| Summary: | This study investigated the preparation of natural based adsorbent clay via acid
modification for the adsorptive removal of chemical oxygen demand (COD) and
ammonical nitrogen from the semi-aerobic sanitary landfill leachate. The effect of
adsorbent dosage, contact time and pH on the adsorption process were evaluated. The
experimental results manifested that the adsorptive removal of COD and ammonical
nitrogen increased with increasing the adsorbent dosage and contact time, recorded the
adsorptive removal of COD and ammonical nitrogen of 71.93% and 68.94%,
respectively, at the adsorbent dosage of 4.5 g/200 mL and pH 7. The experimental data
were modelled using two isotherm models, namely Langmuir and Freundlich isotherm
models. The adsorption equilibrium data were favourably fitted to the Langmuir
isotherm model, with a maximum monolayer adsorption capacity for COD and
ammonical nitrogen of 89.17 mg/g and 151.60 mg/g, respectively. The adsorption
kinetic was tested using pseudo-first-order and pseudo-second-order kinetic models.
The pseudo-second-order kinetic model was best described the adsorption of COD and
ammonical nitrogen onto the acid-activated natural clay, with the coefficients of
correlation, R2 for COD and ammonical nitrogen of 0.998 and 0.997, respectively. The
result demonstrated that the prepared clay based adsorbent is highly feasible for the
effective remediation of sanitary landfill leachate.
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