几种新式太阳能光催化反应器的探讨

本文综述了几种新式的太阳能光催化反应器，对其结构和处理效果进行了比较，并对该法处理水的经济性进行简单的概述，指出光催化法是一种可以充分利用太阳能、具有很大发展潜力的水处理方法。     

太阳能固定膜光催化去除双酚A的特性与效果

以太阳能固定膜光催化中试装置,研究了光解、初始浓度和平均光强等对双酚A(BPA)光催化去除的影响及BPA的矿化和在自来水中的处理效果.试验结果表明,BPA在日光照射下很难光解,其光催化降解呈表观一级反应,在平均光强介于5.7～23.5 W/m2时,表观反应速率常数和平均光强呈线性关系.太阳能光催化对BPA具有良好的矿化作用,但其降解与以UV254为光源的降解有不同的机理.太阳能光催化对自来水中BPA也具有较好的处理效果.     

水溶液中残留四环素的光催化降解的实验研究

由于抗菌素具有抑制微生物生存的作用，通常处理工业废水最有效的“生物氧化降解法”却无法用来有效处理四环素废液，简述了半导体光催化剂在紫外光照射下降解难溶或难分解有机物基本原理，以半导体ＴｉＯ２和ＺｎＯ粉粒为光催化剂进行催化降解四环素废液的实验，其结果表明：半导体ＴｉＯ２光催化降解效果比较好；另外，Ｈ２Ｏ２可以作为ＴｉＯ２光催化剂的助氧化剂来加快四环素的降解，该实验结果有助于光催化剂的深入研究和太阳能     

光催化氧化处理有机废水

介绍了光催化氧化法的原理,对光催化氧化法处理有机废水的可行性进行了试验,探讨了ＣＯＤ随反应时间的变化规律及催化剂用量,温度、浓度的影响。试验表明,光催化氧化可降解象洗涤剂这样难降解的有机物,反应１２０ｍｉｎＣＯＤ去除率可达５０％以上。     

电助光催化氧化反应器的类型和设计要点

电助光催化反应器提供了通过外加电场提高光催化技术处理效率的场所,其构型是决定电助光催化反应效率和进行机理研究的关键要素。本文对当前电助光催化研究中采用的反应器的类型进行了综述,并提出电助光催化反应器设计的一些要点。     

水中氯代有机化合物处理方法及研究进展

对氯代有机物的污染进行治理是水污染控制的重要课题。本文总结了可用于水中氯代有机物处理的一些方法的近期研究成果，同时也讨论了生物法、光催化氧化法和双金属还原法的各自特点及应用前景     

光催化水质净化反应器的研究进展

在全面分析国内外近 10年来光催化反应器的研究成果基础上 ,归纳出了光催化反应器设计的 3个主要因素 :传质速率、紫外辐射在反应器中的分布和光催化剂受光辐照的表面积 ,详细讨论了各类光反应器的结构与特征 ,并概述了太阳能光反应器的设计研究进展 ,最后提出了推进光催化反应器研究进程的建议。     

光催化臭氧氧化法在废水处理中的研究进展

光催化臭氧氧化法作为一种有效的废水处理技术,对难降解的有机废水,具有良好的降解功效。文中分析了UV/O3/Fe2＋、UV/O3/Fe3＋和UV/O3/H2O2体系的反应机理,介绍了光催化臭氧氧化法在废水处理中的应用情况,指出了光催化臭氧氧化法存在的问题和展望。     

炉渣制光催化剂催化降解水中罗丹明B的研究

以废弃的钢铁冶炼炉渣为原料制备了光催化剂GN,并对其进行了X衍射、紫外-可见漫反射吸收光谱、比表面积及孔径分布等物性测试,通过在三相内循环流化床光催化反应器中对罗丹明B废水进行处理,确定了GN的最佳光催化氧化条件.将GN与传统的光催化剂TiO2作比较,结果表明,GN不仅具备较高的光催化活性,而且成本更低,为钢铁冶炼炉渣的循环再利用提供了一种新思路,同时也为光催化氧化技术的工业化应用提供了一条新颖、经济、可行的途径.     

