挥发性有机化合物的净化处理工艺

有机废气中大多含有低浓度的苯、甲苯、苯乙烯、多环芳烃等挥发性有机化合物（VOCs）。治理VOCs污染是大气污染治理的重要邵分。叙述了吸收法、吸附法、生物法和低温等离子体四种技术的废气净化原理和国内外研究进展情况,并对其发展前景和研究方向进行了探讨。文中最后提出了有机废气的联合协同处理方法是今后的一个重要研究方向,并存在巨大的研究空间。     

挥发性有机化合物处理技术

本文主要介绍了脱除工业废气中挥发性有机污染物的各种方法,并阐述了各种方法的特点和影响因素。     

挥发性有机化合物的污染控制技术

随着经济的发展,挥发性有机化合物(VOC)的污染已成为危害人体健康的公害。评述了目前VOC的各种控制技术,并指出了各种方法的适用条件及存在的问题,提出了VOC控制技术的发展方向。     

挥发性有机物处理技术的特点与发展

挥发性有机物(VOCs)产生于有机化工生产过程及有机产品被使用的自身挥发过程,对环境和人类健康有害。本文综述了VOCs的定义、来源、危害、相关法律法规和排放情况。介绍了现有VOCs处理技术,包括化学氧化法、物理分离法、生物分解法、光解法、电化学法以及新兴复合型处理技术等的特点。阐述了这些技术的原理、工艺流程、优势、使用限制和市场的占有率,其中吸附法应用最为广泛,催化燃烧法和低温等离子法发展最快,复合型处理技术处理效果最好且无二次污染是VOCs处理技术发展的一个重要方向。选择合适VOCs处理工艺应依据其主要成分的浓度、气体流量、物化性质等因素并考虑到整个处理工艺的经济效益。并对新兴复合型处理技术的发展趋势作了展望,指出降低成本、简化操作是该技术进一步推广的关键。     

挥发性有机化合物(VOCs)的低温等离子体-催化协同净化

低温等离子体-催化协同净化技术是一种理想的环境污染治理技术。催化剂的加入可提高等离子体反应中污染物的脱除效率和二氧化碳的选择性，减少副产物的产生，并进一步降低能耗。分析了低温等离子体-催化协同净化挥发性有机化合物的效果与净化原理，并从影响污染物降解率的因素、产物分析和反应动力学等机理性研究方面概括了目前国内外在应用该技术去除挥发性有机污染物方面取得的成果，最后提出了该项技术在环境保护领域的应用前景以及研究方向。     

VOCs废气的危害及处理技术综述

VOCs废气是一类对环境和人类产生严重危害的废气。综述了VOCs废气处理技术的原理和国内外研究进展情况,包括吸附法、低温等离子体、光催化氧化和生物处理等。     

炼油污水场挥发性有机化合物(VOCs)处理技术现状

介绍了石化企业炼油污水场挥发性有机化合物(VOCs)的危害以及治理的紧迫性,阐述了目前各种VOCs处理技术的特点,指出其优势和不足。提出单一技术的组合使用能有效提高VOCs去除率,降低投资成本,在工业化应用方面前景广阔。     

低温等离子体处理挥发性有机物的研究进展

针对治理大气中有害物质挥发性有机物(VOCs),阐述并归纳了吸附、冷凝、燃烧、光催化等现有处理技术中的工艺特点,介绍了目前典型技术中极具有研究前景及应用价值的低温等离子体净化技术的工艺原理及研究进展,综述了低温等离子体催化协同技术的催化剂分类及放置方式,重点突出催化协同对处理效果的优化作用,指出了今后低温等离子体催化协...     

低温等离子体处理挥发性有机物的研究进展

针对治理大气中有害物质挥发性有机物(VOCs),阐述并归纳了吸附、冷凝、燃烧、光催化等现有处理技术中的工艺特点,介绍了目前典型技术中极具有研究前景及应用价值的低温等离子体净化技术的工艺原理及研究进展,综述了低温等离子体催化协同技术的催化剂分类及放置方式,重点突出催化协同对处理效果的优化作用,指出了今后低温等离子体催化协同处理挥发性有机物的可能发展方向。     

低温等离子体处理挥发性有机物的研究进展

低温等离子体技术在处理挥发性有机物(VOCs),特别是在对空气中低含量的VOCs的处理中,具有独特的作用.概述了低温等离子体降解VOCs的基本原理及等离子体反应器结构;综述了低温等离子体技术以及和催化剂联合作用在处理VOCs中的应用;并讨论了低温等离子体处理VOCs的进一步研究方向及其应用前景.     

