锰-稀土/Y分子筛复合电催化处理含酚模拟废水

采用浸渍焙烧法制备了以Y分子筛为载体的Mn-RE复合催化剂,置于电解槽内形成反应床体,构建Mn-RE多相催化电解氧化体系处理人工模拟苯酚废水.考察了浸渍液中锰的质量分数、稀土元素组成和质量分数、焙烧温度、焙烧时间对电催化活性的影响,用SEM和XRD等手段对催化剂的微观结构、表面形貌进行了表征,探讨了Mn-RE/Y分子筛催化剂对含酚废水降解的电催化效果.研究表明, Mn-RE/Y分子筛催化剂的最佳制备条件是浸渍液中锰质量分数6%,铈质量分数为3%,焙烧温度为550℃,焙烧时间为5h.Y分子筛中引入Mn、Ce后没有破坏Y分子筛的晶体结构, Mn-RE/Y分子筛催化剂的表面并没有检测到稀土氧化物和锰氧化物的物相.反应过程中, Mn-RE/Y分子筛在阴极和阳极的同时催化氧化作用强化了含酚废水的降解效果.     

CuMnO_x/γ-Al_2O_3对含甲苯废气催化燃烧的性能研究

利用浸渍法制备催化剂CuO/γ-Al2O3、MnOx/γ-Al2O3、CuMnOx/γ-Al2O3,通过实验研究表明:CuMnOx/γ-Al2O3具有更高的催化活性,其T99比其他两种催化剂要低50℃以上。在焙烧温度300、400、500、600℃下制备CuMnOx/γ-Al2O3,比较其催化活性,发现在600℃制备的催化剂要比其他温度下制备的同等催化剂的催化活性高,证明了尖晶石结构在催化燃烧中起着很大的作用。     

新型CuMn/TiO2苯类催化燃烧催化剂的研制及活性实验

采用浸溃法制备了CuMn/TiO2新型甲苯燃烧催化剂,其活性明显优于传统CuMn/γ-Al2O3和Cu-Mn复合氧化物催化剂.研究发现,载体TiO2自身有一定催化活性,而γ-Al2O3则几乎没有活性;TiO2与Cu-Mn之间的协同作用更提高了新型催化剂的活性.XRD、LRS结果显示,CuMn/TiO2催化剂的主要活性相为铜锰尖晶石(CuMn2O4),它的存在是CuMn/TiO2催化活性优良的另一个主要原因.考察了Cu-Mn负载量、铜锰比和焙烧温度对催化剂活性的影响,CuMn/TiO2下对甲苯的去除率达95%以上时催化床层温度为215℃,比CuMn/γ-Al2O3和Cu-Mn复合氧化物对甲苯去除率达95%时分别下降了30℃、50℃左右.     

V-W/TiO_2/γ-Al_2O_3催化剂催化还原NO的研究

掺杂15%TiO2对γ-Al2O3改性制备了TiO2/γ-Al2O3复合氧化物载体,以此复合氧化物及TiO2、γ-Al2O3为载体用浸渍法负载钒钨制备了一系列催化剂,采用比表面积和孔结构分析、X射线衍射(XRD)、高分辨电镜(HRTEM)、原位红外(in situ FT-IR)等技术对载体和催化剂进行宏观-微观表征,同时在模拟氨气选择性催化还原NO(NH3-SCR)的反应条件下对催化剂的脱硝反应活性进行考察,比较研究TiO2掺杂对V2O5-WO3/TiO2和V2O5-WO3/γ-Al2O3催化剂的改性作用。结果发现,少量TiO2掺杂制得的TiO2/γ-Al2O3复合载体中,TiO2和γ-Al2O3之间的协同作用使得V2O5-WO3/TiO2/γ-Al2O3催化剂的选择性催化还原脱硝效率及活性窗口明显优于单一载体制备的催化剂,并表现出了良好的热稳定性;各种表征结果表明,TiO2/γ-Al2O3复合载体中TiO2高度分散在γ-Al2O3上,复合载体具有较大的比表面积,载体表面存在大量的Br?nsted酸位和较多的活性中间产物,这些可能是TiO2/γ-Al2O3复合载体催化剂具有较好SCR活性的原因。     

TiO_2对In-Ag-O/γ-Al_2O_3催化剂上CO选择性还原NO的改性研究

以Ti O2、γ-Al2O3及Ti O2-γ-Al2O3复合氧化物为载体,以In-Ag-O基为活性组分,采用等体积浸渍法制备了一系列In/Ag催化剂,通过XRD、BET、SEM、H2-TPR等技术手段对催化剂表面形态进行分析,并考察了催化剂对CO选择性还原NO的反应活性和载体中Ti O2含量对催化性能的影响.结果表明,Ti O2的添加促进了活性组分铟和银物种的分散,当Ti O2的含量为载体的15%时制备的催化剂活性最高,合适的Ti O2与γ-Al2O3配比使活性组分与载体之间发生了强烈的相互作用,由此提高了CO选择性还原NO的活性.     

