交流变频磁化聚合硫酸铁混凝处理造纸废水

采用交流变频磁场预处理聚合硫酸铁(PFS),用于混凝处理造纸废水。考察了有无磁化作用、PFS加入量、磁化强度、磁化频率、磁化时间等因素对造纸废水的COD去除率和色度去除率的影响。实验结果表明:磁化PFS对造纸废水的处理效果较未磁化时明显提高;在PFS加入量为1 000 mg/L、磁化强度为6 mT、磁化频率为90 Hz、磁化时间为3 min的条件下,处理初始COD为650 mg/L、初始色度为180倍的造纸废水,COD去除率为93.22%,色度去除率为88.89%。     

PCB 77 dechlorination products modulate pro-inflammatory events in vascular endothelial cells

Persistent organic pollutants such as polychlorinated biphenyls (PCBs) are associated with detrimental health outcomes including cardiovascular diseases. Remediation of these compounds is a critical component of environmental policy. Although remediation efforts aim to completely remove toxicants, little is known about the effects of potential remediation byproducts. We previously published that Fe/Pd nanoparticles effectively dechlorinate PCB 77 to biphenyl, thus eliminating PCB-induced endothelial dysfunction using primary vascular endothelial cells. Herein, we analyzed the toxic effects of PCB congener mixtures (representative mixtures of commercial PCBs based on previous dechlorination data) produced at multiple time points during the dechlorination of PCB 77 to biphenyl. Compared with pure PCB 77, exposing endothelial cells to lower chlorinated PCB byproducts led to improved cellular viability, decreased superoxide production, and decreased nuclear factor kappa B activation based on duration of remediation. Presence of the parent compound, PCB 77, led to significant increases in mRNA and protein inflammatory marker expression. These data implicate that PCB dechlorination reduces biological toxicity to vascular endothelial cells.     

Degradation pathways of low-ethoxylated nonylphenols by isolated bacteria using an improved method

Nonylphenol ethoxylates (NPEOs) with low ethoxylation degree (NP_av2EO; containing two ethoxy units on average) and estrogenic properties are the intermediate products of nonionic surfactant NPEOs. To better understand the environmental fate of low-ethoxylated NPEOs, phylogenetically diverse low-ethoxylated NPEO-degrading bacteria were isolated from activated sludge using gellan gum as the gelling reagent. Four isolates belonging to four genera, i.e., Pseudomonas sp. NP522b in γ-Proteobacteria, Variovorax sp. NP427b and Ralstonia sp. NP47a in β-Proteobacteria, and Sphingomonas sp. NP42a in α-Proteobacteria were acquired. Ralstonia sp. NP47a or Sphingomonas sp. NP42a, have not been reported for the degradation of low-ethoxylated NPEOs previously. The biotransformation pathways of these isolates were investigated. The first three strains (NP522b, NP427b, and NP47a) exhibited high NP_av2EO oxidation ability by oxidizing the polyethoxy (EO) chain to form low-ethoxylated nonylphenoxy carboxylates, and then further oxidizing the alkyl chain to form carboxyalkylphenol polyethoxycarboxylates. Furthermore, Sphingomonas sp. NP42a degraded NP_av2EO through a nonoxidative pathway with nonylphenol monoethoxylate as the dominant product.     

Association of PM2.5 pollution with the pattern of human activity: A case study of a developed city in eastern China

Recently, air pollution has attracted a substantial amount of attention in China, which can be influenced by a variety of factors, but the association between air pollution and human activity is not quite clear. Based on real-time online data (January 1, 2014, to December 31, 2014) of air pollution and meteorology reported by official sites, and demographic, economic, and environmental reform data in a statistical yearbook, the influences of meteorological factors (temperature, relative humidity, precipitation intensity, and wind force) and human activities on PM_2.5 pollution were explored. After correlation analysis, logistic regression analysis, and a nonparametric test, weak negative correlations between temperature and PM_2.5 pollution were found. In most cases, festival and morning peak hours were protection and risk factors of PM_2.5 pollution, respectively. In addition, government actions, such as an afforestation project and increasing financial expenditure for energy saving and environmental protection, could greatly contribute to alleviating pollution of PM_2.5. The findings could help officials formulate effective laws and regulations, and then PM_2.5 pollution related to the pattern of human activity would be ameliorated.

