Recovery of Petroleum Sulfonate from Wastewater by Extractive Crystallization

Abstract

Extractive Crystallization was used to recover petroleum sulfonate from wastewater. The simple process significantly reduced power consumption. Ethanol, isopropanol and n-butanol were used as extractant to recover petroleum sulfonate and remove ammonium sulfate. This work systematically studied the effect of different extractants for the wastewater. The results showed that: the crystallization ratio of n-butanol was much lower than that of ethanol and isopropanol with a certain solvent ratio at room temperature, but the purity of the petroleum sulfonate extracted by n-butanol was much larger than that of ethanol and isopropanol. Petroleum sulfonate recovery was in the order of ethanol ＞isopropanol ＞n-butanol. Therefore, suitable extractant and solvent ratio were selected based on different product requirements, which achieved the dual purposes of removing ammonium sulfate and recovering petroleum sulfonate.