Examining the technology acceptance for dismantling of waste printed circuit boards in light of recycling and environmental concerns

The dismantling of printed circuit board assemblies (PCBAs) and the recovery of their useful materials can lead to serious environmental impacts mainly due to their complicated physical structure and the variety of toxic elements contained in their material composition. So far, less attention has been paid to their responsible recycling compared to that of bare printed circuit boards. Combined with other materials recovery process, proper dismantling of PCBAs is beneficial to conserve scarce resources, reuse the components, and eliminate or safely dispose of hazardous materials. In analyzing the generation, resources potential and hazardous risk of scrap PCBAs, technologies used for the dismantling of waste PCBAs have been widely investigated and reviewed from the aspects of both industrial application and laboratory-scale studies. In addition, the feasibility of PCBA dismantling has been discussed, the determinants of which, including the heating conditions and mechanical properties have been identified. Moreover, this paper evaluates the environmental consequences caused by the dismantling of PCBAs.     

二氧化碳回收技术进展

CO2的过量排放对全球的气候变暖有着不可推卸的责任,同时CO2又是一种重要的碳资源,对它的回收和利用将具有很大的经济效益和社会效益。CO2回收的方法主要是膜吸收法、变压吸附法、化学吸收法和低温分离法,特别是离子液体对CO2的吸收,为CO2的减排提供了良好的手段。     

17β3-雌二醇对西伯利亚鲟幼鱼的雌激素效应

为了研究以及评估在利用17β-雌二醇(estradiol-17β,E2)混饲投喂进行人工诱导西伯利亚鲟(Acipenser baerii)性别逆转过程中,外源雌激素处理对西伯利亚鲟幼鱼的雌激素效应以及激素残留风险.实验选取健康的2月龄西伯利亚鲟840尾,设置E2在饲料中的投喂剂量为1 mg·1kg-1(C组)和10 m...     

Fabrication of PVDF nanofibrous hydrophobic composite membranes reinforced with fabric substrates via electrospinning for membrane distillation desalination

To improve the mechanical properties of the electrospun nanofibrous membrane, the nonwoven fabrics and spacer fabrics were employed as support substrates to fabricate polyvinylidene fluoride(PVDF) nanofibrous composite membranes. The influences of the substrate on membrane morphology, hydrophobicity, pore size and pore size distribution,porosity, mechanical strength and permeability were comprehensive evaluated. The electrospun composite membranes had a three dimension bead-fiber interconnected open structure and a rough membrane surface. The membrane surface presented a multilevel re-entrant structure and all the water contact angles were above 140°. In contrast with the pure PVDF nanofibrous membrane, the stress at break and the elastic modulus of the composite membranes increased by 4.5–16 times and 17.5–37 times, respectively. Since the spacer fabrics had less resistance to mass transfer, the membranes composited with spacer fabrics exhibited greater permeate fluxes compared with the composite membranes with the nonwoven fabrics as substrates.During the membrane distillation test, the highest permeate flux was up to 49.3 kg/m~2/hr at the feed temperature of 80°C. The long-time and repeat operation of membrane distillation desalination indicated the fabricated membrane with a good resistance to scaling and wetting.The results suggested the potential of the electrospun composite membrane for membrane distillation application.     

Purification of starch and phosphorus wastewater using core-shell magnetic seeds prepared by sulfated roasting

Core-shell magnetic seeds with certain adsorption capacity that were prepared by sulfated roasting, served as the core of a magnetic separation technology for purification of starch wastewater. XRD and SEM results indicate that magnetite's surface transformed to be porous α-Fe_2O_3 structure. Compared with magnetite particles, the specific surface area was significantly improved to be 8.361 from 2.591 m~2/g, with little decrease in specific susceptibility. Zeta potential, FT-IR and XPS experiments indicate that both phosphate and starch adsorbed on the surface of the core-shell magnetic seeds by chemical adsorption, which fits well with the Langmuir adsorption model. The porous surface structure of magnetic seeds significantly contributes to the adsorption of phosphate and starch species, which can be efficiently removed to be 1.51 mg/L(phosphate) and 9.51 mg/L(starch) using magnetic separation.     

Anaerobic digestion of sludge by different pretreatments: Changes of amino acids and microbial community

•Tryptophan protein, and aromatic protein I/II were the key identified proteins. •Cysteine was more correlated with methane production than other amino acids. •The presence of cysteine can promote methane production and degradation of VFAs. •The presence of cysteine can lower ORP and increase biomass activity. •Predominant Tissierella and Proteiniphilum were noted in pretreated sludge samples. Many studies have investigated the effects of different pretreatments on the performance of anaerobic digestion of sludge. However, the detailed changes of dissolved organic nitrogen, particularly the release behavior of proteins and the byproducts of protein hydrolysis-amino acids, are rarely known during anaerobic digestion of sludge by different pretreatments. Here we quantified the changes of three types of proteins and 17 types of amino acids in sludge samples solubilized by ultrasonic, thermal, and acid/alkaline pretreatments and their transformation during anaerobic digestion of sludge. Tryptophan protein, aromatic protein I, aromatic protein II, and cysteine were identified as the key dissolved organic nitrogen responsible for methane production during anaerobic digestion of sludge, regardless of the different pretreatment methods. Different from the depletion of other amino acids, cysteine was resistant to degradation after an incubation period of 30 days in all sludge samples. Meanwhile, the “cysteine and methionine metabolism (K00270)” was absent in all sludge samples by identifying 6755 Kyoto Encyclopedia of Genes and Genomes assignments of genes hits. Cysteine contributed to the generation of methane and the degradation of acetic, propionic, and n-butyric acids through decreasing oxidation-reduction potential and enhancing biomass activity. This study provided an alternative strategy to enhance anaerobic digestion of sludge through in situ production of cysteine.     

过滤捕集法去除盐酸雾中试研究

含HCl浓度小于350mg／Nm^3的盐酸雾气体，经洗涤水洗涤后再进行过滤捕集处理，出口气体中HCl浓度不大于6．40mg／m^3，去除率大于95％。     

循环流化床锅炉环保技术

介绍了CFB锅炉脱硫、除尘、降低NOx排放的技术特点与效率。     

民国初年北洋政府救灾举措述评

学界有一种观点认为,民初北洋政府漠视救灾,事实并非如此。本文例举了当时内务部等政府部门在救灾方面的措施,其大致可分为消极式的治标举措和积极式的治本举措。其中治标举措包括赈济、调粟、养恤、除害、资遣、蠲缓、放贷类灾后补救办法,积极式的治本举措包括重农、仓储、水利和林垦等。各重治标措施和治本措施的同时并举,显现了民初北洋政府对救灾的重视,学界那种认为政府漠视救灾的观点,值得商榷。     

PRE-ESTIMATE FOR THE CHANGE OF CLIMATIC VULNERABILITY TO AGRICULTURAL PRODUCTION IN LOESS PLATEAU,CHINA

Inrecentyears ,inthebackgroundofstrongglobalenvironmentalchange ,naturalvariationhastheaggravatingtendencyyearbyyearinChina .Additionally ,Chinahasahigheconomicgrowthrateandagreatpopulation ;humanactivitiesinhighriskareas (likeLoessPlateau)areexacerbated ;andbearingcapabilityagainstthedisasterisgenerallyvulnerable .Becauseofthosefactorsabove ,theeconomiclossescausedbythedisastershavebeenincreasing .Therefore ,ithasbecomethescientificbasisofestablishingaregionalsustainabledevelopmenttoprobein…