超声-光催化脱色和降解染料普施安蓝MX-R的动力学模式及其影响因素的研究

在TiO2悬浮体系中,研究了超声波-光催化对普施安蓝MX-R的脱色和降解CODCr的动力学模式,并考察了其影响因素。结果表明：在超声波-光催化反应过程中,MX-R的脱色和降解CODCr均符合一级反应动力学模式;在碱性或酸性条件下,有利于超声波-光催化反应的进行;当超声波功率为640 W时,脱色和降解CODCr的反应速率常数k值达到最大值;随着TiO2投加量的增加,脱色和降解CODCr的反应速率常数k值先增加然后趋于下降或平缓;超声波-光催化对MX-R脱色和降解CODCr反应速率常数k值均是溶液初始浓度的负一级反应。     

TiO2催化的直接枣红染料光化学降解研究

在光解过程中,直接枣红染料的去除在未添加催化剂时是以一级反应动力学模式进行,添加不同的TiO2催化剂不会改变染料降解动力学。在不同焙烧温度下形成的TiO2,性能有差异,具有不同的晶型和吸附性能.除在800℃下焙烧的TiO2以外,其余催化剂的添加都可不同程度地增加染料的去除速率.染料的催化光降解效率与催化剂的吸附能力、晶型结构等有关,其中,催化剂晶型对催化剂催化性能的影响要大于催化剂吸附性能带来的影响.锐钛矿型的TiO2催化活性较高,高的吸附性能也有利于催化效率的提高,表现为在400℃焙烧下获得的TiO2具有最高活性,而具有金红石型的TiO2,催化活性差,甚至于降低了染料的光解效率     

纳米TiO2/玻璃薄膜光催化降解亚甲基蓝的研究

用溶胶 -凝胶法在玻璃表面制备了均匀透明的纳米TiO2 薄膜 .采用高压汞灯为光源 ,敞口固定床反应器对水中染料亚甲基蓝进行了光催化氧化实验 .实验结果表明 :随着涂膜次数的增加 ,薄膜TiO2 负载量增加 ,锐钛矿晶相粒径增大 .TiO2 薄膜对亚甲基蓝氧化降解具有较高的光催化活性 ,降解反应符合一级速率方程 .对亚甲基蓝的暗态吸附及光催化降解机理作了初步探讨     

纳米Ti02／玻璃薄膜光催化降解亚甲基蓝的研究

用溶胶—凝胶法在玻璃表面制备了均匀透明的纳米TiO2薄膜．采用高压汞灯为光源，敞口固定床反应器对水中染料亚甲基蓝进行了光催化氧化实验．实验结果表明：随着涂膜次数的增加，薄膜TiO2负载量增加，锐钛矿晶相粒径增大．TiO2薄膜对亚甲基蓝氧化降解具有较高的光催化活性，降解反应符合一级速率方程．对亚甲基蓝的暗态吸附及光催化降解机理作了初步探讨。     

UV/TiO_2体系中SF Blue染料溶液的降解动力学研究

以市售商品TiO2为光催化剂,以SFBlue制衣染料溶液模拟实际印染废水,研究光照时间、TiO2投加量、染料溶液浓度、pH值、温度对UV/TiO2体系降解染料废液效果的影响和宏观动力学。结果表明,UV/TiO2对SFBlue染料废液具有良好的处理效果,而且在发生光催化降解的同时还伴随着光分解反应,光催化降解反应为表观二级反应,活化能50.1kJ·mol-1,指前因子4.47×105L.mg-1.min-1;光分解反应为表观一级反应,活化能14.8kJ·mol-1,指前因子1.67min-1。UV/TiO2体系降解染料废液受到光照时间、TiO2投加量、染料溶液浓度、pH值、温度等因素的影响,TiO2最佳投加量为1.2g.L-1,染料溶液初始pH值≤3时,TiO2对SFBlue染料具有强烈吸附作用。     

5种偶氮染料溶液的光催化降解实验

以TiO2为催化剂,采用中压汞灯为光源对5种偶氮染料溶液进行了光催化降解的实验研究。结果表明,在上述条件下能够使直接R-F,直接黄y-5 GL,直接耐晒翠蓝B-GL,阳离子B-2RL,直接耐晒蓝B-BRL等偶氮染料水溶液降解脱色,染料脱色为动力学一级反应。5种偶氮染料在初始浓度50mg/L,温度201℃下,经20min光照,其脱色率分别为97.01%、97.90%、88.13%、96.95%、95.74%;CODCr去除率分别为58.64%、40.61%、44.60%、44.71%、55.56%。并讨论了pH值、催化剂用量、脱色时间和染料结构等因素对脱色与降解的影响。     

染料及表面活性剂的太阳光催化降解

制作了一种聚集太阳光光催化反应装置，在纳米半导体TiO2存在下可用于净化染料和表面活性剂污染物，并可使其快速降解并矿化，含有N－甲基助色基团染料的降解伴随脱甲基过程，混合物最大吸收峰发生蓝移，总有机碳（TOC）值降解与污染有关，当降解生成中间体与污染物有较强的竞争吸附时，TOC值升高现象，对不同的污染物降解，有不同的较适宜的TiO2用量。     