挥发性有机化合物催化氧化技术

基于环境友好,对使用催化氧化法去除挥发性有机化合物(VOCs)的原理、特点以及催化剂、工艺流程等研究进行综述。挥发性有机化合物完全催化氧化机理分为:Mars-van Krevelen(MVK)模型、Langmuir-Hinshelwood(L-H)模型和Eley-Rideal(E-R)模型。复合金属氧化物催化剂是研究的热点,去除VOCs的核心是使反应温度降低,即具有低温和高活性的催化剂。延长催化剂寿命、提高去除效率也可以带来良好的节能效果和降低投资成本。对于低浓度和大体积VOCs排放,可通过吸附+催化混合法先进技术实现去除,且成功应用于实践。     

Modeling of volatile organic compounds condensation in fluidized bed

A model of volatile organic compound condensation in dense fluidized bed was used to simulate a new depollution process by separation in fluidized bed. The volatile compounds are condensed and captured by fluidized porous particles before being renewed in an evaporation reactor and recirculated to the condensation riser. This study shows how a large bed height, a small superficial gas velocity, a cold wall temperature provided that the condensation products that do not turn into solid state give a high and stable abatement rate as well as it provides a good use of the internal porosity of the particles. It is also demonstrated that, as already known after thermodynamics constraints, this condensation process is better adapted to high-concentrated effluent and needs a complementary separation system if regulations are severe.     

Coordination polymers: Opportunities and challenges for monitoring volatile organic compounds

Coordination polymers (CPs) are emerging as the next generation of macromolecules for many industrial and technological applications. The highly porous nature of these CPs offers the opportunity to exploit them as very effective adsorbents for gaseous molecules, including volatile organic compounds (VOCs). Release of VOCs into the environment is highly undesirable as they can be extremely harmful to general public health and environmental quality. Lately, a large volume of the scientific literature has pointed toward the potentially important role of CPs in the monitoring and analysis of VOCs, offering unprecedented detection limits. This review discusses the opportunities and challenges for the use of CP materials in such applications, describing their general working principles, analytical performance, advantages, and limitations. Recent progress in the application of CPs in the detection, monitoring, and analysis of VOCs is critically reviewed. The discussion is further extended to cover future applications and current research activities in this emerging analytical field.     

植物释放VOOs的研究

植物源释放的挥发性有机物（BVOCs）占到了全球挥发性有机物（VOCs）排放总量约70％,在生态系统中起着重要的作用,且与人们健康息息相关,对环境安全和人类生存健康具有重要的影响。主要综述了BVOCs中异戊二烯及单萜烯等几种重要的植物释放物,概括了它们的分类、作用、释放影响因素以及对它们的研究情况。     

Combustion of volatile organic compounds in two-component mixtures over monolithic perovskite catalysts

Activity of monolithic perovskite catalysts in oxidation of selected hydrocarbons and oxy-derivatives, oxidized individually and in two-component mixtures, as well as the reaction selectivity were investigated. One bulk perovskite (LaMn₂O₃) catalyst and two catalysts based on LaMn₂O₃ with addition of silver (25 at.%) coated on cordierite support were prepared for the study. The efficiency of oxy-derivatives oxidation was higher than that of hydrocarbon oxidation, but some by-products (first of all aldehydes) were detected in the flue gases. Addition of silver to the active phase improved catalyst activity and selectivity to CO₂ and water. The “mixture effect” on catalyst activity and selectivity depended on composition of the reaction mixture and the catalyst used. The presence of oxy-derivative in the reaction mixture inhibited oxidation of hydrocarbons. Toluene inhibited the process of oxy-derivatives conversion and increased the concentration of incomplete oxidation products.     

