Experimental study of As(V) adsorption onto different adsorbents

The As(V) adsorption onto natural bentonite (B), Fe enriched bentonite (FB) and synthetic magnetic particles (MP) from the aqueous solutions was investigated by batch as well as column tests. The natural materials did not show such good adsorption properties towards As(V) in the batch experiments as MP, whose Q(max) was calculated to 23 mg/g. However, in column experiments the adsorption effect of natural materials was comparable with MP. The model solution with the concentration 30 mg As(V)/L was percolated through the columns filled with the B and FB sample. After two cycles the As(V) concentration was lower than 2 mg/L. The second series of columns were filled with FB/MP/QS and B/MP/QS. Two cycles with the solution concentration of 50 and 100 mg As(V)/L were performed. After the second cycle 74 and 100% of As(V) were removed by FB/MP/QS and B/MP/QS, respectively. In the third series two most effective columns were selected for the second percolation of 100 mg As(V)/L solution. While the adsorption effect of the QS/MP column decreased at 36%, for the QS/B/MP column it was about 24%. The first experimental study showed that natural materials should be used effectively as column fillers to fix finer magnetic particles. On the other hand, their selectivity towards Cu(II) and Zn(II) ions could be beneficial for regeneration of media used in the process of soil bioremediation.