Efficient removal of arsenic from polluted ground water by using a layered double hydroxide exchanger

Abstract

Arsenic concentration in the polluted ground water has been sufficiently reduced from its alarming limit to a permissible one (∼0.02 mg/l) employing the intercalation behaviour of Layered Double Hydroxide (LDH) Mg-Al hydrotalcite. The exchange reaction was very simple and the efficiency of the process remained almost same in many cycles. This efficiency of arsenic removal from contaminated ground water has been drastically improved by pre-treatment with a small amount of dilute aqueous H 2 O 2 to oxidize As(III) to As(V) under acid pH condition followed by its exchange with hydrotalcite. After few exchange cycles the solid exchanger could be easily exchanged with a saturated NaCl solution to regenerate the LDH for further use.