Investigation of Arsenic Removal from Drinking Water Using Ferric Chloride Coagulant

Abstract

Increasing urbanization and industrialization of cities have led to an increase in pollutants and the production of many toxic elements. One of these pollutants is arsenic, which is known as one of the most toxic and dangerous elements in drinking water. The aim of this study was to investigate the method of minimizing the amount of this toxic substance by coagulation and flocculation in drinking water. In order to determine the optimal conditions for arsenic removal by coagulation and flocculation methods, in the first stage, the optimal pH was determined by Jar experiment, then by selecting ferric chloride as a coagulant and lime as coagulant and also the optimal pH. The optimal amount of chemical is obtained, at the end, the residual concentration of arsenic is determined by atomic hydride absorption spectroscopy. According to the concentration of arsenic in the incoming water sample which is equal to 91 micrograms per liter The jar test was performed in two stages with chloroform coagulants, which according to the optimal pH obtained in different concentrations of coagulants and also a constant concentration of coagulants, the arsenic removal efficiency in the best case in chlorofricter coagulants. It reached 98.3%, which is equal to 1.5 micrograms per liter, which according to the standard of the WHO (2011), 10 micrograms per liter had an acceptable result. The result of this study indicates that the coagulation and flocculation method with chloride-chloride coagulant and a constant amount of lime as a coagulant has high efficiency in arsenic removal.