REMOVAL OF ARSENIC FROM DRINKING WATER USING ADSORPTION

Abstract

Increasingly stringent legislation on the permissible concentrations of arsenic in drinking water has led to increased investigations of the occurrence, chemical speciation and mobility of arsenic in natural waters and of methods for removing arsenic during water treatment. Epidemiological studies suggest that there are significant health risks, including cancer, associated with prolonged exposure to elevated arsenic concentrations in drinking water even at quite low concentrations. Although background arsenic concentrations in natural environments are usually low, arsenic concentrations are high in many parts of the world due to mobilization from natural geological sources or at a smaller scale from industrial pollution. While arsenic associated with industrial pollution can be managed by improving process engineering and environmental management practices, making water that has a naturally high arsenic content safe to drink requires some form of water treatment to reduce arsenic concentrations. In the present study laboratory scale experiments have been carried out using the charcoal (CC) and activated carbon (AC) as adsorbent for the removal of Arsenic. Batch experiments were carried out to determine the effect of various factors such as contact time, pH, adsorbent dose and temperature on adsorption process. Results obtained from these results have been analyzed by various kinetics. From the results it is clear that the removal efficiency will be more for AC than CC at its natural pH in water. Moreover the reaction was completed almost 4 h for AC. Temperature study shows that the uptake of metals by adsorbents was more at the normal temperature (30 °C). The parameters of Pseudo-First order and Pseudo-Second order kinetics have been found. Equilibrium isotherms have been analyzed using Langmuir isotherm and Freundlich isotherm, and parameters have been calculated for both isotherms from the plots.