电选法回收利用废印刷线路板

废印刷线路板含有多种有价值的物质,随意丢弃或处理处置方法不当既污染环境,又造成资源流失。采用剪切式破碎和电力分选技术对废印刷线路板的机械分离进行了研究。结果表明,电选法可以实现废印刷线路板中金属和玻璃纤维、树脂的分离;在实验的粒径范围内(-14+20目到-120+200目分为5个粒径级别),金属主要集中在-20+120目粒级范围内,且该粒级范围分选效果最好。     

电选法回收利用废印刷线路板

废印刷线路板含有多种有价值的物质，随意丢弃或处理处置方法不当既污染环境，又造成资源流失。采用剪切式破碎和电力分选技术对废印刷线路板的机械分离进行了研究。结果表明，电选法可以实现废印刷线路板中金属和玻璃纤维、树脂的分离；在实验的粒径范围内（-14＋20目到-120＋200目分为5个粒径级别），金属主要集中在-20＋120目粒级范围内，且该粒级范围分选效果最好。     

微生物浸出印刷线路板中金属的研究进展

印刷线路板作为电子产品中不可缺少的部件,具有成分复杂、环境危害大和资源化价值高等特点,对废印刷线路板成分进行科学有效地分离富集一直是电子废弃物资源化利用研究的热点和难点.从适用的微生物种类、微生物的浸提机制、影响微生物浸提效果的因素等方面综述了微生物在印刷线路板中金属的浸出中的应用研究状况,最后对未来的研究方向进行了展...     

废旧家用电器回收利用及处理处置技术

随着大量家用电器进入报废期,废旧家用电器的资源化回收利用成为一个新的环境问题。介绍了国内外废旧家电的回收利用状况、处理方法和工艺流程,重点介绍了废印刷线路板的处理工艺和废塑料的再生利用,并针对我国的实际问题提出了相应的措施和办法。     

电子线路板树脂粉末资源化技术分析

从电子线路板树脂粉末产生的现状和资源化技术人手，分析了相应技术的优劣、投资运作成本和产品，提出了对江苏省废线路板树脂粉末的处置及资源化利用方面的污染防治和管理对策。     

废线路板资源化利用企业环保准入条件初步研究——以江苏省为例

介绍了中国废线路板资源化利用的主要方法及存在的环境问题.结合江苏省废线路板资源化利用行业的发展现状,分析了对废线路板资源化利用企业制定环保准人条件的必要性,并初步建立了一套废线路板资源化利用企业的环保准人指标体系,对企业布局及要求,原料的来源、运输和贮存,生产工艺和设备,环境保护,安全生产和监督管理等6个方面做出了较为...     

微波超声协同处理废弃印刷线路板中非金属

在相对温和的密闭水相环境中对废印刷线路板中非金属粉末的超声微波协同降解进行了研究。考察了单水热,单微波、单超声及微波超声协同作用下,温度、时间对非金属降解特性的影响。通过对初始物料、固相产物和液相产物的分析初步讨论了超声微波协同作用对废印刷线路板非金属的降解效果。结果表明,在200℃到280℃温度范围内,超声微波协同作用下,非金属中有机组分的降解率可以达到74.11%,固相产物主要是纯度较高的玻璃纤维,液相有机产物主要是苯酚类物质。     

基于FLUENT的废线路板元器件脱焊数值模拟

带元器件的废线路板的手工拆解劳动繁重,在拆解中产生的有害气体损害工人的健康,拆解后的残留物污染环境,因此,废线路板的自动拆解就显得十分必要.针对废线路板上电子元器件自动拆解中焊点的熔焊问题,采用FLUENT计算机软件进行模拟研究,分析了导热介质、初始温度、流体速度对焊点加热熔化效率的影响.结果表明,焊点在初始温度为47...     

