光催化反应器的研究进展

目前,我国光催化领域的研究工作更多的集中在基础和应用基础研究方面,而在光催化技术的工程应用,尤其是光催化反应器工程方面的基础研究和中式工作开展的很少。这一环节的缺失,成为制约我国光催化技术从实验室走向工程应用的短板。综述了近些年来光催化反应器在国际、国内的研究进展,阐明了传统光催化反应器难以批量处理反应液等一系列缺点,指出了光催化反应器以后的研究方向,并进一步阐明了提高光吸收能力的手段和方法,为新型光催化反应器的制备及其向工业化实际应用奠定了基础。     

光催化氧化法降解有机污染物影响因素及其效率提高途径

分析了催化剂类型、污染物性质、反应条件等因素对光催化氧化法降解有机污染物的影响,从催化剂改性、高效光催化氧化反应器及光催化与其他技术联用等方面探讨了提高光催化氧化效率的途径,展望了光催化氧化法发展前景及其工业化应用时需解决的关键问题。     

光催化反应器数学模型研究进展

介绍了光催化反应器数学建模的特点和研究现状。围绕建模的4个关键因素,即光源模型、辐射能传递模型、反应动力学模型、传质问题展开讨论。通过对建模理论的分析,指出了光催化反应器数学建模存在的问题和今后的研究重点。     

浆态光催化反应器有机模拟废水光催化氧化特性与动力学

采用循环式浆态光催化反应器对苯甲酰胺模拟废水光催化氧化特性和动力学进行了研究,系统地考察了操作条件对模拟污染物光催化降解的影响,并与搅拌式和鼓泡床式浆态光催化反应器中苯甲酰胺的降解效果进行对比.结果表明,循环式浆态光催化反应器中光催化剂的用量、污染物的初始浓度和初始pH值对模拟污染物光催化降解性能的影响存在适宜值;体系中H₂PO^-₄、Cl^-、Cu²⁺、Al³⁺对其光催化降解过程有明显的抑制作用.与传统的搅拌式和鼓泡床式浆态光催化反应器相比,循环式浆态光催化反应器中催化剂和废水的混合效果较好,光利用率高,较大程度上减少催化剂的用量和提高废水处理能力.同时,对不同催化剂的用量和污染物初始浓度下的光催化氧化反应动力学研究表明,此过程符合拟一级动力学,催化剂表面反应速率常数k₀和催化剂吸附平衡常数K_TiO2分别为0.0279 min^-1和17.99 L•g^-1.     

转盘式反应器光催化氧化含酚废水的试验研究

设计的新型转盘式光反应器采用同轴多层转盘作为TiO2膜的载体,很大程度上扩大了光与催化剂的接触面积,对光源系统进行优化布置,使光均匀分布在各转盘叶片之间,不仅可以提高光辐射强度还具有良好的传质性能.利用该反应器光催化氧化苯酚废水,考察了反应器各参数对苯酚降解率的影响,试验结果表明该反应器对低浓度苯酚废水具有良好的降解效果,出水水质可以达到国家一级排放标准.同时从工业放大的角度考虑,多叶转盘式光反应器的结构和降解能力决定了它具有潜在的优势.     

太阳能光催化反应器的研究进展

为促进太阳能光催化反应器的研究和开发,从反应器中催化剂的存在形态、反应器的聚光形式以及应用3个方面对太阳能光催化反应器的研究现状进行了系统的综述,对催化剂悬浮型和固定膜型反应器以及聚光型和非聚光型反应器进行了比较,并分析了反应器在实际废水处理或者大批量处理中应用的可行性。     

波纹板填料轻烃脱水过程的研究

本文进行了波纹板填料轻烃脱水过程的实验研究，为设计渡纹板填料轻烃脱水器和开发高效的波纹板轻烃脱水填料提供了依据。本文所建立的波纹板填料轻烃脱水的数学模型的模拟计算结果和实验结果能较好地吻合.     

转筒式负载膜光催化水处理器的设计与模拟

研究了转筒式光催化反应器的模型化设计方法,并与实验结果进行了比较。在自行设计和制造的转筒式光催化反应器中测定了反应器内紫外线的照度分布,在间歇条件下进行了4BS染料光催化降解的实验研究。在此基础上,经数据处理和数学推导,建立了转筒式光催化反应器的数学模型。结合含处理液浓度、催化剂用量、光照度、pH值以及直接光照面积影响在内的降解速率方程,模拟了该反应器中的水处理过程,得到了与实验相吻合的结果。     

