钒取代杂多酸/TiO_2复载催化剂的制备与表征

采用常温法合成了钒取代的杂多酸H4PVW11O40,采用溶胶-凝胶法制备了二氧化钛负载的钒取代杂多酸光催化剂H4PVW11O40/TiO2。红外光谱及X射线衍射粉末手段显示合成的杂多酸及催化剂具有Keggin结构。紫外漫反射的表征结果显示催化剂扩大了光吸收的范围,提高了光催化效率。实验结果表明,该复载催化剂在可见光下有较好的光催化活性,H4PVW11O40/TiO2在120 min内对罗丹明B的光催化降解转化率达到95.36%。     

污水处理中MB光催化降解研究

水污染是人类面临的重要环境问题,光催化是缓解该问题的有效措施之一,因此研究适用于水污染的光催化剂是关键问题。本研究利用水热法制备了氧化锌(ZnO)纳米棒薄膜,探究了不同比例Zn2+前驱体对薄膜生长情况的影响。然后在薄膜上利用溶胶凝胶法淀积了一层二氧化钛(TiO2),得到ZnO/TiO2复合薄膜。利用X射线衍射仪、扫描电镜对纯氧化锌薄膜及淀积二氧化钛后的复合薄膜的结构和形貌进行表征,利用紫外可见光谱仪检测Zn O/TiO2复合薄膜光催化降解有机物的效果。本研究解决了单一光催化剂的电子-空穴对复合率高、污水中光催化剂难以回收的难题,设计的催化剂具有绿色无污染、易于制备、催化效率高的特点。     

Li~+-TiO_2复合纳米光催化剂制备及其光催化降解海产品深加工废水的研究

对Ti O2纳米光催化材料进行掺杂改性,利用溶胶-凝胶法制备出掺杂锂的Li+-Ti O2复合纳米光催化剂,通过X射线衍射分析(XRD)、扫描电镜分析(SEM)等测试技术对所制备的光催化剂形态结构和特性加以表征,用大连市黑石礁海域的海水配制成模拟海产品深加工废水,研究了Li+-Ti O2复合纳米光催化剂光催化降解海产品深加工废水的能力及影响其降解能力的因素,并确定了Li+-Ti O2光催化剂光催化降解海产品深加工废水的优化试验条件。结果表明:Li+-Ti O2复合纳米光催化剂光催化降解海产品深加工废水效率高,锂掺杂量、催化剂用量、p H、氨氮初始浓度、COD初始浓度和过氧化氢(H2O2)用量6个因素影响光催化降解的能力,在优化试验条件下,即锂掺杂量为5%,氨氮初始浓度为80 mg/L,COD初始浓度为300 mg/L,Li+-Ti O2用量为0.9 g/L,H2O2用量为5%,反应时间为2 h,p H值为8时,海产品深加工废水中氨氮和COD的光催化氧化降解率分别达到81.50%和78.67%。     

磷钨酸/二氧化钛纳米材料的合成及光催化性活性测试

运用溶胶凝胶法制备了磷钨酸(HPW)掺杂的二氧化钛(Ti O2)复合纳米光催化剂,利用SEM对样品进行表征,观察纳米材料的微观形貌结构。并利用亚甲基蓝溶液的光催化降解实验评估催化剂的光催化活性。实验结果表明,HPW的掺杂减小了Ti O2纳米颗粒的粒径,有利于增大其比表面积,同时明显提高了Ti O2的光催化活性。     

g-C3N4光催化剂的改性及制备

石墨相氮化碳(g-C3N4)是种非常具有发展前景的光催化剂,较好的光催化性和稳定性,已成为学者研究的焦点.但是其光生电子-空穴对非常容易复合,光生载流子寿命比较短,使得量子效率非常低,进而导致g-C3N4的光催化性能降低,同时限制了光响应范围,致使g-C3N4的应用范围和前景折损.本文通煅烧三聚氰胺(C3N6H6)制备g-C3N4,然后进行半导体(TiO2)复合改性的方法,在不同条件下将g-C3N4和TiO2混合后进一步煅烧制备g-C3N4/TiO2复合光催化剂.对g-C3N4/TiO2复合光催化剂进行光降解氮氧化物试验,通过亚甲基蓝降解和thermo氮氧化物分析进行评价.     

