Treatment of arsenic contaminated water in a laboratory scale up-flow bio-column reactor

Removal of arsenic from aqueous solutions using waste iron columns inoculated with iron bacteria

Arsenic contamination of water resources is one of the serious risks threatening natural ecosystems and human health. This study investigates arsenic removal using a waste iron column with and without iron bacteria in continuous and batch phases. In batch experiments, the effects of pH, contact time, initial concentration of arsenic and adsorbent dose were investigated. Results indicated that the highest arsenate removal efficiency occurred at pH 7 (96.76%). On increasing the amount of waste iron from 0.25 to 1 g, the removal rate changed from about 42.37%-96.70%. The results of continuous experiments on the column containing waste iron showed that as the empty bed contact time increased from 5 to 60 min, the secondary arsenate concentration changed from 23 to 6 µg/l. In experiments involving a waste iron column with iron bacteria, an increase in residence time from 5 to 60 min decreased the secondary arsenate concentration from 14.97 to 4.86 µg/l. The results of this study showed that waste iron containing iron bacteria is a good adsorbent for removal of arsenic from contaminated water.

Microbial transformations of arsenic: perspectives for biological removal of arsenic from water

Arsenic is present in many environments and is released by various natural processes and anthropogenic actions. Although arsenic is recognized to cause a wide range of adverse health effects in humans, diverse bacteria can metabolize it by detoxification and energy conservation reactions. This review highlights the current understanding of the ecology, biochemistry and genomics of these bacteria, and their potential application in the treatment of arsenic-polluted water.

Fast kinetic and efficient removal of As(V) from aqueous solution using anion exchange resins

Glycidyl methacrylate/methelenebisacrylamide resin with immobilized tetraethylenepentamine ligand was prepared. This pentamine containing resin was transformed to two anion exchange resins through treatment by glycidyl trimethylammonium chloride to give (RI) or hydrochloric acid giving (RII). The resins were used to adsorb As(V) at different experimental conditions using batch and column methods. Kinetics and thermodynamic properties as well as the mechanism of interaction between As(V) and resin active sites were discussed. The maximum adsorption capacities of As(V) on RI and RII were found to be 1.83 and 1.12 mmol/g, respectively. The regeneration and the durability of the loaded resin towards the successive reuse were also investigated.