QEE000259
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4Dépt. de Génie Géologique, Laboratoire Eau Energie et Environnement, Ecole Nationale d’Ingénieurs de Sfax, B.P. W. 3038 Sfax, Tunisia. E-mail: nesrine.boujelben@tunet.tn
Nickel is a relatively rare element found in the earth’s crust with a concentration of approximately 20 g / g ͑Alcock 1987͒. Although it occurs naturally in the environment, due to anthropogenic activity excessive amounts of nickel are released from mineral processing, paint formulation, electroplating, porcelain enameling, copper sulphate manufacture, and steam-electric power plants ͑Patterson 1985; Sittings 1976͒. Nickel is one of the toxic heavy metals which are common pollutants of the environment. In humans, nickel can cause serious problems, such as dermatitis, allergic sensitization, and lung and nervous system damage. It is also a known carcinogen ͑Axtell et al. 2003͒. The sorption studies of Ni2+ are essential for nuclear and hazardous waste management. Different sorbents have been considered for Ni2+ immobilization: vermiculite ͑Malandrino et al. 2006͒, zeolite ͑Shanableh and Kharabsheh 1996͒, kaolinite ͑Yavuz et al. 2003͒, hydrous manganese oxide ͑Boonfueng et al. 2006͒, activated carbon ͑Kadirvelu et al. 2001͒, marine green algae ͑Vijayaraghavan et al. 2005͒, etc.
Phosphate minerals have been shown to possess the potential to adsorb heavy metal ions from aqueous solutions ͑MonteilRivera and Fedoroff 2002͒. Of all the inorganic phosphate sources apatites are most readily available. Apatites are often identified by the general formula M10͑XO4͒6Y2, where Me2+ = divalent cation; ͑XO4͒3− = trivalent anion; and Y− = monovalent anion. Apatites of different origin ͑mineral, synthetic, and derived from animal and fish bones͒ have been studied as sorbents of heavy metals ͑Deydier et al. 2003; Keith and McKay 2005; Chen et al. 1997; Saxena and D’Souza 2006; Sheha 2007; Chaturvedi et al. 2006͒. The mechanisms of the metal cations retention are different and include: ion exchange processes ͑Gomez del Rio et al. 2004; Xu et al. 1994͒, adsorption ͑Xu et al. 1994; Vega et al. 2003͒, dissolution/precipitation ͑Xu et al. 1994; Ma et al. 1994͒, and substitution of Ca in HA by other metals during recrystallization ͑coprecipitation͒ ͑Xu et al. 1994; Jeanjean et al. 1994͒. However, because of the limited knowledge on the relative contribution of
Abstract: A study was carried out in batch conditions to examine the removal of nickel ions from an aqueous solution by phosphate rock. The effect of different sorption parameters, such as initial metal concentration, equilibration time, solution pH, and temperature on the amount of Ni2+ sorbed was studied and discussed. The sorption process followed pseudo-second-order kinetics with necessary time of 2 h to reach equilibrium. The maximum removal obtained is at initial pH around 8. Nickel uptake was quantitatively evaluated using the Langmuir and Dubinin–Kaganer–Radushkevich model. The Langmuir adsorption isotherm constant corresponding to adsorption capacity, Q0, was found to be 7.63 mg/ g. The possibility of metal recovery was investigated using several eluting agents. The desorbed amount of nickel decreased continuously with increasing pH, and increased with increasing Ca2+ concentration in leaching solution.
Use of Phosphate Rock for the Removal of Ni2+ from Aqueous Solutions: Kinetic and Thermodynamics Studies
Z. Elouear, Ph.D.1; R. Ben Amor, Ph.D.2; J. Bouzid3; and N. Boujelben, Ph.D.4
DOI: 10.10659͒
CE Database subject headings: Heavy metals; Abatement and removal; Kinetics; Thermodynamics; Desorption.