蒸汽相水解法制备磁性光催化剂Fe_3O_4/SiO_2/TiO_2及其光催化性能

采用蒸汽相水解法,以Fe3O4纳米磁性颗粒为磁核,在其表面包覆一层SiO2来阻止光腐蚀,然后将锐钛矿相纳米氧化钛沉积在Fe3O4/SiO2颗粒表面,从而制得核壳结构的Fe3O4/SiO2/TiO2磁性复合光催化材料。用X射线粉末衍射仪(XRD)、场发射扫描电镜(FE-SEM)、高分辨率透射电子显微镜(HR-TEM)、探针式震动磁强计等手段对所制备的产物的结构、形貌、磁强度性能进行表征。以300W汞灯为光源,用亚甲基蓝和酸性红模拟污水中的有机染料来评价复合光催化剂的性能。结果表明,磁性纳米微球中TiO2的含量越大,其光催化性能越好,含TiO2质量分数50%的F3O4/SiO2/TiO2磁性纳米微球可在180min内降解亚甲基蓝模拟染料废水,降解率达99%,在80min内降解酸性模拟染料废水,降解率达98%。     

实用型光催化氧化水处理器深度处理焦化废水

解决光催化剂与废水的即时分离问题是光催化氧化技术走向实际的关键之一。采用新型的实用型光催化水处理器——连续流即时分离型光催化反应器深度处理焦化废水,发现在适宜的反应时间、TiO2投加量、光辐照强度和初始pH值下是完全可行的。然后在此基础上选用H2O2和Fenton试剂为外加氧化剂,研究了氧化剂强化光催化深度处理焦化废水的效果。结果表明,在UV/TiO2氧化体系中投加H2O2或Fenton氧化剂,可显著提高光催化氧化对COD和色度的去除率;在最佳反应条件下,不同氧化体系对焦化废水的深度处理效果排序为:UV/TiO2/Fenton>UV/TiO2/H2O2>UV/TiO2。     

负载型纳米TiO_2光催化降解酸性红B的研究

为解决传统纳米TiO2光催化氧化工艺催化剂不易分离和载体的比表面积较小、悬浮性差的问题,将纳米TiO2负载在聚丙烯多面球上制备了负载型TiO2光催化剂.利用XRD和氮气吸附法表征了该催化剂的结构特性,并采用其降解酸性红B,考察了初始浓度、曝气量、pH值、H2O2投加量、自由基清除剂及多面球的比表面积等对降解效果的影响.结果表明,偶联剂法制备的TiO2薄膜晶相单一(锐钛矿型),晶体粒度较小,比表面积较大;脱色率会随着酸性红B溶液初始浓度的升高和自由基清除剂(乙醇)的加入而下降,提高溶解氧浓度、增加聚丙烯多面球的比表面积以及酸性条件(pH=3.26时效果最佳)都有利于提高脱色率;投加H2O2也能提高脱色率,但当投加量增至0.5 mg/L后效果不再明显;酸性红B的光催化降解遵循一级反应动力学方程.     

Fe_2O_3/SnO_2催化剂的制备及其光催化降解亚甲基蓝

采用溶胶-凝胶法制备不同Fe_2O_3含量的Fe_2O_3/SnO_2复合催化剂,分析其组成和性质,以亚甲基蓝溶液为染料模型,研究催化剂的光催化降解性能及最佳降解条件。结果表明,Fe_2O_3和SnO_2得到良好的复合,当Fe_2O_3含量为10%时,Fe_2O_3/SnO_2具有良好的催化活性,且降解的最佳条件为添加0.3 mL/L H2O2,pH为7,催化剂用量为15 mg,染料浓度为5 mg/l时,用300 W汞灯照射2 h,亚甲基蓝的降解率最大。     

Ti-Mg-Al复合氧化物催化材料的制备及其加氢脱硫性能

采用pH值摆动法、并流沉淀法制备了Al2O3、TiO2-Al2O3二元复合物、TiO2-MgO-Al2O3和MgO-TiO2-Al2O3三元复合物,并对以其为载体的催化剂进行了催化裂化重汽油加氢脱硫反应性能评价。结果表明,在所制备的TiO2-Al2O3二元复合载体中,TiO2分散在Al2O3表面上,且随其含量的增加TiO2逐渐在Al2O3表面上富集;与TiO2-Al2O3二元复合载体相比,三元复合载体的总孔容和平均孔径减小,但是总酸量增加。相比较而言,TiO2-MgO-Al2O3三元复合载体基催化剂对催化裂化重汽油的脱硫率优于TiO2-Al2O3二元复合载体基催化剂,脱硫率在90%以上,且前者的烯烃饱和率也较低,表明该催化剂具有良好的加氢脱硫选择性。     

