Wu Pingxiao

Microstructural characteristic of montmorillonite and its thermal treatment products

The montmorillonite was studied by different methods, such as chemical analysis, DAT, TG, XRD, IR, AFM and MAS NMR. The experimental results show that the hydroxyl in octahedra sheets begins dehydrating when the thermal treatment temperature reaches 659°C, but the layer structure remains the same, and the corresponding Al(VI) is turned into Al(IV) in octahedra sheets. When the temperature reaches 900°C, the layer structure of montmorillontite is destroyed, and the new mineral phase μ-cordierite is found. When the temperature reaches 1200°C, the μ-cordierite phase loses its stability, and decomposes into cristobalite phase and mullite phase. Meanwhile, the recrystallization phenomenon in thermal treatment products is obvious. There is a small quantity of AlVI signal in MAS NMR spectrum, corresponding to Al of mullite. When the temperature reaches 1350°C, the cristobalite and mullite phases reduce slightly, and more Fe-cordierite phase appears, corresponding to Fe-cordierite spectrum in XRD and MAS NMR.

Structural characteristics of zeolite/TiO2 composite and photocatalysis of toluene degradation

Zeolite/TiO2 composite photocatalysts were prepared by adding a certain amount of mordenite in TiO2, and degradation experiments on toluene through photocatalytic reactions were implemented. In this paper, these photocatalysts were characterized by using SEM, IR, RAMAN, XRD and UV-Vis to shed light on the microstructure and photocatalytic performance of the composite photocatalysts. The results indicated that the structural hydroxy of zeolite can participate in bonding reaction with TiO2, the addition of zeolite can greatly reduce the diameter of nanometer TiO2 particles in the composite photocatalysts, and enhance the ultraviolet light absorptance of the composite photocatalysts. When the percentage content of zeolite reached 20%, the photocatalytic performance of this catalyst would be highest, with the toluene conversion rate up to 94.58%.

铜绿假单胞菌负载Fe(III)对水中六价铬的生物吸附性能研究

采用原位沉积技术将Fe（Ⅲ）负载于铜绿假单胞菌（Pseudomonas aeruginosa，简称Pa）表面制备了Fe（Ⅲ）与细菌的复合体（Fe-Pa），研究了Fe-Pa对水溶液中Cr(Ⅵ)的吸附特性，探讨了最佳合成条件、Fe-Pa投加量、溶液pH值、时间和Cr(Ⅵ)初始浓度等因素对Cr(Ⅵ)吸附效果的影响，同时利用SEM、FT-IR、XPS和Zeta电位对Fe-Pa进行表征分析.吸附实验结果显示，Fe（Ⅲ）浓度为600 mg·L-1、细菌投加量为0.5 g·L-1制备的Fe-Pa效果最佳；Fe-Pa去除Cr(Ⅵ)适宜于酸性条件进行；Fe-Pa对Cr(Ⅵ)的吸附速率较快，60 min内可达到吸附平衡，为自发的吸热吸附，且符合准二级动力学和Langmuir等温模型.表征结果表明，Fe（Ⅲ）成功地负载到铜绿假单胞菌上，为吸附Cr(Ⅵ)提供更多的活性位点，主要机制为静电吸附作用、络合作用和还原作用.经过4次吸附/再生后，Fe-Pa对Cr(Ⅵ)的吸附能力仍在72%以上，表明Fe-Pa具有较好的重复使用性.

ZnO-ZnCr 2 O 4 混合金属氧化物的制备及其光催化降解双酚A

采用共沉淀法制备前驱体ZnCr-LDH，并在不同煅烧温度下制备ZnCr混合金属氧化物（ZnCr-MMO）。同时，利用XRD、SEM、TEM、XPS、PL、UV-vis等对样品的结构、形貌、光学性能进行表征分析。最后，在模拟太阳光照射下，通过光催化降解双酚A研究材料的光催化活性。结果表明，所制备的混合金属氧化物由ZnO和ZnCr2O4组成，煅烧温度越高，结晶度越高；与ZnCr-LDH相比，ZnCr-MMO的紫外-可见吸收光谱在紫外和可见光范围均有较强的吸收；随着煅烧温度的升高，ZnCr-MMO荧光光谱强度先减弱后增强；与ZnCr-LDH相比，ZnCr-MMO的光催化活性明显提高，煅烧温度为700 ℃时制得的ZnCr-MMO光催化活性最高，对BPA的降解率达到75%；该催化剂适于处理pH为5~9的含BPA的废水。