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Arsenic Removal from Groundwater by Goethite Impregnated Calcium Alginate Beads

Basu, H., Singhal, R. K., Pimple, M. V., Reddy, A. V. R.
Water, air, and soil pollution 2015 v.226 no.2 pp. 2251
adsorbents, arsenic, calcium alginate, goethite, groundwater, models, pH, sodium alginate, sorption, sorption isotherms
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 CaCl₂solution. 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.