ALKYD PAINT WASTE CHARACTERIZATION AND DISTILLATION

In the present study the characterization and distillation of alkyd paint waste have been carried out in order to establish the technical viability of organic solvents recovery and to decide upon the best environmental management for the waste stream from a paint spray-booth application in an automotive component factory. The paint is a black primer based on an alkyd resin with toluene and xylene as solvents, black carbon as pigment, fillers, and other minor components.

The paint, paint wastes, and distillation wastes have been characterized by determination of the physicochemical properties of the solid (solvents content and flash point) and determination of ecotoxicity (EC₅₀), total organic carbon (TOC), and metals concentration of the leachates. The highly volatile matter (HVM) content, determined by the weight loss at 200°C, has been used as a parameter to relate with the hazardous wastes regulations based on the characterization parameters EC₅₀, TOC, and flash point.

Distillation experiments have been performed in a simple batch mode with mixtures of paint waste, water, and additives in order to obtain high efficiencies in the recovery of volatile organic compounds and to obtain a final solid with nonhazardous behavior and good manageability qualities. A fractional factorial design (2^3–1) of experiments was carried out in order to study the influence of the distillation variables: water/paint waste ratio (2/1–3/1 (g/g)), temperature (110°–145°C), alkaline additives (Na(OH),CaO, Ca(OH)₂), and amount of other additives (wt.% of bentonite, cement, and Ca(OH)₂) on the solvent recovery, [% VOCs]_Recovery, on the residual volatile organic compounds, [% VOCs]_{Distillation Waste}, and on the total organic content (TOC) of the waste leachates. The present work shows the quantitative results of the alkyd paint waste distillation process under optimum conditions.     

石化中间储罐挥发性有机物排放特征与反应活性

中间储罐是石化企业的主要挥发性有机物(VOCs)排放源,对大气环境产生重要影响。本文对我国某石化企业炼化中间产物、污油、石化中间产物等中间储罐大呼吸过程进行了采样监测,分析了VOCs排放特征并建立了有机污染物图谱。基于OH自由基损失速率和最大增量反应活性法,分别量化了大呼吸过程大气反应活性和臭氧生成潜势(OFP)。结果表明,中间储罐大呼吸过程VOCs浓度高达数万毫克每立方米,单位体积物料周转量VOCs排放强度达到0.55～71.3g/m³。不同储罐排放特征差异大,炼化中间产物及污油储罐VOCs组成以烷烃为主,石化中间产物储罐VOCs以烯烃和芳香烃为主;C₃～C₇烷烃、C₃～C₄烯烃、苯、甲苯和丙酮等是首要污染物。中间储罐大呼吸损耗气具有较高大气光化学反应活性和臭氧生成潜势(OFP),OH自由基损失速率常数接近1.43×10⁴～2.37×10⁶s^-1,OFP达到2.84×10⁵～7.53×10...     

活性炭对挥发性有机化合物的吸附回收研究进展

介绍了挥发性有机化合物(VOCs)的来源、种类、危害、回收意义以及常见的回收技术。VOCs是指除CO、CO₂、H₂CO₃、金属碳化物、金属碳酸盐和碳酸铵外,所有参加大气光化学反应的碳化合物,主要来源于以石化产品为主要燃料的交通工具产生的尾气和工业生产过程中产生的废气等,会对环境造成严重危害。目前主要的处理技术有破坏技术和回收技术,其中活性炭吸附技术已经成为环保领域研究的热点。重点介绍了活性炭对芳香烃、脂肪烃、卤代烃、醇类、醛类、酮类、醚类和酯类这几种主要的VOCs的吸附回收技术及研究进展。     

超临界CO2法再生油气回收用活性炭机理研究进展

储油罐中的原油及汽油等轻质油品在储存或运输过程中,部分轻组分蒸发产生多种对大气有毒、有害的挥发性有机物（VOCs）。在油气回收的终端环节,常采用活性炭对VOCs进行充分吸附达标后排放至大气。对吸附VOCs饱和的活性炭进行脱附再生,既可延长活性炭使用寿命,又可减少固体废弃物处理量。超临界CO₂再生活性炭方法较好地克服了传统的热再生法固有的缺陷,被认为是目前有前途的再生活性炭方法。本文详细阐述了超临界CO₂再生活性炭的机理研究现状,总结了机理研究的关键点及存在的问题,指出了VOCs在超临界CO₂作用下脱附的微观机理及脱附后的VOCs在活性炭中相关传质系数的计算模型为今后机理研究的关键突破口,为超临界CO₂再生活性炭基础理论的进一步完善指明了研究方向。     

