Xu Guoren, Zou Jinlong, Li Guibai
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Environ Sci Technol. 2009 Aug 1;43(15):5902-7. doi: 10.1021/es900139k.
To investigate stabilization of heavy metals in ceramsite made from wastewater treatment sludge (WWTS) and drinking water treatment sludge (DWTS), leaching tests were conducted to find out the effect of SiO2:Al2O3, acidic oxides (SiO2 and Al2O3), Fe2O3: CaO:MgO, and basic oxides (Fe2O3, CaO, and MgO) on the binding ability of heavy metals. Results show that as ratios of SiO2: Al2O3 decrease, leaching contents of Cu and Pb increase, while leaching contents of Cd and Cr first decrease and then increase; under the variation of Fe2O3:CaO:MgO (Fe2O3 contents decrease), leaching contents of Cd, Cu, and Pb increase, while leaching contents of Cr decrease. Acidic and basic oxide leaching results show that higher contents of Al2O3, Fe2O3, and MgO are advantageous to improve the stability of heavy metals, while the binding capacity for Cd, Cu, and Pb is significantly reduced at higher contents of SiO2 and CaO. The solidifying efficiencies of heavy metals are improved by crystallization, and the main compounds in ceramsite are crocoite, chrome oxide, cadmium silicate, and copper oxide. These results can be considered as a basic understanding for new technologies of stabilization of heavy metals in heavily polluted WWTS.
为研究由污水处理污泥（WWTS）和饮用水处理污泥（DWTS）制成的陶粒中重金属的稳定性，进行了浸出试验，以探究SiO₂:Al₂O₃、酸性氧化物（SiO₂和Al₂O₃）、Fe₂O₃:CaO:MgO以及碱性氧化物（Fe₂O₃、CaO和MgO）对重金属结合能力的影响。结果表明，随着SiO₂:Al₂O₃比例降低，Cu和Pb的浸出含量增加，而Cd和Cr的浸出含量先降低后增加；在Fe₂O₃:CaO:MgO变化（Fe₂O₃含量降低）时，Cd、Cu和Pb的浸出含量增加，而Cr的浸出含量降低。酸性和碱性氧化物浸出结果表明，较高含量的Al₂O₃、Fe₂O₃和MgO有利于提高重金属的稳定性，而在较高含量的SiO₂和CaO下，对Cd、Cu和Pb的结合能力显著降低。重金属的固化效率通过结晶得到提高，陶粒中的主要化合物为铬酸铅矿、氧化铬、硅酸镉和氧化铜。这些结果可被视为对重度污染的污水处理污泥中重金属稳定化新技术的基本认识。
