Abstract

Extensive agriculture is the main vector of environmental contamination. The aim of this study is to investigate the adsorption of chromium (III) metal ions from fertilizer wastewater using kaolin clay. The clay was characterized and used for adsorption process in its natural and calcined forms. The major chemical components in the clay were silica (51.68-52.38%) and alumina (25.7-26.41%). The BET specific surface area was 98.84 m2/g for calcined and 70.84 m2/g for natural kaolin. The adsorption data was analyzed by isotherm and kinetic studies. Langmuir and Fruendlich models were utilized for the analysis of the adsorption equilibrium isotherm. The adsorption capacity by calcined kaolin was 82.59 mg/g while onto natural calcined was 63.56 mg/g. The experimental data fitted well into the Langmuir for Cr (III) with regression coefficient (R2) of 0.96% and 0.86% for Cr (III) for calcined and natural kaolin clay respectively. The pseudo-second order kinetic model fitted well for chromium. This proves that kaolin clay is a good material for the removal of chromium ions from fertilizer wastewater.

Key words: adsorption, kaolin clay, chromium, isotherm, kinetics