Review of some Chemical Methods for Arsenic Remediation

The efficiency of As (V) removal from synthetic groundwater containing 10-100 μg dm-3 of As (V) was examined by coagulation, adsorption, chemical precipitation methods at constant pH and coagulant dose. These methods have shown the arsenic removal of 83-99.97% comparable to the previous observations. Of these methods chemical precipitation was found to be most effective for As (V) mitigation in water in which the removal of the species varied from 90-99.97%. A column test using a manganese dioxide (δ-MnO2)-coated sand as an adsorbent was found to be promising for removal of total arsenic in water. In two cycles of downflow column experiments, for input of groundwater sample containing 0.5 mg dm-3 for each of As (III) and As (V), 998-1010 cm3 (breakthrough bed volume) of water having arsenic concentration at the WHO guideline value (0.01 mg dm-3 ) were obtained. The regeneration of the column material by 3.0 dm3 of 0.2 N NaOH followed by backwashing with 3.0 dm3 of deionized water allowed to recover about 97% of arsenic (V) on average for both the cycles.(authors)