二氧化钛光催化剂的表征方法研究

光催化氧化法作为一种非常具有应用前景的有机废水处理方法而成为近年来国内外的一个热点研究领域。二氧化钛因其光催化活性高、适用范围广等优点而引起众多研究者的重视 ,这方面的研究已取得了许多成果。二氧化钛光催化活性的强弱直接影响到该方法在实际中的应用。本文对影响二氧化钛催化活性的因素以及表征这些因素的方法进行了评述。     

Nanomaterials photocatalytic activities for waste water treatment: a review

Water is necessary for the survival of life on Earth. A wide range of pollutants has contaminated water resources in the last few decades. The presence of contaminants incredibly different dyes in waste, potable, and surface water is hazardous to environmental and human health. Different types of dyes are the principal contaminants in water that need sudden attention because of their widespread domestic and industrial use. The toxic effects of these dyes and their ability to resist traditional water treatment procedures have inspired the researcher to develop an eco-friendly method that could effectively and efficiently degrade these toxic contaminants. Here, in this review, we explored the effective and economical methods of metal-based nanomaterials photocatalytic degradation for successfully removing dyes from wastewater. This study provides a tool for protecting the environment and human health. In addition, the insights into the transformation of solar energy for photocatalytic reduction of toxic metal ions and photocatalytic degradation of dyes contaminated wastewater will open a gate for water treatment research. The mechanism of photocatalytic degradation and the parameters that affect the photocatalytic activities of various photocatalysts have also been reported.

     

The photocatalytic disinfection of urban waste waters

In this paper we present the results of the photocatalytic disinfection of urban waste water. Two microbial groups, total coliforms and Streptococcus faecalis, have been used as indexes to test disinfection efficiencies. Different experimental parameters have been checked, such as the effect of TiO2, solar or UV-lamp light and pH. Disinfection of water samples has been achieved employing both UV-lamp and solar light in agreement with data shown by other authors. The higher disinfection rates obtained employing an UV-lamp may be explained by the stronger incident light intensity. Nevertheless no consistent differences have been found between TiO2-photocatalysis and direct solar or UV-lamp light irradiation at natural sample pH (7.8). At pH 5 the presence of TiO2 increases the relative inactivation rate compared with the absence of the catalyst. After the photocatalytic bacterial inactivation, the later bacterial reappearance was checked for total coliforms at natural pH and pH 5, with and without TiO2. Two h after the photocatalytic treatment, CFU increment was almost nill. But 24 and 48 h later an important bacterial CFU increment was observed. This CFU increment is slower after irradiation with TiO2 at pH 5 in non-air-purged samples.     

New large solar photocatalytic plant: set-up and preliminary results

A European industrial consortium called SOLARDETOX has been created as the result of an EC-DGXII BRITE-EURAM-III-financed project on solar photocatalytic detoxification of water. The project objective was to develop a simple, efficient and commercially competitive water-treatment technology, based on compound parabolic collectors (CPCs) solar collectors and TiO2 photocatalysis, to make possible easy design and installation. The design, set-up and preliminary results of the main project deliverable, the first European industrial solar detoxification treatment plant, is presented. This plant has been designed for the batch treatment of 2 m3 of water with a 100 m2 collector-aperture area and aqueous aerated suspensions of polycrystalline TiO2 irradiated by sunlight. Fully automatic control reduces operation and maintenance manpower. Plant behaviour has been compared (using dichloroacetic acid and cyanide at 50 mg l(-1) initial concentration as model compounds) with the small CPC pilot plants installed at the Plataforma Solar de Almería several years ago. The first results with high-content cyanide (1 g l(-1)) waste water are presented and plant treatment capacity is calculated.     

Treatment of chlorinated solvents by TiO2 photocatalysis and photo-Fenton: influence of operating conditions in a solar pilot plant

Titanium dioxide photocatalysis (using 20 0mg l(-1) of TiO2), under aerobic and anaerobic conditions, and photo-Fenton (2 and 56 mg l(-1) iron) were applied to the treatment of different NBCS (non-biodegradable chlorinated solvents), such as dichloroethane, dichloromethane and trichloromethane dissolved in water at 50 mg l(-1). All the tests were performed in a 35-l solar pilot plant with compound parabolic collectors (CPCs) under natural illumination. The two solar treatments were compared with attention to chloride release and TOC mineralisation, as the main parameters. Photo-Fenton was found to be the more appropriate treatment for these compounds, assuming volatilisation as a drawback of photocatalytic degradation of NBCS dissolved in water. In this context, several operating parameters related to NBCS degradation, e.g., treatment time, temperature, hydrogen peroxide consumption and volatility of parent compounds are discussed. The correct choice of operating conditions can very often diminish the problem of volatilisation during treatment.     

Solar-driven photocatalytic treatment of diclofenac using immobilized TiO<Subscript>2</Subscript>-based zeolite composites

The study is aimed at evaluating the potential of immobilized TiO₂-based zeolite composite for solar-driven photocatalytic water treatment. In that purpose, TiO₂-iron-exchanged zeolite (FeZ) composite was prepared using commercial Aeroxide TiO₂ P25 and iron-exchanged zeolite of ZSM5 type, FeZ. The activity of TiO₂-FeZ, immobilized on glass support, was evaluated under solar irradiation for removal of diclofenac (DCF) in water. TiO₂-FeZ immobilized in a form of thin film was characterized for its morphology, structure, and composition using scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDX). Diffuse reflectance spectroscopy (DRS) was used to determine potential changes in band gaps of prepared TiO₂-FeZ in comparison to pure TiO₂. The influence of pH, concentration of hydrogen peroxide, FeZ wt% within the composite, and photocatalyst dosage on DCF removal and conversion efficiency by solar/TiO₂-FeZ/H₂O₂ process was investigated. TiO₂-FeZ demonstrated higher photocatalytic activity than pure TiO₂ under solar irradiation in acidic conditions and presence of H₂O₂.     

