方解石去除废水中高浓度磷酸盐机理与影响因素

采用X射线衍射分析（XRD），透射电镜观测（TEM），红外光谱分析（FT—IR），比表面积（BET）与孔径测试（BJH）分析结合理论计算探讨方解石除磷机理；通过实验考察主要影响因素，并对除磷机理加以验证。结果表明：反应时间、反应温度、pH值、投加量对除磷效率影响显著。BET，BJH与TEM测试表明方解石在整个除磷过程中未出现多孔性结构，比表面积均小于16．0m^2／g，孔容低于0．085cm^3／g，其吸附能力很弱，吸附作用不是除磷的主要机制；XRD与FT-IR测试结果显示生成CaHPO4·2H4O（DCPD）沉淀与DCPD转化为非晶态磷酸三钙（ACP）沉淀是除磷的主要机制，DCPD→ACP的转化过程是去除磷酸盐的主要控制步骤．

Mechanism and Influencing Factors of Concentrated Phosphate Removal by Calcite

The phosphate removal mechanisms of Calcite were investigated with the tests of X-ray diffraction （XRD） analysis, transmission electron microscope （TEM） measurement, fourier transform infrared spectroscopy （FT-IR） analysis , specific surface area by Brunauer-Emmett-Teller（BET） method and pole size distribution by Barrett-Joyner-Halenda （BJH） method. The main influencing factors on phosphate removal were investigated and the removal mechanism was approved. It was shown that phosphate removal efficiency was significantly influenced by reaction time, temperature, pH value and dosage of calcite. And with BET, BJH and TEM tests, no porous materials, less than 16.0 m^2/g for the specific surface area and below 0. 085 cm3/g for total pore volume, were found during the reaction process so as to prove that absorption was not the main way of phosphate removal. And based on XRD and FT-IR tests, it was found that chemical precipitation was the main way of phosphate removal which contained two steps： the formation of CaHPO4 · 2H2O（DCPD） and its transformation to ACP, and the controlling step was DCPD＇s transformation to ACP.