甲酸光催化降解过程中的过氧化氢生成机制

考察了在3种紫外光源（黑光灯、杀菌灯、臭氧灯）的照射下,分别以TiO₂ 与 Pd/TiO₂为催化剂,甲酸降解过程中过氧化氢的生成机制.研究发现,在黑光灯/催化剂条件下,可在纯水中生成过氧化氢,但当催化剂缺失时几乎不能生成.在黑光灯或杀菌灯照射下,甲酸溶液在有催化剂存在时可被稳定分解,但当催化剂不存在时则分解非常缓慢.对各种光源而言,Pd/TiO₂比TiO₂催化降解甲酸的效果好.对光源条件的比较发现,甲酸分解速度与过氧化氢生成速度依次为臭氧灯>杀菌灯>黑光灯.结果表明,甲酸光催化分解初速度与过氧化氢生成的初速度呈正比,过氧化氢生成是光催化降解有机物的关键因素.     

Characterization of a photocatalytic reaction in a continuous‐flow recirculation reactor system

A continuous‐flow recirculation mode, generally called a recycle mode, is known to be practically meaningless except when the reactant is separated from the product at the reactor exit or when the reaction is autocatalytic, because when simply circulating a small amount of the fluid containing a reactant, the reactant concentration in this mode is lowered due to mixing of the fluid at the reactor entrance, leading to a decrease in the conversion at the reactor exit. This mode may, however, be meaningful in photocatalytic reactions with very large film‐diffusional resistance. To indicate the validity of this estimation, therefore, characteristics of a continuous‐flow recirculation reactor have been investigated both theoretically and experimentally. As a result, it is found that by increasing the circulation flow rate the conversion and productivity in this reactor is higher than that in a continuous‐flow reactor because the film‐diffusional resistance is remarkably reduced. Copyright © 2006 Society of Chemical Industry     

铁掺杂氧化锌制备及对有机染料的光催化降解

采用沉淀法制备铁掺杂的纳米氧化锌。通过粉末X射线衍射（PXRD）和红外光谱（IR）对样品及其前驱体进行表征;采用分光光度计测定样品光催化降解有机染料的效果;用扫描电子显微镜（SEM）观测样品的表面形貌。实验结果表明,铁掺杂的氧化锌比纯氧化锌具有更高的催化活性和催化效率。这归因于铁均匀分布在氧化锌中,避免了氧化锌纳米粒子间的团聚,改善了氧化锌表面的性质,在降解有机染料过程中与有机染料大面积接触,对甲基橙和亚甲基蓝具有良好的降解效果,是一种有潜力的光催化降解材料。     

波纹板式换热器的数值模拟

以波纹板式换热器作为研究对象,通过流体力学(CFD)软件,对波纹板内、外流体流动进行了数值模拟研究。板内流体流动研究表明,流体在板内流动时存在流动死区,在这些区域里传热效果很差,导致板壁面出现热点。板间烟气流动研究表明,板片的凹凸波纹结构,起到了强化烟气侧传热的作用,其中凸波纹的作用要明显优于凹波纹,同时波纹板片式换热器的凹波纹区域存在一定的烟气脱体现象。该数值模拟研究结果对提高波纹板式燃气热水器的换热效率有一定的指导意义。     

Non-ideal flow in an annular photocatalytic reactor

This study deals with the modelling of non-ideal flow in a tubular photocatalytic reactor with thin layer of TiO₂ photocatalyst. The objective was to analyse different level of mixing in the photoreactor applying basic principles of chemical reaction engineering. For this purpose photocatalytic oxidation of toluene was used as the model reaction. Photocatalytic reactor was operated in two different flow modes: classic type of an annular reactor with basically ideal (plug) flow with some extent of dispersion and annular flow reactor acted as stirred tank reactor with mixing of reaction mixture accomplished by recirculation. A series of experiments with step input disturbance at the entrance of the reactor with different air flow was performed in order to achieve better understanding of the reactor hydrodynamics. Several reactor models are applied, such as one dimensional model of tubular reactor at the steady state conditions, axial dispersion model at non-stationary conditions and the model of the continuous non-stationary stirred tank reactor. Numerical methods necessary for solving model equations and parameter estimation were described.     

Design and optimization of a new photocatalytic reactor with immobilized ZnO for water purification

The objectives of this work were to study the degradation of the niflumic acid (NIF) with a new solar photocatalytic reactor using immobilized ZnO. The residence time distribution and the reactor efficiency for the NIF removal were studied. Two models for Retention Time Distribution (RTD) have been summarized and compared with the experimental data. Effects on the photocatalytic degradation process owing to various operating parameters conditions were also studied in continue flow. The repetitive operation performance indicates the good reproducibility of the new reactor for NIF degradation. Concerning the energy, the reactor was designed to ensure its energy autonomy through solar energy.     

