Removal of Hg, Fe and Cr from Chemical Oxygen Demand (COD) analysis waste by hydroxide precipitation method

Abstract

Wastewater from Chemical Oxygen Demand (COD) analysis is one of laboratory liquid wastes that is dangerous and potentially polluting the environment due to it contains dissolved heavy toxic metals such as silver (Ag), mercury (Hg), iron (Fe) and chromium (Cr). One of the treatment methods for removing heavy metals on a laboratory scale is precipitation method. The purpose of this research was to determine the most optimum condition for Hg, Fe and Cr removal. Hydroxide precipitation method was used with NaOH as the precipitant. The varied parameter was pH (3,7,9 and 11). Based on the results, the most optimum efficiency of metal Hg, Fe and Cr removal was observed at pH 11, reaching 99% removal efficiency for all metals.