College of Civil Science and Engineering, Yangzhou University, Yangzhou 225127, China.
College of Civil Science and Engineering, Yangzhou University, Yangzhou 225127, China.
J Hazard Mater. 2023 Mar 15;446:130720. doi: 10.1016/j.jhazmat.2023.130720. Epub 2023 Jan 3.
To solve the environmental problems caused by heavy metal pollution, a new cementitious material (basic magnesium sulfate cement, BMSC) was developed for the solidification of Cu/Zn. First, the effects of different amounts of Cu/Zn on the properties (compressive strength, setting time, pH, and leaching toxicity) of the BMSC were investigated. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) were used to investigate the effects of different amounts of Cu/Zn on the phase and microstructure of BMSC. The results showed that Cu/Zn inhibited the hydration of BMSC, reduced compressive strength, and prolonged the setting time. The results of the leaching tests showed that the BMSC system exhibited high immobilization efficiency (up to 99%) for Cu/Zn. Further, the BMSC solidification matrix exhibited excellent acid resistance (compressive strength >40 MPa after 28 days of immersion). The physical phase analysis showed that the main phases of BMSC were the 5Mg(OH)-MgSO-7 HO (5-1-7) phase and Mg(OH), and the crystal structure refinement analysis suggested that Cu/Zn ions were substituted with Mg in the 5-1-7 phase. It was confirmed that the solidification mechanism of BMSC on Cu/Zn is mainly performed by chemical complexation and ionic substitution.
为了解决重金属污染带来的环境问题，开发了一种新型胶凝材料（碱式硫酸镁水泥，BMSC）用于固化 Cu/Zn。首先，研究了不同量的 Cu/Zn 对 BMSC 性能（抗压强度、凝结时间、pH 值和浸出毒性）的影响。采用 X 射线衍射（XRD）、X 射线光电子能谱（XPS）和扫描电子显微镜结合能谱（SEM-EDS）研究了不同量的 Cu/Zn 对 BMSC 相和微观结构的影响。结果表明，Cu/Zn 抑制了 BMSC 的水化，降低了抗压强度，延长了凝结时间。浸出试验结果表明，BMSC 体系对 Cu/Zn 具有很高的固定化效率（高达 99%）。此外，BMSC 固化基体具有优异的耐酸性能（浸泡 28 天后抗压强度>40 MPa）。物理相分析表明，BMSC 的主要物相为 5Mg(OH)-MgSO-7HO（5-1-7）相和 Mg(OH)，晶体结构精修分析表明 Cu/Zn 离子在 5-1-7 相中被 Mg 取代。证实了 BMSC 对 Cu/Zn 的固化机制主要是通过化学络合和离子取代来实现的。