Zr掺杂g-C3N4光催化降解有机污染物

以盐酸胍为前驱体，硝酸锆为锆源，通过热聚合法制备了Zr掺杂的Zr/g-C3N4光催化剂。运用XRD、SEM、UV-Vis DRS、PL、XPS、BET等手段对催化剂的结构、形貌、光学性能进行了表征分析。结果表明：Zr掺杂改性的Zr/g-C3N4光催化剂拓宽了可见光的吸收，增大了比表面积，且降低了光生电子-空穴的复合率，具有较好的光催化活性。可见光照射下，在60 min内，5Zr/g-C3N4对罗丹明B（RhB）的光催化降解率达99.29%，光催化降解过程符合一级动力学方程，其速率常数k= 0.08647 min-1，是纯g-C3N4的8.3倍。捕获剂实验发现降解RhB的主要活性物种为超氧自由基，并推测了可能的反应机理。     

Kapok fiber modified carbon nitride photocatalytic degradation of organic pollutants

A kapok fiber (KF) modified graphite phase carbon nitride (g-C₃N₄) catalyst was prepared by a one-step pyrolysis method, and the photocatalytic degradation of organic pollutants was investigated. The structure and optical properties of KF-CN were characterized by XRD, UV-Vis DRS, TEM, PL, XPS, FT-IR and N₂ adsorption-desorption. The nitrogen adsorption-desorption isotherm results show that the presence of the mesoporous structure can improve the specific surface area of KF-CN. Elemental analysis characterization indicates the biochar modification is conductive to increase the C/N ratio of KF-CN. The XPS characterization also indicates that the introduction of carbon element can change the chemical environment of N element in the lattice of g-C₃N₄ and thus increases the electron density of N element. The photocatalytic degradation of phenol experiment was carried out to investigate the performance of as-prepared kapok fiber modified graphite carbon nitride photocatalysts by using high-pressure sodium lamp as visible light source. The results show the KF(5%)-CN(600) displayed the highest phenol degradation rate constant of 0.259 h^-1, which is 4.2 times of that of neat g-C₃N₄.The activity of KF(5%)-CN(600) does not decrease significantly after 5 cycles, hinting its excellent catalytic stability and structural stability. The possible reaction mechanism was proposed.     

木棉纤维改性氮化碳光催化降解有机污染物

采用一步热解法制备了木棉纤维(KF)改性的石墨相氮化碳(g-C₃N₄)催化剂,并考察了催化剂光催化降解有机污染物的性能。采用XRD、UV-Vis DRS、FT-IR、TEM、XPS、N₂吸附-脱附、PL表征对催化剂进行了结构、形貌、光学性能测试。结果表明,KF改性可以提高催化剂的比表面积,更大的比表面积可以提供更多的活性位点来参与光催化降解过程。UV-Vis DRS结果表明KF改性可以缩小催化剂的禁带宽度,提高催化剂对光能的吸收。在可见光下,KF改性的g-C₃N₄基催化剂对苯酚降解速率常数为0.259 h^-1,是纯g-C₃N₄的4.2倍,且具有优异的催化稳定性和结构稳定性。     

固定膜太阳能光催化反应器的研究现状与展望

通过对负载在颗粒状、玻璃棒类、玻璃纤维网、纸质材料和平板型载体上的固定膜催化剂的比较,提出以玻璃纤维网、纸质材料和平板型材料为载体的固定膜催化剂是太阳能光催化反应器研究的良好选择。概述了薄膜瀑布反应器、阶梯反应器和复合抛物面反应器3种新型固定膜太阳能光催化反应器,并指出了未来太阳能光催化技术的研究方向。     

Polydopamine-coated poly(vinylidene fluoride) membranes with high ultraviolet resistance and antifouling properties for a photocatalytic membrane reactor

We modified poly(vinylidene fluoride) (PVDF) membranes with a polydopamine (PDA) coating for photocatalytic membrane reactor application with appropriate UV resistance and studied the effects of the PDA coating conditions (i.e., coating time and dopamine concentration) and UV irradiation time on the modified PVDF membrane properties. The PVDF membrane that was surface-coated with the appropriate dopamine solution concentration and coating time played a key role in controlling the membrane properties and in protecting the modified membrane against UV radiation. The optimization of the coating condition not only completely protected the modified membrane from free-radical attack initiated through UV irradiation but also improved the membrane hydrophilicity, antifouling properties, filtration performance, and mechanical strength of the membrane. UV irradiation of the membrane that was surface-coated with a high-concentration dopamine solution for a long coating time resulted in a higher mechanical strength than that of the membrane without the application of UV irradiation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47312.