超声协同TiO_2光催化降解4,4′-二溴联苯

以纳米TiO2膜为光催化剂,对4,4′-二溴联苯水溶液进行了超声光催化(US+UV)、光催化(UV)和超声(US)降解,探讨了初始浓度、超声的声强和频率等对降解4,4′-二溴联苯的影响。结果表明,4,4′-二溴联苯的超声光催化降解存在协同效应,降解率随4,4′-二溴联苯初始浓度的增大而下降,随声强和频率的增大而增大。超声光催化过程符合一级动力学方程,反应数率常数为0.011 min-1。超声光催化与光催化的降解产物不同。     

WRF-Chem simulation of East Asian air quality: Sensitivity to temporal and vertical emissions distributions

This study develops fine temporal (seasonal, day-of-week, diurnal) and vertical allocations of anthropogenic emissions for the TRACE-P inventory and evaluates their impacts on the East Asian air quality prediction using WRF-Chem simulations in July 2001 at 30-km grid spacing against available surface measurements from EANET and NEMCC. For NO₂ and SO₂, the diurnal and vertical redistributions of emissions play essential roles, while the day-of-week variation is less important. When all incorporated, WRF-Chem best simulates observations of surface NO₂ and SO₂ concentrations, while using the default emissions produces the worst result. The sensitivity is especially large over major cities and industrial areas, where surface NO₂ and SO₂ concentrations are reduced by respectively 3–7 and 6–12 ppbv when using the scaled emissions. The incorporation of all the three redistributions of emissions simulates surface O₃ concentrations higher by 4–8 ppbv at night and 2–4 ppbv in daytime over broad areas of northern, eastern and central China. To this sensitivity, the diurnal redistribution contributes more than the other two.     

苯并芘和邻苯二甲酸二(2-乙基己基)酯复合暴露对稀有鮈鲫的内分泌干扰效应研究

为评价典型有机污染物共存情况下对长江上游三峡库区特有珍稀鱼类的环境风险,以稀有鮈鲫(Gobiocypris rarus)为对象,研究了多环芳烃和酞酸酯的代表物苯并芘(BaP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)单独及复合暴露而引起的内分泌干扰效应。将成年稀有鮈鲫暴露于不同浓度的BaP(0.1、1μg·L~(-1))、DEHP(10、100μg·L~(-1))和BaP+DEHP((0.1+10)、(1+100)μg·L~(-1))中28 d后,测定了体质系数、性激素含量、下丘脑-垂体-性腺(HPG)轴和肝脏中与生殖相关基因的表达。结果表明:在雌鱼中,单独BaP或DEHP暴露对鱼体性激素含量、基因表达量无显著影响; BaP和DEHP复合暴露时,高浓度组睾酮(T)含量升高但雌二醇(E2)含量下降,fsh、vtg、 cyp17和17β-hsd基因表达量上调,cyp19a则下调,表现出协同毒性。因而雌鱼中性激素水平的改变可能与类固醇合成相关基因表达量的改变有关。而无论在单独暴露或是复合暴露情况下,对雄鱼体内性激素无显著影响。以上检测到的激素或基因表达量的改变主要发生在高剂量的复合暴露组中,而长江上游三峡库区水体中多环芳烃和酞酸酯含量低于暴露的最低浓度,因此推测,库区存在的多环芳烃和酞酸酯同时作用时不会对三峡库区上游水体中的鱼类产生生殖内分泌干扰效应。     

