Norfloxacin, a fluoroquinolone antibiotic, is widely used to treat microbial infections. However, untreated norfloxacin-containing wastewater poses serious threats to the ecosystem and human health. The treatment of waste expanded polystyrene (EPS) by landfilling or incineration could cause environmental problems. In this research, the feasibility of converting EPS into a valuable adsorbent for norfloxacin was evaluated. Results showed that EPS treated with H2SO4 (EPSH2SO4) effectively adsorbed norfloxacin. The optimal sulfonation conditions were 95% H2SO4 and 100 degrees C. Addition of 0.001 M of persulfate during sulfonation obviously shortened the sulfonation time to 7.5 min, and the adsorption ability of modified EPS increased with increasing persulfate dose. Under the experimental conditions of 25 mg L-1 norfloxacin, pH0 6.2, and 0.4 g L-1 EPSH2SO4+persulfate (dry weight), 97.2% of norfloxacin could be removed after 30 min of adsorption. The adsorption ability of EPSH2SO4+persulfate decreased with increasing solution pH(0), and the optimal pH(0) was 6.2. The Langmuir isotherm best described the adsorption behavior of EPSH2SO4+persulfate (q(max) = 140.9 mg L-1, b = 1.97 L mg(-1), R-2 = 0.9992). 1 M HCl effectively regenerated the exhausted EPSH2SO4+persulfate at the optimal solid/solution ratio of 8 g L-1. EPSH2SO4+persulfate maintained excellent adsorption capacity (>80.9%) after eight adsorption-regeneration cycles. (C) 2020 Elsevier Ltd. All rights reserved.
