Efficiency of water purification from oil with aluminum coagulants

Abstract

In this work, the processes of reagent purification of aqueous emulsions from oil using aluminum coagulants, such as: aluminum sulfate, aluminum hydroxide, and aluminum hydroxochloride, were investigated. In emulsion cleaning processes, coagulants were used separately, as well as in the presence of sorbents: bentonite or activated carbon. The results of the conducted studies demonstrate that aluminum sulfate, aluminum hydroxide, and aluminum hydroxochloride in doses of 2–50 mg/dm3 provide a high degree of oil extraction from emulsions. The degree of water purification reaches 97–99 %. It was established that the efficiency of oil extraction from water with the help of aluminum coagulants depends significantly on the chemical composition of the coagulant and the original mineralization of the water. Aluminum hydroxide has the greatest efficiency in removing oil from water, which ensures the maximum reduction of oil concentration in both fresh and mineralized water. The combined use of aluminum coagulants and sorbents such as bentonite and activated carbon is characterized by fluctuating efficiency, which depends on the type of coagulant and sorbent, their concentrations, and the mineralization of the source water. To a large extent, the ambiguity of the presented results can be explained by the heterogeneity of the emulsions. However, it can be unequivocally stated that the use of aluminum coagulants in the processes of removing oil from water of different mineralization is expedient and effective.