摘要
The influences of HCO 3 − , Cl − , and other components on the UV/TiO 2 degradation of the antineoplastic agents ifosfamide (IFO) and cyclophosphamide (CP) were studied in this work. The results indicated that the presence of HCO 3 − , Cl − , NO 3 − , and SO 4 2− in water bodies resulted in lower degradation efficiencies. The half-lives of IFO and CP were 1.2 and 1.1 min and increased 2.3–7.3 and 3.2–6.3 times, respectively, in the presence of the four anions (initial compound concentration = 100 μg/L, TiO 2 loading =100 mg/L, anion concentration = 1000 mg/L, and pH = 8). Although the presence of HCO 3 − in the UV/TiO 2 /HCO 3 − system resulted in a lower degradation rate and less byproduct formation for IFO and CP, two newly identified byproducts, P11 (M.W. = 197) and P12 (M.W. = 101), were formed and detected, suggesting that additional pathways occurred during the reaction of •CO 3 − in the system. The results also showed that •CO 3 − likely induces a preferred ketonization pathway. Besides the inorganic anions HCO 3 − , Cl − , NO 3 − , and SO 4 2− , the existence of dissolved organic matter in the water has a significant effect and inhibits CP degradation. Toxicity tests showed that higher toxicity occurred in the presence of HCO 3 − or Cl − during UV/TiO 2 treatment and within 6 h of reaction time, implying that the effects of these two anions should not be ignored when photocatalytic treatment is applied to treat real wastewater.