Implications: Most of the time, festival and morning peak hours are protection and risk factors for PM_2.5 pollution, respectively. Increasing the percentage of afforestation area and financial expenditure for energy saving and environmental protection could significantly reduce PM_2.5 pollution. The findings can help officials formulate effective laws and regulations, and then PM_2.5 pollution related to the pattern of human activity, especially government action, will be ameliorated.     

水化深度处理渗滤液尾水中的有机物

利用水泥的水化过程易受有机物影响的特点,采用硅酸盐水泥深度处理了垃圾渗滤液膜生物反应器(MBR)工艺出水,考察了不同因素,如投加量、初始pH、反应时间及振荡速率等对于渗滤液尾水中有机物的去除效果以及最佳工艺条件,并分析了渗滤液尾水中有机物的去除机理。结果表明,水化过程对渗滤液尾水中的有机物去除性能良好,且对不同有机物具有一定的选择性,尤其对具有近紫外区(200～400 nm)吸收峰特征的有机物去除效果更佳,同时发现,当投加量为50 g/L、pH=8.3(原渗滤液pH)、反应时间为24 h和振荡速度为200 r/min时,去除效果最佳,其COD、TOC和UV254的平均去除率分别达到55.6%、62.1%和68.8%。     

Gene expression analysis and classification of mode of toxicity of polycyclic aromatic hydrocarbons (PAHs) in Escherichia coli

Escherichia coli is known to respond to certain toxic chemicals through an increased expression of various stress genes. In this study, therefore, the expression of recA, katG, fabA and grpE genes was used as a representative for DNA, oxidative, membrane and protein damage, respectively, after E. coli was exposed to different polycyclic aromatic hydrocarbons (PAHs), i.e., phenanthrene, naphthalene and benzo[a]pyrene. To accomplish this, the expression levels of these four genes were quantified using a real-time RT-PCR analysis when E. coli cultures were under stressful conditions, such as those caused by an exposure to mitomycin C, hydrogen peroxide and phenol. It was found that the primary toxic effect of each chemical is clearly seen when the expression levels of the different genes are compared. Tests with the PAHs showed naphthalene and benzo[a]pyrene to be genotoxic, while phenanthrene had no clear effect on the expression of any of these genes. Based on these results, the effects due to these toxic chemicals and the extent of each stress can be evaluated with ease using the expression levels of different stress responsive genes.     

7级强震备震过程的科普宣传及其减灾意义

随着中国经济的持续发展,公众对高质量生活充满渴望,对防震减灾和社会安全产生了强烈需求.联系到国家科技战略层次高度重视科普宣传的最新动态,提出了7级强震备震科普宣传工作的概念,从备震科普宣传的一般问题、7级强震备震科普宣传的重点问题及意义等方面展开了初步研究讨论.     

基于遥感数据的渤海海冰灾害风险研究

从海冰带来的严重灾害问题出发,针对传统监测方法的局限性,阐述了遥感技术在海冰灾害监测中的优越性.以渤海海冰为例,提出一种海冰灾害风险等级划分方法,即利用遥感技术和地理信息系统制作经纬度间隔为0.2°的网格,然后得到渤海海冰密集度,选择最大冰密集度、平均冰密集度、冰厚和冰期作为等级划分的指标.根据现场观测和多年调查研究,把海冰灾害风险程度分为3个等级零风险、低风险和高风险.结果表明该指标能够反映海冰灾害的风险程度,用该方法描述海冰灾害风险等级可以为海洋预报提供依据.     

Decomposing phenol by the hidden talent of ferromagnetic nanoparticles

Researches on modified Fenton reactions applied in phenol degradation have been focused on reducing secondary pollution and enhancing catalytic efficiency. Newly developed methods utilizing carriers, such as Resin and Nafion, to immobilize Fe(2+) could avoid iron ion leakage. However, the requirement of high temperature and the limited reaction efficiency still restrained them from broad application. Based on a recently discovered "hidden talent" of ferromagnetic nanoparticles (MNPs), we established a MNP-catalyzed phenol removal assay, which could overcome these limitations. Our results showed that the MNPs removed over 85% phenol from aqueous solution within 3h even at 16 °C. The catalytic condition was extensively optimized among a range of pH, temperature as well as initial concentration of phenol and H(2)O(2). TOC and GC/MS analysis revealed that about 30% phenol was mineralized while the rest became small molecular organic acids. Moreover the MNPs were thermo-stable and could be regenerated for at least five rounds. Thus, our findings open up a wide spectrum of environmental friendly applications of MNPs showing several attractive features, such as easy preparation, low cost, thermo-stability and reusability.