title: Removal of Cu2+ and Zn2+ from model wastewaters by spontaneous reduction-coagulation process in flow conditions.
abstract: The treatment of model wastewaters containing heavy metals by spontaneous reduction-coagulation process using micro-alloyed aluminium composite (MAlC) in a laboratory semi-flow system (SFS) has been investigated. Several working parameters, such as treatment time, pH, initial metal concentration and flow rate were studied in an attempt to achieve a higher removal capacity. The residual concentrations of metals were at admissible levels after only 20 min of treatment. Removal rate of Zn(2+) was greater at neutral pH than at acid or basic, while Cu(2+) removal was less affected by pH. Removal constants of both metals decreased as initial metal concentration increased from 20 to 200 mg L(-1). In mixed wastewaters the presence of copper caused increase of Zn(2+) removal efficacy, however, the copper removal was not affected by zinc. The removal mechanisms depend on metals nature and pH: copper was mainly removed by reduction, while zinc by precipitation as hydroxide. The kinetic of process was mass-transport limited, thus increasing of flow rate accelerated removal of metals. The method was found to be highly efficient and faster compared to conventional treatments.
authors.affiliation: Department of Chemistry, Faculty of Sciences and Mathematics, University of Nis, Nis, Serbia. bojic@bankerinter.net
authors.forename: Aleksandar Lj
authors.initials: ALj
authors.lastname: Bojic
authors.forename: Danijela
authors.initials: D
authors.lastname: Bojic
authors.forename: Tatjana
authors.initials: T
authors.lastname: Andjelkovic
mesh_terms: D003300:Copper / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D015032:Zinc / Q000302:isolation & purification*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper; D015032:Zinc