊁Cu2+的吸附量分别为33.68㊁35.51和34.13mg/g㊂EDTA-LDH/zeolite对三种重金属的吸附量接近,对Cd2+㊁Cu2+的吸附量高于LDH,这是因为EDTA-LDH/zeolite去除重金属的主要机制是LDH层间EDTA的螯合作用与沸石的离子交换作用,去除能力较强㊂LDH由于层间含有碳酸根,在表面容易诱导生成K sp极小的碱式碳酸铅(Pb3(CO3)2(OH)2)沉淀,因此LDH对Pb2+的吸附量高于不含碳酸根的EDTA-LDH/zeolite[27-28]㊂Pb3(CO3)2(OH)2的K sp较Cd2+㊁Cu2+的碳酸盐小,更容易形成沉淀,因此对Pb2+的吸附量高于Cd2+和Cu2+㊂图2㊀LDH㊁沸石㊁LDH/zeolite和EDTA-LDH/zeolite的SEM照片Fig.2㊀SEM images of LDH,zeolite,LDH/zeolite and EDTA-LDH/zeolite图3㊀不同pH值条件下LDH㊁EDTA-LDH/zeolite对Cd2+㊁Pb2+和Cu2+的吸附Fig.3㊀Adsorption of Cd2+,Pb2+and Cu2+by LDH and EDTA-LDH/zeolite at different pH conditions2.2.2㊀重金属离子初始浓度对吸附的影响改变Cd2+㊁Pb2+和Cu2+的初始浓度,待反应达到吸附平衡后测定Cd2+㊁Pb2+和Cu2+平衡浓度,分析平衡浓㊀第1期谢修鑫等:EDTA-LDH/zeolite制备及其对重金属离子的吸附375度与吸附量的关系,得到LDH和EDTA-LDH/zeolite对Cd2+㊁Pb2+和Cu2+的吸附等温线,如图4所示㊂随着Cd2+㊁Pb2+和Cu2+浓度增加,LDH对Cd2+㊁Pb2+和Cu2+的吸附量随之增加并趋于稳定㊂LDH在Cd2+㊁Pb2+和Cu2+的平衡浓度为890.00㊁179.47和812.1mg/L时达到吸附饱和,最大吸附量分别为44.00㊁87.63和75.87mg/g; EDTA-LDH/zeolite在Cd2+㊁Pb2+㊁Cu2+平衡浓度为838.93㊁754.13和732.27mg/L时达到吸附饱和,最大吸附量分别为65.33㊁98.35和108.51mg/g㊂EDTA-LDH/zeolite对Cd2+㊁Pb2+㊁Cu2+的最大吸附量均高于LDH㊂图4㊀LDH和EDTA-LDH/zeolite对Cd2+㊁Pb2+和Cu2+的吸附等温线Fig.4㊀Adsorption isotherms of LDH,EDTA-LDH/zeolite for Cd2+,Pb2+and Cu2+LDH和EDTA-LDH/zeolite吸附Cd2+㊁Pb2+和Cu2+的Langmuir拟合结果见图5㊂图5㊀LDH和EDTA-LDH/zeolite吸附Cd2+㊁Pb2+和Cu2+的Langmuir拟合结果Fig.5㊀Langmuir fitting results of LDH and EDTA-LDH/zeolite for Cd2+,Pb2+and Cu2+LDH㊁EDTA-LDH/zeolite吸附Cd2+㊁Pb2+和Cu2+的Langmuir和Freundlich等温模型拟合参数见表1㊂由表1可知,LDH㊁EDTA-LDH/zeolite吸附Cd2+㊁Pb2+和Cu2+的Langmuir模型拟合相关系数R2高于Freundlich 模型,说明三种重金属在LDH和EDTA-LDH/zeolite上的吸附均主要为单层吸附㊂Langmuir模型拟合的LDH和EDTA-LDH/zeolite对三种重金属的最大理论吸附量与试验结果相近㊂2.2.3㊀接触时间对吸附的影响在Cd2+㊁Pb2+和Cu2+的浓度为100mg/L,吸附剂用量为0.05g,溶液pH=6.5的条件下,研究接触时间对LDH和EDTA-LDH/zeolite吸附重金属的影响,结果如图6所示㊂由图可知,LDH和EDTA-LDH/zeolite对Cd2+㊁Pb2+和Cu2+的吸附,前期较为迅速,随着时间的延长,吸附量缓慢增加,直至吸附达到平衡㊂LDH对Cd2+㊁Pb2+和Cu2+的吸附速率为Pb2+>Cu2+>Cd2+,分别在12㊁24㊁48h达到吸附平衡,此时吸附量分别为15.78㊁39.96和19.49mg/g;EDTA-LDH/zeolite对Cd2+㊁Pb2+和Cu2+的吸附平衡时间相同,均为12h,吸附量分别为36.23㊁38.36和37.67mg/g㊂LDH对Cd2+的吸附平衡时间较长,反应速率较低,这可能是由于LDH去除Cd2+的机理主要是类质同象替代,需要较长时间达到反应平衡[29];LDH对Pb2+的吸附速376㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第43卷率最大,这是因为Pb 2+在溶液中快速扩散,与吸附剂外表面接触并被吸附,同时与层间CO 2-3作用,在LDH 表面㊁层间形成诱导沉淀[30]㊂表1㊀LDH ㊁EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+和Cu 2+的Langmuir 和Freundlich 等温模型拟合参数Table 1㊀Fitting parameters of Langmuir and Freundlich isothermal models for LDH ,EDTA-LDH /zeoliteadsorption of Cd 2+,Pb 2+and Cu 2+Material Pollutant Langmuir isotherm Freundlich isotherm q m /(mg㊃g -1)b R 2n K F /(mg㊃g -1)R 2LDHCd 2+45.070.00510.9774 2.3552 2.40030.9561Pb 2+87.710.07880.99998.160045.2450.5986Cu 2+78.10 1.09840.9933 2.4697 5.73390.9022EDTA-LDH /zeolite Cd 2+65.620.00840.9929 2.9248 6.33820.9809Pb 2+100.630.00860.9975 2.2472 5.04920.9512Cu 2+109.160.00500.9962 2.1782 5.33720.9522图6㊀LDH 和EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+和Cu 2+的吸附动力学曲线Fig.6㊀Adsorption kinetic curves of LDH and EDTA-LDH /zeolite for Cd 2+,Pb 2+and Cu 2+㊀㊀LDH 和EDTA-LDH /zeolite 对Cd 2+(a)㊁Pb 2+(b)和Cu 2+(c)的拟二阶动力学拟合结果见图7㊂图7㊀LDH 和EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+和Cu 2+的动力学拟合结果Fig.7㊀Kinetic fitting results of LDH and EDTA-LDH /zeolite adsorption of Cd 2+,Pb 2+and Cu 2+为了研究Cd 2+㊁Pb 2+和Cu 2+在LDH 和EDTA-LDH /zeolite 上的吸附动力学,选择拟一阶和拟二阶动力学模型拟合试验结果,拟合相关参数见表2㊂由表可知,拟二阶动力学模型的拟合程度优于拟一阶动力学,线性相关系数R 2更高,理论吸附量接近试验数据,说明LDH 和EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+和Cu 2+的吸附过程主要受化学吸附的影响㊂对比发现,EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+和Cu 2+的K 2值均大于LDH,说明EDTA-LDH /zeolite 的反应速率更高,反应平衡时的吸附量也更大,可能是因为EDTA-LDH /zeolite第1期谢修鑫等:EDTA-LDH /zeolite 制备及其对重金属离子的吸附377㊀中的EDTA 的螯合作用和沸石的离子交换作用提高了对重金属的吸附能力㊂表2㊀LDH ㊁EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+和Cu 2+的拟一阶和拟二阶动力学模型参数Table 2㊀Fitting parameters of pseudo-first and pseudo-second order kinetic models for LDH ,EDTA-LDH /zeoliteadsorption of Cd 2+,Pb 2+and Cu 2+Material Pollutant Pseudo-first order model Pseudo-second order model k 1/min -1q e (cal)/(mg㊃g -1)R 2k 2/min -1q e (cal)/(mg㊃g -1)R 2LDHCd 2+0.048816.320.93900.001717.130.9712Pb 2+0.166939.850.95970.020339.880.9985Cu 2+0.096820.490.96280.076520.350.9993EDTA-LDH /zeolite Cd2+0.169836.140.94830.092236.22 1.0000Pb 2+0.110138.390.91130.062738.280.9998Cu 2+0.108937.710.83350.085037.63 1.0000当EDTA-LDH /zeolite 投加量为0.05g㊁重金属离子浓度为1500mg /L㊁pH 值为6.5㊁吸附时间为24h时,EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+㊁Cu 2+的最大吸附量分别为65.33㊁98.35和108.51mg /g㊂2.3㊀对混合金属离子的吸附2.3.1㊀pH 值对吸附的影响图8是不同pH 条件下LDH 和EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+㊁Cu 2+混合液中各金属离子的吸附量㊂LDH 和EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+㊁Cu 2+的吸附量均随着pH 升高而增加㊂在pH =4.0~6.5时,LDH 对Cu 2+的吸附量与去除率始终高于Cd 2+㊂在pH =4.0~4.5时,LDH 对Pb 2+的吸附量与去除率为三者中最低㊂在pH =5.0~6.5时,Pb 2+的吸附量与去除率迅速上升,并高于Cd 2+和Cu 2+㊂在pH =6.5时,LDH 对Cd 2+㊁Pb 2+㊁Cu 2+的吸附量分别为21.09㊁38.52㊁23.41mg /g㊂这是由于在较高pH 下溶液中OH -的含量高,Pb 3(CO 3)2(OH)2的溶度积(K sp )较小,Pb 2+更易与LDH 层间CO 2-3反应,形成沉淀㊂对于同价金属阳离子,离子半径越小,表面电荷密度越大,水合能力越强,因此LDH 对Cd 2+㊁Pb 2+㊁Cu 2+的选择性吸附顺序为Cu 2+>Cd 2+>Pb 2+㊂由图8(b)可知,对在pH =4.0~6.0时,EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+㊁Cu 2+的吸附量随pH 增大急剧增加,在pH >6时吸附趋于平衡,此时溶液中90%以上的Pb 2+㊁Cu 2+被去除,80%以上的Cd 2+被去除㊂在pH =6时,EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+㊁Cu 2+的吸附量分别为33.27㊁37.23和38.53mg /g㊂EDTA-LDH /zeolite 对Cd 2+㊁Cu 2+的吸附量始终高于LDH,而对Pb 2+的吸附量仅在pH =4.0~5.5时大于LDH㊂图8㊀不同pH 值条件下Cd 2+㊁Pb 2+和Cu 2+在LDH 和EDTA-LDH /zeolite 上的吸附Fig.8㊀Adsorption of Cd 2+,Pb 2+and Cu 2+on LDH and EDTA-LDH /zeolite under different pH conditions 2.3.2㊀金属离子初始浓度对吸附的影响不同初始浓度条件下,LDH 和EDTA-LDH /zeolite 对Cd 2+㊁Pb 2+㊁Cu 2+的吸附曲线如图9所示㊂随着金属离子初始浓度的增加,吸附在LDH 和EDTA-LDH /zeolite 上的Cd 2+㊁Pb 2+㊁Cu 2+均显著增加㊂由图9(a)可见,在平衡浓度为0~350mg /L 时,Pb 2+㊁Cu 2+的吸附量迅速增加㊂当溶液中Cu 2+的平衡浓度为261.8mg /L 时,LDH 对Cu 2+的吸附量达到55.30mg /g;当Pb 2+的平衡浓度为255mg /L 时,LDH 对378㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第43卷Pb2+的吸附量达到57.99mg/g;LDH对Cd2+的吸附量增长比较缓慢,当溶液中Cd2+的平衡浓度为255mg/L 时,LDH对Cd2+的吸附量仅为26.40mg/g㊂这可能是LDH对重金属的吸附机理不同,对Pb2+㊁Cu2+的作用机理可能主要是诱导沉淀,而Cd2+的去除主要通过类质同象替代[28,30]㊂LDH对Cd2+㊁Pb2+㊁Cu2+的最大吸附容量分别为40.05㊁61.79和64.16mg/g㊂与单一金属离子体系相比,混合金属离子体系中LDH对Cd2+㊁Pb2+㊁Cu2+的最大吸附量均有所降低㊂混合金属离子体系对Cd2+与Cu2+的吸附影响不大,而Pb2+的吸附受到较大影响,LDH对Pb2+㊁Cu2+的主要吸附机理为沉淀作用,表明Pb2+和Cu2+在吸附位点上存在竞争吸附, Cu2+形成的沉淀物比Pb2+更稳定,因此可以占据更多的点位,吸附量影响相对较小㊂由图9(b)可知,当溶液中重金属离子平衡浓度低于216mg/L时,EDTA-LDH/zeolite对Cd2+㊁Pb2+㊁Cu2+的吸附量随重金属离子浓度增加而迅速提高,当重金属离子平衡浓度在216~790mg/L时,吸附量增长相对缓慢,Cd2+㊁Pb2+㊁Cu2+分别在平衡浓度为865.47㊁787.73和768.27mg/L时达到吸附平衡,此时的最大吸附量分别为55.52㊁84.80和93.12mg/g㊂与单一离子体系相比,EDTA-LDH/zeolite对混合溶液中重金属离子的最大吸附量均有所降低㊂与LDH相比,EDTA-LDH/zeolite对重金属离子的吸附能力明显更强㊂在所有平衡浓度下,EDTA-LDH/zeolite对三种重金属的吸附量大小为Cu2+>Pb2+>Cd2+,这是由于EDTA-LDH/ zeolite主要通过螯合作用吸附重金属,而Cu-EDTA的稳定常数最大,因此优先吸附Cu2+㊂图9㊀Cd2+㊁Pb2+㊁Cu2+在LDH和EDTA-LDH/zeolite上的吸附曲线Fig.9㊀Adsorption curves of Cd2+,Pb2+,Cu2+on LDH and EDTA-LDH/zeolite2.3.3㊀接触时间对吸附的影响图10为反应时间对LDH和EDTA-LDH/zeolite吸附混合溶液中Cd2+㊁Pb2+㊁Cu2+的影响㊂从图10(a)中可以看出,在反应前期(0~2h),LDH对Cd2+㊁Pb2+㊁Cu2+的吸附量随接触时间延长而快速增加,在2h处的吸附量分别为12.13㊁38.21㊁16.29mg/g㊂当接触时间为2~24h时,吸附量与去除率增加逐渐放缓,在24h 处达到吸附平衡㊂LDH吸附Cd2+㊁Pb2+㊁Cu2+的速率为Cu2+>Pb2+>Cd2+,这可能是由于吸附剂吸附位点充足,Cu2+在LDH表面产生络合沉淀,Pb2+与层间碳酸根生成稳定的碱式碳酸铅,而Cd2+主要通过类质同象替代被吸附㊂达到反应平衡时,LDH对Cd2+㊁Pb2+㊁Cu2+的吸附量分别为12.66㊁31.09和21.41mg/g, LDH对三种重金属离子的吸附量顺序为Pb2+>Cu2+>Cd2+㊂由图10(b)可见,前1h,EDTA-LDH/zeolite对Cd2+㊁Pb2+㊁Cu2+的吸附迅速增加,1h的Cd2+㊁Pb2+㊁Cu2+吸附量分别为28.57㊁27.99和29.43mg/g㊂随后EDTA-LDH/zeolite对Cd2+㊁Pb2+㊁Cu2+的吸附量小幅度增加直至达到吸附平衡,平衡时间均为24h㊂此时EDTA-LDH对Cd2+㊁Pb2+㊁Cu2+的吸附量分别为38.17㊁38.82㊁38.1mg/g㊂与LDH及EDTA-LDH相比,EDTA-LDH/zeolite吸附重金属离子的速度与去除率稍低于EDTA-LDH(重金属离子浓度100mg/L),但均远超LDH㊂2.4㊀机理讨论前人研究认为尽管LDH结构层带正电,但依然可以吸附水溶液中的金属阳离子,主要原因可能是局部的高pH值使LDH微溶,释放的碳酸根离子作用于金属阳离子,从而在LDH表面发生诱导沉淀;正电荷结构层吸引氢氧根离子,LDH晶体在水溶液中诱导金属氢氧化物形成[28]㊂同时,附着在表面和边缘的电荷补偿第1期谢修鑫等:EDTA-LDH /zeolite 制备及其对重金属离子的吸附379㊀碳酸根离子也能与金属阳离子接触形成不溶性金属碳酸盐㊂因此,金属阳离子与LDH 的反应可能包括金属氢氧化物沉淀㊁金属阳离子在LDH 表面羟基上的吸附㊁通过阴离子交换或结构分解形成金属碳酸盐沉淀㊂图10㊀Cd 2+㊁Pb 2+㊁Cu 2+在LDH 和EDTA-LDH /zeolite 上的吸附动力学曲线Fig.10㊀Adsorption kinetic curves of Cd 2+,Pb 2+and Cu 2+on LDH and EDTA-LDH /zeolite LDH 对重金属离子的吸附量均随着pH 增加而增加,可能是因为在较高的pH 值下,LDH 表面发生脱质子化,与重金属离子的静电斥力减小,LDH 表面羟基对带正电荷的金属阳离子的吸附增强㊂图11为LDH 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的FT-IR 谱㊂对比图1(b)和图11中LDH 吸附前后的FT-IR 变化可以发现3403㊁1359cm -1处的振动带向低波数移动,说明LDH 表面的羟基与重金属离子发生化学结合形成内球配合物㊂同时一些脱质子羟基(Sur-O-)可通过静电吸引与金属阳离子形成外球配合物㊂M 2+在LDH 上的复合吸附可用式(7)㊁(8)描述[31]㊂Sur-OH +M 2+ңSur-O-M 2+(7)Sur-O -+M 2+ңSur-O M 2+(8)LDH 可以通过形成表面沉淀去除溶液中的Cd 2+㊁Pb 2+和Cu 2+㊂溶液中的Pb 2+首先与表面OH -和CO 2-3发生反应,并破坏部分层结构㊂由于Pb(OH)2(K sp =2.8ˑ10-16)的稳定性相对于PbCO 3(K sp =1.5ˑ10-13)更高,可能主要形成Pb(OH)2㊂Cu(OH)2(K sp =1.6ˑ10-19)的稳定性比CuCO 3(K sp =2.5ˑ10-10)高得多,因此更可能生成Cu(OH)2㊂同样,因为K sp (Cd(OH)2)=3.2ˑ10-14<K sp (CdCO 3)=1ˑ10-12,因此更容易生成Cd(OH)2㊂图12为LDH 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的XRD 谱㊂图12表明LDH 吸附Cd 2+㊁Pb 2+均形成碳酸根沉淀,这可能是因为空气中CO 2溶入水使溶液中碳酸根浓度增加并与Cd 2+㊁Pb 2+反应生成PbCO 3㊁Pb 3(CO 3)2(OH)2和CdCO 3㊂对于Cu 2+,因为Cu(OH)2的K sp 非常小(1.6ˑ10-19),因此先形成明显的Cu(OH)2,后形成Cu 