双金属MOFs固载TiO2的合成及光催化性能研究

采用一锅水热法合成了Ti O₂@Ce-Zr BTC复合材料，用于光催化降解罗丹明B(Rh B)溶液。在可见光的照射下，将0.05g的Ti O₂@Ce-Zr BTC投入50m L质量浓度为40mg·L^-1的Rh B溶液中，反应100min时，其降解率为96.6%，且该光催化剂循环降解4次后，降解率仍达79.9%。     

稀土掺杂TiO2的光催化性能研究

以钛酸丁酯、无水乙醇、冰乙酸为原料,以罗丹明B为模拟有机污染物,采用溶胶-凝胶法制备了一系列的TiO₂光催化剂,并利用XRD和物理吸附对催化剂进行了表征。考察了原料配比、凝胶时间、稀土掺杂种类、稀土掺杂量对TiO₂光催化罗丹明B性能的影响。结果表明：当钛酸比为1.5∶1、钛醇比为2∶1、凝胶时间为48 h、Pr掺杂量为2%时,TiO₂光催化罗丹明B的降解率最好。在光催化条件为罗丹明B初始质量浓度为4 mg·L^-1、催化剂质量0.05 g、光反应时间6 h时,罗丹明B的降解率达93.23%。     

Ag@AgCl/TiO2/GO催化剂制备及其光催化性能

以AgNO₃、聚乙烯吡咯烷酮(PVP)、钛酸四正丁酯、石墨烯等为原料，利用溶剂热法合成AgCl/TiO₂/GO复合光催化剂，经紫外光照还原得到Ag@AgCl/TiO₂/GO,并将其应用于罗丹明B的太阳光催化降解反应中。结果表明，该催化剂具有较高的光催化活性和稳定性。在100 mL 3 mg·L^-1罗丹明B溶液中，投加0.5 g·L^-1的Ag@AgCl/TiO₂/GO催化剂，光照75 min后，罗丹明B降解率高达98%以上。     

复合催化剂Ag-Ti/碳纤维的制备及光催化降解罗丹明B

本文采用乙酸钛、AgNO₃和碳纤维为原料,通过溶胶-凝胶法制备了新型Ag/TiO₂负载碳纤维光催化材料。通过XRD、SEM观察了微观形貌和结构。研究发现,所制备的复合光催化材料结晶性能良好,由于Ag的加入,复合光催化材料晶粒细化,催化活性更高。探讨了光催化剂对罗丹明B溶液降解效果的影响,发现当催化剂的用量为0.30g·L^-1、罗丹明B溶液的浓度为6mg·L^-1时,在Ag掺杂比为Ag/TiO₂=2∶1的复合光催化剂情况下,其降解活性最高,可达到88%以上,为解决染料废水的治理提供技术支持。     

甲硫醚降解菌JLM-8的分离鉴定与降解条件优化

从制药厂的活性污泥中分离到一株能以唯一碳源和硫源降解甲硫醚的菌株JLM-8,经过生理生化测试与16S rDNA系统发育树分析鉴定为嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia)。通过测定菌株的生长量、甲硫醚的降解率,利用响应面法优化最佳降解条件,并测定了该菌降解甲硫醚的动力学参数。结果表明:当接种量为25 mg·L^-1时,通过响应面法优化的最佳降解条件为温度31.3℃、pH 7.5,初始甲硫醚浓度50 mg·L^-1时最大预测降解率为98.2%,实验验证降解率为97.9%。菌株降解动力学参数最大比降解速率、半饱和系数、抑制系数分别为2.37 h^-1、143.55 mg·L^-1、51.35 mg·L^-1,临界抑制浓度为78.46 mg·L^-1。     

浅析纳米二氧化钛光催化降解效率的影响因素

本文以罗丹明B(RhB)为目标降解物，研究了锐钛矿型纳米二氧化钛(TiO₂)的光催化降解效率的影响规律。通过比较不同分散剂对纳米TiO₂分散液的分散作用的差别，研究了分散剂对纳米TiO₂的光催化降解效率的影响；同时，也探讨了固含量和溶液pH值等因素对纳米TiO₂光降解效率的作用规律。结果表明：二氧化钛(TiO₂)固含量为5 wt%、六偏磷酸钠为0.8%、pH值为5时，目标降解物罗丹明B(初始浓度2.5ppm)在3h后降解效率达到80.25%。将制备的光催化分散液喷涂在大理石瓷砖表面，48 h内降解甲醛效率达到86.9%。     

