Wang Lei, Jin Jian, Li Xiao-dong, Chi Yong, Yan Jian-hua
State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
Huan Jing Ke Xue. 2010 Aug;31(8):1973-80.
An alkalis assisted hydrothermal process was induced to stabilize heavy metals both from municipal solid waste or medical waste incinerator fly ash and waste water. The results showed that alkalis assisted hydrothermal process removed the heavy metals effectively from the waste water, and reduced leachability of fly ash after process. The heavy metal leachabilities of fly ash studied in this paper were Mn 17,300 microg/L,Ni 1650 microg/L, Cu 2560 microg/L, Zn 189,000 microg/L, Cd 1970 microg/L, Pb 1560 microg/L for medical waste incinerator fly ash; Mn 17.2 microg/L, Ni 8.32 microg/L, Cu 235.2 microg/L, Zn 668.3 microg/L, Cd 2.81 microg/L, Pb 7200 microg/L for municipal solid waste incinerator fly ash. After hydrothermal process with experimental condition [Na2CO3 dosage (5 g Na2CO3/50 g fly ash), reaction time = 10 h, L/S ratio = 10/1], the heavy metal removal efficiencies of medical waste incinerator fly ash were 86.2%-97.3%, and 94.7%-99.6% for municipal solid waste incinerator fly ash. The leachabilities of both two kinds of fly ash were lower than that of the Chinese national limit. The mechanism of heavy metal stabilization can be concluded to the chemisorption and physically encapsulation effects of aluminosilicates during its formation, crystallization and aging process, the high pH value has some contribution to the heavy metal removal and stabilization.
采用碱辅助水热法对城市固体废物或医疗废物焚烧飞灰及废水中的重金属进行稳定化处理。结果表明，碱辅助水热法能有效去除废水中的重金属，并降低处理后飞灰的浸出性。本文研究的医疗废物焚烧飞灰中重金属的浸出浓度分别为：锰17300μg/L、镍1650μg/L、铜2560μg/L、锌189000μg/L、镉1970μg/L、铅1560μg/L；城市固体废物焚烧飞灰中重金属的浸出浓度分别为：锰17.2μg/L、镍8.32μg/L、铜235.2μg/L、锌668.3μg/L、镉2.81μg/L、铅7200μg/L。在[碳酸钠用量（5g碳酸钠/50g飞灰）、反应时间=10h、液固比=10/1]的水热条件下处理后，医疗废物焚烧飞灰中重金属的去除效率为86.2%-97.3%，城市固体废物焚烧飞灰中重金属的去除效率为94.7%-99.6%。两种飞灰的浸出性均低于中国国家标准限值。重金属稳定化的机制可归结为在铝硅酸盐形成、结晶和老化过程中的化学吸附和物理包裹作用，高pH值对重金属的去除和稳定化有一定贡献。