3(OH)2(CO 3)沉淀㊂由图12可见,吸附Cd 2+㊁Pb 2+㊁Cu 2+后的LDH 出现明显的重金属沉淀物相,这表明沉淀作用对LDH 吸附重金属离子起主导作用㊂图11㊀LDH 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的FT-IR 谱Fig.11㊀FT-IR spectra of LDH after adsorption of Cd 2+,Pb 2+and Cu 2+图12㊀LDH 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的XRD 谱Fig.12㊀XRD patterns of LDH after adsorption of Cd 2+,Pb 2+and Cu 2+380㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第43卷前人认为一些阳离子可通过类质同象替代Mg 2+或Al 3+而被去除,但图12未能证实形成了CdAl-LDH㊁CuAl-LDH㊁PbAl-LDH,因此该机理需要进一步研究㊂图13为EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的FT-IR 谱㊂对比图1(b)与图13发现,EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+㊁Cu 2+后FT-IR 谱中1606cm -1处COOH 的振动带向低波数偏移,表明EDTA 参与了对重金属的吸附过程㊂图14为EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的XRD 谱㊂由图14可见,EDTA-LDH /zeolite 通过沉淀作用吸附重金属离子㊂与LDH 相比,EDTA-LDH 去除Cd 2+㊁Pb 2+㊁Cu 2+的能力明显提高(EDTA-LDH 对Cd 2+㊁Pb 2+㊁Cu 2+的最大吸附量分别为106.53㊁110.25和125.48mg /g [32])㊂通过LDH 层间EDTA 的螯合作用,金属离子与EDTA 离子之间形成金属配合物,这些金属配合物被固定在EDTA-LDH 的层间㊂EDTA 分子的四个羧基和两个胺基上的氧有孤对电子,这些孤对电子可以填充在金属离子的空轨道上形成络合物㊂因此,EDTA 具有较强的螯合能力,这也是EDTA 基吸附剂去除重金属离子的主要机理[33]㊂EDTA-LDH /沸石去除Cd 2+㊁Pb 2+㊁Cu 2+的能力较EDTA-LDH 进一步提高,原因可能包括:1)沸石基体使EDTA-LDH 充分分散,暴露出更多吸附位点;2)EDTA-LDH 与沸石间具有协同作用㊂EDTA-LDH 与沸石间存在协同作用是因为EDTA-LDH /沸石对Cd 2+㊁Pb 2+㊁Cu 2+的吸附量明显高于等量EDTA-LDH 和等量沸石对相应重金属离子的吸附量之和(当pH =6时,沸石对Pb 2+㊁Cu 2+的吸附量分别为10.01㊁3.53mg /g [34])㊂EDTA-LDH 与沸石协同作用的方式复杂,比如,LDH 是一种氢氧化物,沸石是一种硅酸盐矿物,二者均具有一定的碱性,EDTA-LDH /沸石进入溶液时,可导致局部pH 值增加,释放的OH -与溶液中的重金属离子结合,形成沉淀析出㊂EDTA-LDH 与沸石间的协同作用方式有待深入研究㊂图13㊀EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的FT-IR 谱Fig.13㊀FT-IR spectra of EDTA-LDH /zeolite after adsorption of Cd 2+,Pb 2+and Cu 2+图14㊀EDTA-LDH /zeolite 吸附Cd 2+㊁Pb 2+㊁Cu 2+后的XRD 谱Fig.14㊀XRD patterns of EDTA-LDH /zeolite after adsorption of Cd 2+,Pb 2+and Cu 2+3㊀结㊀论1)EDTA-LDH /zeolite 对单一溶液中Cd 2+㊁Pb 2+㊁Cu 2+的吸附能力均随pH 值的增大而增大,吸附量在pH =6.5时达到最大,分别为65.33㊁98.35和108.51mg /g㊂EDTA-LDH /zeolite 对几种重金属离子的吸附速率相同,在12h 达到吸附平衡㊂EDTA-LDH /zeolite 对三种重金属离子的去除符合Langmuir 等温吸附模型与拟二阶动力学模型㊂2)EDTA-LDH /zeolite 对混合溶液中Cd 2+㊁Pb 2+㊁Cu 2+的吸附量较单一离子溶液略低,三种金属离子之间存在竞争吸附,EDTA-LDH /zeolite 对三种重金属离子的选择性顺序为Cu 2+>Pb 2+>Cd 2+㊂3)EDTA-LDH /zeolite 对三种重金属离子的去除存在多种机制,主要包括表面络合㊁沉淀反应㊁螯合反应和离子交换㊂。

