Rapid removal of tetracycline antibiotics from water by coagulation-flotation of sodium dodecyl sulfate and poly(allylamine hydrochloride) in the presence of Al(III) ions

摘要

A coagulation-flotation method using an anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic polyelectrolyte, poly(allylamine hydrochloride) [PAH], was designed for rapid removal of tetracycline antibiotics from water. The method was conducted by adding electrically equivalent amounts of SDS and PAH followed by feeding air bubbles. The air bubbles vigorously mixed water and induced the coagulation of SDS-PAH complex to from agglutinative coagulum on water surfaces. In the presence of Al(III) ions, tetracycline in water was collected to the coagulum as an hydrophobic ion-pair of the Al(III)-chelate with a dodecyl sulfate ion (m/z = 736). Fluorometric study using a molecular probe, N-phenyl-1naphthylamine, suggested the formation of hydrophobic region in SDS-PAH complex as well as air/water interfaces for the sorption of the hydrophobic ion-pair. Combined use of 20 mg L-1 SDS, 6.5 mg L-1 PAH, and 1 mg L-1 Al(III) ions allowed nearly complete ( > 99%) removal of tetracycline from water within 5 min. SDS concentration remaining in the treated water was 0.12 0.05 mg L-1, being lower than Japanese water regulation (0.2 mg L-1) of total anionic surfactants. Other tetracyclines and fluoroquinolone antibiotics as well as different acidic and basic pharmaceuticals were nearly completely (>96%) removed from water. Applicability to wastewater treatment was examined by using secondary effluents and synthesized hospital wastewaters. (C) 2017 Elsevier B.V. All rights reserved.