Diameter of Single-Walled Carbon Nanotubes (SWCNTs) as an Effective Factor in the Detection and Degradation of PCBs

Polychlorinated biphenyls (PCBs) are chlorinated organic compounds and well known carcinogenic and toxic pollutants. Currently, their detection and degradation to products with less risk are among environmental and health priorities. Passing 2,2′,4,4′,5,5′-Hexachlorobiphenyl (PCB-153) through the armchair single-walled carbon nanotubes (SWCNTs) (8, 8) and (10, 10) was investigated by Modified Neglect of Diatomic Overlap in the semi-empirical method. The analysis of results suggests that there are meaningful changes in the middle of the tubes. Based on the obtained evidence, the nanotubes have substantial potential to interact with the PCB-153 molecule effectively. The results show that the increased diameter in the armchair SWCNTs improves the detection and degradation potential of the tube to PCBs. According to the calculated thermodynamic parameters, the diameter of nano-structures is an effective factor in PCBs removal efficiency, as it could be helpful to make a more sensitive PCB nano-sensor.     

采用薄膜热电偶的多层印刷电路板原位钻削温度测量

针对工业用多层印刷电路板(PCB)加工过程中钻削温度难以准确测量的技术难题，提出了一种基于薄膜热电偶的PCB各板层原位钻削温度测量方法。根据PCB的截面结构采用材料叠层建模方法对PCB钻削过程进行建模仿真，掌握了钻削过程中PCB钻削温度的分布及变化情况，并确定了传感器最佳镀膜位置为钻头进给方向的垂直底部。采用直流脉冲磁控溅射技术，在不同层数的PCB上制备薄膜热电偶传感器，并对其静、动态性能进行研究，结果表明所研制的温度传感器在30~200 ℃范围内，塞贝克系数为37.4 μV/℃，非线性误差不超过0.65%，动态响应时间为0.095ms。对不同层数的PCB进行了多组钻削温度测量实验，结果显示，钻削过程中4层、12层、20层的最高钻削温度分别为49.30 ℃、53.90 ℃、63.90 ℃，且每组重复实验的温度相对稳定，温度测量误差不超过0.8 ℃。该测量方法为PCB高速钻削工艺改进提供了参考。     

Sewage sludge digestion at increased micropollutant content

Research was conducted, which aim was to evaluate quantitative and qualitative PCB changes in sewage sludge during mesophilic digestion, and the influence of those compound concentration above acceptable level (1.9 mg kg⁻¹ of sludge dry matter), also nickel and cadmium ions, on mesophilic digestion process. Before and after the digestion, concentration of seven PCB congeners, Ni and Cd in particular chemical fractions of the sludge was analyzed.     

线路板污泥和电镀含铜废液同时处理回收铜的新工艺

作者开发出一套将线路板污泥和电镀含铜废液同时处理回收铜的新工艺,利用两种含铜废物自身的特性可以节约化工原料的添加,同时可以有效去除COD,以及实现铜和铁等杂质金属的有效分离,对铜的回收率达95%以上并制备出符合饲料级标准的五水硫酸铜,而且无三废排出。     

PCB废水处理与循环利用技术

介绍了PCB生产废水的分类及特点,综述了PCB生产废水的处理和循环利用技术,分析了各种处理技术的优缺点,阐述了研发或采用新型的化学处理剂和活性吸附剂,并将各种处理方法有机地融合在一起将成为今后PCB生产废水处理与循环利用技术发展的重要方向。     

棕化废液的资源化利用研究

在PCB行业中,随着棕氧化技术代替黑氧化技术,棕化废液的排放量巨大而且成分复杂,从而推动了棕化废液处理技术的发展。文章提出化学沉淀法和Fenton法组合处理棕化废水,并合成氧化铜的新工艺。从而达到了棕化废液资源化利用的目的。     

全球PCB化学品及半导体封装材料市场综述

简要叙述了全球主要国家和地区印制电路板用化学品和半导体封装材料生产情况.并提出在全球电子化学品产业转移的有利条件下,加强自主研发能力,开发高技术产品是我国电子化学品行业发展的方向.     

PCB dry and wet weather concentration and load comparisons in Houston-area urban channels

All 209 PCB congeners are quantified in water in both dry and wet weather urban flows in Houston, Texas, USA. Total water PCBs ranged from 0.82 to 9.4 ng/L in wet weather and 0.46 to 9.0 ng/L in dry. Wet weather loads were 8.2 times higher (by median) than dry weather with some increases of over 100-fold. The majority of the PCB load was in the dissolved fraction in dry weather while it was in the suspended fraction in wet weather. Dissolved PCB loads were correlated with rain intensity and highly developed land area, and a multiple linear regression (MLR) equation was developed to quantify these correlations. PCA generated five PCB components with nearly all positive loadings. They were interpreted as DOC-associated A1248, wet weather primarily suspended fraction A1254/A1260 likely from building sealants, truly dissolved-associated wastewater dechlorination, watershed-sourced PCB 11, and monochlorinated PCBs (likely connected to a different state or source of dechlorination). The PCB 11 component was statistically higher in wet versus dry weather when no other component showed such clear distinctions. Hierarchical cluster analysis (HCA) did not always group dry and wet weather samples from the same location together illustrating the different congener composition that often exists between dry and wet conditions. Four wet weather samples from high percentage developed land (> 90%) watersheds had nearly the same fingerprint suggesting a generic “urban” signature in runoff, which in this case was caused by residual A1254/A1260 PCB stocks and currently produced PCB 11 in consumer goods.     

Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish

Persistent organic pollutants (POPs) encompass an array of anthropogenic organic and elemental substances and their degradation and metabolic byproducts that have been found in the tissues of exposed animals, especially POPs categorized as organohalogen contaminants (OHCs). OHCs have been of concern in the circumpolar arctic for decades. For example, as a consequence of bioaccumulation and in some cases biomagnification of legacy (e.g., chlorinated PCBs, DDTs and CHLs) and emerging (e.g., brominated flame retardants (BFRs) and in particular polybrominated diphenyl ethers (PBDEs) and perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA) found in Arctic biota and humans. Of high concern are the potential biological effects of these contaminants in exposed Arctic wildlife and fish. As concluded in the last review in 2004 for the Arctic Monitoring and Assessment Program (AMAP) on the effects of POPs in Arctic wildlife, prior to 1997, biological effects data were minimal and insufficient at any level of biological organization. The present review summarizes recent studies on biological effects in relation to OHC exposure, and attempts to assess known tissue/body compartment concentration data in the context of possible threshold levels of effects to evaluate the risks. This review concentrates mainly on post-2002, new OHC effects data in Arctic wildlife and fish, and is largely based on recently available effects data for populations of several top trophic level species, including seabirds (e.g., glaucous gull (Larus hyperboreus)), polar bears (Ursus maritimus), polar (Arctic) fox (Vulpes lagopus), and Arctic charr (Salvelinus alpinus), as well as semi-captive studies on sled dogs (Canis familiaris). Regardless, there remains a dearth of data on true contaminant exposure, cause-effect relationships with respect to these contaminant exposures in Arctic wildlife and fish. Indications of exposure effects are largely based on correlations between biomarker endpoints (e.g., biochemical processes related to the immune and endocrine system, pathological changes in tissues and reproduction and development) and tissue residue levels of OHCs (e.g., PCBs, DDTs, CHLs, PBDEs and in a few cases perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonates (PFSAs)). Some exceptions include semi-field studies on comparative contaminant effects of control and exposed cohorts of captive Greenland sled dogs, and performance studies mimicking environmentally relevant PCB concentrations in Arctic charr. Recent tissue concentrations in several arctic marine mammal species and populations exceed a general threshold level of concern of 1 part-per-million (ppm), but a clear evidence of a POP/OHC-related stress in these populations remains to be confirmed. There remains minimal evidence that OHCs are having widespread effects on the health of Arctic organisms, with the possible exception of East Greenland and Svalbard polar bears and Svalbard glaucous gulls. However, the true (if any real) effects of POPs in Arctic wildlife have to be put into the context of other environmental, ecological and physiological stressors (both anthropogenic and natural) that render an overall complex picture. For instance, seasonal changes in food intake and corresponding cycles of fattening and emaciation seen in Arctic animals can modify contaminant tissue distribution and toxicokinetics (contaminant deposition, metabolism and depuration). Also, other factors, including impact of climate change (seasonal ice and temperature changes, and connection to food web changes, nutrition, etc. in exposed biota), disease, species invasion and the connection to disease resistance will impact toxicant exposure. Overall, further research and better understanding of POP/OHC impact on animal performance in Arctic biota are recommended. Regardless, it could be argued that Arctic wildlife and fish at the highest potential risk of POP/OHC exposure and mediated effects are East Greenland, Svalbard and (West and South) Hudson Bay polar bears, Alaskan and Northern Norway killer whales, several species of gulls and other seabirds from the Svalbard area, Northern Norway, East Greenland, the Kara Sea and/or the Canadian central high Arctic, East Greenland ringed seal and a few populations of Arctic charr and Greenland shark.     

基于蓝牙控制的便携式数字微流控系统的研究

设计了一种基于蓝牙通信的便携式系统,相对于传统笨重的微流控设备,更加小巧、易用、价格低廉,通过蓝牙与手机集成,便于进一步的市场化普及。该系统基于电湿润法原理,给电极间施加电压,改变液滴与固体表面的润湿特性,从而使得液滴运动。该系统包括电极阵列、高压模块、控制模块、蓝牙通信模块以及配套APP。最后通过测量液滴的移动速度,对3 μL的液滴,可以达到50 mm/s的速度,满足了微流控系统的需要,证实了该设备的可行性。该研究可以促进微流控设备的低廉化、易用化。