脂肪酰基氨基酸对矿物润滑油生物降解性的影响研究

通过生物降解试验研究了N-月桂酰基谷氨酸、N-月桂酰基甘氨酸、N-月桂酰基丙氨酸和N-油酰基甘氨酸4种脂肪酰基氨基酸对HVI 350矿物润滑油生物降解性的影响,采用高倍电子显微镜分析了生物降解过程中微生物数量和形态变化。结果表明,在矿物润滑油中添加少量脂肪酰基氨基酸后,矿物润滑油的生物降解性能明显改善,且生物降解过程中微生物数量增多、形态发生变化,这可能是脂肪酰基氨基酸增加了微生物的营养,且具有表面活性,有利于细胞的吸收,从而促进了矿物润滑油生物降解。     

Effect of inoculation methods on the composting efficiency of municipal solid wastes

Four types of inoculation methods were studied during the composting of municipal solid wastes and dry grass (MSWG). The methods included a control group as well as initial-stage, two-stage, and multi-stage inoculations. Fulvic acids were extracted from the composting materials and characterized by spectroscopic techniques. The results showed that inoculation of microbes in MSWG enhanced the biodegradation of aliphatics, proteins, and polysaccharides. The inoculation also increased the molecular weight, humic- and fulvic-like compound content, as well as humification degree of the composting products. The inoculation of microbes in MSWG significantly improved composting process and efficiency. The improvement efficiency was in the order of initial-stage < two-stage < multi-stage inoculations. Inoculation of microbes based on composting organic matter composition and temperature enhanced composting efficiency.     

预处理垃圾焚烧飞灰作为碱胶凝材料混合材的研究

试验分析了垃圾焚烧飞灰的主要化学成分及矿物组成,探讨了预处理垃圾焚烧飞灰作为碱胶凝材料混合材的可能性.研究表明,垃圾焚烧飞灰主要由黏土类矿物组成,飞灰直接作为混合材参与水化过程会产生明显膨胀现象,加入30%(质量分数)飞灰制成的矿渣/飞灰试块在成型1 d脱膜时膨胀率达到15.7%,标准养护28 d后无侧压抗压强度只有12.4 MPa.对飞灰进行热活化预处理,900℃条件下活化效果最佳,同样的飞灰掺量下,试块在标准养护28 d后无侧压抗压强度达到46.0 MPa,膨胀现象消失,且碱胶凝材料中重金属稳定性良好.     

水力停留时间对膜生物反应器复合工艺污水处理特性的影响

开发了厌氧-多级好氧/缺氧-膜生物反应器复合工艺,在不同水力停留时间(HRT)下,考察了系统对污染物去除效果及其膜污染的特性.结果表明,在试验选定的HRT范围内,系统对TN和TP的去除率随着HRT的降低而升高,当HRT为8.70、6.96、4.97 h时,系统对TN和TP的平均去除率分别为73.15%、79.76%、81.98%和67.79%、80.99%、92.16%.但是,较低HRT条件下膜通量较高,会加剧膜污染进程.解决这一问题的措施是增加膜组件个数,从而在不提高膜通量的情况下使系统保持较低的HRT,保证系统高效稳定的污染物去除效果.     

pH对沟渠沉积物截留农田排水沟渠中氮、磷的影响研究

通过摇瓶动态实验和箱体静止实验,研究了不同pH条件下沟渠沉积物对农田流失氮、磷的截留效应,分析了pH对氮、磷截留效应及其界面交换作用的影响.结果表明:在实验pH变化范围内,沟渠沉积物对NH 4-N的吸附量和NO-2-N的硝化量以及对TN的截留率都是随着pH的增加而增加;沟渠沉积物对总溶解性磷(TDP)的吸附量随着pH的增加而增加,TP的截留率在5 d前随pH的增加而增加,但在此后基本不发生变化;在不同的pH下,通过影响微生物的活动直接或间接影响氮的界面交换行为,同时pH通过影响沉积物的吸附作用和离子交换作用来影响磷在沉积物-水界面的交换行为.阐明pH对沟渠沉积物氮、磷截留效应的影响有助于掌握氮、磷在农田排水沟渠中的迁移转化机理,从而对控制农业面源污染具有重要的意义.     

