太阳光对湖泊中有机污染物降解的研究进展

论述了太阳光对湖泊水体中有机污染物降解作用的研究，就其降解机理、动力学特征、作用对象及降解产物等作了逐一介绍。阐明了太阳光对生物降解湖泊水体中有机污染物具有协同作用，也概述了光降解作用受pH、溶解性有机物(DOM)、水深与水体运动、地理、水文、水质与气候等因素的影响。并对实验室模拟条件下的降解与自然条件下的降解进行对比，提出今后该领域的发展前景与研究方向。     

邻苯二甲酸酯类有机污染物生物降解性研究进展

本文综述了邻苯二甲酸酯类有机污染物在水体、固体等基质中生物降解性（降解条件、降解率、降解途径等）的研究进展,并对此领域的进一步研究提出了展望     

物理场协同作用降解有机污染物研究进展

有机污染物是环境污染物的主要类型,通过物理场外加能量的作用可实现各种有机污染物的高效降解.对微波、超声波、紫外光、电场、磁场、等离子体这几类主要物理场相互协同降解有机污染物的研究现状进行综述,重点介绍了物理场协同作用降解有机污染物的机制、效果、影响因素及污染物类型,并展望了该类研究今后的应用前景和发展趋势.     

光催化降解水中有机污染物的研究进展

光催化技术是一种新兴、高效、节能的现代污水处理技术,开发能直接利用太阳光的光催化剂是环境领域的研究热点。通过对TiO2光催化降解水中有机物的研究现状进行综述,并对光催化降解水中有机污染物的最新技术以及发展中的存在问题等进行了讨论。     

活性炭纤维上4-氯酚及焦化废水尾水的O3催化氧化降解实验研究

选择YT-1000型活性炭纤维(ACF)作为催化剂,考察ACF与O3协同作用催化降解水溶液中4-氯酚的最佳反应条件,并将该条件应用于焦化废水生物处理尾水中难降解有机污染物的催化氧化.ACF表面具有丰富的微孔结构,对4-氯酚有良好的吸附作用,在动力学上提高了其与O3反应的起始浓度,并且在ACF表面含氧、含氮等基团的催化作用下发生氧化反应,1 L浓度为100 mg/L的4-氯酚水样中投加2 g ACF反应6 min时,吸附作用对TOC的去除率为43.4%.而ACF协同O3作用时的TOC去除率提高到72.5%,协同增效作用为67.1%;在选定的反应条件下,ACF协同O3降解焦化废水生物处理尾水,60 min时的TOC与色度的去除率分别达到56.8%和96.3%.上述研究过程证明了吸附作用与催化作用的协同能有效降解生物过程不能降解的焦化废水中惰性有机污染物.     

Cu2O光催化降解水中对硝基苯酚的研究

用CuCl水解法制备Cu2O粉末,用透射电镜(TEM)和X衍射(XRD)对Cu2O粒子进行了表征.在仿太阳光源的照射下,研究了Cu2O对水中难降解有机污染物对硝基苯酚的光催化降解效果.结果表明,在8 h内,对硝基苯酚几乎完全降解.在催化剂用量为0.2 g时,对浓度为22.4 mg/L的200mL对硝基苯酚溶液有良好的降解效果.降解反应符合一级反应动力学.     

硫酸盐还原条件下三氯乙烯的降解研究

三氯乙烯(TCE)是地下水和土壤中主要的有机污染物之一.以受TCE等氯代烃严重污染的地下泥样为材料,采用室内模拟的方法.研究硫酸盐初始质量浓度为100、500、2 500 mg/L时.硫酸盐对TCE降解的影响.结果表明.高浓度硫酸盐更有利于TCE的降解;在硫酸盐还原条件下,通过添加2-溴乙基磺酸钠抑制产甲烷菌.发现产甲烷菌在TCE的降解过程中起到很重要的作用;硫酸盐浓度变化与TCE降解趋势一致.     

