CeOx/AC催化剂NH3选择性催化还原NO

以用不同浓度的HNO3预处理后的椰壳活性炭为载体,负载铈制备SCR催化剂。利用比表面积分析仪(BET)、X射线衍射(XRD)、扫描电镜(SEM)和催化剂活性实验,探讨了不同变量如金属离子的分布、焙烧温度和载体属性对催化活性的影响。结果表明,HNO3处理后,经500℃焙烧金属铈负载量为7%的催化剂表现出优良的催化性能。在90℃时,NO转化率在90%以上,随温度升高,达到接近100%的NO转化率。     

杭州地区大中型水库富营养化状况及影响因子分析

在2008年和2009年对杭州地区17个大中型水库进行了调查。结果表明：杭州地区大中型水库水质不容乐观,按照单因子指标评价法,只有3个水库符合Ⅱ类水体标准,2个水库符合Ⅲ类水体标准,2个水库为Ⅳ类水体,3个水库为Ⅴ类水体,其余7个水库均为劣Ⅴ类水体,定类指标均是总氮。根据综合营养状态指数结果：丰水期2个水库处于贫营养状态,13个水库处于中营养状态,2个水库处于轻度富营养状态;枯水期16个水库处于中营养状态,1个水库处于中度富营养状态。总氮和总磷作为营养物质是这些水库富营养化的主要影响因素。位于山区源头地区的水库水质最好,位于平原城乡附近的水库其次,位于城市下游及城区附近的水库水质最差     

青竹江水环境耗氧污染物含量分布特征及质量评价

本文对青竹江水环境中耗氧污染物(CODCr、BOD5和NH3-N)含量分布特征进行了探讨,并对青竹江的水质质量进行评价。结果表明,青竹江从上游到下游水体中污染物含量为增加趋势,在时间上也存在一定的变化,枯水期水体中污染物含量高于平水期和丰水期,目前青竹江综合水质可满足Ⅱ类水质标准要求。     

Effect of snow depth and snow duration on soil N dynamics and microbial activity in the alpine areas of the eastern Tibetan Plateau

The effects of snow regimes (including the depth and duration of snow cover) on soil N dynamics and microbial activity in situ were explored in the alpine belt of the eastern Tibetan Plateau. Deeper snow-cover reduced NH ₄ ⁺ -N content, microbial biomass carbon and nitrogen, fungi count, and enzyme activities, whereas did not change net N mineralization. No differences in N pools in the soil, microbial biomass, microbial counts, and enzyme activity were found under the different duration of snow cover, showing that accumulation and release in soil N pools did not be significantly changed by earlier continuous snow cover.     

Aerobic biotransformation of decabromodiphenyl ether (PBDE-209) by Pseudomonas aeruginosa

Aerobic biodegradation of decabromodiphenyl ether (PBDE-209) by Pseudomonas aeruginosa under the influence of co-metabolic substrates and heavy metal cadmium ion was studied, The results showed that certain amount of co-metabolic substrates, such as glucose, sucrose, lactose, starch, and beef extract, would promote the biodegradation of PBDE-209, among which glucose most favorably accelerated PBDE-209 degradation by about 36% within 5 d. The highest degradation efficiency was reached at the ratio of PBDE-209 and glucose 1:5 while excessive carbon source would actually hamper the degradation efficiency. Exploration of influences of cadmium ion on PBDE-209 biodegradation indicated that degradation efficiency was stimulated at low concentrations of Cd²⁺ (0.5–2 mg L⁻¹) while inhibited at higher levels (5–10 mg L⁻¹), inferring that the heavy metals of different concentrations possessed mixed reactions on PBDE-209 bioremoval. Bromine ion was produced during the biotransformation process and its concentration had a good negative correlation with the residues of PBDE-209. Two nonabromodiphenyl ethers (PBDE-208, PBDE-207), four octabromodiphenyl ethers (PBDE-203, PBDE-202, PBDE-197, PBDE-196) and one heptabromodiphenyl ethers (PBDE-183) were formed with the decomposition of PBDE-209, demonstrating that the main aerobic transformation mechanism of PBDE-209 was debromination.     