Destruction of trichloroethylene (TCE) and trichloromethane (TCM) in the presence of selected VOCs over Pt-Pd-based catalyst

Catalytic oxidation of trichloroethylene (TCE) and trichloromethane (TCM) oxidized alone and in two-component mixtures with selected volatile organic compounds (VOCs) such as toluene, n-hexane, ethanol or acetone was investigated over a Pt-Pd-based catalyst on a monolithic, metallic, γ-Al₂O₃-washcoated support. TCE and TCM were more difficult to oxidize than VOCs and temperatures of their 50% conversion (T_50%) amouted to 420 and 330 °C, respectively. All the VOCs added were found to enhance the conversion of the two chlorinated compounds, drecreasing T_50% by 20 °C, at the most, for TCM in the presence of toluene and by 50 °C for TCE in the presence of acetone. Both the chlorinated compounds lowered the conversion of the VOCs added (except that of toluene), and this lowering was particularly distinct with n-heptane; they also raised the concentration of acetaldehyde formed during the oxidation of oxyderivative compounds.     

快干醇酸立体锤纹漆的研制

介绍了快干醇酸立体锤纹漆的制备方法及漆膜性能指标。讨论了醇酸树脂、改性树脂、非浮型铝粉、助剂及溶剂等诸因素对立体锤纹漆的影响。     

聚酯改性铁红醇酸防锈漆的研制

作者利用涤纶生产中的废弃物(聚酯废块、涤纶废丝等,简写为PET)对醇酸树脂改性,进一步调制铁红防锈漆。该漆性能指标达到了辽Q2553-87标准。     

水性丙烯酸铝粉浸涂漆

以非水溶性氨基树脂为接枝聚合母体，先将其用水溶性有机溶剂配成稀溶液，然后加入丙烯酸单体及苯乙烯混合物进行接枝聚合，所得的树脂中加入特种铝粉及各种助剂，配制成水性铝粉浸涂漆。讨论了氨基树脂类型、引发剂、助剂等对漆膜性能的影响，并介绍了施工注意事项。     

Electrochemical stability and surface analysis of a new alkyd paint with low content of volatile organic compounds

This paper presents the results regarding the electrochemical stability and surface analysis of a new alkyd paint with low content of volatile organic compounds in comparison with a conventional alkyd paint. The alkyd films were realized on carbon steel substrate. Dry films thickness in 30–35 μm range was obtained. The experimental tests were carried out in 3% NaCl solution at the 25 °C temperature. The electrochemical techniques (electrochemical impedance spectroscopy (EIS), potentiodynamic and Tafel polarization) and surface analysis techniques (AFM, SEM, EDX) were used to evaluate protective properties of the tested paint films. The correlation of all experimental results established that the new alkyd paint with low content of volatile organic compounds presents better protective performances and lower permeability than conventional alkyd paint. AFM, SEM and EDX indicated a compact, homogenous, non-porous and adherent coating.     

Superb VOCs capture engineering carbon adsorbent derived from shaddock peel owning uncompromising thermal-stability and adsorption property

High applied thermal-stability and superior structural property for activated carbon adsorbent are extremely promising, which also is the determining short slab in volatile organic compounds (VOCs) adsorption applications. Herein, we develop the outstanding engineering carbon adsorbents from waste shaddock peel which affords greatly-enhanced thermal-stability and super structural property (S_Lang?=?4962.6?m²·g^-1, V_micro?=?1.67?cm³·g^-1). Such character endows the obtained adsorbent with ultrahigh adsorption capture performance of VOCs specific to benzene (16.58?mmol·g^-1) and toluene (15.50?mmol·g^-1), far beyond traditional zeolite and activated carbon even MOFs materials. The structural expression characters were accurately correlated with excellent adsorption efficiency of VOCs by studying synthetic factor-controlling comparative samples. Ulteriorly, adsorption selectivity prediction at different relative humidity was demonstrated through DIH (difference of the isosteric heats), exceedingly highlighting great superiority (nearly sixfold) in selective adsorption of toluene compared to volatile benzene. Our findings provide the possibility for practical industrial application and fabrication of waste biomass-derived outstanding biochar adsorbent in the environmental treatment of threatening VOCs pollutants.     