不同晶面暴露的TiO_2光催化降解蒽的性能及途径分析

多环芳烃是一类广泛分布于环境介质中、具有"三致性"的有机污染物,随着工业的迅速发展,其在水体中的污染日趋严重。光催化氧化法是去除这一类难降解有机污染物的有效方法。通过氙灯光源模拟太阳光,以不同晶面暴露的TiO_2为催化剂,对蒽进行催化降解,研究其在不同晶面占主导的TiO_2催化下的光降解机制,分析降解过程中间产物的生成途径。结果表明,蒽的光降解符合一级反应动力学模型,3种晶面占主导的TiO_2降解蒽的速率顺序为:{101}{010}{001},用GC-MS检测到反应过程中的中间产物主要为蒽醌和蒽酮等,剖析了蒽在TiO_2催化下的光降解途径,并进一步证实空穴和氧气是影响蒽光催化降解效率的主要活性物质,而·OH对其影响很小,其中{001}晶面暴露的TiO_2主要通过表面富集的空穴促进蒽的降解及蒽醌的生成,{101}晶面暴露的TiO_2主要通过吸附在其表面的氧气作为电子受体,生成超氧自由基等活性物质,进而氧化去除污染物。     

电离辐照技术在废水处理中的研究进展

以电离辐照(包括放射性核素产生的γ射线和电子加速器产生的电子束)技术为代表的核技术在环境污染治理,如水和废水处理、烟气脱硫脱硝、地下水修复和污泥处理等方面的研究日益引起人们的关注。电离辐射是一种相对简单并可实现大规模工业废水处理的高级氧化技术,具有实际应用潜力。综述了电离辐照在去除水中氯酚类、PPCPs等毒性难降解有机污染物、处理染料、造纸等工业废水、去除铬、汞等重金属离子以及水体消毒方面的研究和应用进展;分析了有机污染物的辐照降解机理和主要影响因素;介绍了电离辐照与其他技术联用强化有机污染物降解的研究。最后对该技术的研究和发展方向提出了建议。     

UV/TiO2光催化降解水体中的邻苯二甲酸二甲酯

酞酸酯是环境中普遍存在的有机污染物(内分泌干扰物)之一。利用UV/TiO2光催化降解水体中的邻苯二甲酸二甲酯(DMP),讨论了溶液pH、TiO2投加量及DMP初始浓度等因素对DMP降解的影响。结果表明,DMP为10mg/L左右时,TiO2投加量为0.2～0.5g/L、pH=7是比较理想的降解条件;DMP初始浓度越高,其降解率则越低。研究了Langmuir-Hinshelwood模式下DMP在TiO2表面的吸附与催化活性的关系,发现DMP主要通过吸附在催化剂的表面而非在溶液本体中发生降解。线性回归计算所得光照条件下的吸附常数远大于无光照条件下的吸附常数,可能是由于UV和TiO2体系之间产生协同效应,提高了UV/TiO2体系对DMP的降解效果。另外,初步分析了可能的降解反应机制。     

Effects of photodegradation of dissolved organic matter on the binding of benzo(a)pyrene

Dissolved organic matter (DOM) in natural waters can bind various organic pollutants, and the affinity of this binding is strongly influenced by the chemical characteristics of the DOM and water pH. This study examined the effects of photochemically induced alteration of the DOM's chemical properties and water pH on the binding of benzo(a)pyrene (BaP). Time- and pH-series of solar-simulated irradiations were performed on a natural water sample and aqueous DOM solutions prepared from aquatic and soil humic substances. The binding affinity of BaP, expressed as a partition coefficient of a compound to DOM, decreased substantially after the DOM samples were irradiated over environmentally relevant radiation doses and pH ranges. The lowering of the pH due to the photoproduction of acidic products often partly offsets the reduction of the binding affinity caused by direct photoalteration of the DOM's chemical structure. The decrease of the binding affinity, after correction for the photoinduced pH change, was positively correlated with the decrease in the molecular weight and the aromaticity of the DOM in the course of irradiation. Increasing O(2) abundance accelerated the decrease of the binding affinity as a result of enhanced DOM photodegradation. Visible light played a more important role in reducing the molecular weight and aromaticity of the DOM than in reducing the content of dissolved organic carbon (DOC) via photoremineralization while the reverse was true for UV radiation, indicating that photochemical reduction of the binding affinity may occur in natural waters at depths greater than UV radiation can reach. A decrease of the affinity of DOM for binding BaP will increase the free dissolved fraction of BaP and thus its availability and toxicity to aquatic organisms. The results from this study may have similar implications for organic pollutants other than BaP.     