基于超临界技术的印刷线路板资源化方法研究

印刷线路板的回收由于其结构和组成材料的复杂性，被认为是电子电器产品回收中的重点和难点之一。提出了将超临界流体技术应用于废弃印刷线路板的回收工艺，研究出了一种环境友好的废弃印刷线路板回收方法。建立了回收模型及回收实验平台，并使用正交实验设计方法对实验进行设计，利用SPSS分析软件对实验数据进行了分析研究并结合实际实验结果得出了最佳工艺参数。通过对反应生成物进行质谱分析，推测出了生成物的主要组分，并据此对反应机理进行了研究。     

世界废弃印刷电路板的机械处理技术现状

电子废话弃物中废印刷电路板的处理,一直是相当复杂的问题。根据废电路板中各种组分的结合方式,采用机械方法进行材料的分离,是经济适用并与环境相协调的处理手段。本文介绍了废 电路板再利用技术采用的各种机械设备,并总结了国外机械处置方法的实践进展。     

PCB and dioxin-like PCB in indoor air of public buildings contaminated with different PCB sources--deriving toxicity equivalent concentrations from standard PCB congeners

Data on dioxin-like PCB in indoor air of buildings with PCB-containing materials and on possible correlation between toxicity equivalent concentrations (TEQ) and levels of non-dioxin-like standard PCB is sparse. As part of a larger survey on indoor-air contamination with PCB, the connection between the concentration of standard PCB congeners and the dioxin-like toxicity expressed as TEQ was investigated. Indoor air samples (n=8) were collected in four public buildings with known PCB sources and total PCB levels in the range from 715 to 2250 ng/m3 and analyzed for the six non-dioxin-like standard PCB (congeners 28, 52, 101, 138, 153, 180), the twelve dioxin-like PCB congeners according to WHO and the 17 2,3,7,8-substituted PCDD/PCDF congeners. In three buildings where PCB were used as flame retardant coatings of acoustic ceiling tiles, PCB 101 had the maximum level among the six standard PCB, while in the building with permanent elastic sealants as PCB source, congeners 28 and 52 dominated the pattern by far. In the case of permanent elastic sealants as PCB source (n=3) a total PCB concentration of 1000 ng/m3 corresponded to a total TEQ level of 0.3-0.6 pg/m3. In contrast, in rooms with acoustic ceiling tiles as PCB source, 1.8-4.7 pg TEQ/m3 per 1000 ng total PCB/m3 were found. Linear regression analysis between PCB and TEQ indicated that PCB 118 might be used to calculate the total TEQ of dioxin-like PCB and PCDD/PCDF. By means of such a correlation it is possible to estimate TEQ by extrapolation from the results of less sophisticated analytical methods. It is tentatively recommended to use PCB 118 for screening purposes or re-evaluation of standard PCB indoor-air measurements. If only the six non-dioxin-like PCB standard congeners are available, a regression algorithm using the sum of PCB 101, 138, 153 and 180 might be used instead.     

Background levels of non-ortho-substituted (coplanar) polychlorinated biphenyls in human serum of Missouri residents

This study characterizes the levels of polychlorinated biphenyls (PCB) congeners PCB 77, PCB 81, PCB 126, and PCB 169, in a group of 150 men and women with no documented exposure to PCBs. Its purpose is to provide current referent levels of coplanar PCBs in Missouri residents and to compare those levels to levels reported in the literature from the United States and other countries. Although this study used an extensive questionnaire assessing potential sources of exposure, no positive relations were found between these exposure sources and participants' PCB levels. The PCB levels for the four congeners measured were lower than any reported in the literature. PCBs 126 and 169 are only two of the dioxin-like congeners; however, their contribution makes up 11% of the total TEQ. Age was significantly related to PCB 126 and PCB 169. For every one-year increase in age, both PCB congeners increased by approximately 0.4 parts per trillion (ppt). There was no gender difference for PCB 126; however, PCB 169 levels were 3 ppt higher in males than females.     