Synthesized magnetic nanoparticles coated zeolite for the adsorption of pharmaceutical compounds from aqueous solution using batch and column studies

The contamination of fresh water with pharmaceutical and personal care products (PPCPs) has risen during the last few years. The adsorption of some PPCPs namely, Diclofenac-Na, Naproxen, Gemfibrozil and Ibuprofen from aqueous solution has been studied, magnetic nanoparticles coated zeolite (MNCZ) has been used as the adsorbent. Batch adsorption experiment was conducted to study the influences of different adsorption parameters such as contact time, solution pH and PPCPs concentrations in order to optimize the reaction conditions. The removal was favored at low pH values. Thus, as pH turns from acidic to basic conditions these compounds were less efficiently removed. The initial concentration does not appear to exert a noticeable effect on the removal efficiency of the studied PPCPs at low concentrations, but it showed less removal efficiency during high concentration of PPCPs especially for Ibuprofen. The removal of Diclofenac-Na was independent on time, while the contact time was of significant effect on the adsorption of Naproxen, Gemfibrozil and Ibuprofen even though these compounds were removed up to 95% during 10 min using MNCZ. From the isotherm adsorption study, the adsorption of PPCPs studied on MNCZ was best fitted with Freundlich isotherm equation. Pseudo-second order model providing the best fit model with the experimental data. Column adsorption study was conducted to compare the removal efficiency of MNCZ with other processes used at drinking water treatment plants (DWTPs), MNCZ showed high removal efficiency (>99%) than other used processes at DWTPs.     

Enhanced sorption of perfluorooctane sulfonate (PFOS) on carbon nanotube-filled electrospun nanofibrous membranes

Multi-walled carbon nanotube-filled electrospun nanofibrous membranes (MWCNT-ENFMs) were prepared by electrospinning. The addition of MWCNTs (0.5 wt.% vs. ENFMs) doubled the specific surface area and tensile strength of the ENFMs. The MWCNT-ENFMs were used to adsorb perfluorooctane sulfonate (PFOS) in aqueous solutions. The sorption kinetics results showed that the sorption rate of PFOS onto the MWCNT-ENFMs was much higher than the sorption rate of PFOS onto the pure ENFMs control, and the pseudo-second-order model (PSOM) described the sorption kinetics well. The sorption isotherms indicated that the sorption capacity of the MWCNT-ENFMs for PFOS (16.29 ± 0.26 μmol g⁻¹) increased approximately 18 times, compared with the pure ENFMs (0.92 ± 0.06 μmol g⁻¹). Moreover, the solution pH significantly affected the sorption efficiency and sorption mechanism. The MWCNT-ENFMs were negatively charged from pH 2.0–10.0, but the electrostatic repulsion between the MWCNT-ENFMs and PFOS was overcome by the hydrophobic interactions between PFOS and the MWCNTs or nanofibers. The strong hydrophobic interactions between PFOS and the MWCNTs played a dominant role in the sorption process. For the pure ENFMs, the electrostatic repulsion was conquered by the hydrophobic interactions between PFOS and the nanofibers at pH > 3.1. In addition to the hydrophobic interactions, an electrostatic attraction between PFOS and the pure ENFMs was involved in the sorption process at pH < 3.1.     

新兴污染物BP-3和BP-4的好氧生物降解性能

采用欧洲经济合作与发展组织（OECD）的生物降解测试标准方法——301F测压呼吸计量法,考察了2-羟基-4-甲氧基二苯甲酮（BP-3）和2-羟基-4-甲氧基二苯甲酮-5-磺酸（BP-4）的好氧生物降解性能,并研究了降解动力学及共代谢现象。实验结果表明：BP-3和BP-4的可生物降解率分别为68.36%和41.34%;根据OECD快速降解性判定标准,BP-3划归为易快速降解物质,而BP-4为不易快速降解物质;两种物质的生物降解可用一级动力学描述,半衰期分别为1.986 d和2.806 d;根据欧盟法规《化学品的注册、评估、授权和限制》（REACH法规）,BP-3和BP-4均非持久性物质;与苯甲酸钠共存时,BP-3和BP-4的降解过程均表现出共代谢现象。     

