沉淀法回收聚苯乙烯泡沫塑料的工艺研究

研究沉淀法回收聚苯乙烯泡沫塑料(EPS)的工艺,利用石油裂解副产物为溶剂回收废旧聚苯乙烯泡沫塑料,以废治废,回收利用。溶剂低毒,对聚苯乙烯泡沫塑料溶解速度快,溶解量大,价廉易得。采用转式间歇投料并附加溶剂挥发分回收装置的工艺,溶剂回收率高,无二次污染,可循环使用。聚苯乙烯塑料(PS)回收率可达99%。     

薄膜干燥法再生聚苯乙烯树脂的研究

利用溶剂溶解回收的聚苯乙烯塑料,将其涂布于不锈钢传送带上,以水蒸气为加热介质,经薄膜干燥法获得再生聚苯乙烯树脂.再生的聚苯乙烯树脂性能优异,溶剂回收率达97%以上.     

废聚苯乙烯泡沫塑料制取涂料及胶粘剂

阐述了利用废旧泡沫塑料研制和开发各种不同用途涂料的进展，研究了利用废聚苯乙烯泡沫塑料制取涂料的方法，讨论了该涂料的配方选择及性能指标。     

一种回收废聚苯乙烯（PS）泡沫塑料方法：蒸汽熔融挤压法的工艺分析

本文介绍了一种可在生产厂内回收废聚苯乙烯(PS)泡沫塑料的简单方法。该法将粉碎后的PS泡沫塑料颗粒装填在成型模具内,经蒸汽加热表面熔融后,外力挤压冷却成型。从而在基本不改变废物原料外型的情况下对其进行低能耗回收,获得性能与原产品较为接近的回收产品。文中对该法的原理、设备、操作工序及工艺条件等作了介绍和分析。     

废聚苯乙烯泡沫塑料制取涂料及胶粘剂

阐述了利用废旧泡沫塑料研制和开发各种不同用途涂料的进展 ,研究了利用废聚苯乙烯泡沫塑料制取涂料的方法 ,讨论了该涂料的配方选择及性能指标     

工业废铝渣制备聚合硫酸铝及其絮凝性能研究

以一家金属材料厂生产过程中产生的废铝渣作为研究对象,通过对溶解条件和聚合工艺的优化,制备了聚合硫酸铝。将制备的聚合硫酸铝分别用于模拟浊度水及高色度高浓度有机工业废水的处理,实验结果表明,利用工业废渣所制得的聚合硫酸铝具有较好的除浊、脱色、去除COD效果。此工艺不仅可回收利用废铝渣,又可省去废渣处置费用,为废铝渣的综合利用提供了实用技术。     

铜酞菁生产中的三废综合治理及其资源化探讨

通过某铜酞菁化工生产企业三废治理及其资源化工艺改进的实践，总结出了一套行之有效的利用酸化工艺废酸的资源化新方法，不但从中回收了高价值的铜泥；同时利用废酸吸收生产工艺中的高含氨尾气，生产硫酸铵，达到了以废治废的目的，整个治理工艺符合循环经济的理念。通过该回收工艺的改进，使上述三废不再进入污水处理系统，从而解决了传统铜酞菁生产废水的高酸度、高盐分、高含氨、高难处理的矛盾，使铜酞菁三废处理易于实行。     

废食用油脂作生物柴油原料的可行性分析

分析了各国废食用油脂的产生、回收和法规管理现状。重点通过分析废食用油脂物化性质，评价利用废食用油脂制造生物柴油的工艺特征和技术可行性。探讨了利用废食用油脂制造的生物柴油产品的品质和环境效益以及使用要求。同时分析了利用废食用油脂制造生物柴油的经济成本和存在的问题。     

污水源热泵机组性能的研究

利用热泵系统回收城市污水中的热能，既开发了一种清洁能源，同时又降低了城市废热的排放，保护了环境。通过对以水源热泵为中心设备的污水热能回收与利用实验装置冬季供暖工况的实验研究，考察了热泵机组在以污水（模拟）为热源时的工作性能，测得热泵机组性能系数为2．61。     

