State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
Waste Manag Res. 2010 Dec;28(12):1133-42. doi: 10.1177/0734242X10362243. Epub 2010 Apr 29.
This study investigated the process of aluminosilicate formation in medical waste incinerator fly ash containing large amounts of heavy metals and treated with alkaline compounds at 375 degrees C and examined how this process affected the mobility and availability of the metals. As a consequence of the treatments, the amount of dissolved heavy metals, and thus their mobility, was greatly reduced, and the metal leaching concentration was below the legislative regulations for metal leachability. Moreover, this process did not produce a high concentration of heavy metals in the effluent. The addition of alkaline compounds such as sodium hydroxide and sodium carbonate can prevent certain heavy metal ions dissolving in water. In comparison with the alkaline-free condition, the extracted concentrations of As, Mn, Pb, Sr and Zn were decreased by about 51.08, 97.22, 58.33, 96.77 and 86.89% by the addition of sodium hydroxide and 66.18, 86.11, 58.33, 83.87 and 81.91% by the addition of sodium carbonate. A mechanism for how the formation of aluminosilicate occurred in supercritical water and affected the mobility and availability of the heavy metals is discussed. The reported results could be useful as basic knowledge for planning new technologies for the hydrothermal stabilization of heavy metals in fly ash.
本研究调查了在 375°C 下用碱性化合物处理含有大量重金属的医疗废物焚烧飞灰中铝硅酸盐形成的过程，并研究了该过程如何影响重金属的迁移性和生物有效性。由于处理的原因，溶解态重金属的量（即其迁移性）大大降低，金属浸出浓度低于金属浸出性的立法规定。此外，该过程未在废水中产生高浓度的重金属。添加氢氧化钠和碳酸钠等碱性化合物可以防止某些重金属离子溶于水。与无碱条件相比，在碱性条件下添加氢氧化钠可使 As、Mn、Pb、Sr 和 Zn 的萃取浓度分别降低约 51.08%、97.22%、58.33%、96.77%和 86.89%，添加碳酸钠可使 As、Mn、Pb、Sr 和 Zn 的萃取浓度分别降低 66.18%、86.11%、58.33%、83.87%和 81.91%。讨论了在超临界水中形成铝硅酸盐以及如何影响重金属的迁移性和生物有效性的机制。报告的结果可以作为在飞灰中利用水热稳定化技术固定重金属的新技术规划的基础知识。