Solar photocatalytic decolorization of methylene blue in water

In this study, a photocatalytic decolorization system equipped with immobilized TiO2 and illuminated by solar light was used to remove the color of wastewater. To examine the decoloring efficiency of this system, photocatalytic decolorization of an organic dye such as methylene blue was studied as an example. The effects of light source, pH, as well as the initial concentration of dye were also investigated. It was observed that the solution of methylene blue could be almost completely decolorized by the solar light/TiO2 film process while there was about 50% color remaining with solar irradiation only. In addition, it was found that the decoloring efficiency of solution was higher with solar light irradiation than with artificial UV light irradiation, even though the artificial UV light source supplied higher UV intensity at 254 nm. The color removal rate of methylene blue with solar light irradiation was almost twice that of artificial UV light irradiation. This phenomena was mainly attributed to that some visible light range of solar light was useful for exciting the methylene blue molecules adsorbed on TiO2 film, leading to a photosensitization process undergoing and decoloring efficiency promoted. This solar-assisted photocatalytic device showed potential application for decoloring organic dyes in wastewater.     

TiO2膜降解水中污染物的稳定性考察与再生方法研究

针对实际水处理中对催化剂性能的要求，以光催化降解苯酚溶液作为探针反应，考察了玻璃纤维网上负载的TiO₂膜催化剂长期使用条件下的稳定性，研究了催化剂在自来水中使用失活后的再生方法。结果表明，经过50次使用之后，膜催化剂120 min反应对苯酚的降解率从100%下降至83%，总体上看，所制催化剂还是具有相当好的稳定性；在反应器中用蒸馏水浸泡配合光催化反应对TiO₂膜催化剂进行原位再生是一种可行的再生途径。     

Photocatalytic degradation of azo dyes by nitrogen-doped TiO2 nanocatalysts

This study examined the photocatalytic degradation of three azo dyes, acid orange 7 (AO7), procion red MX-5B (MX-5B) and reactive black 5 (RB5) using a new type of nitrogen-doped TiO2 nanocrystals. These newly developed doped titania nanocatalysts demonstrated high reactivity under visible light (lambda>390 nm), allowing more efficient usage of solar light. The doped titania were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Experiments were conducted to compare the photocatalytic activities of nitrogen-doped TiO2 nanocatalysts and commercially available Degussa P25 powder using both UV illumination and solar light. It is shown that nitrogen-doped TiO2 after calcination had the highest photocatalytic activity among all three catalysts tested, with 95% of AO7 decolorized in 1 h under UV illumination. The doped TiO2 also exhibited substantial photocatalytic activity under direct sunlight irradiation, with 70% of the dye color removed in 1h and complete decolorization within 3 h. Degussa P25 did not cause detectable dye decolorization under identical experimental conditions using solar light. The decrease of total organic carbon (TOC) and evolution of inorganic sulfate (SO4(2-)) ions in dye solutions were measured to monitor the dye mineralization process.     

纳米Bi2O3/TiO2复合光催化剂的制备及性能研究

以光催化效果为评价标准，采用超声波作用下水解法制备Bi₂O₃/TiO₂复合光催化剂，考察了水解条件和Bi₂O₃掺入量等制备条件对复合光催化剂性能的影响。结果表明，与传统制备方法相比，该方法操作简单、快速；当水和乙醇的比例为4∶1时所得样品的光催化活性最好；Bi₂O₃的掺入拓宽了TiO₂对光的吸收范围，提高了TiO₂的光催化活性，掺入量(Bi₂O₃)为0.25%复合光催化剂催化活性最高；复合光催化剂对多种水溶性染料均具有较好的处理效果。     

Large solar plant photocatalytic water decontamination: Degradation of pentachlorophenol

The photocatalytic degradation of pentachlorophenol in the large solar plant built at the Plataforma Solar de Almeria is presented. Degradation of cubic meters per hour of pentachlorophenol at a concentration of mg L⁻¹ is demonstrated and is easily achieved in short residence times. Details of the plant based on parabolic solar concentrators, together with the examination of the main factors affecting total efficiency are discussed in comparison with small scale laboratory experiments. Experiments carried out with addition of peroxydisulphate show a noticeable increment in the degradation efficiency and are suggested for the treatment of concentrated or refractory pollutants.