气相中甲苯的臭氧-光催化降解

初步研究了气相中中低浓度(10～80mg/m³)甲苯的臭氧-光催化联合降解,考察甲苯初始浓度、气体流量和湿度对降解效率及去除负荷的影响,并与单一光催化降解进行了比较.结果表明,臭氧-光催化对甲苯的降解效率大大高于光催化的降解效率,在较高浓度时效果更为显著;甲苯浓度在10～40mg/m³范围时,臭氧-光催化降解效率高达90%以上,但随甲苯初始浓度升高而缓慢地线性下降;湿度对甲苯的臭氧-光催化降解稍有影响,但去除率变化不超过2.5%.     

光催化氧化/吸收工艺处理垃圾焚烧发电厂恶臭废气

我国南方某城市垃圾焚烧发电厂采用光催化氧化技术/吸收工艺联用技术对难降解恶臭气体进行高效处理,大大提高了恶臭气体的去除效率,实现了该行业废气的无害化处理,取得了良好的效果。运行结果显示,光催化氧化技术/吸收工艺联用技术能实现难降解恶臭气体的高效处理,排放废气可达到《恶臭污染物排放标准》(GB14554-93)中的二级标准。     

Ag/TiO2光催化降解磺基水杨酸的研究

采用光化学沉积法制备了Ag/TiO2 光催化剂 ,并对典型难生物降解的有机污染物磺基水杨酸进行了光催化降解研究。结果表明 ,1 0 %担载量的Ag能显著提高TiO2 光催化活性 ,可在较短时间内实现对磺基水杨酸较高的降解效率。     

负载化纳米TiO_2光催化降解气相甲苯

使用高比表面积的玻璃弹簧为载体,水热合成法制备了TiO2膜光催化剂,并在密闭循环式反应系统中进行甲苯的气相光催化降解实验。考察了气体流速、空气相对湿度、污染物初始浓度和催化剂用量对甲苯降解效率的影响,并采用GC/MS测定光催化降解过程中的气体组分及其含量,没有发现除甲苯以外的其它气相组分,最后测试了催化剂在高污染物浓度时的使用寿命。     

玻璃弹簧负载TiO2光催化降解甲醛的影响因素

利用自制间歇式光催化气体反应器体系作为反应场所,以玻璃弹簧负载TiO₂溶胶作催化剂,在紫外光照射下降解室内污染气体甲醛,探讨了催化剂的酸度、反应器内湿度、甲醛气体浓度和反应时间等因素对甲醛降解率的影响.结果表明:玻璃弹簧负载TiO₂并经pH5的蒸馏水酸浸后作催化剂对甲醛的降解效果最好,90 min内降解率达到57.26%;反应器内的湿度约为50%时甲醛降解率最高,反应90 min时达到82.20%;在0.46～8.10 mg/m3内,初始ρ(甲醛)为5.51 mg/m3时的降解率最高,150 min内达95.10%;延长反应时间,甲醛降解率上升幅度逐渐减小;通过计算降解后甲醛的残余量可知,TiO₂光催化方法可以有效降解甲醛,并能使0.46 mg/m3以内的ρ(甲醛)在150 min内达到国家标准.      

一般性问题

环境研究中心一么力2,23(6)一17一21X701么X)301535气相中甲苯的臭氧一光催化降解/梁夫艳…(清华大学环境科学与工程系)//环境科学/中科院生态 环图X一5 初步研究了气相中中低浓度(10一801119/衬)甲苯的臭氧一光催化联合降解,考察甲苯初始浓度、气体流量和湿度对降解效率及去除负荷的影响,并与单一光催化降解进行了比较。结果表明,臭氧一光催化对甲苯的降解效率大大高于光催化的降解效率,在较高浓度时效果更为显著;甲苯浓度在10一40111酬时范围时,臭氧一光催化降解效率高达oo%以上,但随甲苯初始浓度升高而缓慢地线性下降;湿度对甲苯的臭氧…     

悬浮型光催化纳滤膜反应器对染料中间体H酸溶液的降解

在多组分条件下通过采用悬浮型光催化纳滤膜反应器进行目标污染底物H酸的光催化降解效率及反应动力学研究,控制干扰污染物吐氏酸和变色酸浓度分别为5,10,20,25,40mg/L,控制H酸浓度100mg/L恒定不变.实验结果表明,在单组分光催化纳滤膜反应器中,在Ct/C0?0.7条件下,降解过程遵循L-H零级(0~12min)与L-H一级(12~20min)的混合动力学模型;在多组分光催化纳滤膜反应器中,随着干扰物浓度的增加,在Ct/C0?0.7条件下(约0~20min反应时间段)其降解过程均对应地遵循L-H一级反应动力学模型.通过实验进一步证实,H酸光催化降解动力学的改变主要由耦合光催化反应器内底物和光催化剂表面H酸的浓度差异性引起.     

