硫化零价铁的制备及去除头孢噻肟机理研究

采用后置硫化法制备了硫化纳米零价铁(S-nZVI),并采用X射线光电子能谱(XPS)、X射线衍射(XRD)和透射电镜(TEM)等方法表征了材料表面形貌及元素化学形态等特性.同时,以头孢噻肟为目标污染物,考察了S-nZVI对其去除效率及去除机理等.结果表明,S-nZVI颗粒呈球形,平均粒径为56 nm,材料表面形成一层不连续的低密度FeS/FeSn.硫化率、Fe~(2+)和溶液p H均能影响S-nZVI对头孢噻肟的去除.S/Fe=1/4(质量比),S-nZVI投加量为0.5 g·L~(-1),溶液pH为8时,120 min内头孢噻肟的去除率为82.2%,远大于nZVI的去除率(23.4%).最后,采用液相色谱-电喷雾质谱分析了头孢噻肟的降解产物,发现头孢噻肟的降解主要是由酯基取代反应和内酰胺键的开环反应引起的.     

凋落物添加和去除处理对三江平原小叶章湿地生长季温室气体排放的影响

为了解三江平原小叶章湿地温室气体排放对凋落物处理的响应,利用黑龙江省科学院自然与生态研究所三江平原湿地生态定位研究站内的试验平台,采用静态箱-气相色谱法,分别对去除当年凋落物（NL）、去除当年凋落物和草炭层（NL+NH）、添加当年凋落物（DL）、添加当年凋落物和草炭层（DL+DH）以及空白对照（CK）等5个处理的小叶章湿地进行了生长季温室气体排放通量观测,并同步观测相关环境因子.结果表明：（DL+DH、DL）处理分别使CO₂排放通量增加了21.23%和10.86%;使生长季CH₄排放通量增加了21.37%和9.81%;使N₂O排放通量增加了29.62%和12.76%.（NL+NH、NL）处理分别使CO₂排放通量降低了16.13%和9.41%;使CH₄排放通量增加了65.67%和45.92%;使N₂O排放通量降低了14.36%和16.92%.添加和去除凋落物均未改变CO₂、CH₄和N₂O排放的季节动态.CO₂排放通量与土壤温度出现了显著正相关关系,CH₄和N₂O排放通量未与土壤温度出现显著相关关系.CO₂、CH₄和N₂O排放通量均未与土壤含水量出现显著相关关系.     

Fe/Cu双金属活化过一硫酸盐降解四环素的机制

利用共沉淀法成功制备出绿色、高效、具有磁性的介孔Fe/Cu双金属非均相催化剂(Fe-Cu-400),通过X射线衍射仪(XRD)、比表面积测试仪(BET)、场发射扫描电镜(FESEM)及X射线能谱仪(EDS)等表征手段对催化剂的结构、形貌等进行分析,并用制备的Fe-Cu-400催化剂活化过一硫酸盐(PMS)降解四环素(TC),研究了不同反应条件对降解效果的影响.结果表明Fe-Cu-400/PMS体系具有较好的降解效果,随着PMS浓度和初始p H的提高,TC降解效率明显增加;无机阴离子(H2PO-4、HCO-3、Cl-)均对TC的降解有不同程度的促进作用,而NO-3对TC的降解则表现出较弱的抑制作用.Fe-Cu-400在循环使用5次后仍具有较好活化性能.通过自由基抑制实验和XPS测试分析了Fe-Cu-400/PMS体系的活化机制和分解产生的主要活性物种.通过LC-MS结合TOC分析,推测出TC经水解、脱甲基、脱羟基和脱氨基作用达到降解和矿化.     

高层建筑火灾防烟空气幕的实验研究

通过分析高层建筑火灾时引起烟气流动的因素 ,建立了高层建筑火灾时防烟空气幕流量、吹风口宽度和吹风口的射流速度的计算模型。通过实验研究 ,验证了理论计算的正确性     

负载型二氧化钛光催化降解苯胺

以紫外灯为光湖，在圆柱型光反应器中，负载在镍网上的ＴｉＯ２为催化剂，研究了水中苯胺光催化剂降解行为，结果表明苯胺的降解动力学可用Ｌａｎｇｍｕｉｒ－Ｈｉｎｓｈｅｌｗｏｏｄ方程来描述，对苯胺的浓度、介质ｐＨ、液体流速、氧气浓度和外加Ｈ２Ｏ２等因素对光催化反应的影响进行了研究，并以实验现象予以解释。     

The roles of organic degradation products andselenium in the pathogenesis ofKaschin-Beck disease

An investigation on the organic degradation products and selenium in the pathogenesis of Kaschin-Beck disease was carried out. The results demonstrated that the organic degradation products existed in food and drinking water were the pathogens of the KBD; their leading pathological process of cells would be "membrane injury" due to peroxide. As GSH-Px is a selenium contained enzyme, therefore insufficient selenium would be one of the most important conditions to cause KBD.     

