ARSENIC REMOVAL FROM AQUEOUS SOLUTIONS USING IRON OXIDE COATED SEPIOLITE

In this research, adsorption of arsenic As(V) by iron oxide coated sepiolite (IC-SEP) was studied. Sepiolite which has significant deposits in Turkey and as a low cost natural material, was used as adsorbent after coating with iron oxide. Material characterization study as well as adsorption data affirmed that iron oxide was successfully coated onto sepiolite. Optimum adsorption parameters were determined by batch experiments. As(V) removal was best achieved at neutral pH range. Results showed that removal percentage of As(V) could be over 94% in the conditions of IC-SEP dosage 5.0 mu g/L, contact time 4 h, and initial concentration of 110 mu g/L As(V). Bicarbonate was detected as a major anion possibly interfere As(V) adsorption. Langmuir isotherm model well fitted to equilibrium data; and maximum adsorption capacity was calculated as 0.501 mg/g which is larger than that of several other adsorbents. Kinetics study showed that As(V) adsorption was well described by pseudo second order model. Results suggested that IC-SEP is an easily available and low-cost adsorbent, and can effectively be used to reduce As(V) concentration below the standards, i.e. 10 mu g As/L