The adsorption of cadmium and lead ions from the synthesis wastewater with the activated carbon: Optimization of the single and binary systems

Abstract

In this work, the adsorption of cadmium ions (Cd (II)) and lead ions (Pb (II)) in a single and binary component system with activated carbon were investigated in series of batch laboratories studies. The effective operating parameters like initial pH (pH0), initial concentration of metal ions, contact time, and temperature on the adsorption were investigated. The validation of the kinetic study shows that the adsorption process is better prediction by the pseudo-second-order model. The extended Freundlich and Langmuir isotherms were applied to the study of the binary system. The results show that the metal ion adsorption capacities of activated carbon have increased with increasing pH, and it was found that pH solution about 5.5–6 was the optimal pH value for maximum Pb capacity and 7–8 for Cd (II). Response surface methodology (RSM) was applied to find optimal conditions, that were perceived as follows: the initial pH: 6.3, temperature: 56.8 °C and shaking speed: 308 rpm. The order of adsorption capacity values for each metal ions was as follows: Pb (II): 9.30 mg. g−1 > Cd (II): 9.26 mg. g−1.