氧化剂协同即时成膜型光催化反应器降解有机物

研究了“表观”即时成膜型UV／TiO2光催化反应器降解水中有机污染物的过程中,外加氧化剂与UV／TiO2体系之间的协同效应。在UV／TiO2体系中单独投加H2O2或O3可以提高光催化氧化有机污染物的速率和效率,同时投加H2O2和O3时则光催化氧化的协同作用更加显著,可大大缩短反应时间。不同反应体系的表观速率常数排序为：UV／H2O2／O3／TiO2〉UV／O3／TiO2〉UV／H2O2／TiO2〉UV／O3〉UV／H2O2〉UV／TiO2。     

高岭土负载氧化锌／氧化钛制备光催化功能材料的研究

以硫酸钛、硫酸锌、高岭土、尿素、无水乙醇等为原料,水热法制备了氧化锌／氧化钛复合纳米粉体以及高岭土负载纳米氧化锌／氧化钛复合粉体;利用X-射线衍射（XRD）对所得粉体进行了表征,研究了不同粉体对甲基橙溶液的光催化降解效果,制备出了光催化性能良好的高岭土负载纳米氧化锌／氧化钛复合粉体。     

H2O2/TiO2 photocatalytic oxidation of metol. Identification of intermediates and reaction pathways

The applicability of H2O2 to increase the efficiency of TiO2 photocatalytic degradations was investigated. The photographic developer metol [N-methyl-p-aminophenol] that does not adsorb on the surface of TiO2 particulates was used as a model for this purpose. It was proved that metol was mineralised under oxidation with H2O2/TiO2/UV through different thermal and photochemical reactions. Identification of intermediates by both HPLC-electron impact-MS and HPLC-electrospray ionisation-MS helped to elucidate the role of H2O2 and TiO2 in the degradation process and to establish degradation pathways. Intermediates yielded were partially oxygenated aromatic species and dimers, which were amenable to oxidation. The optimal degradation conditions found for mineralisation were 0.4 M H2O2, 5 mg/ml TiO2, pH 9 and irradiation centred at 360 nm (4.9 mW/cm2). The use of oxidants opens an interesting medium to the treatment of effluents containing a diversity of organics since they increase substantially the efficiency of TiO2 photocatalytic degradations.     

铌掺杂对Ce-Nb-TiO_2系压敏陶瓷结构与电性能的影响

研究了铌对Ce,Nb掺杂的二氧化钛压敏陶瓷结构和电性能的影响。结果表明,在1 350℃烧结条件下,掺入0.8%Nb2O5的样品具有优良的综合电性能,显示出低的压敏电压(U1mA=7.22V/mm)、高的非线性系数(α=5.76),是一种很有潜力的新型电容-压敏陶瓷材料。铌掺杂主要是Nb5+对Ti4+的掺杂取代,该掺杂存在一饱和值。Nb2O5在不同的掺杂浓度下,存在的形式和位置不同,同时与一些低熔点化合物相如Ce2Ti2(Si2O7)O4等相互作用,使得样品的电性能发生变化。     

Adsorption of Cu(II) from industrial liquid waste on Na-bentonite and Al-PILC following a full factorial design

The paper reports a study of the performance of Maghnia bentonite in a purified and modified state for the removal of Cu(II) from industrial liquid waste in the region of Oran (North West Algeria). Bentonite was firstly treated to produce a Na-bentonite, then modified with an aluminum solution containing molar ratio OH/Al of 1.8 and finally calcined at 450 °C. The polymer [AlO₄Al₁₂(OH)₂₄(H₂O)₁₂]⁷⁺ formed in solution was adsorbed by surface complexation on the bentonite, which is known to have a high capacity to fix metal cations. The prepared materials were characterized by DRX, BET and EDX. In order to find the optimum conditions, a full factorial design of 2⁴ allowed us to determine the main effects and interactions of the factors studied: pH, mass of materials, contact time and temperature. The results obtained show that the best rate of adsorption of copper requires a pH = 10, a mass = 0.8 g, a stirring time = 80 min, and a temperature = 25 °C. The adsorption capacity of treated bentonite increased considerably from 4.147 mg/g for Na-bentonite to 7.173 mg/g for pillared aluminum bentonite. This shows the strong adsorption of copper compared with Na-bentonite, caused by its high surface area.     

