Photocatalytic activity of TiO2 containing anatase nanoparticles and rutile nanoflower structure consisting of nanorods

A series of TiO2 with different crystal phases and morphologies was synthesized via a facile hydrothermal process using titanium nbutoxide and concentrated hydrochloric acid as raw materials. The photocatalytic activity of the samples was evaluated by degradation of Methyl Orange in aqueous solution under UV-Visible light irradiation. On the basis of detailed analysis of the characterizing results of high-resolution transmission electron microscopy, X-ray powder diffraction measurements, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller measurement, it was concluded that the photo-activity of the catalyst is related directly to the 3D morphology and the crystal phase composition. An excellent catalyst should have both a futile 3D flower-like structure and anatase granulous particles. The 3D flower-like structure could enhance light harvesting, as well as the transfer of reactant molecules from bulk solution to the reactive sites on TiO2. In addition, the optimum anatase/rutile phase ratio was found to be 80：20, which is beneficial to the effective separation of the photogenerated electron-hole pairs.     

碳源对厌氧氨氧化脱氮性能影响的试验研究

分别研究了无机碳源和有机碳源对厌氧氨氧化反应脱氮性能的影响。接种稳定运行的复合式UASB厌氧氨氧化反应器污泥至ASBR反应器进行批式试验,考察不同碳酸氢钠浓度及COD浓度条件下的氮素转化情况,研究碳源对厌氧氨氧化脱氮效果的影响。厌氧氨氧化反应适宜的进水碳酸氢钠浓度为1.5～2.0 mg/L,超过30 mg/L时有机碳源的存在对厌氧氨氧化反应产生抑制作用,COD浓度超过60 mg/L时反应器表现出反硝化特性。无机碳源对厌氧氨氧化反应的影响表现在提供充足碳源和调节反应器pH的综合作用,较高浓度的COD对厌氧氨氧化反应具有抑制作用。     

总氮总磷在线自动监测仪的现状与问题

总氮总磷在线自动监测仪已在中国水质自动监测系统中得到广泛应用。其生产厂家日趋成熟、相关标准逐步出台、仪器性能基本达标。但在实际应用过程中,该仪器仍有许多问题需要进一步认识与改进。从测定方法、国家标准、前处理、自动标定、检出限等几个方面,分析了该仪器存在的问题,并提出了相关建议。     

Hexabromocyclododecane and tetrabromobisphenol A in sediments and paddy soils from Liaohe River Basin, China: Levels, distribution and mass inventory

Hexabromocyclododecane(HBCD) and tetrabromobisphenol A(TBBPA) are two kinds of brominated flame retardants and widely present in the environment and biota. The levels,spatial distributions and mass inventories of HBCD and TBBPA were investigated in sediments and paddy soils from the Liaohe River Basin in northeast China. The concentrations of ΣHBCD and TBBPA were in the range of not detected(nd) to 4.02 ng/g dry weight(dw) and 0.03 to 4.06 ng/g dw, respectively. γ-HBCD was dominated in sediments,while the abundance of α-HBCD was relatively high in paddy soils. The spatial distributions of HBCD and TBBPA in surface sediments and paddy soils indicated that the local point-input was their major source. The significant correlation between total organic carbon(TOC) contents and the HBCD levels suggested that TOC content also exerted an influence on the distribution of HBCD in sediments. Meanwhile, it was found that the irrigation with river water was not the major transportation pathway of HBCD and TBBPA in paddy soils. Based on the study, it was estimated that there were about 1.67 tons HBCD and 2.20 tons TBBPA deposited into sediments of the Liaohe River system every year. The total mass inventories of HBCD and TBBPA in sediments were far higher than that in paddy soils.     

