Optimization of the recovery of plastics for recycling by density media separation cyclones

Material recovery processes are presented as the optimum option for recycling plastic wastes as a means of recovering hydrocarbon resources. There exist a large variety of automated material recovery processes for recycling of such wastes but each with significant limitations. Of these, the separation based on differences in densities is advocated as the optimum process either for producing recycled products or preparing wastes for subsequent recovery processing.Density separation processes based on cyclone type density media separation (DMS) is presented as an important, potential method for increasing plastics recycling process capacities. It is demonstrated to have the capacity to separate a significantly larger range of particle sizes than those presently processed industrially. The mathematical relationship for the prediction of quality of typical LARCODEMS type density media separations by particle size and density as expressed by the Ecart Probable is presented.A proposed device configuration is presented for density media separation to optimize the recovery and purity of both density fractions produced. It is also suggested that to be economically viable, a large scale of operation is required for industrial plastics recycling operations recovering and producing a number of different plastics with a purity to be used as a substitute for virgin material.     

链状高分子金属配合物催化氧化苯乙烯

利用链状Salen型高分子希夫碱金属配合物PLSBM(M:CoⅡ,MnⅡ,ZnⅡ,CuⅡ)作为催化剂,催化分子氧氧化苯乙烯.结果表明,在不添加任何助剂和共还原剂的条件下,氧化产物以苯甲醛(Ⅰ)和环氧苯乙烷(Ⅱ)为主,PLSBCuⅡ具有最佳的催化活性和产物选择性.考察了影响氧化反应的因素,发现在反应温度为90℃、反应时间为9h和催化剂与苯乙烯用量比为1mg∶2mL时,苯乙烯具有最优的转化率(61％)和产物选择性(Ⅰ:57％,Ⅱ:36％).     

介质阻挡放电降解苯乙烯的研究

研究了介质阻挡放电(DBD)常压下降解流动态苯乙烯时,不同电压、流速、初始浓度及湿度下苯乙烯的降解情况.结果表明,DBD降解苯乙烯15~20min即可达稳定,产物主要为CO、CO₂和H₂O;电压4800V时有少量带苯环的气态及固态物质产生,且随电压的升高而减少,到7500V时红外光谱已无法检测到;高电压下放电可以取得90%左右的降解率,产生带苯环的气态物质和结焦物质较少.流速在1.5cm/s,浓度为3000mg/m³,相对湿度为20%左右时,降解效果最好.     

液体吸收-活性炭吸附净化苯乙烯废气

介绍了液体吸收-活性炭吸附净化苯乙烯废气的原理.当吸收液中石油类物质占总体积的40％时吸收率最佳,小试液体吸收段对苯乙烯废气的吸收率在74％-97.6％之间,在工业净化装置中使用该吸收液,对苯乙烯废气的吸收率在60％-97.4％之间.活性炭对苯乙烯的吸附率为自重的30％.工业净化装置中,两种方法并用苯乙烯废气的净化效率在94.8％以上.该方法关键是寻找高效的吸收液和设计实用的净化装置.     

Investigation of protein-styrene oxide adducts as a molecularbiomarker of human exposed to styrene

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生物法净化低浓度苯乙烯有机废气填料的选择及运行功效

采用培养驯化的污泥菌种,对1#陶粒、2#陶粒、塑料小球和沸石4种填料进行生物挂膜,通过对比筛选,选择性能优越的1#陶粒作为滴滤塔填料净化苯乙烯废气,结果表明,在进气量Q=0.6 m3/h,循环喷液量L=90 L/min,进气负荷小于180 g/(m3·h),去除负荷可达到163 g/(m3·h),苯乙烯净化效率达到90%以上.     

废聚苯乙烯的化学回收方法

废聚乙烯（ＰＳ）转化为燃料油和化学品的化学回收方法,分为废ＰＳ单独裂解及废ＰＳ与其它废塑料混合裂解两种方式,分别阐述了两种回收方式的研究成果和工艺现状,并就存在的问题进行了讨论。     

用增强灵敏度的~32P后标记法测定DNA-环氧苯乙烯加合物

DNA加合物是具有亲电性化学致癌物与DNA形成共价相联的化合物,是化学致癌物损伤DNA的主要形式,能够灵敏准确地分析DNA加合物的方法是研究DNA损伤     

Atmospheric Volatile Organic Compound Monitoring. Ozone Induced Artefact Formation

Assessment of population exposure to VOC in ambient atmospheres is receiving heightened interest as the adverse health effects of chronic exposure to certain of these compounds are identified. Active (pumped) and passive samplers are the most commonly used devices for this type of monitoring. It has been shown, however, that these devices, along with all other preconcentration techniques, are susceptible to ozone interference. It is demonstrated that this interference occurs even at low ozone concentrations and that it may result in the under-estimation of population exposure. A convenient and effective ozone scrubbing method is identified and successfully applied and validated for both active and passive samplers for a range of VOC.     

用生物滴滤塔净化苯乙烯废气

用内部填充有陶粒的生物滴滤塔净化苯乙烯废气,考察了气体流量、液体喷淋量及氮源对苯乙烯废气净化效果的影响。,进口苯乙烯质量浓度为300～4500mg／m^3时,气体流量和进FI苯乙烯质量浓度对苯乙烯的去除率影响显著,当气体流量为0．3m^3／h时,苯乙烯去除率达87％以上。实验结果表明：在气体流量为0．9m^3／h时,液体喷淋量对苯乙烯废气的净化效果影响不明显;降低进口苯乙烯质量浓度和增大生物滴滤塔的有效传质面积,有利于苯乙烯的净化;用浓度为0.0017mol／L的NaNO3作氮源时苯乙烯的去除效果优于用NH4Cl作氮源时苯乙烯的去除效果。