Effects of black carbon and montmorillonite clay on multiphasic hexachlorobenzene desorption from sediments

The desorption kinetics of hexachlorobenzene (HCB) in four freshly spiked artificial sediments were determined using a polymeric adsorbent Tenax-mediated desorption. The sediments included a standard sediment (SS) prepared as per Organisation for Economic Cooperation and Development 218 guidelines and three derived artificial sediments prepared by supplementing the SS sediment with various levels of black carbon (lamp black soot) and/or montmorillonite clay. The desorption kinetics exhibited biphasic behavior, i.e., a fast desorbing fraction followed by a slow desorbing fraction. The addition of either lamp black soot or montmorillonite clay resulted in the reduction of the fast desorbing fraction (Ffast) of HCB in three derived sediments compared with SS sediment. Both black carbon and montmorillonite clay treatment effects on the fast desorbing fraction were statistically significant for the four artificial sediments. The black carbon treatment (i.e., addition of 0.5% wt/wt lamp black soot) effect was an average reduction of Ffast by approximately 11%, whereas the montmorillonite treatment (i.e., addition of 15% wt/wt montmorillonite clay) effect was an average reduction of Ffast by approximately 17%. The presence of soot black carbon particles reduced the desorption rate of HCB in sediments since black carbon exhibits very high sorption capacity and extremely slow diffusion rate compared with those of the natural organic matter in sediment.     

Analysis of di-n-butyl phthalate and other organic pollutants in Chongqing women undergoing parturition

In this study, 40 healthy women from Chongqing undergoing parturition were recruited and samples of venous blood, umbilical cord blood, breast milk and urine were collected for analysis of organic pollutants by GC/MS. A total of 292 different organic pollutants were detected, including 156 in venous blood, 139 in umbilical cord blood, 176 in breast milk and 138 in urine. Nine different PAEs were detectable in the samples: di-n-butyl phthalate (DBP), bis(2-methylpropyl) phthalate, butyl-8-methyl-nonyl phthalate, di-ethyl phthalate, butyl-2-methylpropyl phthalate, butyloctyl phthalate, di-dodecyl phthalate, di-isodecyl phthalate, and di-tridecyl phthalate. DBP was one of the chemicals detected at the highest frequency (48.82%). DBP concentrations were 84.75 ± 33.52, 52.23 ± 32.50, 57.78 ± 35.42 and 24.93 ± 18.67 μg/l in venous blood, umbilical cord blood, breast milk and urine, respectively. This study represents the first investigation of organic pollutants in a Chongqing population.     

基于3D GIS的城市灾害应急系统初步研究——以北师大北太平庄校区为例

随着近几十年GIS、空间数据库、三维可视化等技术的发展,3DGIS技术已经被广泛应用到城市规划、城市设计、公共安全以及城市工程等各个方面。同时,3DGIS为防灾减灾以及应急响应和管理,特别是城市区域内的应急处置提供了一个可靠的工具。通过3DGIS提供的实时环境和分析工具,可以实现灾害事件重现、推演和和灾害管理分析,为减灾和应急处置提供有效的策略支持。主要分析了城市灾害应急系统的结构,研究了基于网络结构的城市逻辑结构及分析方法,以北京师范大学北太平庄校区为例,通过对城市内部复杂结构的抽象,提取城市应急管理中最重要的因素和信息,利用3DGIS技术建立城市三维环境和城市网络逻辑模型,模拟了城市应急处置过程。同时,通过对以社区为单元的城市应急系统的建设考察了该系统在整个城市应急管理系统中应用的可行性。     

Preparation of a titanium dioxide photocatalyst codoped with cerium and iodine and its performance in the degradation of oxalic acid

A novel class of visible light-activated photocatalysts was prepared by codoping TiO(2) with cerium and iodine (Ce-I-TiO(2)). The particles were characterized using the Brunauer-Emmett-Teller method, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Visible light absorption. Particles of Ce-I-TiO(2) had greater photoabsorption in the 400-800 nm wavelength range than iodine-doped TiO(2) (I-TiO(2)). The effects on the photocatalytic degradation of oxalic acid under visible light or UV-Visible light irradiation were investigated. The photocatalytic activity of Ce-I-TiO(2) calcined at 673 K was significantly higher than that of Ce-I-TiO(2) calcined at 773 K and I-TiO(2) calcined at 673 K in aqueous oxalic acid solution under visible light or UV-Visible light irradiation. Under visible light irradiation, oxalic acid was first adsorbed on the surface of the catalysts rather than reacted with free radicals in the bulk solution, and then oxidized by (·)OH(ads) to CO(2), which was verified by studying the effects of nitrogen purging and scavengers, as well as by gas chromatography/mass spectrometry.     