Levels of PCB 126 and PCB 153 in plasma and tissues in goats exposed during gestation and lactation

The aim of the present study was to gain knowledge about the disposition of the PCB congeners 126 and 153 in a goat model where pregnant does were given oral doses of PCB from day 60 of gestation until delivery. The goat kids were thus exposed to PCB during gestation and lactation. The doses of PCB 153 and PCB 126 were 98 and 49 ng/kg body wt/day, respectively. PCB levels were measured in plasma from the does at day 90 of gestation and at delivery, and in plasma from the kids at birth and four weeks post partum. Concentrations of PCB were analysed in brain, liver and fat tissue from the does six weeks after delivery and in liver and fat tissue from the kids at nine months of age. The ratio of estimated body burden to ingested dose in the does, was 0.95 +/- 0.07 for PCB 153 and 0.41 +/- 0.03 for PCB 126. Approximately 9% of PCB 153 and 6% of PCB 126 was transferred from the mothers to their kids during gestation and lactation. Prenatal exposure contributed to a much lower fraction of the body burden than postnatal PCB intake via milk, due to the fact that almost 100% of the PCB 153 transferred from the does to kids was transferred via milk, and the PCB 126 intake via milk was threefold higher than the calculated body burden. The hepatic PCB 126 concentration in both does and kids was significantly higher than the concentration in fat, in contrast to PCB 153, where the highest concentrations were found in fat. A significant difference in body burden between the does at delivery, the newborn kids, and the kids at four weeks of age, did not influence the plasma concentration of PCB 153 on a fat weight basis, which showed no difference with sampling time. Our results suggest that PCB 126 and PCB 153 have different pharmacokinetic properties. The higher levels of PCB 126 in liver tissue compared to fat tissue confirm the concept of hepatic sequestration. The similar blood concentration of PCB 153 in the does at delivery and their newborn kids despite the considerable difference in body burden, suggests a high degree of placental transfer. This supports previous observations that low molecular weight, lipid-soluble, non-polar chemicals reach the fetus to the greatest possible extent. For PCB 153, the body burden may provide the appropriate dose metric at steady state, but may give a minor underestimation of PCB 126 at low environmental exposure levels due to hepatic sequestration.     

The estimation of consumer health risk associated with organochlorine xenobiotics in hard smoked cheese in Poland

The aim of this study was to estimate the health risks associated with consumption of smoked cheeses, which are popular in Poland. The analysis covered polychlorinated biphenyl (PCB) indicator congeners (ndl-PCBs: PCB 28, PCB 52, PCB 101, PCB 138, PCB 153, PCB 180), dioxin-like PCBs (dl-PCBs): non-ortho (PCB 77, PCB 81, PCB 126, PCB 169) and mono-ortho (PCB 105, PCB 114, PCB 118, PCB 156, PCB 157), as well as organochlorine pesticides (OCPs: αHCH, βHCH, γHCH, heptachlor, aldrin, heptachlor epoxid isomer B, dieldrin, pp'DDE op′DDD, pp′DDT, pp′DDD, op′DDT, endrin). The pesticide residues detected in the examined cheese were below the maximum residues levels. The estimated daily intake [lifetime average daily dose (LADD)] referring to the sum of the compounds varied within 4.21·10^?7–3.92·10^?6 mg·kg^?1·day^?1 and was significantly lower than the tolerable daily intake/acceptable daily intake (TDI/ADI) for individual compounds. The health hazard quotient, being the exact measure of the magnitude of exposure potential or a quantifiable potential for developing non-carcinogenic health effects after an averaged exposure period, was also very low, ranging from 2.87·10^?6 to 5.32·10^?5. The obtained results confirmed that the intake of rennet cheese does not pose any consumer health risk in Poland.     

