Fluoroquinolone antibiotics are widely used in human and veterinary medicine. However, untreated fluoroquinolone seriously threatens the ecosystem and human health. In this study, deep eutectic solvents (DESs) were applied for the hydrolysis of waste feathers, and the keratin particles (KPs) in a low-cost teabag were utilized to adsorb fluoroquinolone norfloxacin. Results showed that choline chloride/ethylene glycol DES rapidly hydrolyzed feathers within 10 min, and the undissolved particles effectively adsorbed norfloxacin. Adding KOH markedly shortened the hydrolysis time (6 min) and increased the adsorption ability of KPs. The optimum hydrolysis conditions were DES ratio of 1 g: 4.67 g, KOH of 35.68 g L-1, and temperature of 90 °C. When KPDES+KOH of 2 g L-1, norfloxacin of 25 mg L-1, and pH0 7 were used, 94% of norfloxacin was removed in 60 min. A low-cost teabag effectively separated the KPs from the solution after adsorption and did not decrease the adsorption ability of the KPs. The Langmuir isotherm model well described the adsorption behavior of KPsDES+KOH (qmax = 79.36 mg g-1, R2 = 0.9972). In addition, acetone efficiently regenerated the exhausted KPsDES+KOH. The KPs maintained >80% of its adsorption ability after seven cycles of regeneration.
Keywords: Adsorption; Deep eutectic solvent; Waste feather.
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