Introduction
each process in removing metals, it seems that the abovementioned four mechanisms could all be involved ͑Chaturvedi et al. 2006͒. Compared to other heavy metals, little attention has been paid on Ni2+ removal by apatites. Perrone et al. ͑2001͒ have investigated the nickel sorption on synthetic carbonate fluoroapa-
basic media. Recently, a comparative study of the retention of Cd, Cr, Cu, Ni, and Zn by four sorbent materials ͑hydroxy-apatite, clinoptilolite, an organoclay, and an organoclay/anthracite blend͒ was conducted by batch and column experiments ͑Tillman et al. 2005͒. All materials tested were found to be useful for heavy metal retention, but hydroxyapatite ͑HAP͒ had better performance for water treatment due to its greater efficiency for the retention
Nickel is a relatively rare element found in the earth’s crust with a concentration of approximately 20 g / g ͑Alcock 1987͒. Although it occurs naturally in the environment, due to anthropogenic activity excessive amounts of nickel are released from mineral processing, paint formulation, electroplating, porcelain enameling, copper sulphate manufacture, and steam-electric power plants ͑Patterson 1985; Sittings 1976͒. Nickel is one of the toxic heavy metals which are common pollutants of the environment. In humans, nickel can cause serious problems, such as dermatitis, allergic sensitization, and lung and nervous system damage. It is also a known carcinogen ͑Axtell et al. 2003͒. The sorption studies of Ni2+ are essential for nuclear and hazardous waste management. Different sorbents have been considered for Ni2+ immobilization: vermiculite ͑Malandrino et al. 2006͒, zeolite ͑Shanableh and Kharabsheh 1996͒, kaolinite ͑Yavuz et al. 2003͒, hydrous manganese oxide ͑Boonfueng et al. 2006͒, activated carbon ͑Kadirvelu et al. 2001͒, marine green algae ͑Vijayaraghavan et al. 2005͒, etc.
Phosphate minerals have been shown to possess the potential to adsorb heavy metal ions from aqueous solutions ͑MonteilRivera and Fedoroff 2002͒. Of all the inorganic phosphate sources apatites are most readily available. Apatites are often identified by the general formula M10͑XO4͒6Y2, where Me2+ = divalent cation; ͑XO4͒3− = trivalent anion; and Y− = monovalent anion. Apatites of different origin ͑mineral, synthetic, and derived from animal and fish bones͒ have been studied as sorbents of heavy metals ͑Deydier et al. 2003; Keith and McKay 2005; Chen et al. 1997; Saxena and D’Souza 2006; Sheha 2007; Chaturvedi et al. 2006͒. The mechanisms of the metal cations retention are different and include: ion exchange processes ͑Gomez del Rio et al. 2004; Xu et al. 1994͒, adsorption ͑Xu et al. 1994; Vega et al. 2003͒, dissolution/precipitation ͑Xu et al. 1994; Ma et al. 1994͒, and substitution of Ca in HA by other metals during recrystallization ͑coprecipitation͒ ͑Xu et al. 1994; Jeanjean et al. 1994͒. However, because of the limited knowledge on the relative contribution of
Abstract: A study was carried out in batch conditions to examine the removal of nickel ions from an aqueous solution by phosphate rock. The effect of different sorption parameters, such as initial metal concentration, equilibration time, solution pH, and temperature on the amount of Ni2+ sorbed was studied and discussed. The sorption process followed pseudo-second-order kinetics with necessary time of 2 h to reach equilibrium. The maximum removal obtained is at initial pH around 8. Nickel uptake was quantitatively evaluated using the Langmuir and Dubinin–Kaganer–Radushkevich model. The Langmuir adsorption isotherm constant corresponding to adsorption capacity, Q0, was found to be 7.63 mg/ g. The possibility of metal recovery was investigated using several eluting agents. The desorbed amount of nickel decreased continuously with increasing pH, and increased with increasing Ca2+ concentration in leaching solution.
Use of Phosphate Rock for the Removal of Ni2+ from Aqueous Solutions: Kinetic and Thermodynamics Studies
Z. Elouear, Ph.D.1; R. Ben Amor, Ph.D.2; J. Bouzid3; and N. Boujelben, Ph.D.4
DOI: 10.10659͒
CE Database subject headings: Heavy metals; Abatement and removal; Kinetics; Thermodynamics; Desorption.
Introduction
each process in removing metals, it seems that the abovementioned four mechanisms could all be involved ͑Chaturvedi et al. 2006͒. Compared to other heavy metals, little attention has been paid on Ni2+ removal by apatites. Perrone et al. ͑2001͒ have investigated the nickel sorption on synthetic carbonate fluoroapa-
basic media. Recently, a comparative study of the retention of Cd, Cr, Cu, Ni, and Zn by four sorbent materials ͑hydroxy-apatite, clinoptilolite, an organoclay, and an organoclay/anthracite blend͒ was conducted by batch and column experiments ͑Tillman et al. 2005͒. All materials tested were found to be useful for heavy metal retention, but hydroxyapatite ͑HAP͒ had better performance for water treatment due to its greater efficiency for the retention