Phase transitions in R2 SnCl6-type crystals (R = NH3 C2H3, NH3C2H5 and N(CH3)4)

The thermal dilatation in (NH₃ ·CH₃) SnCl₆, (NH₃ · C₂H₅) SnCl₆ and [N(CH₃)] SnCl₆ was measured, and as the results it has turned out that (NH₃ ⁶·C₂H₅) SnCl₆ and [N(CH₃)₄]₂ SnCl₆ undergo the first order transitions at 128 K and 158 K, respectively. The low temperature phases of (NH · C₂H₅) SnCl₆ and [N(CH₃)₄]₂ SnC1₆ are found to be monoclinic and tetragonal, respectively, No phase transition was observed in (NH₃ ·CH₃)₂ SnCl₆ down to 77 K.     

An environmentally friendly hydroformylation using carbon dioxide as a reactant catalyzed by immobilized Ru-complex in ionic liquids

A mixed ionic liquid [bmim][Cl + NTf₂] system was successfully used as a reaction medium for Ru-catalyzed hydroformylation of 1-hexene with carbon dioxide in the absence of toxic CO and any volatile organic solvents. The yields and TONs are higher than those reported previously using conventional organic solvents. The product can be readily separated by distillation, and the reaction medium containing the Ru-catalyst was successfully recycled.     

超临界CO2作用下甲苯在活性炭中的脱附机理

对吸附挥发性有机物（volatile organic compounds,VOCs）饱和的活性炭进行脱附再生,既可延长活性炭使用寿命,又可减少固体废弃物处理量。超临界CO₂脱附活性炭能够较好地克服传统的热处理法固有的缺陷,被认为是目前较有前途的方法,但脱附机理尚不明确。本文采用分子动力学模拟为研究手段,以甲苯的脱附过程为研究对象,研究了在活性炭纳米孔隙中超临界CO₂分子的扩散、CO₂分子与甲苯分子的相互作用、脱附后的甲苯分子在CO₂相中的扩散等行为,从分子层面揭示了超临界CO₂分子的强扩散性、CO₂分子与甲苯分子之间作用能的大小以及CO₂大幅度地改善甲苯的流动性在微观脱附机理中起决定性作用。     

The role of carbon deposition on precious metal catalyst activity during dry reforming of biogas

Gold and palladium were supported on a mesoporous TiO₂ for total oxidation of volatile organic compounds (VOCs). Mesoporous high surface area titania support was synthesised using of Ti(OC₂H₅)₂ in the presence of CTMABr surfactant. After removing the surfactant molecules, 0.5 or 1.5 wt% of palladium and 1 wt% of gold were precipitated on the support by, respectively, wet impregnation and deposition–precipitation methods. The activity for toluene and propene total oxidation of the prereduced samples follows the same order: 0.5%Pd-1%Au/TiO₂ > 1.5%Pd/TiO₂ > 0.5%Pd/TiO₂ > 1%Au-0.5%Pd/TiO₂ > 1%Au/TiO₂ > TiO₂. Moreover, a catalytic comparison with samples based on a conventional TiO₂, shows the catalytic advantage of the mesoporous TiO₂ support. The promotional effect of gold added to palladium could be partly explained by small metallic particles (TEM), but meanly by metallic particles made up of Au-rich core with a Pd-rich shell. Moreover, the hydrogen TPR profile of 0.5%Pd-1%Au/TiO₂ shows only the signal attributed to small PdO particles. Gold also implies a protecting effect of the support under reduction atmosphere. Operando diffuse reflectance infrared fourier transform (DRIFT) spectroscopy was carried on and allowed to follow the VOCs oxidation and the formation of coke molecules, but also a metallic electrodonor effect to the adsorbed molecule which increases in the same order as the activity for oxidation reaction. The presence of coke after test was also shown by DTA–TGA by exothermic signals between 300 and 500 °C and by EPR (g = 2.003).     