Metal-doped carbon aerogels as catalysts during ozonation processes in aqueous solutions

The efficiency of Co(II)-, Mn(II)-, and Ti(IV)-doped carbon aerogels for the transformation of ozone into (*)OH radicals was investigated. The carbon aerogels had a markedly acid surface character (pH(PZC approximately equal) congruent with 3-4) with very high surface oxygen concentrations (O approximately equal with 20%). X-ray photoelectron spectroscopy (XPS) analyses of the samples showed the oxidation state of the metals was +2 for Co and Mn and +4 for Ti. The presence of Mn(II)-doped carbon aerogel enhanced ozone transformation into (*)OH radicals, whereas the presence of Co(II) and Ti(IV) carbon aerogels presented no activity in this process. Moreover, it was observed that an increase in the concentration of Mn in the surface of the aerogel increases its efficiency to transform ozone into (*)OH radicals, with an Rct value ([OH]/[O(3)]) of 5.36 x 10(-8) for the aerogel doped with 16% of surface Mn(II) compared to an R(ct) of 2.68 x 10(-9) for conventional ozonation. Regardless of the aerogel used, XPS analysis of the ozonated aerogel samples showed an increase in the concentration of surface oxygen when the exposure to ozone was longer. However, presence of oxidized metal species after ozone treatment was only detected in the case of the Mn-doped aerogel, (Mn(III) and Mn(IV)). CO(2) activation of carbon aerogel produced a marked increase in its efficiency to transform ozone into (*)OH radicals compared with non-activated sample. The efficiency of Mn activated carbon aerogel to transform ozone into (*)OH radicals was greater than that of Witco commercial activated carbon or H(2)O(2) in the ozonation of water from Lake Zurich (Zurich, Switzerland).     

TiO2光催化涂料的制备及其对NOx气体的降解性能

以钛酸丁酯为前驱体,无水乙醇为溶剂,采用溶胶一凝胶法制备了纳米TiO<,2>粉体;结合自制有机硅树脂制备了TiO<,2>光催化涂料,并研究了其对NO<,x>气体的降解作用.结果表明,在紫外灯照射下,涂料对NO<,x>气体的降解率在5min内可达85%;在荧光灯照射下达到相同降解率所需时间较长.研究结果可为光催化涂料在环境改善方面的应用提供参考.     

Photocatalytic oxidation of aqueous ammonia in model gray waters

This study investigated the TiO2 photocatalytic degradation of aqueous ammonia (NH4+/NH3) in the presence of surfactants and monosaccharides at pH approximately 10.1. Initial rates of NH4+/NH3 photocatalytic degradation decreased by approximately 50-90% in the presence of anionic, cationic, and nonionic surfactants and monosaccharides. Through correlation analysis, we concluded that scavenging of hydroxyl radical (.OH) by the products of surfactant/monosaccharide photocatalytic degradation, including carbonate and formate, could explain approximately 80% of the variance in initial rates of NH4+/NH3 removal in our system. Addition of a supplemental .OH source (H2O2) enhanced the rate of NH4+/NH3 degradation in the presence of the surfactant Brij 23 lauryl ether (Brij 35), further supporting the idea that .OH scavenging is the mechanism by which surfactants and monosaccharides decreased initial rates of NH4+/NH3 photocatalytic degradation. Despite slowed rates of NH4+/NH3 degradation, both surfactants/monosaccharides and NH4+/NH3 were removed by TiO2 photocatalysis, indicating that this process can effectively remove both carbonaceous and nitrogenous biochemical oxygen demand from gray water.     

Photocatalytic oxidation and ozonation of catechol over carbon-black-modified nano-TiO2 thin films supported on Al sheet

The photocatalytic activity of the carbon-black-modified nano-TiO2) (CB-TiO2) thin films was 1.5 times higher than that of TiO2 thin films in degrading Reactive Brilliant Red X-3B. Photocatalytic oxidation and ozonation of catechol over CB-TiO2 thin films supported on Al sheet was investigated. The experiments showed that ozone concentrations had an important effect on TOC removal. The combined photocatalysis with UV irradiation and ozonation (TiO2/UV/O3) process considerably increased TOC removal rate compared to combined photocatalysis with UV irradiation and oxygen oxidation (TiO2/UV/O2) process, ozonation alone (O3) process, combined ozonation and UV irradiation (UV/O3) process. The complete mineralization of catechol followed pseudo-zero-order kinetics dependent upon ozone (oxygen) concentration and indicated catechol concentration did not affect the kinetics during UV/O3 and TiO2/UV/O3 (O2) processes. The kinetic study showed that the rate constants in the complete mineralization of catechol with TiO2/UV/O3 are 1.32-1.80 times higher than that of UV/O3 with the same concentration of ozone. The rate constants are 2.56-5.36 times higher than the maximal rate constants of TiO2/UV/O2 and 4.68-9.8 times higher than the maximal rate constants of TiO2/UV.     

光催化协同臭氧降解蒽醌染料废水

采用光催化协同臭氧技术降解蒽醌染料分散艳蓝E-4R,研究了光催化／臭氧法处理染料的主要影响参数,结果表明：增加臭氧的流量有利于提高脱色率,溶液初始pH值则对降解的影响较小,在光催似臭氧体系中,对降解起到主要作用的是·OH的氧化作用。