Removal of arsenic in a sand filter coupled with zero valent iron

Arsenic (As) in wastewater has negative effects on the environment and human health, hence As containing wastes must be handled properly. Given the accessibility of metallic iron, studies investigating into the potential application of zerovalent iron in the removal of arsenic are promising. In this study, the performance of sand filter blended with several kinds of zero valent iron (Fe⁰), such as iron wool, iron fillings, and iron nails, were compared. These materials were combined in a sand filter column, and the efficiency was calculated using the As concentrations in the influent and effluent samples. Experiments were carried out in order to compare performance as a function of Fe⁰ dose and contact time. The outcome of this investigation showed that sand filter containing iron wool had a better removal efficiency of arsenic removal than iron filings and iron nails. The results in all columns showed that as dosage was increased, removal efficiency of arsenic increased significantly. In case of contact time the results revealed that arsenic can effectively be removed from water in the first 48 h. The early adsorption response is quick in all columns, but get slower as time goes on. The highest removal efficiency was 99.6% and the lowest removal efficiency was 82.7%.