Persulfate (PS) activation have been extensively considered as a promising technology for removing recalcitrant pollutants, due to their production of radicals with superior oxidation reactivity. However, a catalyst with high reactive and convenient recovery for PS activation still remains to be developed. In this work, the silver-doped bismuth ferrite (Agx-BiFeO3, x = 0.1, 0.2, 0.3 and 0.4) catalysts with variable Ag content were synthesized via a facile sol-gel method and applied as heterogeneous catalyst in PS activation for tetracycline (TC) degradation. Ag0.4-BiFeO3 presented the best catalytic activity compared with other Ag doped BiFeO3 composites, 91% TC could be efficiently removed within 60 min under optimized conditions and the reaction rate constant was 0.0338 min-1. On the basis of the characterization analysis and catalytic test results, Ag could be the effective active site in PS activation and had a significant effect on PS activation. Moreover, the initial pH has negligible effect on the catalytic performance, indicating that Ag0.4-BiFeO3/PS system could work in a wide pH range. The results of electron spin-resonance spectroscopy and radical quenching tests suggested that both SO4- and OH radicals were involved in the Ag0.4-BiFeO3/PS system. The possible mechanism of Ag0.4-BiFeO3 activating PS and the major degradation pathway of TC degradation were proposed. At last, the reusability experiment results proved that Ag0.4-BiFeO3 catalyst still has a high catalytic performance after 4 times used.

中文翻译：

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Ag掺杂的BiFeO3复合材料对过硫酸盐的非均相活化可降解四环素。

由于过硫酸盐（PS）产生的自由基具有出色的氧化反应活性，因此过硫酸盐（PS）活化已被广泛认为是去除顽固污染物的有前途的技术。然而，对于PS活化具有高反应性和方便回收率的催化剂仍待开发。在这项工作中，通过简便的溶胶-凝胶法合成了Ag含量可变的银掺杂铋铁氧体（Agx-BiFeO3，x = 0.1、0.2、0.3和0.4）催化剂，并将其作为非均相催化剂用于PS活化四环素（ TC）降解。与其他掺Ag的BiFeO3复合材料相比，Ag0.4-BiFeO3具有最佳的催化活性，在最佳条件下60min内可有效去除91％的TC，反应速率常数为0.0338min-1。根据表征分析和催化测试结果，Ag可能是PS活化的有效活性位点，对PS活化有显着影响。此外，初始pH对催化性能的影响可忽略不计，表明Ag0.4-BiFeO3 / PS体系可以在较宽的pH范围内工作。电子自旋共振光谱和自由基猝灭测试的结果表明，SO4-和OH自由基都与Ag0.4-BiFeO3 / PS系统有关。提出了Ag0.4-BiFeO3活化PS的可能机理和TC降解的主要降解途径。最后，可重复使用性实验结果证明，Ag0.4-BiFeO3催化剂使用4次后仍具有较高的催化性能。此外，初始pH对催化性能的影响可忽略不计，表明Ag0.4-BiFeO3 / PS体系可以在较宽的pH范围内工作。电子自旋共振光谱和自由基猝灭测试的结果表明，SO4-和OH自由基都与Ag0.4-BiFeO3 / PS系统有关。提出了Ag0.4-BiFeO3活化PS的可能机理和TC降解的主要降解途径。最后，可重复使用性实验结果证明，Ag0.4-BiFeO3催化剂使用4次后仍具有较高的催化性能。此外，初始pH对催化性能的影响可忽略不计，表明Ag0.4-BiFeO3 / PS体系可以在较宽的pH范围内工作。电子自旋共振光谱和自由基猝灭测试的结果表明，SO4-和OH自由基都与Ag0.4-BiFeO3 / PS系统有关。提出了Ag0.4-BiFeO3活化PS的可能机理和TC降解的主要降解途径。最后，可重复使用性实验结果证明，Ag0.4-BiFeO3催化剂使用4次后仍具有较高的催化性能。4-BiFeO3 / PS系统。提出了Ag0.4-BiFeO3活化PS的可能机理和TC降解的主要降解途径。最后，可重复使用性实验结果证明，Ag0.4-BiFeO3催化剂使用4次后仍具有较高的催化性能。4-BiFeO3 / PS系统。提出了Ag0.4-BiFeO3活化PS的可能机理和TC降解的主要降解途径。最后，可重复使用性实验结果证明，Ag0.4-BiFeO3催化剂使用4次后仍具有较高的催化性能。