The OH-induced degradation mechanism of 4-chloro-2-methylphenoxyacetic acid (MCPA) with two forms in the water: a DFT comparison

The initial degradation mechanisms of OH and 4-chloro-2-methylphenoxyacetic acid (MCPA) including molecular form and anionic form are studied at the MPWB1K/6-311+G(3df, 2p)//MPWB1K/6-31+G(d, p) level. Possible reaction pathways of H-atom abstraction and OH addition are considered in detail. By result comparison analysis, it is found that the reaction mechanisms for OH and two forms of MCPA are different, and most reactions for anionic MCPA are easier than those for molecular MCPA. For H-atom abstraction reactions, the calculated energies show that OH abstracting H-atom from -CH₃ group of molecular MCPA is the most kinetically favorable process; the potential energy surface for anionic MCPA indicates that H-atom in -CH₂ group is slightly easier to be abstracted than that in -CH₃ group. For OH addition reactions, the addition of OH to the C1 site is the initial step for molecular MCPA and the predominant product is 4-chloro-2-methylphenol (denoted P3), while the C4 site is the most reactive site for anionic MCPA and the primary product results from the hydroxylation of the aromatic ring, which is in good agreement with the experimental observation. In additional, results from PCM calculations show that most reactions in water phase are more kinetically favorable than those in gas phase, though the mechanisms discussed above will not be changed.     

上海市大气污染物排放现状评价、预测及对策研究

通过对1985-2001年间上海市大气污染物排放情况的考察,分析了SO2排放强度和人均SO2排放量等大气污染物排放指标变化的原因;与国内主要城市和美国的大气污染物排放指标对比情况表明,上海市大气污染物排放强度在国内处于较低的水平,但与发达国家相比还有较大差距;采用Sigmoid模型对上海市大气污染物排放进行了预测;提出了降低大气污染物排放的几点对策.     

以法矫正企业行为

从2004年初的川化沱江污染到2005年末的吉化松花江污染和广东韶关冶炼厂北江污染,无不令国人瞩目。甚至引起国际关注。三起污染事件影响的人群从数十万到数百万不等。仅川化沱江污染就导致近百万群众饮水中断达26天,直接经济损失约3亿元。沱江生态环境遭受严重破坏,据专家估计,需要5年时间才能恢复事故前水平。（华西都市报）     

Concurrent catalytic removal of typical volatile organic compound mixtures over Au-Pd/α-MnO2 nanotubes

α-MnO_2 nanotubes and their supported Au-Pd alloy nanocatalysts were prepared using hydrothermal and polyvinyl alcohol-protected reduction methods, respectively. Their catalytic activity for the oxidation of toluene/m-xylene, acetone/ethyl acetate, acetone/m-xylene and ethyl acetate/m-xylene mixtures was evaluated. It was found that the interaction between Au-Pd alloy nanoparticles and α-MnO_2 nanotubes significantly improved the reactivity of lattice oxygen, and the 0.91 wt.% Au0.48 Pd/α-MnO_2 nanotube catalyst outperformed the α-MnO_2 nanotube catalyst in the oxidation of toluene, m-xylene, ethyl acetate and acetone. Over the0.91 wt.% Au0.48 Pd/α-MnO_2 nanotube catalyst,(i) toluene oxidation was greatly inhibited in the toluene/m-xylene mixture, while m-xylene oxidation was not influenced;(ii) acetone and ethyl acetate oxidation suffered a minor impact in the acetone/ethyl acetate mixture; and(iii) m-xylene oxidation was enhanced whereas the oxidation of the oxygenated VOCs(volatile organic compounds) was suppressed in the acetone/m-xylene or ethyl acetate/m-xylene mixtures. The competitive adsorption of these typical VOCs on the catalyst surface induced an inhibitive effect on their oxidation, and increasing the temperature favored the oxidation of the VOCs. The mixed VOCs could be completely oxidized into CO_2 and H_2 O below 320°C at a space velocity of 40,000 m L/(g·hr). The 0.91 wt.% Au0.48 Pd/α-MnO_2 nanotube catalyst exhibited high catalytic stability as well as good tolerance to water vapor and CO_2 in the oxidation of the VOC mixtures. Thus, the α-MnO_2 nanotube-supported noble metal alloy catalysts hold promise for the efficient elimination of VOC mixtures.