纳米Fe_3O_4/膨润土的制备、表征及光催化降解焦化废水

以铝柱撑膨润土负载纳米Fe_3O_4制备出性能良好的复合型催化剂。结合X射线粉末衍射(XRD)、扫描电镜(SEM)和比表面孔隙分析(BET)对催化剂的晶相、比表面积和粒度进行表征。负载的纳米Fe_3O_4粒径约为20～30nm,均匀分散到膨润土表面,未发生明显的团聚。在紫外光作用下用该催化剂对焦化厂二沉池出水进行深度处理。结果表明,在催化剂投加量为0.7 g/L,pH为2.5,温度40℃,H_2O_2初始浓度为17.6mmol/L的反应条件下,二沉池出水(化学需氧量COD=140mg/L,色度=400度)经催化氧化降解后,COD和色度可分别降低到54.44 mg/L和10度,达到国家工业再生用水水质标准GB/T 19923-2005(COD≤60 mg/L,色度≤30度)。催化剂重复使用4次时,废水COD和色度去除率保持稳定。

Synthesis,Characterization and Photocatalytic Degradation for Coking Wastewater of Fe_3O_4 Nanoparticles/Bentonite

Al-pillared clays supported Fe_3O_4 nanoparticles were prepared as composite catalyst.XRD,BET and SEM were used to study its microstructure,surface area and average particle size.The supported Fe_3O_4 nanoparticles with a size about 20～30 nm existed on the surface of clays,with better dispersing and no obvious aggregation than that without bentonite support.The obtained catalyst was applied for advanced treatment of sedimentation tank effluent of coking process under UV. Results indicated that COD and chroma of the wastewater could be reduced from 140 mg/L and 400 to 54.44 mg/L and 10 respectively in the conditions as catalyst dosage 0.7 g/L,initial pH 2.5,temperature 40 t and initial H_2O_2 concentration 17.6 mmol/L,which could satisfy the recycled water standard of GB/T 19923-2005 with COD less than 60 mg/L and chroma less than 30.The removal rates of COD and chroma in 4 cycles remained stable.