title: Recovery of nickel from aqueous solutions by complexation-ultrafiltration process with sodium polyacrylate and polyethylenimine.
abstract: The recovery of nickel from aqueous dilute solutions by complexation-ultrafiltration process with sodium polyacrylate (PAAS) and polyethylenimine (PEI) was studied. Experiments were performed as a function of aqueous pH, polymer/Ni(2+) ratio and background electrolyte concentration. At optimum experimental conditions, the nickel removal rate reaches 99.5% using PAAS and 93.0% using PEI as the complexation agent. The nickel removal rate was found to decrease as the adding salt NaCl concentration increases for both complexation agents. A series of experiments implied that the mechanism could be the compressing electric double layer other than the competitive complexation. Diafiltration technique was further performed to regenerate complexation agents and recover nickel. The nickel removal rates were found to be close to those obtained with the original PEI and PAAS. Finally, Langmuir-type binding isotherm equation was employed to evaluate the extent of nickel bound to PAAS and PEI. The overall results from the two-step process of complexation-UF and decomplexation-UF separation showed that it could be a promising method for nickel removal and recovery from aqueous solutions.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. jhshao@sjtu.edu.cn
authors.forename: Jiahui
authors.initials: J
authors.lastname: Shao
authors.forename: Shu
authors.initials: S
authors.lastname: Qin
authors.forename: Joshua
authors.initials: J
authors.lastname: Davidson
authors.forename: Wenxi
authors.initials: W
authors.lastname: Li
authors.forename: Yiliang
authors.initials: Y
authors.lastname: He
authors.forename: H Susan
authors.initials: HS
authors.lastname: Zhou
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009532:Nickel / Q000737:chemistry*; D009994:Osmolar Concentration; D011094:Polyethyleneimine / Q000737:chemistry; D059027:Recycling / Q000379:methods; D012996:Solutions; D014462:Ultrafiltration; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D012996:Solutions; D014874:Water Pollutants, Chemical; C006903:carbopol 940; D009532:Nickel; D011094:Polyethyleneimine