钢渣对水体中磷的去除性能及机制解析

Analysis of the Performance and Mechanism of Phosphorus Removal in Water by Steel Slag

针对不同类型钢渣在除磷过程中存在的显著差异,以电炉渣为研究对象,探讨了环境因素(吸附时间、吸附温度)对钢渣除磷的影响,验证了其对磷酸盐、焦磷酸盐及实际水体的除磷效果,联合采用扫描电镜(SEM)、能量色散X射线能谱(EDS)、X射线荧光光谱(XRF)和X射线衍射光谱(XRD)技术探究其除磷机制,对比分析了钢渣与陶粒和沸石的除磷效率,并对钢渣除磷的安全性能进行了评估.结果表明,吸附时间显著影响钢渣除磷效果,当吸附时间为30 min时钢渣对质量浓度范围为1~20 mg·L^(-1)的磷酸盐溶液的去除率均可达到97%以上.温度对实验所用钢渣的除磷效果影响并不显著.钢渣对焦磷酸盐吸附能力弱于正磷酸盐,其对初始质量浓度为3 mg·L^(-1)的焦磷酸盐的去除率为82.45%.光谱分析结果表明,钢渣除磷的主要机制为化学吸附并辅以物理吸附,Ca HPO_(4)·2H_(2)O为主要沉淀物质.钢渣对生物池出水和湿地系统中的磷素去除效果显著,总磷去除率分别为98.36%和93.33%.对比可知,钢渣对磷酸盐的去除效果优于陶粒和沸石,其对PO_(4)3-的去除率分别为96%、40%和10%.钢渣浸出液中各重金属含量均符合地表水Ⅰ类标准要求,钢渣安全可靠.

In view of the significant differences in phosphorus removal processes by different steel slags,electric furnace slag was taken as the research object to discuss the effects of environmental factors,including the adsorption time and adsorption temperature,on phosphorus removal and to verify the phosphorus removal performances of steel slag for phosphate,pyrophosphate,and actual water bodies.With the help of spectral techniques including scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),X-ray fluorescence spectroscopy(XRF),and an X-ray diffractometer(XRD),the phosphorus removal mechanisms of steel slag were explored.Moreover,the phosphorus removal abilities of different absorptive media of steel slag,ceramsite,and zeolite were compared,and the safety performances of phosphorus removal by steel slag were evaluated.The results showed that the adsorption time significantly affected the phosphorus removal efficiency of steel slag.The phosphorus removal efficiencies of phosphate solutions with a concentration range of 1-20 mg·L^(-1)using steel slag could reach over 97%when the adsorption time was 30 min.The effect of temperature on phosphorus removal by steel slag was not significant.The pyrophosphate adsorption capacity of steel slag was weaker than that of orthophosphate,and the removal rate of pyrophosphate with an initial concentration of 3 mg·L^(-1)was 82.45%.Spectral analysis showed that the mechanisms of phosphorus removal by steel slag were chemical adsorption assisted by physical adsorption,and calcium-phosphorus was the main precipitate component.Ca HPO_(4)·2H_(2)O was the main precipitate.Steel slag exhibited excellent phosphorus removal properties for removing phosphorus in the biological pond effluent and wetland system,achieving total phosphorus removal rates of 98.36%and 93.33%,respectively.In comparison,the phosphate removal performance of steel slag was better than that of ceramsite and zeolite,and the removal efficiencies of PO_(4)3-were 96%,40%,and 10%,respectively.The contents of heavy metals in the leaching solution of steel slag met the requirements of the Class I standard of surface water;thus,the steel slag was safe and reliable.