MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, China.
MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
J Hazard Mater. 2023 Sep 15;458:131909. doi: 10.1016/j.jhazmat.2023.131909. Epub 2023 Jun 21.
Interaction of antibiotics with metal ions in aquatic environments, commonly occurring to form complexes, may affect the migration, transformation and reactivity of residual antibiotics. This study demonstrates the photolysis of Fe(III) by UV irradiation at pH 3.5, as an advanced oxidation process, to produce •OH for the abatement of a common broad-spectrum antibiotic compound, tetracycline (TET). The dimethylamino (-N(CH)) and hydroxyl (-OH) groups of TET were determined as the binding sites for the complexation with Fe(III) via a series of novel characterization approaches. The complexation stoichiometry of Fe(III)-TET complexation, including the complexation ratio, constants and percentages, was determined via a complexometric titration based on the UV differential spectroscopy. The complexation constant was determined to be 21,240 ± 1745 L·mol under the designed conditions. Complexation of TET with Fe(III) enhanced its degradation in the UV/Fe(III) process, through the promotion of the •OH generation by inhibiting hydrolysis-precipitation process of Fe(III) and enhancing Fe(III)/Fe(II) cycle and the acceleration of mass transfer between •OH and TET. This finding provides new insights into the role of complexation in the fate of residual antibiotics in the UV/Fe(III) process. The reduced overall ecotoxicity during the TET abatement, evaluated by the toxicity variation through ECOSAR program, provides the UV/Fe(III) process with a theoretical feasibility for water decontamination in actual applications.
抗生素与水生环境中的金属离子相互作用，通常形成配合物，可能会影响残留抗生素的迁移、转化和反应活性。本研究展示了在 pH 3.5 下通过 UV 照射使 Fe(III)光解，作为一种高级氧化工艺，产生•OH 以去除常见的广谱抗生素化合物四环素（TET）。TET 的二甲氨基（-N(CH)）和羟基（-OH）基团被确定为与 Fe(III)形成配合物的结合位点，通过一系列新的表征方法。通过基于 UV 差光谱的络合滴定法确定 Fe(III)-TET 配合物的络合化学计量比，包括络合比、常数和百分比。在设计条件下，确定配合常数为 21,240±1745 L·mol。TET 与 Fe(III)的配合物增强了其在 UV/Fe(III)过程中的降解，通过抑制 Fe(III)的水解-沉淀过程来促进•OH 的生成，增强 Fe(III)/Fe(II)循环，并加速•OH 和 TET 之间的质量转移。这一发现为配合物在 UV/Fe(III)过程中残留抗生素命运中的作用提供了新的见解。通过 ECOSAR 程序评估毒性变化，在 TET 去除过程中整体生态毒性降低，为 UV/Fe(III)工艺在实际应用中的水净化提供了理论可行性。
