柠檬酸强化钢渣湿法烧结烟气脱硫及机理

在鼓泡反应器中考察了添加柠檬酸强化钢渣湿法烧结烟气脱硫的影响因素,包括钢渣粒度,吸收浆液浓度、进口二氧化硫浓度、停留时间,p H值,柠檬酸与钢渣的浸泡时间等,结果表明,柠檬酸浓度为2.0 mmol/L、钢渣浓度为4%、二氧化硫进口浓度为1 500 mg/m3、烟气停留时间为7 s、钢渣强化时间为2 h、钢渣粒度200目,脱硫率达到90%以上。经4 mmol/L的柠檬酸强化后的钢渣浆液脱硫率比单纯钢渣浆液提高18.41%,达到90.99%的脱硫率,且有效反应时间延长50%,达到60 min以上。柠檬酸的加入,一方面促进了钢渣碱性组分溶解,另一方面在吸收液中形成柠檬酸和柠檬酸盐缓冲体系,增加了气液界面SO2浓度,提高了SO2的气液传质速率。     

回收萘法苯酐生产废水中的富马酸

采用催化异构化、碱溶、脱色、酸析、过滤等工艺处理萘法苯酐生产废水,回收其中的富马酸。考察了碱的品种、碱溶pH、活性炭加入量、酸析pH等对富马酸产品外观质量和收率的影响。实验得到最佳工艺条件:采用氢氧化钠作为碱溶用碱,碱溶pH为6,活性炭加入量为0.5%(w),酸析pH为2。在此最佳工艺条件下制备的富马酸产品外观为白色,纯度达到99.1%,产品收率为72.8%。按30 kt/a苯酐生产装置计,每年可回收富马酸660 t,年利润429万元。     

萃取净化废水中镉的动力学研究简

采用恒界面池研究了二壬基萘磺酸（简称DNNSA或HD）-煤油体系萃取废水中镉离子的动力学。考察了搅拌转速、二壬基萘磺酸浓度、镉离子浓度和温度对萃取速率的影响,并得到了DNNSA萃取废水中镉离子的萃取动力学方程。实验结果表明,镉离子的萃取速率在200 r/min时出现与搅拌强度无关的化学反应动力学“坪区”,FT-IR结果表明,反应产物为磺酸盐;在动力学“坪区”,镉离子萃取速率随着萃取剂浓度、水相中的镉离子浓度增加而增加;随着温度升高,萃取速率增加,萃取活化能为11.8 kJ/mol。     

The influence of hydrodynamic processes on zooplankton transport and distributions in the North Western Mediterranean: Estimates from a Lagrangian model

A Lagrangian module has been developed and coupled with the 3D circulation model Symphonie to study the influence of hydrodynamic processes on zooplankton transport and distributions in the North Western Mediterranean (NWM). Individuals are released every 3 days from March to August 2001 in two initial areas: around the DYFAMED sampling station in the central Ligurian Sea and in the Rhône river plume. Then the individuals are tracked for 40 days either as passive particles or with a simple diel vertical migration (DVM) pattern. The simulations suggest strong seasonal patterns in the distributions of the individuals released around the DYFAMED sampling station. Individuals spread all over the NWM basin after 40 days but different patterns occur depending on the season, the initial depths of release and the capacity of DVM. Offshore-shelf transport only occurs in April and May with particles ending up in the Gulf of Lions (GoL) in low concentrations. In other months, the Northern Current (NC) can be considered as a barrier for particles entering the GoL from the offshore sea. A quarter to a half of passive individuals released in the Rhône river plume remain in the GoL. The rest is transported by the NC towards the Catalan Sea. Applying a simple DVM scheme does not increase the retention of particles on the shelf.     

Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs) in surface and tap water around Lake Taihu in China

Perfluorinated compounds (PFCs) are ubiquitously distributed in the environment mainly as perfluoro-carboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs). In this paper, six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East China. Predominant PFCs were perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), of which the concentration ranges were 6.8–206 and 1.2–45 ng·L⁻¹, the geometric means were 35.3 and 9.4 ng·L⁻¹, and the median (quartile range) values were 31.4 (34.4) and 10.4 (10.7) ng·L⁻¹, respectively. Other PFCs were also detected but in much lower concentrations than PFOA. The sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area, and this area was also a possible source of PFCs contaminations in Shanghai district in the downstream. PFCs distributions were found different in the upstream, downstream and north part of Lake Taihu. Occurrences of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people. A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health, but chronic risks from PFOA in the tap water should be considered in the downstream regions.     

