挤压法制备Fe-Al-Ce复合氧化物颗粒除氟性能及地下水处理应用

Defluoridation performance and application of granular Fe-Al-Ce trimetal oxide adsorbent by extrusion method for fluoride removal from groundwater

利用粘结挤压法将Fe-Al-Ce复合氧化物粉末材料制备成颗粒材料(GFAC),进行表征、静态和动态吸附除氟性能评价和现场应用。结果显示,优选GFAC颗粒直径为1.6 mm,具有较高的压缩破坏强度33.80 N和除氟性能。GFAC颗粒对氟的吸附过程符合准二级反应动力学方程,吸附速率受膜扩散和内扩散共同控制;在pH 7.0±0.2条件下,GFAC颗粒对氟的饱和吸附容量达到51.28 mg/g(25℃,Langmuir等温吸附模型)。不同空间流速(SV)下动态实验出水穿透(1mg/L)时对氟的累积吸附量分别为5.69 mg/g(SV=1 h-1)、5.61 mg/g(SV=2 h-1)、2.83 mg/g(SV=5 h-1),高于常见活性氧化铝除氟剂(AA,1.77 mg/g,SV=1 h-1)及其他报道的颗粒除氟剂。GFAC颗粒在河北现场成功用于实际高氟地下水的处理,在原水氟浓度(3.7±0.3)mg/L和pH 8.0±0.2条件下,对氟的累计吸附量为3.16 mg/g,明显高于AA(0.83mg/g),具有较好的应用前景。

The Fe-Al-Ce trimetal oxide powder was granulated via extrusion with binder.The granular adsorbent（GFAC） was investigated through characterization,bantch,column study and field application.The results showed that the optimum GFAC was 1.6 mm cylinder granule diameter with high compress strength 33.80 N and adsorption capacity.The adsorption process well fitted the pseudo-second-order kinetic equation and the adsorption rapid was controlled by film diffusion and intrapaticle diffusion.The maximum fluoride adsorption capacity for GFAC was 51.28 mg/g（25℃,Langmuir model） at pH 7.0 ± 0.2.In column studies,the accumulated fluoride adsorption capacities of the GFAC were 5.69 mg/g（SV=1 h-1）,5.61 mg/g（SV=2 h-1） and 2.83 mg/g（SV=5 h-1） at the breakthrough point（1.0 mg/L）,respectively,which was much higher than activated alumina（AA,1.77 mg/g,SV=1 h-1） and other reported granular adsorbents.For fluoride bearing groundwater（fluoride concentration（3.7 ± 0.3）mg/L,pH 8.0 ± 0.2）,the GFAC exhibited the accumulated fluoride adsorption capacity of 3.16 mg/g,while AA was 0.83 mg/g,showing an attractive application perspective.