CNTs负载TiO2对茜素红溶液的降解研究

以钛酸四丁酯为前驱体,冰醋酸为水解抑制剂,采用溶胶-凝胶法制备纳米TiO₂/CNTs复合催化剂。测定复合催化剂对不同浓度茜素红溶液的光降解活性,并对光催化降解动力学进行研究。结果表明,在CNTs负载质量分数7.5%、焙烧温度450 ℃和焙烧时间3.5 h条件下制备的TiO₂/CNTs复合催化剂光催化活性得到提升。相同条件下,TiO₂/CNTs对150 mg·L^-1茜素红溶液的最终降解率达67%,而TiO₂的最终降解率只有56%。复合催化剂光催化活性提升的原因是CNTs负载后光催化粒子在紫外光照射下生成更多的氢氧根活性自由基。光催化降解动力学符合Langmuir-Hinshelwood方程,催化剂对污染物的表观吸附是整个反应的“瓶颈”。随着反应浓度的增大,光催化降解反应的反应级数由一级反应逐渐下降为零级反应。     

碳酸银光催化性能研究

银系光催化剂制备方法简单且带隙较窄,在可见光照射下具有良好的光催化效果,因此受到人们的广泛关注。以罗丹明B为降解物,在模拟可见光条件下利用碳酸银进行光催化降解实验,比较同等条件下碳酸银和二氧化钛的光催化性能,探究了碳酸银在不同pH、降解物质量浓度和催化剂投加量条件下的光催化活性,并利用总有机碳（TOC）分析矿化程度。通过X射线衍射仪（XRD）、激光拉曼光谱仪（RRS）、傅里叶变换红外光谱仪（FT-IR）和紫外吸收光谱仪（UV-Vis）对碳酸银进行表征并分析其晶相组成。结果表明,在同等条件下碳酸银对罗丹明B的光催化降解速率远大于二氧化钛,并且在溶液pH小于7、碳酸银投加量为 1 g/L条件下催化剂对质量浓度为5 mg/L的罗丹明B染料的光催化降解效果最好,紫外灯照射100 min后罗丹明B染料降解率达到98%以上,最终矿化率达到66%。     

Fe_3O_4/TiO_2复合物在光催化降解罗丹明B的应用

以Fe_3O_4/TiO_2为催化材料,分别研究了催化剂在不同催化剂的投加量、不同pH以及不同光照条件下对罗丹明的光催化效果,并用表观速率常数k评价催化剂的光催化活性。研究表明:罗丹明B的光催化反应为一级动力学反应,且在Fe_3O_4/TiO_2复合物投加量在20 g·L~(-1)、pH=6、紫外光照射的条件下降解效率最高。     

5-氯水杨醛-罗丹明B荧光探针的合成及其识别性能研究

以水合肼、5-氯水杨醛和罗丹明B为原料,合成了5-氯水杨醛-罗丹明类衍生物探针L,目标化合物5-氯水杨醛罗丹明B联肼经核磁、红外光谱和质谱进行了表征,采用紫外光谱法和荧光光谱法研究了其与金属离子的识别性能。结果表明,该探针可选择性紫外识别Cu²⁺和荧光识别Hg²⁺,在1.0～12.0μmol·L^-1范围定量检测Cu²⁺,R=0.998 6,检出限为0.53μmol·L^-1;在3.0～7.0μmol·L^-1范围定量检测Hg²⁺,580 nm处的荧光强度与Hg²⁺浓度呈良好的线性关系,相关系数(R)=0.997 4,检出限为0.56μmol·L^-1。Job’s曲线表明,探针L与Cu²⁺、探针L与Hg²⁺的结合物质的量的比均为1∶1,并对其响应机理进行了探讨。     

Improvement in photocatalytic activity of morphologically controlled Pd-supporting TiO2 particles via sol–gel process using inkjet nozzle

The purpose of the present study is to prepare palladium-supporting porous titania particles via a sol–gel process using an inkjet nozzle and to improve the photocatalytic activity of the particles. The morphology of titania particles produced by the sol–gel process using an inkjet nozzle was evaluated by scanning electron microscopy and nitrogen physisorption measurements. The photocatalytic activity of the obtained titania particles was evaluated using the changes in the concentration of a methylene blue solution under UVC light irradiation and the effect of palladium supported on the inner and outer surfaces of the titania particles on the photocatalytic activity was investigated.The titania particles prepared by inkjet processing exhibited spherical porous structures. The particle and pore size distributions of the obtained titania particles were more uniform than those of the titania particles prepared using the non-inkjet nozzle. The titania particles supporting palladium on the inner and outer surfaces exhibited a faster rate of photocatalytic degradation than the titania particles supporting palladium on only the outer surface, with anatase titania particles exhibiting the highest rate of photocatalytic degradation. Thus, we have successfully improved the photocatalytic activity of titania particles by supporting palladium on the inner and outer titania surfaces. This sol–gel process using an inkjet nozzle is an effective method for the preparation of porous titania particles supporting palladium on their inner and outer surfaces.     

