Arsenic removal using novel combined Fe/Mn adsorbent modified with silica

Arsenic pollution has become a dominant environmental concern in recent years. Various techniques for arsenic removal from water have been developed. However, these techniques efficiently remove arsenic from drinking water but require toxic and expensive chemicals and generate a large amount of exhaust sludge, which is not always regenerable. In this study a novel Fe-Mn-Si oxide material was prepared from environmentally friendly and low-cost materials through a co-precipitation process. Batch adsorption experiments were conducted to study adsorption kinetics, adsorption capacity and the effect of temperature and pH on the adsorption of arsenic on Fe-Mn-Si oxide. The maximum adsorption capacity was found to be 9.62, 10.18, and 10.50 mg/g at 25, 35, and 45 °C, respectively. The results compare favorably with those obtained using other adsorbents. The used Fe-Mn-Si oxide could be regenerated using a NaOH solution; 73.4% of the adsorbed arsenic was desorbed by 0.2 N NaOH. Results from this study demonstrate the potential usability of Fe-Mn-Si oxide as a good arsenic-selective adsorbent.