Human biomonitoring of polychlorinated biphenyls and polychlorinated dibenzodioxins and dibenzofuranes in teachers working in a PCB-contaminated school

Eighteen teachers from a highly contaminated school and 11 teachers from a control school participated in this study. Total polychlorinated biphenyl (PCB) indoor air concentration (six indicator congeners x 5) was beyond 12000 ng/m3 in some rooms of the contaminated school. PCB 28 and PCB 52 were the prevailing congeners. Whole blood was taken from each participant by the local health authority, pooled in two groups and analysed for the six PCB indicator congeners, non-ortho PCBs and polychlorinated dibenzodioxins (PCDD)/polychlorinated dibenzofurans (PCDF). Blood analysis showed elevated mean PCB 28 and PCB 52 levels for the exposed group, however the two groups were almost identical with regard to PCB 101, 138, 153 and 180. Moreover no difference can be observed for the concentration of non-ortho PCBs and PCDD/PCDF. The data support the finding, that heavy indoor air contamination with low chlorinated PCBs causes an increase of PCB 28 and PCB 52 blood levels. However, this increment was small compared to their total PCB load.     

Effects of dietary wheat bran on absorption and accumulation of PCBs in rats

Polychlorinated biphenyls (PCBs) are toxic environmental contaminants, which tend to accumulate in the food chain. Since dietary intake is the most important exposure route, PCB body burden may be affected by taking proper dietary measures. In the present study, diets were supplemented with either wheat bran or its cellulose based placebo in order to study the effect of bran consumption on the absorption of dietary PCBs and the excretion of initially stored PCBs. During the period of PCB intake, faecal PCB excretion was elevated by consumption of wheat bran as compared to the placebo. Hence, apparent faecal PCB digestibilities as well as PCB retentions in the whole body were lower in the wheat bran consuming rats. After ending PCB consumption, dietary wheat bran had only a minor effect on faecal PCB output while accumulation in the body was not affected. When PCBs were consumed for a longer time, a small but significant reduction of apparent faecal PCB digestibility was found. However, PCB content in the body kept increasing while PCB retention as percent of intake remained almost constant. Furthermore, differences among individual PCB congeners in metabolic susceptibility and hydrophobic characteristics had an impact on their accumulation in the body.     

Assays of polychlorinated biphenyl congeners and co-contaminated heavy metals in the transgenic Arabidopsis plants carrying the recombinant guinea pig aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system

The transgenic Arabidopsis plant XgD2V11-6 carrying the recombinant guinea pig (g) aryl hydrocarbon receptor (AhR)-mediated β-glucuronidase (GUS) reporter gene expression system was examined for assay of polychlorinated biphenyl (PCB) congeners and co-contaminated heavy metals. When the transgenic Arabidopsis plants were treated with PCB126 (toxic equivalency factor; TEF: 0.1) and PCB169 (TEF: 0.03), the GUS activity of the whole plants was increased significantly. After treatment with PCB80 (TEF: 0), the GUS activity was nearly the same level as that treated with 0.1% dimethylsulfoxide (DMSO) as a vehicle control. After exposure to a 1:1 mixture of PCB126 and PCB169, the GUS activity was increased additively. However, after exposure to a mixture of PCB126 and PCB80, the GUS activity was lower than that of the treatment with PCB126 alone. Thus, PCB80 seemed to be an antagonist towards AhR. When the transgenic plants were treated with each of the heavy metals Fe, Cu, Zn, Cd and Pb together with PCB126, Cd and Pb increased the PCB126-induced GUS activity. On the other hand, Fe, Cu and Zn did not affect the PCB126-induced GUS activity. In the presence of the biosurfactant mannosylerythritol lipid-B (MEL-B) and the carrier protein bovine serum albumin (BSA), the PCB126-induced GUS activity was increased, but the Cd-assisted PCB126-induced GUS activity was not affected. Thus, MEL-B and BSA seemed to increase uptake and transport of PCB126, respectively.     

