Activated carbon adsorption of heavy metal chelates from single and multicomponent systems

Abstract

Depart men t of C h em i cal Eng i neer i ng , U n iversi ty of Kentucky , Lexi ng ton, Kent u c ky 40506-0046 An extensive experimental investigation was conducted with activated carbon to establish the adsorption (equilibrium and kinetics) behavior of several metals from single and two metals systems in the presence of complexing agents. Triethylenetetramine (TRZEN) and EDTA were used as complexing agents. The extent of adsorption was found to be a function of metal and ligand types, ligand to metal ratio, p H , and metal chelate species distribution. Selective separation of valuable metals can also be achieved by the addition of complexing ligands to a mixture of strongly complexable metal (such as Cd2+ and Ni2+) and weakly complexable metal (such as Ba2+ and Ca2+).

Removal of nickel from aqueous solution by the bacterium Bacillus thuringiensis

“…The biosorption experiments were carried out using the batch equilibrium technique at different pH (4)(5)(6)(7)(8) values and temperatures (25,35, 45 • C). Equilibrium biosorption was determined by using 1 g l −1 of the dried and ground bacterium suspension sample to which different initial metal concentrations was added.…”

“…While the nickel(II) ion concentration in plating rinse can approach 2-900 mg −1 , wastewater from paint and ink formulation, porcelain enameling, copper sulphate manufacture industries record effluent nickel(II) ion concentrations that varies from 0 to 40, 0.25 to 67 and around 22 mg l −1 [3]. A number of conventional methods have been used to remove nickel(II) ion from wastewater streams, such as adsorption on activated carbon [4]; chemical precipitation [5]; crystallization in the form of nickel carbonate [6]. However, these methods are ineffective or expensive when initial metal concentrations in wastewaters are low, or when very * Fax: +90 388 2250114.…”

Development and evaluation of Mn oxide-coated composite adsorbent for the removal and recovery of heavy metals from coal processing wastewater. Final report, December 1995

“…This technique has several potential disadvantages. For example, complexing agents may need to be removed before a precipitation step because these agents may inhibit precipitation (Bhattacharyya and Cheng, 1987). The minimum solubility of different metals in a wastewater generally occurs at different pHvalues.…”

“…Most applications and research on activated carbon emphasize organics removal. However, a number of investigators have suggested using activated carbon to remove heavy metals form aqueous solutions ( Sigworth and Smith, 1972;Huang and Wu, 1977;Huang and Bowers, 1979;Bowers and Huang, 1980;Hayes and Leckie, 1982;Netzer and Hughes, 1984;Bhattacharyya and Cheng, 1987;Corapcioglu and Huang, 1987;Ku and Peters, 1987;Gajghate et. al., 1992;Kuennen et al 1992;Reed and Matsumoto, 1992;Reed and Arunachalam, 1994).…”

“…They tested 14 different activated carbons for Cu(Q, Pb(E), Ni(II), and Zn(Q removal fiom aqueous solutions. They concluded that carbon type7 pH, and Surface loading were the most important factors affecting the amount of metal removal, and the adsorption reaction could be described with a Surface complex formation modeL Bhattacharyya and Cheng (1987) also reported that in the presence of complexing agents the amount of metal adsorption onto activated carbon was based on metal and ligand types, ligand-to-metal ratio, pH, and metal chelate species distriiution.…”