Evaluation of Aluminum-Coated Pumice as a Potential Arsenic(V) Adsorbent from Water Resources

In this study, the removal of As (V) from water resources by using aluminum-coated pumice as a new adsorbent was assessed. The features of the adsorbent coating layer were observed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM).The effects of various parameters such as adsorbent doses, pH, contact time, arsenate initial concentration and interfering ions in arsenic adsorption and achieving high removal efficiency were studied. The results showed that the adsorption of As (V) was extremely influenced by the phosphate interfering ions. It was also defined that more than 98% of As (V) was removed by 10 g/L of the adsorbent with initial As (V) concentration of 250 μg/L at pH=7 and in 160 minutes. The adsorption equilibriums were analyzed by Langmuir and Freundlich isotherm models. Such equilibriums showed that the adsorption data was well fitted with Freundlich isotherm model (R2>0.99). The data achieved from the kinetic studies were processed by kinetic models of pseudo-first-order and pseudo-second-order. The results indicated that the pseudo-second-order model could describe the adsorption of As (V) by pumice coated with alum (R2>0.92). According to achieved results, it was defined that aluminum-coated pumice not only was an inexpensive absorbent, but also a quite effective factor in removal of As (V) from water resources.