蜂窝陶瓷负载TiO2光催化降解邻-氯苯酚水溶液

采用溶胶 -凝胶技术 (Sol-Gel)制备以蜂窝陶瓷为载体的负载型TiO2 光催化剂。探讨工艺条件对催化降解效果的影响 ;结果表明 ,蜂窝陶瓷表面浸涂 5层TiO2 薄膜 ,经 50 0℃焙烧后 ,具有较高的光催化活性。在紫外光照射下 ,该催化剂降解 1 .0× 1 0 - 3mol/L邻氯苯酚水溶液 2 .5h ,降解率达到 1 0 0 % ;在O3的协同效应下 ,降解率在 1 .5h即可达到 1 0 0 %     

MWNTs/TiO2对典型氯苯类化合物的光催化降解研究

研究复合光催化剂MWNTs/TiO2对典型氯苯类有机化合物光催化降解动力学及主要光降解路径.结果表明,同一初始浓度和相同光催化降解实验条件下,60min时典型氯苯类有机化合物的光降解率均达到90%以上.其中六氯苯和五氯苯的光催化降解速率常数分别为0.0664h-1和0.0670h-1,其大小明显高于其它氯苯类化合物.1,二氯苯的光催化降解反应速率常数仅为0.0430h4--1,在典型氯苯类化合物中最小.三氯苯的3种同分异构体——1,3-三氯苯、24-三氯苯和1,5-三氯苯的光催化降解速率常数分别为0.0547h2,1,,3,-1、0445h0.-1和0.0439h-1.六氯苯的主要光催化降解路径为:HCB→PeCB→1,2,3,5-TeCB→1,2,4-TCB→1,4-DCB.     

氮掺杂二氧化钛复合催化膜降解甲苯气体研究

采用溶胶-凝胶法以聚丙烯(PP)中空纤维膜为载体制备了N-Ti O2/PP复合催化膜,并考察了其催化降解甲苯有机废气的性能.结果发现,紫外光催化的甲苯降解率可达84%,去除负荷为89.8 g·m-3·h~(-1),自然光催化的甲苯降解率可达63.9%,去除负荷为69.25 g·m-3·h~(-1).同时,采用紫外-可见光谱(UV-Vis)、X-射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)表征了N-Ti O2/PP复合催化膜,并采用GC-MS分析甲苯降解过程的中间产物并推测甲苯反应过程机理.采用GC-MS分析出口气样的研究结果表明,苯(C6H6)、苯甲醛(C7H6O)、苯乙酸(C8H8O2)、丙烯醛(C3H4O)、甲酸甲酯(C2H4O2)为甲苯光催化降解的中间产物.N-Ti O2/PP复合催化膜降解甲苯的机制为甲苯气体通过中空纤维膜传质到N-Ti O2/PP复合催化膜,光催化产生羟基自由基,甲苯气体被羟基自由基氧化成中间产物,并继续降解为最终产物二氧化碳和水.     

四川呷村多金属矿床地球化学特征及成因

呷村矿床是一个特大型的含金、稀土富银多金属矿床.成矿地质特征与日本黑矿相似.矿床形成于中低温、较低压的环境.成矿溶液为中等盐度、低密度水热体系.铅等成矿元素主要来自岛弧火山岩,硫和锶来自深部岩浆和海水,成矿水介质以大气降水为主,为典型海底火山热液—喷气沉积成因的块状硫化物矿床.     

Spontaneous resolution of a cystic hygroma in a fetus with Turner syndrome

The prenatal detection of a cystic hygroma (CH) in a fetus with a 45,X karyotype is described. The cystic hygroma underwent spontaneous resolution and a healthy baby with Turner syndrome was subsequently born. The implications for genetic counselling are discussed.     

无组织排放源对周围环境影响预测

提出了预测无组织排放源对其周围附近大气环境质量影响的方法，并计算了某新建项目炼胶厂硫化车间无组织排放的恶臭污染物硫化氢气体，在拟选厂址周围１ｋｍ２范围内的地面平均浓度，预测和评价了该污染物的环境影响．同时分析了影响地面平均浓度的因素     

Groundwater pollution due to discharge of tannery effluents in Upper Palar basin, Tamilnadu, India: an assessment through mass transport modeling

The groundwater regime in Upper Palar basin, Tamilnadu has been highly contaminated in several locations due to discharge of effluents from a large number of tanneries. At some places total dissolved solids (TDS) concentration in groundwater was found as high as 8000 mg/l. Transmissivity and storativity of the regional aquifer were estimated at a few locations. The porosity and dispersivity values were not determined in the field. These parameters were assumed based on data available for similar geological formations elsewhere. The aquifer conceptualization thus arrived at formed the basis of a numerical groundwater flow model which was constructed using the finite difference method. The flow model was calibrated for steady state and then for transient condition for the period of 1984-92. The computed heads and calibrated parameters of the flow model were used to compute groundwater velocities. The migration of contaminants for a 20 year period was computed using the hydraulic heads and effective porosity value in a pathline model using FLOWPATH software. Mass transport model was constructed using Method of Characteristics (MOC) computer code in a separate model. The seepage rate of effluent is assumed at a rate of 30% of that discharged on the surface. The mass concentration of solute in the effluent reaching the water table was assumed as 40%, the same as in the surface effluent. The mass transport model was calibrated for a 20 year period. Prediction of contaminant migration from different clusters in the basin was analyzed. The prediction results indicated elevated TDS concentration of more than 4000 mg/l from most clusters. Also the area of the contaminated zone is likely to double in 20 years from contaminated zone of 1992.     

