Removal of heavy metals from paint industry's wastewater using Leca as an available adsorbent

ABSTRACT

The ability of light expanded clay aggregate to remove Pb++ and Cd++ from paint industry's effluents was studied at different levels of adsorbent, contact time and pH in April 2008. For this purpose, Pb and Cd removal from paint industry effluents were studied in batch reactors. Pb and Cd measurements have been taken with non-flame atomic absorption techniques and test methods were adapted from 19 th edition of standard methods for the examination of water and wastewater. In this study, different amounts of Leca [1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 g/L] were investigated. The amount of adsorbed Pb [II] and Cd [II] exposure to Leca increased from 1.41 to 3 mg/g and 0.22 to 0.75 mg/g, respectively. The maximum removal efficiency for Pb was 93.75% at pH = 7 and exposure to 10 g/L of Leca, while for Cd, it was nearly 89.7% at the same condition. In this study, adsorption process of lead and cadmium was fitted with Freundlich adsorption isotherm [R2Pb = 0.97 and R2Cd = 0.98]. The sufficient contact time was deemed 1-2 h for Cd and Pb. According to the results, Leca is recommended as a low cost and available adsorbent to remove lead and cadmium from industrial wastewater