孕激素左炔诺孕酮长期低剂量暴露对雄性斑马鱼的生殖毒性

孕激素是广泛使用的高生物活性药物,其残留广泛存在于水环境中,对水生生物造成潜在威胁。本论文研究孕激素左炔诺孕酮(LNG)长期暴露对雄性斑马鱼的生殖毒性。将斑马鱼胚胎暴露于环境相关浓度的LNG(10, 33, 100 ng·L~(-1))至性成熟(受精后142 d),得到100%的雄性斑马鱼。将得到的雄鱼与未暴露的雌鱼配对,结果发现100 ng·L~(-1) LNG处理组雄鱼使得未暴露雌鱼产卵的数量较对照组雄鱼使得未暴露雌鱼产卵的数量显著减少。33和100 ng·L~(-1)处理组雄鱼与未暴露雌鱼配对所得子代在受精后7 d内的存活率较对照组雄鱼与未暴露雌鱼配对所得子代的存活率显著降低。33 ng·L~(-1) LNG显著升高总活力、活跃精子活力、平均路径速度、直线运动速度、曲线运动速度等精子活力参数,但其他浓度的LNG并不影响精子的活力。LNG在33和100 ng·L~(-1)的浓度下显著降低雄鱼血浆中11-酮基睾酮(11-KT)的含量,且在3个浓度下均显著降低雄鱼血浆中雌二醇(E2)的含量,但对睾酮(T)无明显影响。此外,LNG暴露可干扰雄鱼大脑和精巢中孕激素受体(npr, mprα, mprβ)、雌激素受体(erα, erβ)以及雄激素受体(ar)的转录,可能通过这些受体途径参与生殖调控。研究结果表明环境相关浓度的左炔诺孕酮长期暴露可导致雄性斑马鱼的生殖内分泌干扰效应,并提示:仅雄鱼单独受孕激素暴露影响,也可能对鱼类种群的生殖产生深远影响。     

Characteristics and management of domestic waste in a rural area of the Tibetan Plateau

In the rural area of the Tibetan Plateau (RATP), the characteristics of domestic waste, people’s environmental awareness, people’s willingness to pay and their influence factors were firstly studied by questionnaires, field samplings and laboratory tests. The results showed that, in the RATP, the generation of domestic waste was 85 g?d-1 per capita and it was mainly composed of plastics, inert waste, kitchen waste, glass and paper. The waste bulk density, moisture content, ash, combustible and low calorific value were 65 kg?m-3, 19.25%, 44.90%, 35.85% and 10,520 kJ?kg-1 respectively. These characteristics are influenced by income sources and geographical position to some extent. Classified collection should be promoted widely on the household and the village basis. Compost, fermentation, landfill, bioreactor landfill and semi-aerobic landfill have been approved as effective techniques to treat domestic waste, except incineration. The distance of 50–800 m between each collection facility and the disposal fee of around $0.8 per month per household are suggested. For suburbs or large population villages, it’s better to treat domestic waste by the centralized way. But for the remote rural areas, a decentralized way is proposed. Significantly, the educational and economic influence should be considered into an effective domestic waste management program.

Implications:?The current situatio n of the environment in the rural areas of the Tibetan Plateau (RATP) was surveyed. There, the generation of organics and moisture of domestic waste were low but ash, recyclables, and combustibles were high. People’s knowledge of domestic waste was absent but their participation in management was strong. Based on the current situation, compost, fermentation, and landfill were effective but incineration was inappropriate. Also, a localized mini landfill for a cluster of villages and or settlements was the best method there.     

Adding infection to injury: synergistic effects of predation and parasitism on amphibian malformations

We explored the importance of interactions between parasite infection and predation in driving an emerging phenomenon of conservation importance: amphibian limb malformations. We suggest that injury resulting from intraspecific predation in combination with trematode infection contributes to the frequency and severity of malformations in salamanders. By integrating field surveys and experiments, we evaluated the individual and combined effects of conspecific attack and parasite (Ribeiroia ondatrae) infection on limb development of long-toed salamanders (Ambystoma macrodactylum). In the absence of Ribeiroia, abnormalities involved missing digits, feet, or limbs and were similar to those produced by cannibalistic attack in experimental trials. At field sites that supported Ribeiroia, malformations were dominated by extra limbs and digits. Correspondingly, laboratory exposure of larval salamanders to Ribeiroia cercariae over a 30-day period induced high frequencies of malformations, including extra digits, extra limbs, cutaneous fusion, and micromelia. However, salamander limbs exposed to both injury and infection exhibited 3-5 times more abnormalities than those exposed to either factor alone. Infection also caused significant delays in limb regeneration and time-to-metamorphosis. Taken together, these results help to explain malformation patterns observed in natural salamander populations while emphasizing the importance of interactions between parasitism and predation in driving disease.     

