苯二甲酸酯的微生物降解与转化

综述国内外有关苯二甲酸酯化合物对环境的污染以及微生物对该类物质的降解与转化,指出：①ＰＡＥｓ已在全球范围的大气、水体、土壤中达到了普遍检出的程度;②微生物能够降解利用ＰＡＥｓ;③ＰＡＥｓ的微生物降解反应速率符合一级反应动力学方法方程;④混合微生物的联合代谢作用较纯培养降解ＰＡＥｓ效果好;⑤ＰＡＥｓ在微生物酶的作用下,先水解生成单酯与苯二甲酸,然后在好气条件下进行代谢与转化,最终可生成ＣＯ２和水。     

奇异的死亡谷

2005年暑假,我们一家三人游览了美国西部的死亡谷。死亡谷位于加利福尼亚、内华达和犹他三州交界的大沙漠中,呈椭圆形,高山环伺,南北长约300公里,东西宽约20公里,是一个巨大的地理博物馆,各     

表面活性剂强化超滤法处理亚甲基蓝废水

采用无机陶瓷超滤膜和低浓度阴离子表面活性剂十二烷基苯磺酸钠(SDBS)处理亚甲基蓝(MB)模拟废水,考察了废水中SDBS、MB浓度及废水pH对超滤过程的影响.实验结果表明:SDBS浓度影响MB在最大吸收波长处的吸光度值;当废水中SDBS浓度为1.20 mmol/L(即25℃时的临界胶束浓度)、废水中MB浓度为1.00 mmol/L、废水pH为9.0时,超滤效果最好;在此条件下,透过液中SDBS浓度和MB浓度分别为0.06 mmoL/L和0.01 mmol/L,MB的截留率为99.2%,膜通量为309.6 L/(m~2·h).SDBS对MB超滤过程的强化机理主要为MB与SDBS形成结合体析出及SDBS胶束的增溶作用.     

华南引种优质牧草气候适应性的研究

本文对我国南方有发展前途的三种热带牧草和三种温带牧草所历时两年的分期播种试验进行了总结。试验研究表明,热带牧草与温带牧草的生长发育、产草量形成与气象条件关系密切。同时还对热带牧草越冬、温带牧草越夏的气象指标进行了鉴定。分别找到了热带牧草的霜冻指标、平流寒害指标以及温带牧草的热害指标。此外,还对华南引种优质热带牧草和温带牧草进行了气候适应性评价。合理布局问题亦进行了探讨。并提出华南地区建设人工草场宜牧林农结合,中小型为主的观点。     

Estimation of septic tank setback distances based on transport of E. coli and F-RNA phages

Setback distances between septic tank systems and the shorelines of Lake Okareka, New Zealand were determined from model simulations for a worst-case scenario, using the highest hydraulic conductivity and gradient measured in the field, removal rates of the microbial indicators (Escherichia coli and F-RNA phages) determined from a column experiment, and maximum values of the design criteria for the disposal system, and assuming an absence of an unsaturated zone, a continuous discharge of the raw effluent from a failed or non-complying treatment system (both indicators at concentrations of 1x10(7) counts/100 ml) into the groundwater and no sorption of pathogens in the aquifer. Modelling results suggest that the minimal setback distances were 16 m to satisfy the New Zealand Recreational Water Quality Guidelines for E. coli <126 per 100 ml (Ministry for the Environment, 1999) and 48 m to meet the Drinking-Water Standards for New Zealand 2000 for enteric virus <1 per 100 l (Ministry of Health, 2000). These distances may be applicable for other lakeshores in pumice sand aquifers with groundwater velocities <7 m/day. Findings of laboratory column and batch experiments provided an insight into the microbial attenuation and transport processes in pumice sand aquifers. Bacterial removal was predominately through filtration (87-88%) and partially by die-off (12-13%), while viral removal was by both die-off (45%) and filtration (55%). In addition, microbial die-off in groundwater without aquifer material (i.e., free microbes) was much lower than die-off in groundwater with aquifer material (i.e., sorbed microbes) and contributed only 2-6% to the total removal. This implies that the setback distances estimated from die-off rates for the free microbes, determined in the laboratory without considering aquifer media and other removal processes, which are often reported in the literature, could be larger than necessary.     

Polycyclic aromatic hydrocarbons in coastal sediments of Southern Terengganu,South China Sea,Malaysia: source assessment using diagnostic ratios and multivariate statistic

Environmental Science and Pollution Research - Surface sediments along the Southern Terengganu coast (≤7 km from the coast) were analyzed for polycyclic aromatic hydrocarbons (PAHs). The...     

N,P-codoped carbon quantum dots-decorated TiO2 nanowires as nanosized heterojunction photocatalyst with improved photocatalytic performance for methyl blue degradation

Environmental Science and Pollution Research - N,P-doped carbon quantum dots (N,P-CQDs) are deemed as a promising candidate to environmentally friendly materials owing to the inexpensive,...     

炭黑尾气用于精煤干燥新技术的探讨与应用

论述了炭黑尾气的组成、成分分析,国内外利用技术发展状况,利用技术工艺,以及根据工程实例,提出了炭黑尾气用于精煤干燥机燃烧炉燃料的利用新技术,给我国炭黑生产企业尾气利用提供了有益的借鉴,也丰富了我国炭黑尾气的利用技术范畴。