新型钒氧簇合物(BiVO_4)的光催化性能研究

钒氧簇合物作为一类同多酸类的化合物,很可能具有一些光催化性质。本文以硝酸铋、偏钒酸铵为原料,采用水热合成法制备了钒酸铋;以可见光光催化解罗丹明B作为模型反应,详细考察了合成条件(模板剂种类、陈化时间、晶化温度),并采用X-射线粉末衍射(XRD)、傅立叶变换红外(FT-IR)、拉曼光谱(Raman)和紫外-可见漫反射(UV-Vis-DRS)等手段对样品的理化性能进行了详细表征。结果表明:BiVO4的最佳合成条件是以四丙基氢氧化铵为模板剂,陈化时间为1d,晶化温度为170℃;在可见光下对罗丹明B具有良好的光催化性能,辐照5h,罗丹明B溶液的脱色率可达90.6%。     

Bi and Al co-doped anatase titania for photosensitized degradation of Rhodamine B under visible-light irradiation

Although TiO₂ is a wide band gap semiconductor, it demonstrates photodegradation activity under visible light irradiation after dye sensitization. Compared with esterification between the surface hydroxyl group of TiO₂ and the carboxylic group of dyes, electrostatic interaction between TiO₂ and dye shows better photosensitized performance. In this work, Bi/Al co-doping anatase titania (Ti_1-xBi_2x/3Al_2x/3O₂ (0 ≤ x ≤ 0.3)) is designed to enhance the electrostatic interaction. The effect of Al ions is to enhance the solubility of Bi³⁺ into titania nanocrystals. A new band gap is generated after high concentration of Bi element doping, which not only promotes the absorption of visible light, but also improves the utilization of photogenerated carriers. Based on the results of transmission electron microscopy, light absorption, photodegradation activity and density functional theory calculations, it is found that bismuth dopant is the electron capture site. It first accumulates electrons through photocatalytic degradation reaction to enhance electrostatic adsorption between the catalyst and the positively charged dye molecules, and finally realizes high-efficiency photosensitization degradation of Rhodamine B. In addition, the sensitized titania has excellent photodegradation recyclability.     

芴与噻吩共聚物敏化半导体在可见光下催化降解罗丹明B

可见光照射下,芴与噻吩共聚物(PFT)敏化TiO2和ZnO具有优良的催化性能,降解罗丹明B的实验表明,PFT/TiO2的催化活性明显高于PFT/ZnO. 经过2 h LED(Light-emitting Diode)灯照射,PFT/TiO2体系中,罗丹明B完全降解为无色物质,矿化率48%;而PFT/ZnO体系中,同样条件下,2 h后还存在大量有色的罗丹明B降解中间产物,矿化率只有24.6%. 罗丹明B的降解过程分两个阶段,第一阶段最大吸收峰降低的同时,发生光谱蓝移,最终脱色生成罗丹明,第二阶段罗丹明继续降解为CO2和H2O,TOC的去除主要发生在第二阶段.     

坡缕石/Al掺杂CdS复合材料光催化降解罗丹明B

采用溶剂热法制备了坡缕石/Al掺杂CdS复合材料(PGS/CdS-Al),运用XRD、XPS、SEM、UV-Vis DRS及PL对材料的结构、形貌以及光学性能进行了表征.结果表明,Al元素成功掺杂到CdS中,CdS的晶体结构没有改变,但其禁带宽带变宽.可见光照射下,该复合材料对孔雀石绿、亚甲基蓝、甲基橙、结晶紫、罗丹明B有机染料均有光催化降解活性,且对罗丹明B的光催化降解效果最好.光照40 min,质量浓度为0.67 g/L 15％PGS/CdS-Al(15％为PGS的负载量,以生成的CdS质量计)对30 mL质量浓度为20 mg/L罗丹明B的降解率为98.7％,反应主要活性基团是h+.该降解反应符合一级动力学,反应速率常数为0.067 min–1.     

