Journal of Hazardous Materials ( IF 13.6 ) Pub Date : 2020-11-18 , DOI: 10.1016/j.jhazmat.2020.124567 Fansong Liu , Qiujing Xu , Huizhi Liang , Haiying Wang , Cheng Zhong , Xiaobo Min , Liyuan Zhang
Stabilization of arsenic sulfur slag (As-S slag) is of high importance to prevent the release of deadly As pollutants into environment. However, the molecular understanding on the stability of As-S slag is missing, which in turn restricts the development of robust approach to solve the challenge. In this work, we investigated the structure-stability relationship of As-S slag with adopting various As-S clusters as prototypes by density functional theory (DFT). Results showed that the configuration of S multimers-covering-(As2S3)n is the most stable structure amongst the candidates by the analysis of energies and bonding characteristics. The high stability is explained by orbital composition that the 4p-orbital (As) binding with 3p-orbital (S) decreases energy level of highest occupied molecular orbital (HOMO). Inspired from the calculations, an excess-S-based hydrothermal method was successfully proposed and achieved to promote the stabilization of As-S slag. Typically, the As concentration from the leaching test of stabilized As-S slag is only 0.8 mg/L, which is much lower than the value from other stabilized slag.
中文翻译:
硫化砷团簇密度泛函理论计算的硫化砷渣稳定机理
稳定砷硫渣(As-S渣)对于防止致命的As污染物释放到环境中非常重要。但是,缺乏对As-S炉渣稳定性的分子理解,这反过来又限制了解决该挑战的可靠方法的发展。在这项工作中,我们通过密度泛函理论(DFT)研究了采用各种As-S团簇作为原型的As-S炉渣的结构稳定性关系。结果表明,通过能量和键合特征分析,S多聚体-(As 2 S 3)n构型是候选物中最稳定的结构。高稳定性是由与4p轨道(As)结合的轨道组成解释的3p轨道(S)降低最高占据分子轨道(HOMO)的能级。从计算中得到启发,成功地提出并实现了基于过量S的水热法,以促进As-S渣的稳定化。通常,来自稳定的As-S炉渣的浸出试验的As浓度仅为0.8 mg / L,远低于其他稳定的炉渣的As浓度。