Sorption of naphthalene and phosphate to the CTMAB–Al 13 intercalated bentonites

Abstract

This work aimed to develop novel bentonite based sorbents that could simultaneously remove hydrophobic organic compounds (HOCs) and phosphate from water. Cetyltrimethyl ammonium bromide (CTMAB) and hydroxy-aluminum (Al 13) were used to intercalate bentonite simultaneously or sequentially to prepare series of inorganic–organic bentonites (IOBs). Structures of the prepared IOBs were characterized, and their sorptive characteristics towards naphthalene and phosphate were investigated. Results showed that both CTMAB and Al 13 could intercalate into bentonite's interlayers if they were simultaneously used or if CTMAB was first used for the intercalation. The resulting IOBs were as effective as the CTMAB modified bentonites in sorption of naphthalene from water, and they were shown to be more effective in sorption of phosphate from water than the Al 13 pillared bentonite. However, if Al 13 was first used for the intercalation, the interlayers of the bentonites would be “locked” by the intercalated Al 13, and thus CTMAB could hardly further intercalate bentonite. As a result, the obtained IOBs showed weak sorption efficiency towards naphthalene, and its sorption capacity towards phosphate was also lower than the corresponding Al 13 pillared bentonites. Results of this work showed that IOBs prepared with proper processes could be efficient sorbents towards both HOCs and phosphate.