ZnFe_(2)O_(4) 改性清淤污泥透水砖对初期雨水典型污染物净化效果及其吸附特性

Purification effect and adsorption characteristics of main pollutants in initial rain runoff by ZnFe_(2)O_(4) modified desilting sludge permeable brick

为将水体清淤污泥有效资源化利用,并同步解决初期雨水径流污染问题,合成ZnFe_(2)O_(4)用于改性清淤污泥透水砖。运用场发射扫描电子显微镜、能谱分析仪、X射线衍射仪等手段对改性前后清淤污泥透水砖进行材料表征,分析表面形貌、元素组成及晶体结构;通过ZnFe_(2)O_(4)掺混比试验筛选最优配比,并开展初期雨水径流净化试验及吸附试验。结果表明:1)ZnFe_(2)O_(4)改性大幅提升了清淤污泥透水砖对悬浮物和磷酸盐的理论最大吸附量;2)改性前后清淤污泥透水砖对磷酸盐的吸附趋于单分子层吸附,且为自发吸热过程;3)未改性清淤污泥透水砖对悬浮物的吸附过程符合多分子层吸附,而ZnFe_(2)O_(4)改性清淤污泥透水砖更符合单分子层吸附;4)ZnFe_(2)O_(4)改性清淤污泥透水砖对悬浮物和磷酸盐的吸附性能及净化效果均明显优于未改性清淤污泥透水砖,可作为功能性透水铺装材料应用于海绵城市。

In order to effectively utilize the desilting sludge from water body and solve the pollution problem of initial rain runoff simultaneously,the ZnFe_(2)O_(4) was synthesized to modify desilting sludge permeable brick.The surface morphology,elemental composition and crystal structure of prepared desilting sludge permeable bricks were analyzed by SEM,EDS and XRD.The appropriate ZnFe_(2)O_(4) mixing ratio permeable brick was screened through the ZnFe_(2)O_(4) mixing ratio test,and the inital rain purification experiments and adsorption of the prepared desilting sludge permeable bricks were carried out.The experimental results showed that:1)the ZnFe_(2)O_(4) modification greatly improved the theoretical maximum adsorption capacity of desilting sludge permeable bricks for suspended solids and phosphate.2)Before and after modification,the adsorption of phosphate by desilting sludge permeable bricks tended to be mono-molecular adsorption,and it was a spontaneous endothermic process.3)The adsorption process of unmodified desilting sludge permeable bricks to suspended solids was consistent with multi-molecular layer adsorption,while ZnFe_(2)O_(4) modified desilting sludge permeable bricks were more consistent with mono-molecular adsorption.4)ZnFe_(2)O_(4) modified desilting sludge permeable brick had the better adsorption performance and purification effect on suspended solids and phosphate than those of unmodified desilting sludge permeable bricks,and could be recommended as a suitable permeable material for use in sponge cities.