半干法脱硫技术的应用与分析

NID半干法脱硫技术结构简单,具有较高的脱硫率.通过在NID脱硫技术实施中的调试和运行,分析其工艺特点和工艺控制要点,并提出了存在的问题和对策.     

长江水系河流与水库中鲤鱼的元素含量特征

针对长江三峡水库蓄水后引起水库汞活化效应对生态与环境的影响问题,系统地分析了长江水系水库与河流鲤鱼肌肉的Ａｓ,Ｃｄ,Ｃｕ,Ｆｅ,Ｈｇ,Ｍｎ,Ｐｂ,Ｓｅ,Ｎａ,Ｍｇ等元素含量的分布特征。并以丹江口水库－汉江,陈村水库－青戈江为例,用多元分析证明水库与河流的鲤肌肉中Ａｓ,Ｓｅ,Ｈｇ,Ｃｄ等元素含量存在显著差异,同时指出水库汞活化效应引起的鱼体汞含量增加是该元素的一种生物地球化学现象,并利用同一水系水库     

Tissue-dependent distribution and accumulation of chlorobenzenes by vegetables in urban area

Five seasonal vegetables from three growing sites in Hangzhou city, Zhejiang Province, were studied for the levels of four chlorobenzenes(CBs): o-dichlorobenzene (o-DCB), p-dichlorobenzene (p-DCB), m-dichlorobenzene (m-DCB), and 1,2,4-trichlorobenzene (1,2,4-TCB). Samples of each vegetable from each site were subdivided into leaves, stems, and roots, and these subsamples were analyzed separately for the levels of accumulated CBs. Relations between the levels of CBs in vegetables with the total organic carbon (TOC) of the soil, the lipid content of the vegetable, and the physicochemical properties of CBs were established. Results showed that o-DCB, p-DCB, m-DCB, 1,2,4-TCB were present in all vegetables analyzed. For spinaches (Spinacia oleracea), Chinese cabbages (Brassica rapa var. pekinensis), and celery (Apium graveolens var. dulce), the highest level of CBs was with roots, followed by leaves. While for radishes (Raphanus sativus), and carrots (Daucus carota subsp. sativus), the highest level was with leaves, followed by stems. The accumulation of CBs was found to have a good correlation with the plant-tissue lipid content, the contaminant air-water Henry's coefficient (H), the contaminant octanol-water partition coefficient (K(ow)), and the physiological characteristics of the vegetables.     

背角无齿蚌钙调蛋白基因的克隆及Ca2+和Cd2+对其表达的影响

钙调蛋白(CaM)是Ca2+结合蛋白,参与程序性细胞死亡、自噬、肌肉收缩、炎症和免疫应答等多种生物学过程.为探讨Ca2+和Cd2+对背角无齿蚌(Anodonta woodiana)的生理效应,克隆出AwCaM1全基因序列,分析Ca2+和Cd2+对AwCaM1表达的影响.结果显示,背角无齿蚌AwCAM1 cDNA全长由6...     

太湖地区不同土地利用影响下水稻土重金属有效性库变化

在太湖地区调查选择了乡镇工业环境、集约化农业丰产方及长期肥料试验地等几种人类农业利用类型和环境影响的地块,采集水稻土耕层样本作若干重金属的有效性库分析.结果表明,各种环境和利用影响下太湖地区水稻土重金属有效性库都存在升高的趋势,其程度介于30%至200%,且以表层最为突出.近工业区环境和长期单施化肥下这种有效性库变化最为剧烈,其土壤Cu、Pb有效性库分别达到7.96～2.15 mg·kg^-1、24.7～3.47mg·kg^-1和8.34～4.42 mg·kg、9.01～4.95 mg·kg^-1.这种有效性升高伴随着总量的积累趋势可能是太湖地区土壤环境质量演变的当前特点,这必须在本地区农业与食物安全中备加关注.     

凹凸棒石处理电泳漆废水研究

凹凸棒石及其活化产物对阳极电泳漆废水ＣＯＤ和色度有较好的吸附去除能力，对ＣＯＤ的吸附作用符合Ｆｒｅｕｎｄｌｉｃｈ吸附等温式并呈现一级反应动力学的特征。提高温度和在较高的酸度或碱度条件下均将有利于ＣＯＤ的去除。常温下与聚丙烯酰胺组合使用，可使ＣＯＤ值较高的废水达到或接近排放标准。凹凸棒石经过适当处理可重复使用，效果良好。