基于锥形异质芯结构的高灵敏度SPR折射率传感器4、武汉理工大学；5、武汉烽理光电技术有限公司摘要：本文提出一种基于锥形异质芯结构的高灵敏度光纤表面等离子体共振(Surface plasmon resonance, SPR)折射率传感器。

实验结果表明，折射率灵敏度在1.33 ~ 1.43范围内呈非线性递增，待测溶液折射率越接近光纤折射率，增长速率越快。

当折射率为1.43时灵敏度最大可达8135.5 nm/RIU。

平均灵敏度为3762.3 nm/RIU，是传统异质芯结构的1.25倍。

关键词：折射率传感器，SPR，锥形异质芯结构1.引言由于光纤表面等离子体共振(Surface plasmon resonance, SPR)传感器对折射率变化的高灵敏度[1-4]，在生化传感、食品安全、环境监测等领域发挥着至关重要的作用[5]。

不仅如此，光纤以其体积小、抗电磁干扰、灵敏度高等优势可在众多领域发挥重要作用[6]。

目前以光纤纤芯为基底的光纤SPR传感器类型有端面研磨角度[7]、侧面抛磨型[8,9]。

通常这样的加工方法耗时长，实验操作难度大，使光纤机械强度降低、重复性差等问题。

以光纤包层为基底的光纤SPR 传感器需要将光纤纤芯中的传输光泄露耦合至光纤包层中，以使倏逝场与金属薄膜接触才能发生SPR效应，其研究结果相对较少，目前的方法有拉锥结构 [10, 11]、异质芯结构 [12-14]，U型结构 [15]，这些方法都能有效的激发高阶包层模。

为进一步提高灵敏度，本文设计了一种基于锥形异质芯结构的高灵敏度SPR 折射率传感器，用于折射率测量。

SPR传感器由锥形单模光纤(Tapered single-mode fiber, TSMF)和两端熔接的多模光纤(Multi-mode fiber, MMF)组成。

本文从实验上证明了该传感器的性能与传统异质结构SPR传感器相比具有更高的灵敏度。

该折射率传感器具有生物检测和离子检测的潜力。