Waste expanded polystyrene modified with H2SO4/biodegradable chelating agent for reuse: As a highly efficient adsorbent to remove fluoroquinolone antibiotic from water

• Published in: Chemosphere (Oxford) Vol. 288; p. 132619
• Main Authors: Chang, Shih-Hsien, Lu, Chun-Cheng, Lin, Chi-Wen, Wang, Kai-Sung, Lee, Ming-Wei, Liu, Shu-Hui
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2022
• Subjects: [S,S]-ethylenediamine-N,N′-disuccinic acid (EDDS); Adsorption; Fluoroquinolone antibiotic; Regeneration; Waste expanded polystyrene; Waste expanded polystyrene; Regeneration; Adsorption; [S,S]-ethylenediamine-N,N′-disuccinic acid (EDDS); Fluoroquinolone antibiotic
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.132619

Untreated wastewater containing fluoroquinolone antibiotics poses serious hazards to aquatic species and human health; therefore, treatment of waste expanded polystyrene (EPS) is a crucial environmental matter. In this study, waste EPS was modified with a H2SO4/biodegradable chelating agent, [S,S]-ethylenediamine-N,N′-disuccinic acid (EDDS), and used for highly efficient adsorption of the fluoroquinolone antibiotic ciprofloxacin. When ciprofloxacin of 25 mg/L was used, the H2SO4-modified EPS (EPSH2SO4) adsorbed 60.5% of the ciprofloxacin. During sulfonation, adding a low dose of EDDS markedly improved the adsorption ability of EPSH2SO4+EDDS. The optimal modification conditions were 95% H2SO4, 0.002 M EDDS, 80 °C, and 40 min. The increased adsorbent doses enhanced the adsorption. Approximately 0.2 g/L of EPSH2SO4+EDDS could effectively adsorb 97.8% of the ciprofloxacin (554.3 mg/g) within 30 min. Solution pH0 greatly influenced the adsorption, and the most suitable pH0 was 6. The Langmuir isotherm accurately described the adsorption behaviors of both EPSH2SO4 and EPSH2SO4+EDDS (R2 = 0.997–0.998). The adsorption ability of EPSH2SO4+EDDS (qmax = 1250 mg/g) was 32 times higher than that of EPSH2SO4 (qmax = 38.6 mg/g). A total of 1 M HCl effectively regenerated the exhausted adsorbent. The optimal solid/liquid ratio and time were 0.08 g/20 mL and 60 min, respectively. The regenerated EPSH2SO4+EDDS maintained a high adsorption ability (87.2%) after 10 regeneration cycles. The results thus indicate that the EPSH2SO4+EDDS adsorption–regeneration process is a potential approach to remove ciprofloxacin from water. [Display omitted] •Sulfonated expanded polystyrene (EPSH2SO4) adsorbed 60.5% of ciprofloxacin.•Adding 0.002 M EDDS during modification markedly improved its adsorption.•The EPSH2SO4+EDDS had a high adsorption ability (qmax=1250 mg/g).•Adsorption ability of EPSH2SO4+EDDS was 32.3 times higher than that of EPSH2SO4.•EPSH2SO4+EDDS kept a high adsorption after 10 cycles of regeneration.