Schwertmannite (SCH) as an adsorbent for Cr(VI) removal has been widely investigated. However, there are limited reports on photoreduction driven dissolution of SCH loaded with Cr(VI) (SCH–Cr(VI)) and the fate of Cr(VI) in the presence of dissolved organic matter (DOM). In this study, the effect of tartaric acid (TA) on the stability of SCH–Cr(VI) exposed to simulated solar radiation was examined. The results demonstrated that TA could greatly enhance the release of the dissolved total Fe (TFe) from SCH–Cr(VI). Conversely, the dissolved total Cr (TCr) obviously declined. Low pH promoted the liberation of TFe and TCr. The presence of ions including Al³⁺, Ca²⁺, K⁺ and CO₃²⁻ exerted different impact on the photoreductive dissolution of SCH–Cr(VI) induced by TA. On the basis of the species distribution of iron and chromium and the characterization of the solid samples, the underlying mechanism is proposed for the transformation and the fate of Cr(VI). Cr(VI) was reduced to Cr(III) by Fe(II) generated from Fe(III)-TA_n via ligand to metal charge transfer. The produced Cr(III) was adsorbed by SCH or co-precipitates with Fe(III). Thus, this study helps us to gain an insight into the mobility and fate of Cr(VI) in acid mining drainage containing DOM, and will help design remediation strategies for Cr contamination.

Schwertmannite（SCH）作为去除Cr（VI）的吸附剂已被广泛研究。但是，关于在溶解有机物（DOM）存在下，光还原驱动的含Cr（VI）（SCH-Cr（VI））的SCH的溶解以及Cr（VI）的命运的报道有限。在这项研究中，研究了酒石酸（TA）对SCH-Cr（VI）暴露于模拟太阳辐射下的稳定性的影响。结果表明，TA可以大大增强SCH–Cr（VI）中溶解的总Fe（TFe）的释放。相反，溶解的总Cr（TCr）明显下降。低pH值促进TFe和TCr的释放。离子包括Al ³⁺，Ca 2 ⁺，K ⁺和CO ₃ ^2-的存在对TA诱导的SCH–Cr（VI）的光还原溶解产生不同的影响。根据铁和铬的种类分布和固体样品的特征，提出了六价铬的转化和归宿的潜在机理。Cr（VI）通过Fe（III）-TA _n通过配体到金属的电荷转移而生成的Fe（II）还原为Cr（III）。生成的Cr（III）被SCH吸附或与Fe（III）共沉淀。因此，本研究有助于我们深入了解含DOM的酸性采矿废水中Cr（VI）的迁移率和命运，并有助于设计Cr污染的补救策略。