生态城市建设指标体系与综合评价研究

城市生态系统是社会、经济和自然三个子系统构成的复合生态系统。本文探讨了生态城市指标体系及其评价标准,并采用综合加权方法确定评价指标的权重,建立了生态城市评价的灰色关联度模型。结合南京生态城市系统的现状进行了综合评价,为南京生态城市发展战略的制定以及生态城市的管理提供决策指导。     

Dry deposition velocity of total suspended particles and meteorological influence in four locations in Guangzhou, China

Dry deposition velocity of total suspended particles (TSP) is an effective parameter that describes the speed of atmospheric particulate matter deposit to the natural surface. It is also an important indicator to the capacity of atmosphere self-depuration. However, the spatial and temporal variations in dry deposition velocity of TSP at different urban landscapes and the relationship between dry deposition velocity and the meteorological parameters are subject to large uncertainties. We concurrently investigated this relationship at four different landscapes of Guangzhou, from October to December of 2009. The result of the average dry deposition velocity is (1.49 ± 0.77), (1.44 ± 0.77), (1.13 ± 0.53) and (1.82 ± 0.82) cm/sec for urban commercial landscape, urban forest landscape, urban residential landscape and country landscape, respectively. This spatial variation can be explained by the difference of both particle size composition of TSP and meteorological parameters of sampling sites. Dry deposition velocity of TSP has a positive correlation with wind speed, and a negative correlation with temperature and relative humidity. Wind speed is the strongest factor that affects the magnitude of TSP dry deposition velocity, and the temperature is another considerable strong meteorological factor.We also find out that the relative humidity brings less impact, especially during the dry season. It is thus implied that the current global warming and urban heat island effect may lead to correlative changes in TSP dry deposition velocity, especially in the urban areas.     

5种沉水植物对重金属富集能力的对比研究

为了探求不同的沉水植物对水体中重金属吸收富集能力的差异,采用原子吸收光谱法,对淮河支流东风渠水体及水体中常见的5种沉水植物:菹草、黑藻、龙须眼子菜、穗花狐尾藻及小茨藻进行了铅(Pb)、镉(Cd)、锌(Zn)、铜(Cu)含量分析。结果表明:5种沉水植物样品中重金属含量远远高于水体重金属背景值,对重金属Cu、Pb、Cd、Zn的富集系数为58~1 515,对Zn富集最强,最大富集量达到242.42 mg/kg,富集系数为1 515。不同的沉水植物对重金属的吸收富集优势存在明显差异,利用沉水植物来修复水体重金属污染时,须依据不同的污染元素来选择合适的沉水植物。     

淮南塌陷区煤矸石充填复垦的碳减排效益

煤矸石由于其堆积物的高含碳量和高自燃风险,是一类巨大的碳排放源,其温室气体排放问题不容忽视,但是很少有人研究煤矸石和碳排放的关系。本文以淮南矿区塌陷区煤矸石充填复垦为例,计算了煤矸石堆存带来的潜在碳排放量、矸石山侵占土地生态系统碳储量变化及塌陷区生态系统碳储量变化。结果表明,淮南矿区煤矸石山堆存碳密度远远超过了其覆盖的当地原本自然生态系统碳储存密度,二氧化碳排放潜在风险很高。煤矸石充填复垦,能固定煤矸石中的大量的碳,还可以增加塌陷区生态系统的碳储量,有着很好的碳减排效益。     

重庆主城区大气总悬浮颗粒中有机碳和元素碳污染特征分析

在四个季节采样分析的基础上，本文报道了重庆市主城区江北区(商住区)和缙云山(清洁对照点)两个监测点总悬浮颗粒物质量浓度的空间分布和季节变化特征，同时利用热分解示差热导法元素分析仪测定了TSP中的OC和EC浓度，探讨了OC和EC含量并与北京相应功能区的TSP质量浓度及其OC和EC浓度进行了比较。结果表明：重庆市商住区和对照点TSP年均质量浓度均小于北京市商住区和对照点；重庆市商住区OC和EC年均质量浓度高于北京市商住区，北京市对照点OC和EC年均质量浓度高于重庆市对照点。两个城市的四个监测点OC／EC年均值均大于2．0，说明两城市城区二次污染比较严重。     

工业废气中甲苯的生物降解研究

采用生物膜填料塔进行净化低浓度甲苯废气的研究结果表明，构成生物膜的假单胞菌属中的短杆菌对废气中甲苯有很强的生化降解能力，每升体积的生物膜填料对甲苯的生化去除量最大可达１０４．４ｍｇ／ｈ，且当入口气体甲苯浓度约低于２．０ｍｇ／Ｌ时，单塔净化效率可保持在８０％以上。反应级数的转换约在其液相浓度为０．８—１．２ｍｇ／Ｌ（相当于气相浓度约１．７—２．１ｍｇ／Ｌ）时发生。