Uptake of As(V) from groundwater using Fe-Mn oxides modified kaolin clay: Physicochemical characterization and adsorption data modeling

Abstract

The present study evaluated the effectiveness of Fe-Mn modified kaolin clay in the uptake of As(V) from the solution. The elemental composition was characterized using X-ray fluorescence (XRF), while the surface morphology was characterized using Scanning Electron Microscopy (SEM). The surface area, pore diameter, and pore volume were determined using Brunauer, Emmett, and Teller (BET) and Barrett-Joyner-Halenda (BJH) techniques. The effociency of the Arsenic removal of the adsorbent was evaluated using batch experiments. The results showed that the percentage of As(V) removal is optimum at acidic pH and decreased as the solution pH becomes more alkaline. The adsorption kinetics data fitted better to pseudo-second-order compared to the pseudo-first-order of reaction kinetics. The adsorption isotherm data fitted to the Langmuir isotherm model showing a maximumadsorption capacity of 2.44mg/g, adsorbate concentration range of 1-30mg/L, and adsorbent dosage of 0.4 g/100 mL. The value of ΔG° of the thermodynamic parameter was found to be negative, while ΔH° and ΔS° were found to be positive. For the regeneration-reuse study, the percentage of removal was found to be > 85% after the sixth cycle of reuse. The results obtained from this study showed that Fe-Mn modified kaolin (FMK) is suitable for use in the uptake of As(V) from groundwater.