The magnetic solid phase extraction material (MnFe 2 O 4 @TiO 2 ) was prepared by coating TiO 2 on MnFe 2 O 4 through an in-situ formation method. The structure and properties of MnFe 2 O 4 @TiO 2 were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), nitrogen adsorption–desorption experiment, and vibrating sample magnetometer (VSM). The conditions for magnetic solid phase extraction (MSPE) of quinolone antibiotics were optimized, and an MSPE-HPLC method was established to determine quinolone antibiotics in water samples. The optimal conditions for MSPE are MnFe 2 O 4 @TiO 2 amount of 15 mg, extraction time of 15 min, 5 mL of methanol solution with 20 % ammonia as eluent, and elution time of 1 min. Under the optimal conditions, 50 mL 0.1 mg/L mixed standard solutions of fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin have achieved enrichment multiples of 67.8, 72.1, 59.6, 55.8, and 60.7, respectively. The linear range of five antibiotics determined by MSPE-HPLC is 0.004–1 mg/L with the relative standard deviations (RSDs) of 2.1 %–4.9 % and the limits of detection (LODs) of 0.0006–0.0020 mg/L. The method is applied to the determination of the five antibiotics in rice paddy water and fish pond water; the recoveries range from 78.9 to 105.8 %, and the RSDs (n = 5) are 3.6 %–8.7 %.
Diversified emerging contaminants pose significant threats to human health and the environment, greatly impeding the reuse of reclaimed water. Currently, photoelectrocatalytic (PEC) technology has been proven as an effective and feasible method for removing contaminants, but its application is limited by complex preparation process of PEC anode. Herein, a novel magnetic attraction synthesis approach was proposed to develop a PEC anode named MnFe 2 O 4 -TiO 2 nanotube arrays. The Magnet-MnFe 2 O 4 -TiO 2 (MMT) anode presented several advantages, including a narrower band gap, decreased charge recombination rates, and minimal electron transfer resistance. The PEC system equipped with MMT anode achieved high degradation efficiencies, removing 76.4 % of 17α-ethinylestradiol (EE2) in 60 min and completely degrading tetracycline (TC) in 10 min. Various pathways for the generation of reactive radicals were clarified in the PEC system, including photocatalysis, electrocatalysis and Fenton reaction. The contributions of each reactive radical were examined, wherein ·OH and ·O 2 − were primary contributors to the degradation of EE2 and TC, respectively. The identification of degradation products also verified the vital roles of reactive radicals in the degradation of two pollutants. This study explored the feasibility of a magnetic attraction synthesis strategy in enhancing the PEC performance to remove trace pollutants in reclaimed water.
危险品化学品经营许可证（带存储）