A GPS-based system for recording the flight paths of birds

 The GPS recorder consists of a GPS receiver board, a logging facility, an antenna, a power supply, a DC-DC converter and a casing. Currently, it has a weight of 33 g. The recorder works reliably with a sampling rate of 1/s and with an operation time of about 3 h, providing time-indexed data on geographic positions and ground speed. The data are downloaded when the animal is recaptured. Prototypes were tested on homing pigeons. The records of complete flight paths with surprising details illustrate the potential of this new method that can be used on a variety of medium-sized and large vertebrates. Received: 2 February 2000 / Accepted in revised form: 17 April 2000     

Split notochord syndrome variant: prenatal findings and neonatal management

Spilt notochord syndrome is an extremely rare form of spinal dysraphism characterized by a complete cleft of the spine and a persistent communication between endoderm and ectoderm. A variant of split notochord syndrome was diagnosed in a 25-week-old fetus showing a prolapsed congenital colostomy and a spinal cystic lesion. The final diagnosis included protruding colon segment, imperforate anus with a rectourethral fistula and lipomyelomeningocele. The ultrasound features of the condition and the post-natal management are discussed. The neonate was successfully treated with a posterior sagittal anorectoplasty, while the lipomyelomeningocele was resected at a later stage. Copyright © 2005 John Wiley & Sons, Ltd.     

阿尔泰诺尔特地区晚古生代的沉积环境和古地理分析

诺尔特地区位于新疆阿尔泰东北部，地理位置属富蕴县，该地区主体构造为北东向，出露地层为前震旦系富蕴群，震旦系哈巴河群，泥盆系忙代恰组和石炭系红山嘴组，其中后两者占主导地位，泥盆系为一套类复理石建造，主要岩性有粉砂岩，细砂岩，钙质粉砂岩和少量火山岩；石炭系红山嘴组可以分为三个段，一段为粉砂岩，粉砂质泥岩，细砂岩与粉砂岩交替的韵律沉积岩，岩屑砂岩等，二段为粉砂质泥岩，粉砂岩，钙质粉砂岩和生物屑灰岩，三段火山物质大量出现，下部为火山碎屑 和陆源碎屑的混合沉积，上部以凝灰岩为主，顶部出现火山砾岩，根据岩性特征和沉积构造分析，泥盆系的沉积环境为浅海－半深海，以大陆斜坡为主，石炭系的沉积环境为浅海陆棚，滨岸和开阔台地，其中又包括一些小环境，通过沉积环境的分析，可以得出三种沉积相模式。     

上海市青浦城厢地区可吸入颗粒物污染状况分析

为了研究青浦城厢地区可吸入颗粒物污染状况,分析了2005年至2010年空气质量资料,结果表明:青浦城厢地区首要污染物为PM10,其质量浓度呈逐年下降趋势。PM10浓度的月度变化幅度比较大,全年PM10浓度及超标率呈现"高一低一高"的变化趋势。春、冬季比较高,夏、秋季比较低。PM10质量浓度的日变化非常明显,呈现出"双峰"状分布。PM2.5和PM10的平均比值为0.531,表明该地区可吸人颗粒物中细颗粒物的比例较高,细颗粒物对人群的健康影响更为严重。PM10和PM2.5各月日均值之间和各月均值之间均呈高度相关,线性关系非常显著,二者之间回归直线关系存在,可用回归方程y=ax+b进行计算。     

Direct numerical simulation of the motion of circular pollutant particles in Newtonian fluid

An improved implementation of distributed multiplier/fictitious domain method is presented for the direct numerical simulation of particulate flow. The key improvement is to replace a finite-element triangulation for the velocity and a “twice-coarser“ triangulation for the pressure with a rectangular discretization for the velocity and pressure. For code validation, the sedimentation of a single particle in a twodimensional channel was simulated. The results showed that the simulation is independent of the mesh size as well as the time step. The comparison between experimental data and this simulation showed that our code can give a more accurate simulation on the motion of particlesthan previous DLM code. The code was then applied to simulate the sedimentation of 600 particles in a rectangular box. The falling course ispresented and discussed. At the same time, this simulation also demonstrates that the method presented in this paper can be used for solving the initial problems involving a lager number of particles exaclly with computing durations kept at acceptable levels.     

序批式活性污泥法工艺MATLAB仿真模型的初步建立

序批式活性污泥法工艺（SBR）是目前应用很广的一种污水处理工艺，本文在国际水协会（IWA）的ASM1模型的基础上，建立了SBR工艺反应模型，通过模型检验可发现，该模型能较好地模拟SBR工艺反应中的微生物处理过程，具有很大的发展前景。