Simultaneous removal of acid dye and cationic surfactant from water by bentonite in one-step process

Organobentonite is suggested as potential super-sorbents for the removal of organic pollutants such as dyes from wastewater. Limited by the high operation cost and the complicate process of its synthesis, however, organobentonite is not widely applied in wastewater treatment. Based on the truth that organobentonite was normally synthesized by cationic surfactants and bentonite with cationic exchanging, a one-step process was proposed here to remove an acid dye (Orange II) and a cationic surfactant (cetyltrimethylammonium bromide, CTMAB) simultaneously from wastewater using bentonite alone. The effects of contact time, pH and inorganic salt on the removal of the acid dye and surfactant from wastewater were also examined. High removal efficiencies (>99%) of Orange II and CTMAB by bentonite were observed. In the one-step process, the cationic surfactants in the wastewater were utilized to form organobentonite and then available for the removal of acid dye as sorbents. Furthermore, the separated synthesis process of organobentonite was consequently deleted. Therefore, this one-step process would be an efficient, simple and low cost for the treatment of organic wastewater especially for textile wastewater and makes it possible that bentonite could be applied widely in wastewater treatment as sorbent.