催化湿式氧化工艺中负载型催化剂的研制

研究了过渡金属氧化物和稀土金属氧化物对乳化液废水催化湿式氧化工艺中的催化活性，得出：CuO的活性高于MnO2,Co3O4未表现出催化活性。CeO2、Nd2O3、Sm2O3均表现一定活性：制备了CuO／γAl2O3，Mn／γAl2O3负载型催化剂及其复合负载型催化剂，并对它们各自的催化活性和稳定性进行了研究。发现：Cu／γAl2O3负载型催化剂用于乳化液废水处理，200℃反应2h，CODCr去除率为88．4％，达到均相催化效果，比非催化提高13.0％，Mn／γAl2O3表现出负催化作用．复合负载型催化剂的活性低于Cu／γAl2O3。     

NH_3的低温复相选择性催化氧化

采用Cu-Ag/Al2O3复合催化剂在低温下选择性催化氧化 NH3.实验结果表明,Ag/Al2O3 和 Cu/Al2O3分别具有高氧化活性和高 N2选择性的优点;一定负载量范围内,Cu-Ag/Al2O3复合催化剂既具有高氧化活性(介于Ag/Al2O3和Cu/Al2O3之间),又具有Cu/Al2O3的高N2选择性,当反应温度为280℃时,Cu5%-Ag5%/Al2O3对NH3的氧化率大于96%,N2选择性大于95%.催化剂表面上形成的Ag2O 颗粒及其大小是影响催化剂选择性的一个重要因素.     

NH3的低温复相选择性催化氧化

采用Cu-Ag/Al2O3复合催化剂在低温下选择性催化氧化NH3.实验结果表明,Ag/Al2O3 和Cu/Al2O3分别具有高氧化活性和高N2选择性的优点;一定负载量范围内,Cu-Ag/Al2O3复合催化剂既具有高氧化活性(介于Ag/Al2O3和Cu/Al2O3之间),又具有Cu/Al2O3的高N2选择性,当反应温度为280℃时,Cu5%-Ag5%/Al2O3对NH3的氧化率大于96%,N2选择性大于95%.催化剂表面上形成的Ag2O颗粒及其大小是影响催化剂选择性的一个重要因素.     

Al2O3负载Cu2O-臭氧催化氧化芴酮生产废水

以Al2O3负载Cu2O为催化剂,研究芴酮废水在臭氧条件下的氧化降解反应,为芴酮废水的治理提供一种新的处理方法。研究表明,Al2O3负载Cu2O的催化剂加速了臭氧氧化反应,使芴酮废水的氧化降解加快。影响芴酮废水氧化降解的主要因素有臭氧流量、废水的pH值、催化剂用量以及反应器的高度等。加大臭氧流量及增加催化剂用量,均有利于芴酮废水的降解。处理3 L芴酮废水时适宜的反应条件：臭氧流量为25 mg/h,催化剂用量为20 g,反应器的高度H为1 600 mm,废水初始pH为11。在该条件下1.75 h,废水的脱色率为91.2%,COD去除率为90.5%。     

CuO/Al_2O_3和CeO_2/Al_2O_3催化氧化菲的实验研究

多环芳烃(PAHs)是一类持久性有机污染物,由于具有"三致"效应受到人们广泛关注,高效经济地捕集PAHs意义深远。选取一种典型的PAHs菲为研究对象,通过浸渍法制备Cu O/Al2O3和Ce O2/Al2O32种催化剂,采用固定床催化反应装置研究其对菲的催化能力,考察活性组分、负载率、气体流量、反应温度对菲去除率的影响。结果表明,随着负载率的升高,2种催化剂对菲的去除率均呈现增大的趋势,Cu O/Al2O3和Ce O2/Al2O3对菲催化效果最好的负载率分别为18%和25%;随着气体流量的增加,18%Cu O/Al2O3对菲的去除率逐渐下降,18%Ce O2/Al2O3没有明显变化;随着反应温度的升高,2种催化剂对菲的去除率均逐渐增加,18%Cu O/Al2O3和18%Ce O2/Al2O3对菲的去除率分别在300℃和325℃得到显著提升;通过对比不同负载率及工况下菲的去除率可以发现,Cu O/Al2O3对菲的催化能力要优于Ce O2/Al2O3。     