新形势下环境维权发展与研究

随着环境污染形势的加剧、社会民众环保意识的提高,环境维权开始在中国逐渐发展起来,虽然目前仍处于初级阶段,面临着诉讼维权困难、相关体制不健全等众多问题,但环境维权在新形势下已经呈现出诸多新的特征.本文通过对常州外国语学校"常外"事件进行分析,阐述了中国目前环境维权事件所具备的新特征,并在此基础上,从转变政府职能、拓展利益诉求渠道、加强法治力度三个角度出发,对政府管理提出相关建议,希望能够完善环境维权制度、促进环境维权在中国的健康发展.     

Pilot study for the treatment of sodium and fluoride-contaminated groundwater by using high-pressure membrane systems

High-pressure membrane process is one of the cost-effective technologies for the treatment of groundwater containing excessive dissolved solids. This paper reports a pilot study in treating a typical groundwater in Huaibei Plain containing excessive sodium, sulfate and fluoride ions. Three membrane systems were set up and two brands of reverse osmosis (RO), four low-pressure RO (LPRO) and one tight nanofiltration (NF) membranes were tested under this pilot study. An apparent recovery rate at about 75% was adopted. Cartridge filtration, in combination with dosing antiscalent, was not sufficient to reduce the fouling potential of the raw water. All RO and LPRO systems (except for the two severely affected by membrane fouling) demonstrated similar rejection ratios of the conductivity (~98.5%), sodium (~98.5%) and fluoride (~99%). Membrane fouling substantially reduced the rejection performance of the fouled membranes. The tight NF membrane also had a good rejection on conductivity (95%), sodium (94%) and fluoride (95%). All membranes rejected sulfate ion almost completely (more than 99%). The electricity consumptions for the RO, LPRO and NF systems were 1.74, 1.10 and 0.72 kWh?m^-3 treated water, respectively. The estimated treatment costs by using typical RO, LPRO and tight NF membrane systems were 1.21, 0.98 and 0.96 CNY?m^-3 finished water, respectively. A treatment process consisting of either LPRO or tight NF facilities following multi-media filtration was suggested.     

Catalytic wet air oxidation of phenol,nitrobenzene and aniline over the multi-walled carbon nanotubes (MWCNTs) as catalysts

Wet air oxidation (WAO) is one of effective technologies to eliminate hazardous, toxic and highly concentrated organic compounds in the wastewater. In the paper, multi-walled carbon nanotubes (MWCNTs), functionalized by O₃, were used as catalysts in the absence of any metals to investigate the catalytic activity in the catalytic wet air oxidation (CWAO) of phenol, nitrobenzene (NB) and aniline at the mild operating conditions (reaction temperature of 155°C and total pressure of 2.5 MPa) in a batch reactor. The MWCNTs were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), gas adsorption measurements (BET), fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The functionalized MWCNTs showed good catalytic performance. In the CWAO of phenol over the functionalized MWCNTs, total phenol removal was obtained after 90 min run, and the reaction apparent activation energy was ca. 40 kJ·mol^-1. The NB was not removed in the CWAO of single NB, while ca. 97% NB removal was obtained and 40% NB removal was attributed to the catalytic activity after 180 min run in the presence of phenol. Ca. 49% aniline conversion was achieved after 120 min run in the CWAO of aniline.     

Concentration levels of disinfection by-products in 14 swimming pools of China

Swimming has become a popular exercising and recreational activity in China but little is known about the disinfection by-products (DBPs) concentration levels in the pools. This study was conducted as a survey of the DBPs in China swimming pools, and to establish the correlations between the DBP concentrations and the pool water quality parameters. A total of 14 public indoor and outdoor pools in Beijing were included in the survey. Results showed that the median concentrations for total trihalomethanes (TTHM), nine haloacetic acids (HAA9), chloral hydrate (CH), four haloacetonitriles (HAN4), 1,1-dichloropropanone, 1,1,1-trichloropropanone and trichloronitromethane were 33.8, 109.1, 30.1, 3.2, 0.3, 0.6 µg∙L⁻¹ and below detection limit, respectively. The TTHM and HAA9 levels were in the same magnitude of that in many regions of the world. The levels of CH and nitrogenous DBPs were greatly higher than and were comparable to that in typical drinking water, respectively. Disinfection by chlorine dioxide or trichloroisocyanuric acid could substantially lower the DBP levels. The outdoor pools had higher TTHM and HAA9 levels, but lower trihaloacetic acids (THAA) levels than the indoor pools. The TTHM and HAA9 concentrations could be moderately correlated with the free chlorine and total chlorine residuals but not with the total organic carbon (TOC) contents. When the DBP concentration levels from other survey studies were also included for statistical analysis, a good correlation could be established between the TTHM levels and the TOC concentration. The influence of chlorine residual on DBP levels could also be significant.