城市污水生物处理过程中结合型和游离型胞外抗生素抗性基因的产生特征

胞外抗生素抗性基因是抗性基因的重要存在形式,可能通过转化重新进入细胞表达抗药性.因此其具有严峻却隐蔽的健康风险,且不同形态胞外抗生素抗性基因的风险存在显著差异,然而当前针对胞外抗性基因风险的研究极为稀少.本研究以序批式活性污泥反应器(SBR)为例,考察了污水生物处理过程中结合型和游离型胞外抗性基因产生的时空特征,以及曝气强度和污泥负荷的影响.结果 表明,SBR启动期2种胞外抗性基因均大量产生,且游离型胞外抗性基因的增加倍数和持续时间高于结合型:稳定运行后2种胞外抗性基因的丰度显著下降.从胞内外抗性基因的比重来看,好氧阶段以胞外抗性基因为主,且游离型胞外抗性基因比例达60％以上;厌氧阶段以胞内抗性基因为主,且结合型胞外抗性基因比例升高(7.5％～31.9％);出水中游离型胞外抗性基因占据绝对优势,比例达66.5％ ～ 86.9％.曝气强度提高使2种胞外抗性基因丰度显著提高,但游离型胞外抗性基因提高程度(2.2倍～12.2倍)高于结合型(2.1倍～62倍).污泥负荷提高同样导致2种胞外抗性基因丰度提高,但游离型胞外抗性基因提高程度(1.3倍～7.8倍)低于结合型(1.9倍～ 13.3倍).研究表明,大量胞外抗性基因将在污水生物处理过程中产生,并随污水排放至环境中,是水环境中抗生素抗性基因(ARGs)的重要来源之一.     

旋转射流作用下吸气流动的特性研究

通过试验对旋转射流作用下吸气流动进行了较全面的研究,研究内容包括临界送风速度、最佳喷口宽度及吸气流场特性等。结果表明:旋转射流作用下吸气流动存在一个临界送风速度,且其与排风量、喷口宽度及射流轴向倾角等因素有关;存在一个临界吹吸比为最小值所对应的最佳喷口宽度;旋转射流屏蔽作用下的抽吸流场具有中部压力较低和提高抽吸能力的作用;旋转射流作用下吸气流动不仅能有效地控制有害物扩散,而且可以实现远距离捕集有害物及以较小的排风量排放有害物。     

西维因对雄性罗非鱼(GIFT Oreochromis niloticus)内分泌干扰效应的研究

在实验室条件下研究了西维因对罗非鱼的急性毒性以及在不同暴露浓度下的西维因(0.064,0.8和5mg·L-1)对雄性罗非鱼性腺系数、血清雌二醇、睾酮含量的影响以及对卵黄蛋白原的诱导效应,以期对其环境雌激素效应研究有所贡献。结果表明:西维因对罗非鱼的24、48、72和96h的LC50分别为30.21、25.16、19.76和17.86mg·L-1。长期暴露于低剂量的西维因中,会使雄性罗非鱼精巢系数降低;对其血清雌二醇的合成具有诱导作用,当浓度为0.8mg·L-1时,诱导作用最强,此时血清雌二醇的含量为218.83pg·mL-1;卵黄蛋白原的含量随着西维因浓度的升高,逐渐增多,当处理浓度为5mg·L-1时,达到最大为393.01μg·L-1;随着西维因浓度的升高,睾酮含量逐渐降低,西维因的浓度为5mg·L-1时,睾酮含量达到10.58mol·L-1,差异极显著(p<0.01),这可能是由于西维因对雄性罗非鱼具有雌激素效应。     

Identification and ecotoxicity assessment of intermediates generated during the degradation of clofibric acid by advanced oxidation processes

The aim of this study was to identify the intermediates in clofibric acid degradation under various advanced oxidation processes, namely ultraviolet (UV), UV/H₂O₂, vacuum ultraviolet (VUV), VUV/H₂O₂, and solar/TiO₂ processes, as well as to assess the toxicity of these intermediates. Eleven intermediates have been detected by gas chromatography-mass spectrometer, most of which were reported for the first time to our best knowledge. Combining the evolution of the dissolved organic carbon, Cl^- and specific ultraviolet absorption at 254 nm, it could be deduced that cleavage of aromatic ring followed by dechlorination was the mechanism in solar/TiO₂ process, while dechlorination happened first and accumulation of aromatic intermediates occurred in the other processes. Different transformation pathways were proposed for UV-, VUV-assisted and solar/TiO₂ processes, respectively. The acute toxicity was evaluated by means of Photobacterium phosphoreum T₃ spp. bioassay. It was believed that aromatic intermediates increased the toxicity and the ring-opening pathway in solar/TiO₂ process could relieve the toxicity.     

Temporal variation of heavy metal pollution in urban stormwater runoff

Stormwater runoff from three types of urban surfaces, a parking lot, a street, and a building roof, was monitored during four rainfall events that occurred in the one-year period from June 2009 to June 2010. The event mean concentrations (EMC) of dissolved copper (Cu), lead (Pb), zinc (Zn), manganese (Mn), and iron (Fe) exceeded China’s National Water Quality Standards for Surface Water. The degree of heavy metal contamination was related to the type of underlying surfaces. Additionally, the concentration of dissolved heavy metals peaked shortly after the runoff began and then declined sharply as a result of adequate flushing. First flush effects of varying degrees were also observed during all of the monitored rainfall events based on the first flush ratio (FF₂₅). Redundancy analysis revealed that four environmental variables (rainfall depth, intensity, antecedent dry weather period and type of underlying surface) had significant effects on the strengths of the first flush effects, accounting for 72.9% of the variation in the FF₂₅. Dissolved metals presented varying first flush effects on different underlying surfaces that occurred in the following relative order: parking lot>roof>road for low intensity and high runoff volume rainfall events; parking lot>road>roof for high intensity and low runoff volume events. The relative strength of the first flush for dissolved heavy metals was Fe, Mn>Cu, Zn>Pb.