Arsenic removal from water by chemisorption filters

The concept of multiple separation by chemisorptive filters was applied and investigated in the process of arsenic removal from water. Chemisorption filters were made by the paper manufacturing method and consisted of cellulose, cationic and anionic ion exchangers, activated carbon and a corresponding chemical agent. In this work chemisorption filters were activated with Ag+, Mg2+, Cu2+, Al3+ and Fe3+ ions, and their chemical contribution to total arsenic removal from the water was analyzed. It was concluded that Cu2+ ions exhibited the best removal effect. Using a chromatographic continuous system with multifunctional filters, which combines the effects of adsorption, ion exchange and filtration, a decrease in the arsenic concentration was determined; for an active layer of 8 mm and a contact time of 2 s it was more than 1000-fold. All processes were performed in batch and chromatographic continuous systems under equilibrium or dynamic conditions. The results of the investigations have shown that arsenic removal is valence dependent (the removal of pentavalent arsenic was more effective). The initial concentration, pH and pollutants in anionic forms, which affected the selectivity, were important for all the processes investigated. The mechanisms of pollutant removal were determined on the basis of measurements of active Cu2+ ion propagation inside the filter structure. By correlating the front propagation of active ions and the pollutant output concentration a more exact model for the removal process was obtained.