化学工业废物处理与综合利用

X780.31200603018Al2O3催化臭氧化处理邻苯二甲酸二甲酯/周云瑞…(清华大学环境科学与工程系)∥环境科学/中科院生态环境研究中心.-2006,27(1).-51~56环图X-5Al2O3催化剂对邻苯二甲酸二甲酯(DMP)溶液臭氧化过程的影响结果表明:Al2O3可以显著提高臭氧氧化的效果,反应120min后,TOC的去除率从单独臭氧氧化的23.9%提高到55.1%。实验中还考察了制备条件对Al2O3催化剂活性的影响并确定了反应的最佳工艺条件。在实验考察的范围内:焙烧温度600℃,Al2O3粒径为0.5~1.0mm时催化活性最高;最佳反应工艺条件为:催化剂投加量20g/L,混和气体流速200m…     

La1-xAlxFeO3催化剂降低甲醇/柴油二元燃料发动机非常规排放研究

采用喷雾热分解法制备了一系列钙钛矿型催化剂La_(1-x)Al_xFeO_3(x=0、0.3、0.5、0.7),采用X射线衍射仪和扫描电子显微镜,表征了La_(1-x)Al_xFeO_3相组成和微观形貌,评价了催化剂表面化学形态和催化活性指标.在发动机试验台架上,对甲醇/柴油发动机尾气中的甲醛、甲醇、1,3-丁二烯和N_2O进行了催化降解试验.结果表明:在La_(1-x)Al_xFeO_3中掺杂适宜量的Al有助于提高催化剂活性,改善催化剂比表面积和孔容积.当Al掺杂量为0.5时,所制备的La_(0.5)Al_(0.5)Fe O_3催化剂对甲醇、甲醛、丁二烯和N_2O的起燃温度(T50)分别为192、172、180和212℃,完全转化温度(T90)分别为227、205、240和324℃,呈现了良好的低温催化活性.对甲醇、甲醛、1,3-丁二烯和N_2O最大比排放分别为5.2×10~3、0.6×10~3、0.02和11.23 mg·k W~(-1)·h~(-1).与原发动机比排放相比,转化率达到了92%以上.表明La0.5Al0.5Fe O_3为适宜用于甲醇/柴油发动机尾气中非常规排放物低温催化降解的催化剂.     

Co-Fe催化剂上乙醇制氢反应研究

采用溶胶凝胶法制备了负载型Co-Fe催化剂，提出并考察了二段重整制氢的可行性及制氢效果，在水醇比2．5、氧醇比0．5、液空速12h^-1、床层温度523℃、Co-Fe催化剂作用下的乙醇转化率为97．0％，H2选择性为2．80，H2产率为2．72。Cu催化剂作用下的CO的变换反应有效地降低了CO含量，提高了H2含量。     

焦油模型物甲苯催化重整制氢热力学模拟研究

应用Aspen Plus软件,对焦油模型化合物甲苯进行了水蒸气重整制氢热力学模拟研究。分析反应温度、水蒸气与甲苯进料比对甲苯转化率、H_2O、H_2、CO、CO_2、CH_4等产物组成的影响,得到适宜的重整反应条件,从而为焦油水蒸气重整制氢及其工程应用提供参考。结果表明:高温、高水蒸气与甲苯进料比有利于H_2生成。综合考虑,在常压下,温度为950℃、水蒸气与甲苯进料比为7时是甲苯水蒸气重整制氢最佳的反应条件。     

ZnO包覆Al_2O_3的制备表征及光催化性能研究

采用化学沉积法制备了ZnO包覆Al2O3光催化剂,并通过X射线衍射(XRD)、扫描电镜(SEM)进行了表征。在自制的光化学反应器中,以中压汞灯作光源,一定浓度的甲基橙为光催化反应模型化合物,研究了光催化剂的活性。考察了甲基橙初始浓度、催化剂加投量、pH值、温度、光照强度、反应液体积等因素对脱色率的影响。实验结果表明,ZnO包覆Al2O3复合光催化剂具有较高的光催化活性。在250W中压汞灯下光照3h,0.10g复合光催化剂能使200mL,10mg/L甲基橙溶液的脱色率达到92.21%。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.