Arsenic Removal from Groundwater by Goethite Impregnated Calcium Alginate Beads

摘要

In the present work, goethite (α-FeO(OH)) impregnated calcium alginate (Cal-Alg-Goe) beads were used to sorb the arsenic from groundwater without disturbing its physicochemical characteristics. Beads were formed by dropwise addition of homogenized mixer of goethite and 4 % sodium alginate solution in 0.2 M CaCl_2 solution. Charge, size, and morphology of sorbents were characterized by using various techniques. The results of batch sorption experiments suggest that Cal-Alg-Goe beads are very effective for removal of arsenic in the pH range 3.0 to 7.5, and sorption was more than 95 % in the concentration range of 10-10,000 ng mL~(-1). Beads were successfully tested for groundwater samples collected from areas having elevated levels of arsenic. Equilibrium sorption follows Langmuir isotherm model, and the maximum arsenic uptake calculated was 30.44 mg g~(-1). The sorption kinetics could be explained by pseudo-first-order model, and the time needed for equilibrium was 24 h.