Reduction of mercury emissions from anthropogenic sources including coal combustion

Mercury(Hg)ranks number three,after arsenic(As)and lead(Pb),on the Substance Priority List of the Agency for Toxic Substances and Disease Registry(ATSDR,2019).M...     

热应力对混凝土结构的影响及其处理方法

对广钢轧钢厂厂房环境及结构不同区段、不同部位的温度情况,对结构损坏现状及混凝土的强度和碳化情况进行了检测鉴定,并对其缺陷进行了分析,提出了加固处理方法.     

Fate of 14C-acetyl sulfamethoxazole during the activated sludge process

Environmental Science and Pollution Research - Compared to antibiotic parent molecule, human metabolites are generally more polar and sometimes not less toxic in wastewater. However, most...     

Heavy metal availability,bioaccessibility, and leachability in contaminated soil: effects of pig manure and earthworms

A pot experiment and a leaching experiment were conducted to investigate the effects of earthworms and pig manure on heavy metals (Cd, Pb, and Zn) immobility, in vitro bioaccessibility and leachability under simulated acid rain (SAR). Results showed manure significantly increased soil organic carbon (SOC), dissolved organic carbon (DOC), available phosphorus (AP), total N, total P and pH, and decreased CaCl₂-extractable metals and total heavy metals in water and SAR leachate. The addition of earthworms significantly increased AP (from 0.38 to 1.7 mg kg^?1), and a downward trend in CaCl₂-extractable and total leaching loss of heavy metals were observed. The combined earthworm and manure treatment decreased CaCl₂-extractable Zn, Cd, and Pb. For Na₄P₂O₇-extractable metals, Cd and Pb were decreased with increasing manure application rate. Application of earthworm alone did not contribute to the remediation of heavy metal polluted soils. Considering the effects on heavy metal immobilization and cost, the application of 6% manure was an alternative approach for treating contaminated soils. These findings provide valuable information for risk management during immobilization of heavy metals in contaminated soils.

     

Effective utilization of dichloromethane by a newly isolated strain Methylobacterium rhodesianum H13

An effective dichloromethane (DCM) utilizer Methylobacterium rhodesianum H13 was isolated from activated sludge. A response surface methodology was conducted, and the optimal conditions were found to be 4.5 g/L Na₂HPO₄·12H₂O, 0.5 g/L (NH₄)₂SO₄, an initial pH of 7.55, and a temperature of 33.7 °C. The specific growth rate of 0.25 h^?1 on 10 mM DCM was achieved, demonstrating that M. rhodesianum H13 was superior to the other microorganisms in previous investigations of DCM utilization. DCM mineralization paralleled the production of cells, CO₂, and water-soluble metabolites, as well as the release of Cl^?, whereas the carbon distribution and Cl^? yield varied with DCM concentrations. The facts that complete degradation only occurred with DCM concentrations below 15 mM and repetitive degradation of 5 mM DCM could proceed for only three cycles were ascribed to pH decrease (from 7.55 to 3.02) though a buffer system was employed.     

Contrasting effects of silicates on cadmium uptake by three dicotyledonous crops grown in contaminated soil

The effects of several silicates (talcum powder (TP), calcium silicate (CS), sodium silicate (SS), and potassium silicate (PS)), in comparison with other amendments (quicklime (QL) and potassium dihydrogen phosphate (PDP)) on cadmium (Cd) uptake by three dicotyledonous crops (Amaranthus hypochondriacus L. Cv. ‘K112’, Amaranthus tricolor L., and Brassica oleracea var. albiflora Kuntze) were investigated in Cd–contaminated soil. The effects of both application methods of amendments (singly and combined) and timing of application were also evaluated. Sodium silicate was the most effective in reducing crop Cd uptake and translocation, which was diminished by 51 % in roots, 53 % in stems, and 72 % in leaves on average. Application of CS amendment showed greater efficiency than PDP amendment in decreasing Cd uptake by crops and resulted in increased biomass. Potassium silicate only slightly decreased shoot Cd concentration. Combination of PDP and SS was able to overcome the inhibitory effect of SS on crop yield while decreasing Cd concentrations in roots, stems and leaves of the tested crops by average rates of 52, 65, and 68 % respectively. Applications of SS and PS significantly reduced the root-to-shoot Cd transfer factor. We found that Si accumulation in crops was not associated with lower Cd concentration, indicating that Si in crops may play a major role in alleviating metal stress rather than inhibiting crop Cd accumulation. We suggested that the inhibitive effect of silicates on crops Cd uptake was majorly attributed to the properties of the silicates, those were their specific effects on soil pH and cations, which increased Cd adsorption by soil and suppressed Cd uptake from soil solution by increasing the relative dissolved concentrations of competing cations.     

孔径对微孔曝气充氧性能的影响

孔径是微孔曝气产品最重要的参数之一,研究孔径对微孔曝气氧传质的影响对于提高微孔曝气器充氧性能有重要意义。本研究在1.5 m水深条件下对不同大小孔径的钟罩型塑料微孔曝气器充氧性能进行评价。结果发现,在实验条件下,微孔曝气器的阻力损失RL、标准氧总转移系数KLas、标准氧转移速率SOTR,标准氧转移效率SOTE及理论动力效率E随孔径增大而显著减小。     

Characteristic Study of Ambient Air Total Gaseous Mercury (TGM) Concentrations During Rainy and Non-Rainy Periods at a Traffic Site in Taiwan

This investigation studied the concentrations of ambient air total gaseous mercury (TGM) during the rainy periods at the Hung-Kuang traffic sampling site in central Taiwan from May 26 to June 16, 2014. The results were compared with those of a previous study for ambient air TGM during non-rainy daytime and nighttime periods at the Hung-Kuang traffic sampling site, which was conducted during March 21 to July 20, 2012. The observed mean concentration of ambient air TGM was 1.16 ng/m³ during the rainy periods at the Hung-Kuang traffic sampling site. The mean ambient air TGM concentrations were higher in the non-rainy sampling period in daytime than in the rainy sampling period from this study. The mean ratio of non-rainy sampling period in daytime to that of rainy sampling period for ambient air TGM were 3.15. Furthermore, the mean ambient air TGM concentrations were higher in the non-rainy sampling period in nighttime in than in the rainy sampling period for this study. The mean rations for non-rainy sampling period in nighttime to that of the rainy sampling period for ambient air TGM were 2.70. The results obtained in this study also revealed that the ambient air TGM concentrations during the rainy period had the lowest concentrations when compared with the other sampling sites in other world regions.     

汽车电气和电子部件的环境试验总体要求与可靠性研究

本文针对3.5 t以下汽车电气和电子部件,采用ISO 16750系列标准和多个主流整车企业近年来实际使用的供货规范中关于环境试验与可靠性的要求,对于车辆中不同电子电气部件的环境试验序列与方案的设置、试验中和试验后的参数验证测试进行了详细解析。     

汽车电气和电子部件环境可靠性与关键试验解析

本文针对3.5 t以下汽车电气和电子部件,基于ISO 16750和IEC 60068-2系列标准中的专业基础性试验及方法,重点阐述了主流整车企业使用的供货规范VW 80000最新版中关于环境可靠性试验的增补和变更项目,对于汽车部件环境试验中3个关键试验项目:密封性试验、冷却回路压力脉动试验、冷凝与气候试验,进行了详尽的解析。