Removal of Cu2+ and Zn2+ from model wastewaters by spontaneous reduction-coagulation process in flow conditions.
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.
Bojic
Aleksandar Lj
ALj
Department of Chemistry, Faculty of Sciences and Mathematics, University of Nis, Nis, Serbia. bojic@bankerinter.net
Bojic
Danijela
D
Andjelkovic
Tatjana
T
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*
D014874:Water Pollutants, Chemical; D003300:Copper; D015032:Zinc