Removal of Arsenic and Heavy Metals From Potable Water by Bauxsol Immobilized onto Wool Fibers

Abstract

Arsenic and heavy metals in drinking water are of particular concern. Of them arsenic is the most potent toxin as well as it is a carcinogen. Arsenic exists in groundwater as uncharged arsenite or anionic arsenate depending on the reducing or oxidizing environment, and the former is more toxic and more difficult to remove than the latter. In this work, varous types of filters made from Bauxsol immobilized onto wool were investigated to remove arsenite and heavy metals from water. Several techniques were investigated to immobilize Bauxsol onto wool, and of them the exhaustion technique was found the best. Two types of Bauxsol, unneutralized (Bauxsol-A) and acid-neutralized (Bauxsol-B), have been investigated, and the removal efficiency of arsenite by Bauxsol-B was found considerably higher (53.3%) than that of Bauxsol-A (34.4%). A pilot-scale trial of Bauxsol-B-bonded wool fiber-packed column-based filtration system showed that it successfully removed arsenite, lead, copper, and zinc from water, but the best results were obtained for the removal of lead and copper as their removal reached 100 and 96%, respectively. The increase in contact time had a significant effect on the removal efficiency; e.g., the removal of copper increased from 10.2 to 96% when the contact time was increased from 5.4 to 86.4 min. The developed filtration system could be used for the removal of arsenic, lead, copper, and zinc from potable water.