纳米TiO_2-Al_2O_3负载CuMnO_x对甲苯的催化燃烧

研究采用改进的溶胶-凝胶法制备了TiO2-Al2O3复合载体,并用浸渍法制备CuMnOX/TiO2-Al2O3催化剂,通过对甲苯废气催化燃烧的实验,分别考察了Cu-Mn负载量、Cu/Mn摩尔比、焙烧温度及载体对催化剂制备过程及催化剂活性的影响。实验结果表明:活性组分负载量25%,铜锰活性组分的配比Cu:Mn=1:2,焙烧温度500℃是浸渍法制备CuMnOX/TiO2-Al2O3催化剂较佳的工艺条件;XRD衍射图谱表明,500℃下铜锰尖晶石的存在是催化剂催化活性优良的主要原因;由复合载体制备的CuMnOX/TiO2-Al2O3催化剂比单一载体制备的CuMnOX/Al2O3催化剂具有更高的甲苯转化率,其T99比单一载体要低20℃以上。     

光助Fenton反应催化剂Fe/Al2O3的制备及其对六氯苯的催化活性研究

采用超声促进浸渍法制备了光助Fenton催化剂Fe/Al2O3,利用该催化剂对六氯苯（HCB）进行光助Fenton氧化降解,考察了浸渍液浓度、浸渍温度、灼烧温度和灼烧时间等制备条件对其催化降解六氯苯的活性的影响,确定了制备Fe/Al2O3的工艺条件,并对制得的催化剂进行表征。结果表明,超声促进浸渍法制备非均相光助Fenton反应催化剂Fe/Al2O3的最佳工艺条件为：浸渍液浓度25mmol/L,浸渍温度40℃,焙烧温度500℃,焙烧时间3h。在此条件下制备的催化剂对六氯苯的降解具有较高的催化活性。     

催化湿式氧化法处理桉木CTMP模拟废水

通过浸渍法制备固载金属非均相型催化剂,用于催化湿式氧化处理桉木CTMP模拟废水。结果表明:在焙烧温度400℃,焙烧时间4h,浸渍液浓度为6%,浸渍时间为5h下制得的CuO/γ-Al2O3催化剂的催化活性最好;在反应时间为8h,鞣酸溶液pH为4.5,H2O2加入量为0.2mL,催化剂用量为4g的条件下处理鞣酸溶液的效果最好,鞣酸去除率>90%。     

Catalytic performance of copper and cerium oxides-based γ-Al_2O_3 on combustion of toluene

以γ-Al2O3为载体,以复合氧化物CuxCe1-xO2为活性组分,其中,x=0.1,0.2,0.4,0.6,0.8,通过浸渍法制备了一系列CuxCe1-xO2/γ-Al2O3催化剂.在固定床反应器中评价了催化剂对甲苯的催化活性,通过XRD、SEM对催化剂进行表征,并运用ICP-MS分析并计算Cu、Ce的摩尔比以及活性组分的负载量.结果表明,在CuxCe1-xO2/γ-Al2O3催化剂中Cu、Ce摩尔比的实际值与理论值相近,活性组分的负载量在19%以上,而且对甲苯都有较好的低温催化活性,其中当x=0.2时,即Cu0.2Ce0.8O2/γ-Al2O3催化剂对甲苯的催化活性最高,其中T10=160℃,T90=265℃;当甲苯的进口浓度在700～3000mg·m-3时,进口浓度对Cu0.2Ce0.8O2/γ-Al2O3催化剂的催化活性影响较小,且经过连续80h的稳定性操作后转化率仍然保持在90%以上.     

Pd-W-Cu/γ-Al_2O_3催化氢还原脱硝的基本性能研究

采用浸渍法制备Pd-W-Cu/γ-Al2O3催化剂,用XRD和SEM方法对该催化剂进行了表征.以氢气作为还原剂,在间歇式反应器中对催化还原地下水中硝酸盐进行了实验研究,考察了催化剂制备方法对催化还原硝酸盐性能的影响.结果表明,W的添加改善了Pd的分散性,提高了催化剂的活性和选择性.金属Pd/W/Cu质量比、浸渍顺序和焙烧温度对催化性能有较大影响.Pd/W/Cu质量比为3∶1∶1,Pd、Cu和W3种金属组分同时浸渍,焙烧温度为400℃时,催化剂的活性和选择性最高.在NO3--N初始浓度为100mg·mL-1条件下,催化反应60min后水中NO3--N和NO2--N浓度均为0mg·mL-1,NH4+-N浓度为2.5mg·mL-1.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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