树脂纽扣废物的焚烧污染特征

有机树脂纽扣废物是一种典型的危险废物,且通常会加入含重金属和氯元素的颜料。将产生广泛的脲醛树脂和不饱和树脂纽扣废物作为对象,研究其焚烧处理过程中的特征分解温度、气相污染物及重金属分布规律,旨在为其污染控制提供科学依据。结果表明,脲醛树脂纽扣废物的热分解温度范围为240～600℃,特征性的气相污染物为NO;不饱和树脂纽扣废物的热分解温度在180～600℃,特征性气相产物为CO₂、H₂O、CO、CH_n、R-OH、R-CHO和R-COOH,这些物质与原料中的氯元素为二英类物质的形成提供了条件。具有装饰功能的树脂纽扣中Pb、Zn、Cu、Bi和Ti含量较高,主要来自含铅[PbCO₃和Pb（OH）₂]珠光浆和氯氧化铋（BiOCl）珠光浆等颜料,基于这些金属在焚烧过程中的分配特征,应重点控制Pb和Bi释放。     

Corrosion of selected ceramic materials in hot gas environment

The temperature dependence of the hot gas corrosion behaviour of various ceramic materials (Al₂O₃, ZrO₂ (Y-TZP), mullite, ZrSiO₄ and YAG) was investigated. The tests were performed in a high temperature burner rig at temperatures between 1200 °C and 1500 °C, a total pressure of 1 atm with a water vapour partial pressure of 0.24 atm, a gas flow velocity of 100 m/s and test times of about 130–300 h.

ZrO₂ (Y-TZP) showed absolutely no corrosion, however, a very high susceptibility to thermal shock and phase transformation was observed.

The other materials suffered degradation above 1300 °C. This was the consequence of the formation and evaporation of volatile hydroxides (e.g. Si(OH)₄ and Al(OH)₃). YAG showed a low corrosion rate and the formation of a protective surface layer. The corrosion susceptibility of these materials was found to be higher with increasing temperature.

Thermochemical calculations of the partial pressure of volatile species formed in reaction with water vapour, affirm the observed differences in corrosion behaviour.     

Preparation of alumina microshells by the emulsion evaporation technique

Spherical hollow alumina powders (alumina microshells) were prepared from evaporation of water-in-oil (w/o) type emulsions by employing an aqueous Al(NO₃)₃ solution as water, mineral oil as the organic phase and a non-ionic surfactant, Arlacel 83, as the emulsifier. It was found that 65% mineral oil, 30% aqueous Al(NO₃)₃ and 5% Arlacel 83 composition produced stable, w/o type emulsions by mechanical stirring at 20°C. The aluminum ion concentration was varied between 0·25 and 2·0 to investigate its effect on the emulsion droplet size. Alumina microshells obtained from the evaporation of w/o emulsions were characterized with respect to size and distribution. The influence of aluminum ion concentration on these properties was also studied.     

含氯挥发性有机物废气在CeO_2基催化剂上的低温催化燃烧净化:从高活性到高稳定性再到高选择性

挥发性有机物(VOCs)造成的环境污染问题备受关注,采用高效催化剂通过催化燃烧方式在低温下后处理净化是解决VOCs污染的主要途径之一。由于VOCs种类繁多、实际应用工况复杂,因此该净化途径对催化剂的要求十分苛刻,广谱性、耐高温、抗中毒、高选择性的高效催化剂的研发仍然是该领域关注的核心问题。作为VOCs分支之一的含氯挥发性有机物(CVOCs)由于存在的广泛性、自身毒性、多氯副产物甚至是二噁英的二次生成以及催化剂Cl中毒失活等问题,成为VOCs催化燃烧领域近年来特别关注和亟待攻克的热点。本文简要综述本课题组15年来有关CVOCs在CeO_2基催化剂上低温催化燃烧的进展,详细介绍从高活性CeO_2催化剂的发现,到CeO_2抗氯中毒失活(稳定性)、抑制多氯副产物(选择性)通用策略的提出。     

纳米b-Ni(OH)2的制备及其储锂性能

以Ni(NO₃)₂·6H₂O和NaOH为原料采用化学沉淀法制备了Ni(OH)₂电极材料。采用X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)表征了样品的微观结构,结果表明该样品是具有片状纳米次级结构的β-Ni(OH)₂。采用循环伏安(CV)和电化学充放电测试研究了该β-Ni(OH)₂样品的储锂性能,结果发现该样品作为锂离子电池负极材料具有非常高的储锂活性,在50 mA·g^-1电流密度下其第3次循环放电比容量高于1550 mA·h·g^-1;样品电极中的碳含量对其循环性能和倍率性都有显著影响,通过交流阻抗(EIS)测试分析了样品电极中碳含量的作用机理。