Sulfide minerals are important in immobilizing toxic contaminants in reducing environments. Iron sulfide (FeS) is ubiquitous in anoxic conditions and is a good scavenger of various organic and redox sensitive contaminants and heavy metals. Despite its contaminant removal capabilities, FeS has not been used as a practical adsorbent in contaminant removal due to its rapid oxidation under atmospheric conditions. To increase its applicability, we developed a method of modifying FeS by the addition of NaBH₄ to form the less oxygen-sensitive NaBH₄–FeS. We conducted oxidation tests using laboratory batch testing and real-time synchrotron X-ray absorption spectroscopy (XAS). The Fe K-edge XAS results showed that the oxidation rate of NaBH₄–FeS was eight times slower than that of unmodified FeS while maintaining comparable contaminant removal capacities for Cr(VI) and As(III). The results of mechanistic density functional theory (DFT) calculations demonstrated that the oxidation of FeS occurred through electron transfer from sulfur of FeS to an oxidizing agent of oxygen, and that the hydride ion provided by NaBH₄ retarded electron transfer from the FeS surface.

硫化物矿物在还原环境中固定有毒污染物方面很重要。硫化铁（FeS）在缺氧条件下无处不在，并且是各种对有机和氧化还原敏感的污染物和重金属的良好清除剂。尽管具有去除污染物的能力，但由于FeS在大气条件下会迅速氧化，因此尚未被用作去除污染物的实用吸附剂。为了提高其适用性，我们开发了一种通过添加NaBH ₄来改性FeS的方法，以形成对氧敏感性较低的NaBH ₄ -FeS。我们使用实验室批处理测试和实时同步加速器X射线吸收光谱（XAS）进行了氧化测试。Fe K-edge XAS结果表明NaBH ₄的氧化速率-FeS比未改性的FeS慢八倍，同时保持了相当的Cr（VI）和As（III）污染物去除能力。机械密度泛函理论（DFT）的计算结果表明，FeS的氧化是通过电子从FeS的硫转移到氧的氧化剂而发生的，而NaBH ₄提供的氢化物离子阻碍了电子从FeS表面的转移。