Optimization of Chromium(III) Sorption by Activated Sludge Using Response Surface Methodology

Abstract

Increased level of chromium due to the anthropogenic activity in environment poses significant threat to human health. This study aims to optimize the removal process of Cr (III) in aqueous solution using activated sludge as adsorbent. Response surface methodology was employed to assess the removal efficiency considering cumulative effect of pH and contact time. The optimal removal efficiency of Cr (III) onto activated sludge was determined as 25.64 mg/g at pH = 4 and 5 g/L biomass dosage. Furthermore, the quantitative relationship between Cr (III) uptake and variable parameters was used to optimize the control level of each parameter by a full factorial design method. The analysis of variance demonstrates that the model was very significant statistically. It shows also that the removal of Cr (III) was affected by the studied factors. The model was statistically tested and verified by experimentation. Therefore, it‘s clear that the response surface methodology gives not only valuable information on interactions between the evaluated parameters but also leads to identify the optimum values of the studied factors. The results obtained will be helpful for improving and understanding the removal process of heavy metals and will lead to develop an efficient process for cleaner environment.