TiO_2光催化降解活性艳兰KN-R的动力学研究

以纳米二氧化钛为光催化剂,研究了溶液pH值,TiO2投加量,H2O2用量及染料起始浓度对光催化降解活性艳兰KN-R动力学的影响.结果表明,TiO2光催化降解活性艳兰KN-R的反应遵循准一级反应动力学方程,且表观反应速率常数随溶液pH值的升高及染料起始浓度的降低而增大;TiO2和H2O2的投加量均存在一个最佳值,在本实验条件下,它们分别为0.5 g.l-1和2.0×10-2mol.l-1,低于或超过该值都会导致降解速率的下降.     

TiO2光催化降解有机物的动力学研究

对影响锐钛矿型TiO2光催化降解有机化合物反应的因素进行了分析,提出在TiO2光催化过程中,当外界条件确定后,有机分子在催化剂表面的吸附是整个降解过程控制步骤,根据这一结论导出其分解过程的动力学方程r＝kKACA/(1+KACA),该方程和实验情况相符.     

TiO2/H2O2光催化体系降解亚甲基蓝的动力学研究

采用TiO2/H2O2催化体系对亚甲基蓝的光催化降解性能进行了动力学研究,结果表明:TiO2和H2O2的光催化反应符合动力学一级反应规律;TiO2的多相催化反应有诱导期,反应速度较慢;H2O2的均相催化没有诱导期,反应速度较快;TiO2和H2O2的复合催化可同时利用不同波段的光,能提高光的利用率,加快HO自由基的生成及其在水中的传递,加快了有机物的降解过程,提高降解速度.     

天然染料混合二氧化钛光降解醋酸纤维的研究

采用天然染料提取液,添加碱和Ti O2制备复合光敏剂,利用紫外可见分光光度计(UV-Vis)测试天然染料的吸收曲线,筛选出吸收峰较大、吸光效果较强的天然染料光敏剂.对添加复合光敏剂的醋酸纤维薄膜进行光催化降解测试和差热-热重(DSC-TG)以及扫描电镜(SEM)的表征.结果表明:紫草、紫苏天然染料在可见光区域的吸收较好,且两者混合后,吸收峰线性叠加,吸光度增强;天然染料添加Na OH后,吸收峰增强并发生红移;将Ti O2加入紫草和紫苏的碱性提取液中,复合光敏剂对醋酸纤维薄膜的光催化降解效果进一步提高.     

多孔结构TiO2纳米膜的光催化活性及其动力学研究

考察了多孔结构TiO2 膜的光催化活性 ,并通过X射线衍射 (XRD)、电镜分析 (SEM)、光电能谱分析 (XPS)对催化剂表面进行了表征 ,结果表明 :TiO2 的晶型为锐钛矿型 ,粒子平均半径为 32 .94nm ;这种结构TiO2 纳米膜在对甲基橙的降解中显示了较好的光催化活性 ( 5 0min光照后 ,最高降解率达到了 92 .1% ) ;对光催化动力学进行了初步研究 ,结果表明 ,光催化降解在所考察范围内为一级反应     

Kinetics of the hydrogen absorption and desorption processes of hydrogen storage alloys: A review

High hydrogen absorption and desorption rates are two significant index parameters for the applications of hydrogen storage tanks.The analysis of the hydrogen absorption and desorption behavior using the isothermal kinetic models is an efficient way to investigate the kinetic mechanism.Multitudinous kinetic models have been developed to describe the kinetic process.However,these kinetic models were de-duced based on some assumptions and only appropriate for specific kinetic measurement methods and rate-controlling steps(RCSs),which sometimes lead to confusion during application.The kinetic analysis procedures using these kinetic models,as well as the key kinetic parameters,are unclear for many researchers who are unfamiliar with this field.These problems will prevent the kinetic models and their analysis methods from revealing the kinetic mechanism of hydrogen storage alloys.Thus,this review mainly focuses on the summarization of kinetic models based on different kinetic measurement methods and RCSs for the chemisorption,surface penetration,diffusion of hydrogen,nucleation and growth,and chemical reaction processes.The analysis procedures of kinetic experimental data are expounded,as well as the effects of temperature,hydrogen pressure,and particle radius.The applications of the kinetic models for different hydrogen storage alloys are also introduced.     

零价铁催化还原降解酸性紫红B的动力学及影响因素

酸性紫红B的零价铁催化还原降解遵守一级动力学，随着铁粉比表面积的增大及溶液pH的降低，反应动力学常数增大．依据紫外可见光谱，推测反应机理为酸性紫红B的偶氮键断裂，被还原加氢。     

Ordered mesoporous tungsten oxide and titanium oxide composites and their photocatalytic degradation behavior

Highly ordered mesoporous WO3/TiO2 (MWTs) composite materials with tunable chemical compositions were obtained by a surfactant template-assisted evaporation-induced selfassembly (EISA) processes. The structure properties of the MWT materials were characterized by small angle XRD, TEM and N2 sorption. The resultant materials showed large amount of ordered mesopores and high chemical homogeneity. With increasing crystallinity degree, the order degrees of mesostructure turned worse gradually. The MWT hybrids exhibited excellent visible light response due to the addition of WO3 with narrow band gap. Photocatalytic performances of the MWT samples were determined by measuring the photo-degradation of rhodamine B dye and phenol under simulated solar light irradiation. The effect of material parameters such as surface area, crystallinity and chemical compositions in the binary heterostructured system on photocatalytic performance were discussed in details.     

