Removal of chromium (III) metal ions from fertilizer wastewater using kaolin clay

Abstract

Extensive agriculture is the main vector of environmental contamination. The aim of this 
study was to investigate the adsorption of chromium (III) metal ions from fertilizer waste
water using kaolin clay. The clay was characterized and used for the 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 Brunauer–Emmett–Teller specific 
surface area was 98.84 m2/g for calcined and 70.84 m2/g for natural kaolin. The adsorp
tion data were analyzed by isotherm and kinetic studies. Langmuir and Freundlich mod
els 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 model for Cr(III) with regression coef
ficients (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.