Monitoring the photochemical degradation of triclosan in wastewater by UV light and sunlight using solid-phase microextraction

Photo solid-phase microextraction (photo-SPME) is applied for the first time to study the photochemical behavior of an emerging pollutant, triclosan, in real contaminated wastewater samples using a solar simulator. In this study, water samples are extracted by SPME and then, the fiber coating is irradiated for a selected time. This on-fiber procedure, so-called photo-SPME, followed by gas chromatography-mass spectrometry makes it possible to study photodegradation kinetics and the generation of byproducts. Several photoproducts were identified in the real samples including the 2,8-dichlorodibenzo-p-dioxin, dichlorophenols and a compound tentatively identified as other DCDD congener or a dichlorohydroxydibenzofuran. Accordingly, it was possible to postulate main photodegradation mechanisms. Photo-SPME demonstrated slower kinetics in wastewater than in spiked ultrapure water probably due to the presence of dissolved organic matter. This technique was extensively compared with conventional aqueous photodegradation showing high similarity. The influence of pH on the triclosan photolysis and on the triclosan-dioxin conversion was also investigated in wastewater. Photodegradation of triclosan and formation of 2,8-DCDD occurred independently of sample pH. This study represents an advance in the use of photo-SPME to understand the photochemical fate of environmental organic pollutants and demonstrates its clear advantages with real samples.     

Can radiation chemistry supply a highly efficient AO(R)P process for organics removal from drinking and waste water? A review

The increasing role of chemistry in industrial production and its direct and indirect impacts in everyday life create the need for continuous search and efficiency improvement of new methods for decomposition/removal of different classes of waterborne anthropogenic pollutants. This review paper addresses a highly promising class of water treatment solutions, aimed at tackling the pressing problem of emerging contaminants in natural and drinking waters and wastewater discharges. Radiation processing, a technology originating from radiation chemistry studies, has shown encouraging results in the treatment of (mainly) organic water pollution. Radiation (“high energy”) processing is an additive-free technology using short-lived reactive species formed by the radiolysis of water, both oxidative and reducing, to carry out decomposition of organic pollutants. The paper illustrates the basic principles of radiolytic treatment of organic pollutants in water and wastewaters and specifically of one of its most practical implementations (electron beam processing). Application examples, highlighting the technology’s strong points and operational conditions are described, and a discussion on the possible future of this technology follows.     

UV-light induced mineralization of organic matter bound chlorine in Lake Bjän,Sweden--a laboratory study

Surface water and aqueous solutions of isolated organic matter from a humic rich lake in southern Sweden were exposed to artificial UV radiation to investigate the UV light induced influence on organic matter bound chlorine in natural systems. It was found that the photodegradation of organic matter bound chlorine was more pronounced than the photodegradation of organic carbon. After 120 h of irradiation of the isolated organic matter, only 35% of the initial organochlorine was still in the solution compared to about 70% of the dissolved organic carbon (DOC). A similar result was obtained for unfractionated surface water. Furthermore, our results indicate that the loss of organic chlorine was mainly due to a mineralization of organic chlorine into chloride ions. The total decrease of organic chlorine after 120 h was 32 microg Cl(org) l(-1), of which the major part disappeared in the initial irradiation phase. A similar increase was observed in the chloride concentration (34 microg Cl(-) l(-1)).     

影响有机污染物在土壤中的迁移、转化行为的因素

本文介绍了有机污染物在土壤中的吸附与解吸附、渗滤、挥发和降解等行为过程。探讨了吸附与解吸附机理、土壤有机质含量和类型、水分含量及温度等对此过程的影响。依据某些典型的化合物行为模型,论述了影响土壤中有机污染物渗滤的因素。有机污染物需要先从土壤深层迁移至地表,然后挥发至大气,在土壤中迁移的速率较慢,控制着整个挥发过程,可用Ｆｉｃｋ 第二定律来描述。有机污染物在土壤中的非生物降解主要包括氧化－ 还原、光解和水解等反应。土壤中的Ｏ２ 含量、土壤有机质成分和含量、辐射强度、光谱分布、土壤水分含量、温度和ｐＨ 值等都会影响非生物降解过程。其中有些因素通过影响微生物的生物活性,还影响有机污染物的生物降解     