构建TiO2柱状多层石墨烯纳米复合材料作为降解环丙沙星的高效光催化剂

We successfully constructed TiO₂-pillared multilayer graphene nanocomposites (T-MLGs) via a facile method as follows: dodecanediamine pre-pillaring, ion exchange (Ti4+ pillaring), and interlayer in-situ formation of TiO₂ by hydrothermal method. TiO₂ nanoparticles were distributed uniformly on the graphene interlayer. The special structure combined the advantages of graphene and TiO₂ nanoparticles. As a result, T-MLGs with 64.3wt% TiO₂ showed the optimum photodegradation rate and adsorption capabilities toward ciprofloxacin. The photodegradation rate of T-MLGs with 64.3wt% TiO₂ was 78% under light-emitting diode light irradiation for 150 min. Meanwhile, the pseudo-first-order rate constant of T-MLGs with 64.3wt% TiO₂ was 3.89 times than that of pristine TiO₂. The composites also exhibited high stability and reusability after five consecutive photocatalytic tests. This work provides a facile method to synthesize semiconductor-pillared graphene nanocomposites by replacing TiO₂ nanoparticles with other nanoparticles and a feasible means for sustainable utilization of photocatalysts in wastewater control.     

负载型氧化亚铜材料降解有机废水的性能及机理分析 汪慧静,刘淑娟,尚晓涵,薛建良*

摘要：为提高氧化亚铜的光降解性能和解决粉末状氧化亚铜难以回收利用的问题,研究了将氧化亚铜负载到陶粒上,得到陶粒-Cu2O复合材料,研究材料的降解性能和机理。结果表明,在无光和光照条件下陶粒、Cu2O、陶粒-Cu2O三种材料对亚甲基蓝具有明显不同的降解效率,且光照条件下降解效率明显提高,这说明在光照条件下,陶粒-Cu2O材料两者协同作用,不仅有吸附作用,而且有光降解效果;分析加入H2O2对陶粒--Cu2O复合材料降解性能的影响,发现Cu2O产生的电子-空穴对可以加速H2O2的水解,产生大量的强氧化性基团,有效的提高光降解性能;进一步分析陶粒-Cu2O复合材料的降解机理发现,陶粒-Cu2O降解污染物分为三个阶段,其中第一个阶段吸附起主导作用符合一维线性模型,第二个阶段光降解起重要作用,符合y = -0.0069x2 + 1.1843x + 26.978模型,第三阶段趋于平稳。     

负载型纳米TiO2光催化降解水中微量二氯乙烷

利用负载型纳米TiO2作为光催化剂对水中微量二氯乙烷进行紫外光催化降解处理。研究表明二氯乙烷光催化降解属表观一级反应动力学过程。不同的二氯乙烷初始浓度、光强和催化剂用量等因素对二氯乙烷的光催化降解具有不同的效果。初始浓度在4．821—22．838mg/L范围内，随着初始浓度的增大，二氯乙烷光催化降解的反应速率常数持续增大；光强的平方根与反应速率常数呈直线相关；随催化剂用量的增加，反应速率常数呈增大趋势。     

A kinetic model for describing effect of the external surface concentration of TiO_2 on the reactivity of egg-shell activated carbon supported TiO_2 photocatalys

The porous support supported TiO2 is considered to be the promising photocatalyst due to the fact that it is easily recovered from water and has high capacity to mineralize pollutants. Obviously, the expected structure of this kind of photocatalyst is egg-shell, that is, TiO2 is mainly on the external surface of the porous support. The reactivity of the supported photocatalyst strongly depends on the concentration of TiO2 on the external surface of the porous support. In this study, a kinetic model was developed to describe the effect of the external surface concentration of TiO2 (CESC) on the reactivity of egg-shell activated carbon (AC) supported TiO2 photocatalysts. It was found that the obtained model precisely described the effect of CESC, on the reactivity of TiO2/AC photocatalysts. This study can be used to deeply understand the performance of TiO2/AC catalysts and to provide valuable information on designing efficient supported TiO2 photocatalysts.     

纳米TiO2薄膜的制备及光催化活性研究

用溶胶一凝胶法在玻璃基片上制备了均匀透明的Ti02薄膜，并以苯酚的降解反应为模型，研究了纳米Ti02薄膜的光催化活性．结果表明薄膜晶粒大小为23．0nrn，呈锐钛矿型，沿(101)晶面具有择优取向性；10h内苯酚的降解率为66％，苯酚光催化降解反应符合一级动力学规律．