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...     

挥发性有机化合物处理技术的研究进展

简要介绍了挥发性有机化合物（VOCs）的来源、危害以及控制的意义,对VOCs现有处理技术从回收方法和消除方法两个方面进行了详细评述,并指出其优势和不足。同时,着重阐述了光催化氧化法以及变压吸附技术的研究进展,并提出了进一步研究的方向。     

Forward osmosis coupled with lime-soda ash softening for volume minimization of reverse osmosis concentrate and CaCO3 recovery: A case study on the coal chemical industry

• Forward osmosis (FO) coupled with chemical softening for CCI ROC minimization • Effective removal of scale precursor ions by lime-soda ash softening • Enhanced water recovery from 54% to 86% by mitigation of FO membrane scaling • High-purity CaCO₃ was recovered from the softening sludge • Membrane cleaning efficiency of 88.5% was obtained by EDTA for softened ROC Reverse osmosis (RO) is frequently used for water reclamation from treated wastewater or desalination plants. The RO concentrate (ROC) produced from the coal chemical industry (CCI) generally contains refractory organic pollutants and extremely high-concentration inorganic salts with a dissolved solids content of more than 20 g/L contributed by inorganic ions, such as Na⁺, Ca²⁺, Mg²⁺, Cl⁻, and SO₄²⁻. To address this issue, in this study, we focused on coupling forward osmosis (FO) with chemical softening (FO-CS) for the volume minimization of CCI ROC and the recovery of valuable resources in the form of CaCO₃. In the case of the real raw CCI ROC, softening treatment by lime-soda ash was shown to effectively remove Ca²⁺/Ba²⁺ (>98.5%) and Mg²⁺/Sr²⁺/Si (>80%), as well as significantly mitigate membrane scaling during FO. The softened ROC and raw ROC corresponded to a maximum water recovery of 86% and 54%, respectively. During cyclic FO tests (4 × 10 h), a 27% decline in the water flux was observed for raw ROC, whereas only 4% was observed for softened ROC. The cleaning efficiency using EDTA was also found to be considerably higher for softened ROC (88.5%) than that for raw ROC (49.0%). In addition, CaCO₃ (92.2% purity) was recovered from the softening sludge with an average yield of 5.6 kg/m³ treated ROC. This study provides a proof-of-concept demonstration of the FO-CS coupling process for ROC volume minimization and valuable resources recovery, which makes the treatment of CCI ROC more efficient and more economical.     

Application of interval 2-tuple linguistic MULTIMOORA method for health-care waste treatment technology evaluation and selection

The management of health-care waste (HCW) is a major challenge for municipalities, particularly in the cities of developing countries. Selection of the best treatment technology for HCW can be viewed as a complicated multi-criteria decision making (MCDM) problem which requires consideration of a number of alternatives and conflicting evaluation criteria. Additionally, decision makers often use different linguistic term sets to express their assessments because of their different backgrounds and preferences, some of which may be imprecise, uncertain and incomplete. In response, this paper proposes a modified MULTIMOORA method based on interval 2-tuple linguistic variables (named ITL-MULTIMOORA) for evaluating and selecting HCW treatment technologies. In particular, both subjective and objective importance coefficients of criteria are taken into consideration in the developed approach in order to conduct a more effective analysis. Finally, an empirical case study in Shanghai, the most crowded metropolis of China, is presented to demonstrate the proposed method, and results show that the proposed ITL-MULTIMOORA can solve the HCW treatment technology selection problem effectively under uncertain and incomplete information environment.     

Comprehensive source identification and apportionment analysis of five heavy metals in soils in Wenzhou City,China

Environmental Geochemistry and Health - The source identification and apportionment of heavy metals (HMs) is a vital issue for restoring contaminated soil. In this study, qualitative approaches [a...     

北部湾潮间带沉积物和双壳类动物中的重金属:污染特征与生物积累

环北部湾经济的迅猛发展对沿岸生态环境的人为干扰日益增强,其中潮间带受到的影响更大.研究该区域沉积物的重金属污染特征、来源及生物积累程度,对于北部湾的环境保护及管理十分重要.2011年10月,对北部湾潮间带13个站位的沉积物中7种重金属(Hg、Pb、Cd、Cr、Cu、Zn、As)、Al及总有机碳(TOC)含量和细颗粒(＜63 μm)比例进行测定,同时测定2种双壳类动物(波纹巴非蛤Paphia undulate和文蛤Meretrix meretrix)软组织中重金属含量.通过计算富集因子(EF)和生物-沉积物积累因子(BSAF),对沉积物中每种重金属的来源和生物积累潜力进行分析.结果表明,与世界其他海域相比,北部湾潮间带沉积物中重金属整体污染水平较低,但站位间差异明显;沉积物中的Cd、Pb、Zn、Cu主要来自人为污染,Cr、As和Hg则主要来自天然来源.双壳类动物体内重金属含量在站位间存在较明显差异,波纹巴非蛤和文蛤BSAF值由大到小依次为Cd (861％,1028％)＞Zn (281％,369％)＞Hg(243％,222％)＞Cu(125％,169％) ＞As(38％,42％)＞Cr(37％,23％)＞Pb(3.3％,2.2％);两种生物对Hg、As的积累程度差异不大,波纹巴非蛤对Pb、Cr的积累程度明显高于文蛤,对Cu、Zn、Cd的积累程度则明显低于文蛤.Pearson相关性分析表明,在粒径小、有机质多的沉积物中,多数重金属的生物可利用性降低,不易被双壳类动物吸收利用.     

尾矿库溃坝风险评价——以一电解金属锰项目尾矿库为例

尾矿库是一个具有高势能的人造泥石流危险源,一旦溃坝,将对下游居民及生态环境造成严重影响.通过对国内外尾矿库溃坝事故的分析,得出导致溃坝的主要原因:排洪因素、地质因素、施工因素及管理因素.结合一电解锰公司尾矿库实例,发现恒丰尾矿库有因不良地质及超储发生溃坝风险的可能性,一旦发生溃坝,将对下游600m范围内的房屋、农田、交通、水利等设施造成影响,在此基础上,针对溃坝风险,提出相应的对策措施.