The improvement on diclofenac (DCF) degradation by Fe(II)-activated persulfate (PS) combined with bisulfite (BS) was investigated. It was observed that the introduction of BS in Fe(II)/PS process enhanced the circulation of Fe(III/II) and kept Fe(II) at a high concentration, resulting a rapid and continuous DCF degradation. The initial pH, reagent dosages and reaction temperature played important roles on DCF removal in BS/Fe(II)/PS process. The main iron species in this system were FeHSO₃⁺, Fe²⁺ and FeOHSO₃H⁺, and their variation trends were calculated by the software of MINITEQ 3.1. Based on the alcohols quenching experiments, SO₄⁻ was confirmed to be the prominent reactive radical for DCF oxidation in BS/Fe(II)/PS process. Moreover, the probable DCF degradation mechanism was proposed based on the detected intermediate products and density functional theory (DFT) calculation. The BS/Fe(II)/PS system presented a synergistic effect for rapid and steady DCF degradation through the occurred cycle of Fe(II/III) (i.e., oxidation of Fe(II) by PS and then reduction of Fe(III) by BS) and solved the drawbacks of slow initial reaction of Fe(II)/BS and weak durability of Fe(II)/PS. This study could provide an effective and environmentally friendly approach to sewage treatment.

研究了Fe（II）活化的过硫酸盐（PS）结合亚硫酸氢盐（BS）对双氯芬酸（DCF）降解的改善。观察到，在Fe（II）/ PS工艺中引入BS增强了Fe（III / II）的循环，并使Fe（II）保持在高浓度，从而导致DCF快速连续地降解。初始pH，试剂用量和反应温度对BS / Fe（II）/ PS工艺中DCF的去除起重要作用。该系统中的主要铁种类为FeHSO ₃ ⁺，Fe ²⁺和FeOHSO ₃ H ⁺，并通过MINITEQ 3.1软件计算了它们的变化趋势。基于该醇猝灭实验，SO ₄ ^-被证实是BS / Fe（II）/ PS工艺中DCF氧化的主要反应自由基。此外，基于检测到的中间产物和密度泛函理论（DFT）计算，提出了可能的DCF降解机理。BS / Fe（II）/ PS系统通过发生的Fe（II / III）循环（即PS氧化Fe（II）然后还原Fe（III））呈现了快速稳定DCF降解的协同效应。解决了Fe（II）/ BS的初始反应缓慢和Fe（II）/ PS的耐久性差的缺点。这项研究可以为污水处理提供一种有效且环保的方法。