Competitive removal of lead copper and cadmium ions by sorptive flotation using marble wastes

Abstract

Marble waste (MW) is a by-product available worldwide in large amounts. In this study, the potential of marble waste for the removal of lead, copper and cadmium ions from aqueous solution using sorptive flotation was investigated. The results indicated that maximum adsorption capacity was 24.695, 19.4675 and 7.91 mg/g dry marble within 90 minutes contact time at pH 5-6 and the maximum removal efficiency obtained by sorptive flotation at relatively short time in single system was about 99.95%, 84.58% and 78.697% for Pb(II), Cu(II) and Cd(II) ions, respectively, also, results show that the removal efficiency decreased in binary and ternary system compared with single component system. The sequence for metal ions removal in single, binary and ternary systems was Pb > Cu > Cd. Chemical analysis of marble wastes indicated that it consists mainly of calcite (CaCO3) and to some extent of quartz (SiO2) which were responsible for sorption of metal ions. In addition, the experimental data indicated that the sorption of these metal ions fitted well the Langmuir isotherm for single system and extended Langmuir for binary and ternary system. Kinetic studies showed that a pseudo second order model was more suitable than the pseudo first order model.