Microwave photocatalysis II: novel continuous‐flow microwave photocatalytic experimental set‐up with titania‐coated mercury electrodeless discharge lamps

BACKGROUND: A continuous‐flow microwave photocatalytic reactor was set up consisting of a glass tube equipped with microwave powered mercury electrodeless discharge lamps (EDLs) coated with thin films of nanoporous titanium(IV) oxide. The effect of operational parameters on photocatalytic degradation of aqueous mono‐chloroacetic acid (MCAA) by a TiO₂/UV/MW process was investigated. RESULTS: Studies were carried out at a relatively high concentration of MCAA (0.1 mol L^?1), and revealed that reaction temperature and light intensity of the EDLs depend inversely on the flow rate, but that the 366 nm line intensity of EDL is directly proportional to the reaction temperature. The photodegradation of MCAA was enhanced by heating and significantly enhanced by air bubbling of the reaction mixture in the glass reservoir at laboratory temperature. The photocatalytic efficiency increased with the number of titania‐coated EDLs inserted in the glass tube reactor. CONCLUSIONS: It was found that the operational parameters (i.e. flow rate, reaction temperature, number of titania‐coated EDLs, and air bubbling) had important effects on degradation efficiency. The photocatalytic degradation of MCAA on thin films of titanium(IV) oxide in the continuous‐flow microwave photoreactor can be enhanced in the TiO₂/UV/MW system. Copyright © 2009 Society of Chemical Industry     

Photocatalytic Degradation of Phenol with Fe-Titania Catalysts

Iron titanate (FeTiO₃) obtained from rich titanium and iron mineral presented some absorption of UV light and photocatalytic activity for the degradation of phenol in aqueous solution. However, most of the reactant is converted to carboxylic acids that remain in the reaction mixture because natural ilmenite do not produce enough HO^? radicals to completely mineralize the original reactant at the same rate as pure titania (Degussa P25). The XRD analysis of Fe-titania catalysts prepared by simple mixing of FeTiO₃ and TiO₂ showed that the structure of TiO₂ is not modified when small amounts of FeTiO₃, in the order of 10% weight, are well mixed with pure titania. Therefore, the photocatalytic activity of these catalysts is not affected by the presence of FeTiO₃. But, heavy ilmenite particles induce the separation of the catalysts particles after the photocatalytic degradation processes.     

新型BiOBr光催化剂的制备及性能研究

采用水热合成法制备BiOBr可见光催化剂,选择适合的溴源,考察了水热反应温度和时间对制备催化剂的影响。同时采用XRD、BET、Uv-vis紫外-可见光谱等手段对样品进行了表征。研究了BiO-Br可见光照射下的光催化活性。结果表明,在水热反应温度为160℃、水热反应时间为8h的条件下,制备的BiOBr纳米材料具有很好的光催化活性,在降解罗丹明B染料时降解率达93%,BiOBr的晶型结构受反应条件的影响,它的禁带宽度为2.69eV。     

Microwave hydrothermal synthesis of Sr doped ZnO crystallites with enhanced photocatalytic properties

Pure and Sr²⁺ doped ZnO crystallites were successfully synthesized via a microwave hydrothermal method using Zn(NO₃)₂·6H₂O and Sr(NO₃)₂·6H₂O as source materials. The phase and microstructure of the as-prepared Zn_1−xSr_xO crystallites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ultraviolet–visible spectrum (UV–vis) and photochemical reaction instrument were used to analyze the photocatalytic properties of the particles. XRD results show that the diffraction peaks of the as-prepared Zn_1−xSr_xO crystallites shifted slightly toward lower 2θ angle with the increasing of Sr²⁺ doping concentration from 0% to 0.3%. The pure ZnO crystallites with lamellar structure are found transforming to a hexagonal columnar morphology with the increase of Sr²⁺ doping concentration. UV–vis analysis shows that the particles have a higher absorption in UV region with a slightly decreased of optical band (E_g) gap. The photocatalytic activity of Sr²⁺ doped ZnO crystallites was evaluated by the Rhodamine B (RhB) degradation in aqueous solution under visible-light irradiation. Compared with the pure ZnO particles, the photocatalytic properties of the Sr²⁺ doped ZnO crystallites are obviously improved. The photocatalysis experiment results demonstrate that the 0.1% Sr²⁺ doped ZnO exhibits the best photocatalytic activity for the degradation of Rhodamine B.