Congener-specific accumulation of polychlorinated biphenyls in ovarian follicular wall follows repeated exposure to PCB 126 and PCB 153. Comparison of tissue levels of PCB and biological changes

OBJECTIVE: Small (SF), medium (MF) and large (LF) preovulatory porcine follicles were isolated and incubated in an Erlenmeyer flask containing 5 ml of medium with addition of PCB 126 or PCB 153 to test differences in their accumulation in the follicular wall. METHODS; The follicles were incubated in M199 medium at 37 degrees C with constant shaking at 70 rpm, for 6 days. The media were changed every day and repeated dose 25 pg/ml of PCB 126 or 25 ng/ml of PCB 153 was added each day till 6 days of culture. Media were collected every day and frozen for steroid analysis by RIA. 24 h after the last treatment follicles were frozen for further polychlorinated biphenyls (PCB) content analysis. PCB concentrations in the follicular wall were analysed by mass spectrometry. RESULTS: 3.3%; 3.6% and 5.6% of total PCB 126 dose, and 71%; 71.4% and 30.4% of total PCB 153 dose accumulated in SF, MF and LF follicles, respectively. The accumulative effect of PCB was manifested by the disruption of estradiol (E2) secretion. In SF antiestrogenic action of PCB 126 was observed during the whole time of exposure while PCB 153 decreased E2 till 4 days of culture and then estrogenic action was observed. In MF, both these congeners decreased E2 till 5 days of exposure and then estrogenic actions were noted with the highest magnification in the case of PCB 126. In LF both PCB studied increased E2 till 3 days of exposure with the highest magnification of PCB 126, then antiestrogenic action was noted. Testosterone secretion was generally affected in a pattern oposite to that of E2 suggesting action on P450arom activity. CONCLUSION: The results of these studies demonstrated that disruption of aromatization process in the follicles following repeated exposure to both congeners is not directly correlated with the bioaccumulation or amount of PCB within the follicular wall.     

超临界CO_2流体环境中线路板分层实验分析

在超临界CO2流体环境下,当温度达到240℃以上时,印刷线路板就会发生分层现象。同时,在实验中发现在非超临界流体环境下,当温度达到260℃以上时,线路板也会发生分层现象。从线路板粘接材料发生热解反应的角度出发,在对比超临界CO2流体环境下与非超临界流体环境下的线路板分层效果的基础上,对超临界CO2流体环境下的线路板分层做出合理分析,最后发现临界CO2流体对线路板分层过程有促进作用,并对其分层效果有优化作用。     

Assays of polychlorinated biphenyl congeners and co-contaminated heavy metals in the transgenic Arabidopsis plants carrying the recombinant guinea pig aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system

The transgenic Arabidopsis plant XgD2V11-6 carrying the recombinant guinea pig (g) aryl hydrocarbon receptor (AhR)-mediated β-glucuronidase (GUS) reporter gene expression system was examined for assay of polychlorinated biphenyl (PCB) congeners and co-contaminated heavy metals. When the transgenic Arabidopsis plants were treated with PCB126 (toxic equivalency factor; TEF: 0.1) and PCB169 (TEF: 0.03), the GUS activity of the whole plants was increased significantly. After treatment with PCB80 (TEF: 0), the GUS activity was nearly the same level as that treated with 0.1% dimethylsulfoxide (DMSO) as a vehicle control. After exposure to a 1:1 mixture of PCB126 and PCB169, the GUS activity was increased additively. However, after exposure to a mixture of PCB126 and PCB80, the GUS activity was lower than that of the treatment with PCB126 alone. Thus, PCB80 seemed to be an antagonist towards AhR. When the transgenic plants were treated with each of the heavy metals Fe, Cu, Zn, Cd and Pb together with PCB126, Cd and Pb increased the PCB126-induced GUS activity. On the other hand, Fe, Cu and Zn did not affect the PCB126-induced GUS activity. In the presence of the biosurfactant mannosylerythritol lipid-B (MEL-B) and the carrier protein bovine serum albumin (BSA), the PCB126-induced GUS activity was increased, but the Cd-assisted PCB126-induced GUS activity was not affected. Thus, MEL-B and BSA seemed to increase uptake and transport of PCB126, respectively.