【题目】Divergent redistribution behavior of arsenic and antimony during schwertmannite transformation in presence of cysteine

【期刊】Environmental Pollution

【第一作者】程藐莎

【摘要】Schwertmannite, a key metastable iron phase in acid mine drainage, governs the environmental geochemical fate of As(V) and Sb(V). The stability of schwertmannite and the fate of the associated contaminants are readily influenced by reducing organic matter. This study investigated the transformation of schwertmannite and the differential partitioning of co-precipitated As(V) and co-precipitated Sb(V) driven by cysteine at pH 6.5. The results show that cysteine induced the transformation of schwertmannite into goethite in the absence of As(V) and Sb(V). The co-precipitated Sb(V) accelerated this transformation, while As(V) inhibited the process and altered the pathway toward lepidocrocite. Both effects intensified with increasing metalloid loading. Notably, in the coexisting system of As(V) and Sb(V), the two metalloids exhibited a synergistic inhibitory effect, with an inhibitory strength surpassing that of the single systems. As(V) remained strongly associated with the solid phase, redistributing primarily from poorly crystalline forms to surface-adsorbed forms, with minimal transfer to the aqueous phase. In the Sb(V)-schwertmannite system, Sb(V) tended to migrate into the residual fraction, whereas in the As(V)-Sb(V)-schwertmannite system, the introduction of As(V) promoted the redistribution of Sb(V) toward surface-adsorbed forms, thereby substantially increasing its release into the aqueous phase. Throughout all reaction systems, no As(III) or Sb(III) was detected, with As(V) and Sb(V) remaining the dominant redox species. These findings provided critical insights for predicting the combined environmental dynamics of arsenic and antimony in acid mine drainage scenarios and designing differentiated remediation approaches.

【文章链接】https://doi.org/10.1016/j.envpol.2026.128019