A comparison study on high-temperature water–gas shift reaction over Fe/Al/Cu and Fe/Al/Ni catalysts using simulated waste-derived synthesis gas

A comparative study on Fe/Al, Fe/Al/Cu, and Fe/Al/Ni catalysts in high-temperature water–gas shift reaction (HT–WGS) using simulated waste-derived synthesis gas has been carried out. The metal oxide (Cu and Ni) and aluminum incorporated Fe catalysts were designed to get highly active HT–WGS catalysts. Despite the high CO concentration in the simulated waste-derived synthesis gas, Fe/Al/Cu catalyst exhibited the highest CO conversion (84 %) and 100 % selectivity to CO₂ at a very high gas hourly space velocity (GHSV) of 40,057 h^?1. The outstanding catalytic performance is mainly due to easier reducibility, the synergy effect of Cu and Al, and the stability of the magnetite.     

化学沉淀法强化常规工艺应急去除水中的镉

在常规工艺基础上,通过投加氢氧化钠,实验进行了应急去除重金属镉的研究。实验结果表明,该方法能有效去除饮用水水源的镉,效果稳定,可进行应急处理。对pH、镉初始浓度和混凝剂投加量3个影响因素的灰色关联分析表明,3个因素对镉去除效果影响的大小排序为:滤后水pH>混凝剂投加量>镉初始浓度。在水源镉突发污染时,在原有常规水处理工艺基础上,通过控制滤后水pH可实现对重金属镉的去除,pH的控制值与水源水质有关。     

Photocatalytic degradation of contaminants of concern with composite NF-TiO2 films under visible and solar light

This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO₂) for the removal of contaminants of concern in wastewater under visible and solar light. Monodisperse anatase TiO₂ nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO₂ by direct incorporation into the sol–gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high-resolution transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO₂-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO₂?+?monodisperse TiO₂ (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO₂-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO₂-P25. Using NF-TiO₂ layer-by-layer with monodisperse TiO₂ (50 nm) under solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5?×?10^?3?min^?1 for caffeine, 12.5 and 9.0?×?10^?3?min^?1 for carbamazepine, and 10.9 and 5.8?×?10^?3?min^?1 for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO₂-based films compared to the direct addition of nanoparticles into the sol.     

Adsorption behavior of light green anionic dye using cationic surfactant-modified wheat straw in batch and column mode

An agricultural by-product, natural wheat straw (NWS), was soaked in 1 % cationic surfactant (hexadecylpyridinium bromide, CPB) solution for 24 h (at 293 K), and modified wheat straw (MWS) was obtained. Analysis of FTIR, XFR, and nitrogen element showed that CPB was adsorbed onto surface of NWS. Then, MWS was used as adsorbent for the removal of light green dye (LG, anionic dye) from aqueous solution. The experiment was performed in batch and column mode at room temperature (293 K). Sodium chloride (up to 0.1 mol/L) existed in solution was not favor of LG dye adsorption. The equilibrium data were better described by Langmuir isotherm, and adsorption capacity of q _m from Langmuir model was 70.01?±?3.39 mg/g. In fixed-bed column adsorption mode, the effects of initial LG concentration (30, 50, 70 mg/L) and flow rate (6.5, 9.0, 14.5 mL/min) on adsorption were presented. Thomas and modified dose–response models were used to predict the breakthrough curves using nonlinear analysis method, and both models can fit the breakthrough curves. Theoretical and experimental breakthrough curves were drawn and compared. The results implied that MWS can be used as adsorbent material to remove LG from aqueous solution.