Support effect on complete oxidation of volatile organic compounds over Ru catalysts

Catalytic combustion of ethyl acetate, acetaldehyde, and toluene was investigated on various supported Ru catalysts prepared by the impregnation method, and the effect of reduction treatment on the activity was examined. Among the as-calcined catalysts tested, Ru/CeO₂ showed the highest activity for all tests regardless of the pre-treatment in hydrogen atmosphere. The catalytic activity of Ru/SnO₂ was significantly degraded by the reduction treatment, whereas the activity of Ru/ZrO₂ and Ru/γ-Al₂O₃ was enhanced. To reveal these phenomena, the as-calcined and reduced catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and BET surface area. The dispersion of ruthenium on the supports was evaluated by chemisorption methods of carbon monoxide. The catalytic activity was strongly related to ruthenium species easily oxidizable and reducible at low temperatures. Such ruthenium species were loaded on CeO₂ in a highly dispersed state, resulting in the highest activity.     

Removal of volatile organic compounds by cryogenic condensation followed by adsorption

Removal of volatile organic compounds (VOCs) from gaseous effluents by cryogenic condensation and adsorption has been studied. Mathematical models have been developed to predict the extent of removal of a binary mixture of VOCs in air by these two methods under a wide range of operating conditions. The model results are verified with the published work. A model parametric study carried out in this work suggests that if the concentrations of VOCs in the effluent stream vary over a wide range, condensation followed by adsorption is an effective technique to control the emissions. Condensation is found to be suitable if the VOCs emission levels are high (>1%). On the other hand, if the emission levels are low i.e. parts per millions (ppm) or sub ppm, adsorption is a preferred technique for removing the VOCs from the effluent stream. The model results in this work have significance from the perspective of understanding the mechanism of removal of VOCs by these two methods, determining the key operating parameters that control the removal process and also, defining an effective VOC control strategy.     

Catalytic oxidation of trichloroethylene in two-component mixtures with selected volatile organic compounds

The activity of two noble metal catalysts (Pt and Pd) on metallic monolithic support and one perovskite (La_0.5Ag_0.5MnO₃) on cordierite monolith was tested in the oxidation of selected volatile organic compounds (VOCs) and trichloroethylene (TCE), oxidized alone and in two-component mixtures of TCE with a non-halogenated compound. Only over the Pt catalyst each compound in the reaction mixtures strongly enhanced TCE oxidation. Over Pd, promoting effect on TCE oxidation was observed for toluene and ethanol only. Over perovskite, each non-chlorinated compound was found to inhibit TCE oxidation. The presence of TCE was found to inhibit the oxidation of each compound added over both noble metal catalysts, but it had no influence on the oxy-derivatives oxidation over the perovskite catalyst.     

Gas-solid adsorption of selected volatile organic compounds on titanium dioxide Degussa P25

This paper focuses on the adsorption of gaseous trichloroethylene, toluene and chlorobenzene on the photocatalyst TiO₂ Degussa P25. An optimized EPICS (Equilibrium Partitioning In Closed Systems) methodology was used to study equilibrium partitioning. For the three compounds investigated, equilibrium adsorption was reached within of incubation. Adsorption isotherms, determined at a temperature (T) of and relative humidities (RH) of 0.0% and 57.8% were found to be linear (R²>0.993,n=5), indicating that no monolayer surface coverage was reached in the concentration interval studied ). Within the linear part of the isotherm, the influence of both relative humidity and temperature was investigated in a systematic way and discussed from a thermodynamic point of view. Data analysis resulted in a double linear regression for 22% ?RH?90% and . The equilibrium adsorption coefficient represents the equilibrium concentration ratio and ΔU_ads is the internal energy of adsorption . At RH=0.0%, experimental K values were a factor 5-10 higher than those expected from the regression equation, indicating that another adsorption mechanism becomes important below monolayer surface coverage of TiO₂ by water vapour molecules. Since surface interactions are of primary importance in photocatalytic reactions, this paper contributes to a better understanding of the basic mechanisms of TiO₂ mediated heterogeneous photocatalysis and is an interesting tool for developing optimized mathematical models.