垃圾焚烧飞灰处理高浓度含磷废水的动力学

Kinetics of Concentrated Phosphates Removal by Municipal Solid Waste Incineration Fly Ash

采用能谱分析(EDS),荧光光谱分析(XRF),透射电子显微镜(TEM)测试的手段结合水化学理论研究了垃圾焚烧(MSWI)飞灰去除废水中高浓度磷酸盐的动力学。结果表明:MSWI飞灰除磷速率较快,303 K下30 min磷去除率95%;除磷过程宏观表现为吸热过程,但对外加能量要求较低;除磷反应对MSWI飞灰中的重金属有很好的稳定化效果,反应后溶液中重金属未检出。化学沉淀是MSWI飞灰除磷的主要机制,Ca、Fe、Zn等均可为反应提供阳离子。反应物PO43-与可溶性产物的内扩散过程是飞灰除磷的控制步骤,宏观动力学过程适用于球体内扩散控制模型,磷酸盐反应率与时间的关系可描述为1-3(1-X)2/3+2X=kt,实验得到表观活化能约10.06 kJ/mol。

Kinetics of phosphates removal by Municipal Solid Waste Incineration （MSWI） fly ash were investigated with the tests of EDS, XRF and TEM. It was shown that 95% of phosphates was removed by MSWI fly ash in 30rain under 303 K. The process was heat in-taking process whereas the heat amount required was small. Heavy metals were stabilized during the process and no heavy metals were detected in solution after reaction. Chemical precipitation was the main way of phosphates removal. Ca,Fe,Zn etc. can provide cations for phosphates removal reaction. The macro kinetics of phosphates removal by MSWI fly ash can be represented by the model of sphere internal diffusion control. And internal diffusion process of PO4^3- and soluble products were the controlling step. The relation between reaction rate of phosphate （X） and reaction time （t） can be represented as 1-3（1-X）2/3＋2X=kt; the apparent activation energy was about 10.06kJ / mol