反溶剂沉淀废旧电子塑料溶液过程中溴系阻燃剂的转移行为及分离

为了减少废旧电子塑料带来的环境污染及健康风险,选择柠檬烯为溶剂、正丙醇为反溶剂,调查了从电子塑料溶液沉淀回收聚苯乙烯(PS)过程中溴系阻燃剂的转移行为,讨论了沉淀工艺参数对阻燃剂分离效果的影响规律,确定了分离阻燃剂的沉淀条件。实验结果表明:难溶解的阻燃剂主要通过析出晶体转移到沉淀中,易溶解的阻燃剂通过溶剂携带转移到沉淀中。较高温度或较少正丙醇用量有利于提高十溴联苯醚(Deca BDE)的分离效果;较低温度或较大正丙醇用量有利于四溴双酚A(TBBPA)的分离,高速搅拌能抑制沉淀颗粒团聚、减少沉淀物中的溶剂含量,可同时改善Deca BDE和TBBPA的分离效果。10%的塑料溶液在正丙醇用量为1∶1、40℃及3 000 r·min~(-1)的条件下进行沉淀,能获得粒径为0.92mm左右的再生PS颗粒,塑料溶液中90%以上的多溴联苯醚(PBDEs)、95%以上的TBBPA被脱除。     

高酚焦化废水萃取脱酚预处理

为了降低高酚焦化废水中挥发酚的浓度，实验研究了磷酸三丁酯煤油溶液在不同条件下对高酚焦化废水进行萃取脱酚预处理的效果。结果表明，萃取时间为8min，磷酸三丁酯煤油浓度为30％，温度低于40％，pH低于8．0，萃取比（油／水）R=1：2时，经过萃取后分水挥发酚浓度由4165mg降低到127．62mg／L，去除率高达96．94％，为后续生化处理奠定了基础。而萃取剂经过氢氧化钠溶液反萃取再生后，萃取剂的回收利用率可达94．25％以上。     

Air Pollution Abatement Facilities at Soybean Processing Plants

Soybean processing plants are typical of facilities in which solvent extraction is the major unit operation employed. Hexane solvent is used to treat soybeans, producing both a vegetable oil and a residue meal product. The hexane solvent is separated from the oil and the meal, recycled and used again in a closed loop fashion. At several points in the process vent streams are produced resulting in the atmospheric discharge of hexane vapor. This represents an air pollution problem and facilities are required to eliminate the problem. An economic analysis of pollution abatement requirements for soybean plants indicates that thermal incineration is the optimum system that can be used. However, at high levels of hexane content in the vent streams, a combination of activated carbon adsorption of the smaller stream plus thermal incineration of the larger stream should prove the most desirable form of pollution abatement. The analysis given in this report can be used to determine which pollution abatement system should be used, depending upon the hexane content of the vent streams.     

Management, disposal and recycling of waste industrial organic solvents in Hong Kong.

An attempt has been made to establish a mass balance of industrial organic solvents in Hong Kong. It is estimated that only a small portion, less than 4%, of all the organic solvents consumed in Hong Kong are collected as waste solvents and properly treated, while the remainder are used either in the formulation of solvent containing products, or are lost to the environment through vapour emissions, leaks and spills, or dumped illegally. It was found that solvent recycling has been a common practice in some industries but the existing level of solvent recycling in Hong Kong is difficult to estimate. About 87.4% of all the waste organic solvents disposed of at the licensed facilities are potentially recyclable although whether they can be recycled in practice depends on many factors. Examples of existing waste organic solvent management and recycling practices from selected industries in Hong Kong are presented. The economic feasibility of current and future potential recycling systems is evaluated for a few selected cases. An integrated waste organic solvent management strategy is proposed to minimize adverse impacts of organic solvents to the environment and human health.     

Effects of pollutants on laccase activities of Marasmius quercophilus, a white-rot fungus isolated from a Mediterranean schlerophyllous litter

Marasmius quercophilus is a white-rot fungus involved in carbon recycling in Mediterranean ecosystems because of its laccase production. Here we described the effect of metal ions and halide salts, on laccase activity in order to point out the action of such environmental pollutants on this enzyme of major importance. Furthermore we tested organic solvent effects on laccase reaction since reaction mixture including solvent can be used in the transformation of xenobiotics. In the case of metal ions, we found that chloride ions were responsible for inhibition while CuSO(4) and MnSO(4) enhanced laccase activity. When halides were tested, we showed the following degree of inhibition: F(-)>Cl(-)>Br(-). Furthermore we found that I(-) was oxidized by laccase with I(2) as the product of the reaction. With ABTS, 50% of the laccase activity remains for solvent concentration ranging from 40% to 60% depending on the solvent used while with syringaldazine solvent concentration ranged from 50% to 70%. The organic solvent effects observed were probably a result of enzyme denaturation and of both enhancement of oxidised product solubilisation and of substrate solubilisation (for syringaldazine). These results show that laccase from M. quercophilus is not rapidly inhibited by certain environmental pollutants which sustains its role in carbon turnover under pertubation. However the strong effect of chloride ion on laccase activity should be further investigated with in situ studies since this could drastically influence carbon recycling in litters from Mediterranean littoral locations.     