The evaluation of heavy metal accumulation and application of a comprehensive bio-concentration index for woody species on contaminated sites in Hunan,China

Fast-growing metal-accumulating woody plants are considered potential candidates for phytoextraction of metals. Shuikoushan mining, one of the biggest Pb and Zn production bases in China, presents an important source of the pollution of environment during the last 100 years. Over 150 km² of fertile soil have been contaminated by the dust, slag, and tailings from this mining. The goal of the present work has been to determine the content of Pb, Zn, Cd, and Cu in wild woody plants (18 species) naturally growing in this area. Two hundred five plant and soil samples from 11 contaminated sites were collected and analyzed. In addition, to assess the ability of multi-metal accumulation of these trees, we proposed a predictive comprehensive bio-concentration index (CBCI) based on fuzzy synthetic assessment. Our data suggest some adult trees could also accumulate a large amount of metals. Pb concentrations in leaves of Paulownia fortunei (Seem.) Hemsl. (1,179 mg/kg) exceeded the hyperaccumulation threshold (1,000 mg/kg). Elevated Pb concentrations (973.38 mg/kg) were also found in the leaves of Broussonetia papyrifera (L.) Vent., with a Pb bio-concentration factor of up to 0.701. Endemic species, Zenia insignis Chun exhibited huge potential for Zn and Cd phytoextraction, with the highest concentrations of Zn (1,968 mg/kg) and Cd (44.40 mg/kg), characteristic root nodules, and fast growth rates in poor soils. As for multi-metal accumulation ability, native species B. papyrifera was calculated to have the most exceptional ability to accumulate various metals simultaneously (CBCI 2.93), followed by Amorpha fruticosa L. (CBCI 2.72) and Lagerstroemia indica L. (CBCI 2.53). A trend of increasing metal from trunks to leaves (trunks?<?branches?<?leaves) and towards fine roots has been shown by metal partitioning between tissues. The proposed CBCI would allow for the selection of suitable trees for phytoremediation in the future.     

Neurotoxicological evaluation of microcystin-LR exposure at environmental relevant concentrations on nematode Caenorhabditis elegans

Previous studies have not examined the adverse effects of microcystin-LR (MC-LR) at environmental relevant concentrations on the development and functions of nervous system. The neurotoxic effects of MC-LR exposure on neurotransmitter systems were investigated in Caenorhabditis elegans. After exposing L1 larvae to 0.1, 1, 10, and 100 μg?l^?1 of MC-LR for 8 and 24 h, the adverse effects on GABAergic, cholinergic, serotonergic, dopaminergic, and glutamatergic neurons were examined. The expression levels of genes required for development and functions of GABAergic neurons were further investigated. Body bend frequency and head thrash frequency decreased significantly after MC-LR exposure for 8 h at concentrations more than 1 μg?l^?1 and after MC-LR exposure for 24 h at concentrations more than 0.1 μg?l^?1. Loss of GABAergic neurons increased significantly in a dose-dependent manner after MC-LR exposure at concentrations more than 0.1 μg?l^?1. In contrast, no obvious neuronal losses or morphologic changes were observed in cholinergic, serotonergic, dopaminergic, and glutamatergic neurons in MC-LR-exposed nematodes. Quantitative real-time PCR assay further showed that expression levels of unc-30, unc-46, unc-47, and exp-1 genes required for development and function of GABAergic neurons decreased significantly in nematodes exposed to MC-LR at concentrations more than 0.1 or 1 μg?l^?1. MC-LR at environmental relevant concentrations caused neurobehavioral defects, which may be largely due to the neuronal loss and the alterations of expression level of genes required for GABAergic neurotransmitter system in C. elegans.