Designing Novel Magnesium Oxysulfate Cement for Stabilization/Solidification of Municipal Solid Waste Incineration Fly Ash
Designing Novel Magnesium Oxysulfate Cement for Stabilization/Solidification of Municipal Solid Waste Incineration Fly Ash
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设计用于稳定/固化城市固体废物焚烧飞灰的新型硫氧镁水泥
DOI：
10.1016/j.jhazmat.2021.127025
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发表时间：
2021
影响因子：
13.6
通讯作者：
Daniel C.W. Tsang
中科院分区：
文献类型：
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作者：
Lei Wang;Yuying Zhang;Liang Chen;Binglin Guo;Yongshan Tan;Keiko Sasaki;Daniel C.W. Tsang
城市垃圾焚烧飞灰是一种典型的危险废物。在这项研究中，创新的硫氧镁水泥（MOSC）的粘合剂被设计用于稳定/固化（S/S）的垃圾焚烧飞灰，专注于MOSC粘合剂和典型的金属阳离子（Pb 2+）/含氧阴离子（AsO 33-）之间的相互作用。实验结果表明，Pb和As对高硫酸盐5 MS体系的反应有轻微的抑制作用，而对低硫酸盐10 MS体系的反应有明显的抑制作用。5 MS粘结剂系统表现出优异的固定效率（99.8%）的铅和砷。扩展X射线吸收精细结构谱表明，Pb 2+在MOSC体系中与SO 42-/OH-配位，在5 Mg（OH）2·MgSO 4·7 H2O（5−1−7）相的内部结构中取代了Mg 2+离子位置。与此相反，AsO 33-取代的SO 42-位与5-1-7结构的大层间空间中的Mg 2+形成内球络合物。随后的垃圾焚烧飞灰S/S实验表明，垃圾焚烧飞灰中的少量活性硅干扰MOSC反应，并对Pb，As和其他元素的固定效率产生不利影响。通过使用33wt%的定制MOSC粘结剂处理垃圾焚烧飞灰，可以获得令人满意的S/S性能。
Municipal solid waste incineration (MSWI) fly ash is a typical hazardous waste worldwide. In this study, an innovative magnesium oxysulfate cement (MOSC) binder was designed for stabilization/solidification (S/S) of MSWI fly ash, focusing on the interactions between MOSC binder and typical metallic cations (Pb2+)/oxyanions (AsO33-). Experimental results showed that Pb and As slightly inhibited the reaction of high-sulfate 5MS system but significantly suppressed the reaction process of low-sulfate 10MS system. The 5MS binder system exhibited excellent immobilization efficiencies (99.8%) for both Pb and As. The extended X-ray absorption fine structure spectra suggested that Pb2+coordinated with SO42-/OH-in the MOSC system and substituted Mg2+ion sites in the internal structure of 5Mg(OH)2·MgSO4.7H2O (5−1−7) phase. In contrast, the AsO33-substituted SO42-sites with the formation of inner-sphere complexes with Mg2+in the large interlayer space of the 5–1–7 structure. Subsequent MSWI fly ash S/S experiments showed that a small amount of reactive Si in MSWI fly ash interfered with the MOSC reaction and adversely influenced the immobilization efficiencies of Pb, As, and other elements. Through the use of 33 wt% tailored MOSC binder for MSWI fly ash treatment, a satisfying S/S performance could be achieved.