Integrated bioleaching of copper metal from waste printed circuit board—a comprehensive review of approaches and challenges

Waste electrical and electronic equipment (e-waste) is the most rapidly growing waste stream in the world, and the majority of the residues are openly disposed of in developing countries. Waste printed circuit boards (WPCBs) make up the major portion of e-waste, and their informal recycling can cause environmental pollution and health risks. Furthermore, the conventional disposal and recycling techniques—mechanical treatments used to recover valuable metals, including copper—are not sustainable in the long term. Chemical leaching is rapid and efficient but causes secondary pollution. Bioleaching is a promising approach, eco-friendly and economically feasible, but it is slower process. This review considers the recycling potential of microbes and suggests an integrated bioleaching approach for Cu extraction and recovery from WPCBs. The proposed recycling system should be more effective, efficient and both technically and economically feasible.     

Informal e-waste recycling: environmental risk assessment of heavy metal contamination in Mandoli industrial area,Delhi, India

Nowadays, e-waste is a major source of environmental problems and opportunities due to presence of hazardous elements and precious metals. This study was aimed to evaluate the pollution risk of heavy metal contamination by informal recycling of e-waste. Environmental risk assessment was determined using multivariate statistical analysis, index of geoaccumulation, enrichment factor, contamination factor, degree of contamination and pollution load index by analysing heavy metals in surface soils, plants and groundwater samples collected from and around informal recycling workshops in Mandoli industrial area, Delhi, India. Concentrations of heavy metals like As (17.08 mg/kg), Cd (1.29 mg/kg), Cu (115.50 mg/kg), Pb (2,645.31 mg/kg), Se (12.67 mg/kg) and Zn (776.84 mg/kg) were higher in surface soils of e-waste recycling areas compared to those in reference site. Level exceeded the values suggested by the US Environmental Protection Agency (EPA). High accumulations of heavy metals were also observed in the native plant samples (Cynodon dactylon) of e-waste recycling areas. The groundwater samples collected form recycling area had high heavy metal concentrations as compared to permissible limit of Indian Standards and maximum allowable limit of WHO guidelines for drinking water. Multivariate analysis and risk assessment studies based on total metal content explains the clear-cut differences among sampling sites and a strong evidence of heavy metal pollution because of informal recycling of e-waste. This study put forward that prolonged informal recycling of e-waste may accumulate high concentration of heavy metals in surface soils, plants and groundwater, which will be a matter of concern for both environmental and occupational hazards. This warrants an immediate need of remedial measures to reduce the heavy metal contamination of e-waste recycling sites.     

Migration of 1,1,1-trichloroethane in soil

The depth profile of the concentrations of the title chlorinated solvent in soil has been examined in order to detect its diffusion behaviour upon heavy surface pollution.     

江苏省“十二五”废旧家电处理预测及环境监管对策研究

废弃电器电子产品具有较高的回收利用价值,同时处理不当会导致二次污染。介绍了江苏废弃电器电子产品回收、处理现状,并作预测分析,提出了管理对策和措施。     

Elimination of VOC Emissions from Surface Coating Operations

Collectively, surface coating operations using paints with hydrocarbon solvents may well be the largest industrial source of volatile organic compounds (VOC) and hazardous air pollutants (HAP). Most surface coating operations involve the manual application of paint with spray equipment inside a paint spray booth. The booth exhaust system collects the solvent fumes and then exhausts them through a stack to the atmosphere. Stack emissions are characteristically high in flow rate and low in concentration. Since control equipment is sized based on exhaust flow rate rather than concentration, control of VOC and HAP requires large, expansive abatement equipment. Simple, effective designs employing recycling of air have greatly reduced the exhaust flow rate and the cost of the control equipment. However, these designs are not popular because they are burdened by various flaws, notably worker endangerment. The Mobile Zone recirculation system can be incorporated into new construction or retrofitted to existing spray booths and will reduce the exhaust volumes ranging from 65 to 95 percent without adversely affecting the production rate, production quality or worker safety.