Chen Jie, Zhu Wanchen, Shen Yizhe, Fu Congkai, Li Minjie, Lin Xiaoqing, Li Xiaodong, Yan Jianhua
State Key Laboratory of Clean Energy Utilization, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China.
State Key Laboratory of Clean Energy Utilization, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China; Key Laboratory of Clean Energy and Carbon Neutrality of Zhejiang Province, Jiaxing Research Institute, Zhejiang University, 1300 Dongshengxilu Road, Jiaxing, 314031, China.
Chemosphere. 2023 Jun;326:138465. doi: 10.1016/j.chemosphere.2023.138465. Epub 2023 Mar 20.
Municipal solid waste incineration fly ash (MSWI FA) stabilization/solidification using calcium carbonate (CaCO) oligomer is an efficient, low-carbon disposal method. The insoluble Ca in FA was converted to free-Ca, utilizing for CaCO oligomer preparation, which was crystallized and polymerized by thermal induction to develop continuous cross-link or bulk structures for stabilization/solidification of potentially toxic elements (PTEs, e.g., lead (Pb) and zinc (Zn)). Experimental results showed that the weakly alkaline acid-leaching suspension provided an excellent condition for the generation of CaCO oligomers, with Pb and Zn immobilization reaching over 99.4%. With the acid strengthening of the suspension, H took the lead in protonating with TEA and limiting the capping action of TEA, which was harmful to the synthesis of CaCO oligomers. Ethanol with a low dielectric constant was considered an ideal solvent for oligomer production, and triethylamine (TEA) as a capping agent established hydrogen bonds (N⋯H) with protonated CaCO. HO molecules competed with the protonated CaCO molecules for TEA with ethanol concentration decreasing, resulting in erratic precipitation of CaCO molecules and significantly elevated leaching risk of Pb and Zn. The sequential extraction procedure, pH-dependent leaching, and geochemical analysis results revealed that the dissolution/precipitation of Ca, Pb, and Zn in treated FA was mostly controlled by the carbonate mineral phases. Moreover, the low boiling points of ethanol and TEA can be recovered for recycling. The gel-like, flexible combination of CaCO oligomers and FA particles formed by FA offers great resource utilization potential via a controlled crystallization polymerization process.
使用碳酸钙（CaCO）低聚物对城市固体废弃物焚烧飞灰（MSWI FA）进行稳定化/固化处理是一种高效、低碳的处置方法。飞灰中不溶性的钙被转化为游离钙，用于制备CaCO低聚物，通过热诱导使其结晶并聚合，形成连续的交联或块状结构，以稳定/固化潜在有毒元素（PTEs，例如铅（Pb）和锌（Zn））。实验结果表明，弱碱性酸浸出悬浮液为CaCO低聚物的生成提供了良好条件，铅和锌的固定率达到99.4%以上。随着悬浮液酸性增强，H率先与三乙胺（TEA）质子化，限制了TEA的封端作用，这对CaCO低聚物的合成有害。低介电常数的乙醇被认为是低聚物生产的理想溶剂，三乙胺（TEA）作为封端剂与质子化的CaCO形成氢键（N⋯H）。随着乙醇浓度降低，HO分子与质子化的CaCO分子竞争TEA，导致CaCO分子沉淀不稳定，铅和锌的浸出风险显著升高。连续提取程序、pH依赖浸出和地球化学分析结果表明，处理后飞灰中钙、铅和锌的溶解/沉淀主要受碳酸盐矿物相控制。此外，乙醇和TEA的低沸点可以回收再利用。飞灰形成的CaCO低聚物与飞灰颗粒的凝胶状、柔性组合通过可控的结晶聚合过程具有巨大的资源利用潜力。
