Hexavalent Chromium Removal from Wastewater Using Scrap Iron

Hexavalent Chromium is one of the heavy metals found in industrial effluents, which is both very toxic to humans and dangerous for the environment. Conversion of Cr(VI) to Cr(III) is useful because the species with a higher mobility and greater toxicity is in this way transformed into one with less mobility and lower toxicity. For this purpose, zero-valent metals, such as scrap iron, can be used as electron donors for the conversion of Cr(VI) to Cr(III). In this study, the effect of pH was studied on reduction of Cr(VI) by scrap iron. It was found that scrap iron would reach its maximum reduction capacity at the beginning of the experiment when lower pH level was low. Results showed that the highest reduction capacity was 12.5 mg Cr(VI) for 1g of scrap iron at pH=2.0. Increasing pH to 7.3, however, reduced the reduction capacity of scrap iron to 1.9 mg Cr(VI)/g of scrap iron. Based on the findings of this study, it may be concluded scrap iron has the potential to be used as an effective method for Cr(VI) removal in wastewater treatment provided wastewater pH is not extremely acidic since the H+ ions at this pH level may lead to the rapid corrosion of scrap iron.