Analysis of extinction in ultraviolet and visible spectra of water bodies of the Paraguay and Brazil wetlands

The extinction spectra in ultraviolet and visible radiation were analyzed using filtered and unfiltered water samples obtained in 11 open water bodies in the Neembucù (Paraguay) and Pantanal (Brazil) wetlands. The role of dissolved and suspended matter in the total extinction was analyzed between 260 nm and 700 nm. The chromophoric dissolved organic matter (CDOM) was the major component in extinction of considered ultraviolet radiation (260-400 nm). The differences in CDOM concentrations explained the main pattern of extinction of the ultraviolet radiation in the samples. Nevertheless, differences between the studied water bodies were found also to depend on the rate of photodegradation and photobleaching. The methodology developed in the present study was to distinguish "humic optic waters" according to quantity and quality of dissolved and suspended matter present. In the "humic optic water", the penetration of 10% of incident UV radiation and the photoactive layer are estimated. The influence of particulate matter increases in the total extinction of the wavelengths higher than 400 nm. The integral of the extinction curve of suspended matter in the visible wavelengths (400-700 nm) was found to relate with the total suspended solids and chlorophyll concentrations.     

Study of chlorothalonil photodegradation in natural waters and in the presence of humic substances

Photodegradation of chlorothalonil was studied in different natural waters (sea, river and lake) as well as in distilled water under natural and simulated solar irradiation. The effect of dissolved organic matter (DOM) such as humic and fulvic substances on the photodegradation rate of chlorothalonil was also studied in simulated sunlight. The presence of DOM enhanced the photodegradation of chlorothalonil with the exception of seawater. The kinetics were determined through gas chromatography electron capture detection (GC/ECD) and the photodegradation proceeds via pseudo-first-order reaction in all cases. Half-life ranged from 1 to 48 h. In natural and humic water chlorothalonil photodegradation gave rise to two different intermediates compared to distilled water demonstrating that the transformation of chlorothalonil depend on the constitution of the irradiated media and especially from DOM. The byproducts identified by GC/MS techniques were: chloro-1,3-dicyanobenzene, dichloro-1,3-dicyanobenzene, trichloro-1,3-dicyanobenzene and benzamide.     

Photodegradation of pentachlorophenol by sunlight in aquatic surface microlayers

Photodegradation of pentachlorophenol (PCP) in aquatic surface microlayer (SM) was examined under natural sunlight. SM samples were collected using a glass plate, along with corresponding subsurface waters. PCP was added to samples of the SM and subsurface water. When all samples were exposed to the same natural sunlight conditions, the first order photodegradation rates of PCP in the SM water samples were different from those of PCP in corresponding subsurface water samples. The difference was correlated with the enrichment of dissolved organic carbon (DOC) in SM compared to the corresponding subsurface waters. Enhanced photodegradation in SM may be due to increased abundance of photoreactants related to the UV-absorbing properties of dissolved organic materials in the SM as the result of photo-induced reactions. Effects of environmental factors, pH and salinity, on photodegradation process of PCP in SM were also evaluated.     

环境水体微污染有机物及其去除技术研究进展

水体有机污染物因其生物毒性对人体健康和生态环境造成了严重的危害。随着环保技术的发展,高浓度有机污染物已得到很好的去除。检测水平的不断提高使微量有机污染物日益受到广泛关注。为了深入地研究微污染有机物及其去除技术,对微污染有机物的种类、性质和危害进行了详细阐述,并综述了国内外生物法、膜处理技术、高级氧化技术、吸附技术对微污染有机物的去除效果,总结了各种技术的优缺点。     

Effective collection of hydrophobic organic pollutants in water with aluminum hydroxide and hydrophobically modified polyacrylic acid

Polyacrylic acid was hydrophobically modified with dodecylamine and used as a coagulant for coprecipitation of hydrophobic organic pollutants from water. The polymer coagulant induced effective aggregation of aluminum hydroxide having hydrophobic regions which are essential for the incorporation of hydrophobic organic pollutants. Recoveries of the organic pollutants increased with increasing the dodecylamine content, which indicated that the dodecylamine moiety played an important role in the formation of hydrophobic area on the precipitate. Different hydrophobic organic pollutants that had hardly been removed by the conventional coprecipitation were successfully collected by the proposed method.