title: Comparison of biosorbents with inorganic sorbents for removing copper(II) from aqueous solutions.
abstract: In comparison with several other reported inorganic sorbents, Camellia tree leaf and primary sludge obtained from a settling tank as a pretreatment to the activated sludge system in a Hong Kong sewage treatment plant were evaluated for removing Cu(II) from aqueous solutions. Experimental data were modeled by the Langmuir isotherm equation to estimate the maximum sorption capacity (q(max)). Results show that, at pH 5.6, biosorbents, Camellia tree leaf and primary sludge in particular, exert higher sorption capacities (q(max)>40 mg g(-1)) than inorganic sorbents, Na-montmorillonite (q(max)=33.3 mg g(-1)), fly ash (q(max)=18.8 mg g(-1)), and goethite powder (10.3 mg g(-1)). Furthermore, a pseudo second-order kinetic model was found to properly describe the experimental data for both bio- and inorganic sorbents. Sorption of Cu(II) on the Camellia tree leaf and primary sludge were much faster than that on the inorganic sorbents. In addition, desorption tests revealed that the desorption capacities of the two biomaterials are higher than the other selected materials; and much more Cu(II) can be retrieved from the Cu(II)-loaded biosorbents. Finally, increasing solution pH was found to greatly increase q(max) and accelerate sorption processes.
authors.affiliation: Department of Civil Engineering, Environmental Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. cexiao@ust.hk
authors.forename: Feng
authors.initials: F
authors.lastname: Xiao
authors.forename: Ju-Chang Howard
authors.initials: JC
authors.lastname: Huang
mesh_terms: D000327:Adsorption; D003300:Copper / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008962:Models, Theoretical; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000191:economics / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper