Effect of pH and Dissolved Oxygen on the Cr(VI) Removal by Zero-Valent Iron

Chromate [Cr(VI)] is an industrial contaminant in groundwater and soil, and known as a carcinogen material. In this study, the effect of pH and dissolved oxygen (DO) for Cr(VI) removal by Zero-Valent Iron (ZVI) was investigated using batch and column experiments. Under oxic condition, 5 mg/L Cr(VI) in batch experiments was completely removed by 1 g ZVI at pH 4, 5, 6, and 8 within 10, 1, 3, and 4 h of mixing, respectively. In anoxic conditions, 5 mg/L Cr(VI) was completely removed by 1 g ZVI at pH 4 and 5 within 10 and 2 h, respectively. This result showed that the most effective removal of Cr(VI) occurred at pH 5 in both oxic and anoxic conditions. In addition, the pH effect for Cr(VI) removal proved that the removal capacity of Cr(VI) at influent pH 5 was higher than that at influent pH 7.5 in column experiments. Base