Elif Senturk

The treatment of zinc-cyanide electroplating rinse water using an electrocoagulation process

This paper investigates the treatment of zinc-cyanide electroplating rinse water using an electrocoagulation process (ECP). The effects of operating parameters such as electrode material, current density (2.5-40 A/m(2)), operating time (0-60 min), initial pH (5-12) and electrode connection mode (monopolar parallel (MP-P), monopolar series and bipolar series) on the ECP were evaluated to find the optimum operating conditions. At 20 A/m(2), 60 min, the highest removal efficiencies were obtained with 85 and 99% for Fe and 64 and 33% for Al electrodes, for cyanide and zinc, respectively. The optimum operating conditions were found to be 30 A/m(2) and 40 min, for the Fe electrode at the original pH (9.5) of the rinse water. Considering efficiency and economy, the MP-P connection mode was determined as the optimum connection mode.

Dynamic biosorption characteristics and mechanisms of dried activated sludge and Spirulina platensis for the removal of Cu2+ ions from aqueous solutions

Abstract During biosorption, removal is ensured by several mechanisms that occurred between living or nonliving microorganisms and transporting metal ions. In this study, the kinetics, equilibrium, and thermodynamics of the biosorption of Cu2+ onto dried activated sludge and Spirulina platensis from aqueous solution were investigated at different experimental conditions. The biosorption characteristics were investigated with respect to some of the significant parameters including the effect of pH, biosorbent dosage, and temperature. The Langmuir, Freundlich, and Temkin equilibrium adsorption models were studied. Results showed that Langmuir isotherm model fitted well the experimental data followed by the other isotherm models used. In order to determine the mechanism of the biosorption, kinetic models were applied. The results of the kinetic studies indicated that the biosorption processes fitted the pseudo-second-order model. The thermodynamic parameters were also calculated, and the values indicated tha...