This study applied a mineral material of FeS to activate sulfite for efficient degradation of TTC in the presence of Cu(II) based on the identified complexation mechanism through UV–Vis spectra, FTIR spectroscopy and DFT calculation. pH plays an important role in TTC degradation and the initial pH of 6 and 7 were the divide in the contributions of FeS/sulfite oxidation and complex-precipitation. TTC-Cu(II) exhibits a superior promoting effect on the TTC degradation in FeS/sulfite system due to the improvement of TTC electron transfer reactivity and Fe(II) dissolution from FeS. Moreover, the formation of Cu(I) improved the recycling of Fe(II) from Fe(III). Dissolved oxygen-dependent free radicals’ generation was confirmed, and TTC degradation was mainly attributed to SO₄^·− and ·OH. The characterization of FeS surface through XPS, XRD, SEM-EDS, Fe(II) deactivation tests, together with the comparison of pseudo-first-order rate constants for TTC degradation by FeS and ferrous ion supported the important role of surface and dissolved Fe(II) in sulfite activation. Furthermore, reasonable degradation pathways of TTC have been proposed according to the detected products by LC-MS. This work highlights the important role of pH, DO and Cu(II) complexation in sulfite activation and TTC degradation, furnishing theoretical support for further relevant studies.

本研究基于通过 UV-Vis 光谱、FTIR 光谱和 DFT 计算确定的络合机制，应用 FeS 矿物材料激活亚硫酸盐，以在 Cu (II) 存在下有效降解 TTC。pH 在 TTC 降解中起着重要作用，初始 pH 值 6 和 7 是 FeS/亚硫酸盐氧化和复合物沉淀贡献的分界线。由于 TTC 电子转移反应性的提高和 Fe(II) 从 FeS 中溶解，TTC-Cu (II) 对 FeS/亚硫酸盐体系中的 TTC 降解表现出优异的促进作用。此外，Cu (I) 的形成改善了 Fe (II) 从 Fe (III) 的回收。证实了溶解氧依赖性自由基的产生，TTC降解主要归因于SO ₄ ^{· -}和哦。通过 XPS、XRD、SEM-EDS、Fe (II) 失活测试对 FeS 表面的表征，以及 FeS 和亚铁离子对 TTC 降解的伪一级速率常数的比较支持了表面和溶解 Fe 的重要作用(II) 在亚硫酸盐活化中。此外，根据LC-MS检测的产物提出了TTC的合理降解途径。这项工作突出了 pH、DO 和 Cu (II) 络合在亚硫酸盐活化和 TTC 降解中的重要作用，为进一步的相关研究提供了理论支持。