Fenton氧化法处理偶氮染料丽春红2R废水的研究

采用Fenton氧化法处理偶氮染料丽春红2R模拟废水,研究不同因素对丽春红2R模拟废水的降解效果。结果显示,p H=3.0、H2O2浓度为2 mmol/L、c(Fe2+)/c(H2O2)=1∶5条件下,Fenton氧化法对丽春红2R模拟废水反应体系的降解效果最佳。此外,在室温(30℃)和p H=3.0条件下,模拟出Fenton氧化降解丽春红2R的初始动力学方程为R=dm/dt=0.00198[c(Ponceau2R)]0.7234[c(Fe2+)]0.5297[c(H2O2)]0.3574。通过LC-MS图对Fenton氧化降解丽春红2R过程中间产物的分析,从而推断出该染料氧化降解的路径。     

金刚烷胺模拟废水Fenton氧化及其中间产物分析

采用Fenton试剂氧化法处理模拟金刚烷胺废水,研究不同反应条件下Fenton试剂对金刚烷胺的去除效果,确定反应的最佳条件。结果表明:当反应温度为常温(23～25℃),pH为4,H2O2投加量为3000mg/L,H2O2与Fe2+的质量比为1.28时,处理含金刚烷胺浓度为500mg/L废水,CODCr去除率为30%～80%,处理效果良好。因此,Fenton试剂可以有效降解金刚烷胺。通过Fenton反应,金刚烷胺废水的可生化性得到提高,B/C由0提高到0.1～0.4。对Fenton氧化金刚烷胺的中间产物的分析发现,Fenton氧化反应5min后,系统中没有检出金刚烷胺。反应30min后,中间产物已基本完全降解。     

Fenton试剂处理酸性玫瑰红B的研究

采用Fenton试剂处理酸性玫瑰红B染料废水,考察了FeSO4投加量、H2O2投加量、pH值和反应时间对处理效果的影响,研究了原水的氧化还原电位和TOC的变化规律,评价了它的可生化性。结果表明,最佳pH值为3,FeSO4的适宜投加量为8mmol/L,H2O2最佳投加量为50mmol/L,此时COD去除率和脱色率分别为77.1%和92.8%,处理后该染料废水的可生化性大大提高。     

纳米磁铁矿/生物质炭催化对Fenton氧化降解苯酚的增强机理

以生物质炭负载纳米磁铁矿(nMBC)作为催化剂,采用非均相Fenton反应体系对模拟苯酚废水进行氧化降解处理研究,确定n MBC—Fenton法处理苯酚废水的最佳工艺条件,并揭示其强化机理。实验结果表明:对于质量浓度为50 mg/L的苯酚废水,其最佳降解条件为温度为45℃,pH为3.0,H_2O_2浓度为5 mmol/L,nMBC用量为2.0 g/L。反应进行20 min后,苯酚去除率可达约100%。nMBC剂量、废水初始pH和温度等因素均对处理效果有较大影响,其中pH决定苯酚去除率,而nMBC剂量是影响降解速率的主要因素。此外,nMBC—Fenton法催化氧化降解苯酚过程符合准一级动力学反应(R~2>0.97)。     

Fenton氧化技术处理印染废水的试验研究

采用Fenton试剂对含分散红E-4B和活性艳兰KN-R染料组成的模拟印染废水进行氧化处理,考察了H2O2和Fe2＋浓度、pH、反应时间等因素对去除效果的影响。在H2O2投加量为5.0ml/L,Fe-SO4.7H2O投量为1.1g/L,pH为3,反应25min后静置5min的条件下,初始COD为700mg/L,色度为1200倍的废水的COD去除率可达到95%,脱色率达97%。结果表明,Fenton试剂对该废水可以起到很好的处理效果。     

Fenton试剂对水中酚类物质的去除效果研究

采用Fenton试剂对苯酚、对氯酚、2 ,4 二氯酚、2 ,6 二氯酚、间甲酚、对硝基酚和邻硝基酚模拟水样进行处理 ,并考察了H2 O2 及FeSO4 浓度、pH、反应温度和反应时间对Fenton试剂降解酚类物质的影响 ,得出Fenton试剂降解酚类物质非常有效 ,当H2 O2 浓度为4mmol/L、FeSO4 浓度为 0 .5mmol/L ,在pH为 3 ,室温条件下反应 40min则Fenton试剂对试验所做 7种浓度为 50mmol/L的酚类物质的去除率均在 98%以上。为该工艺处理实际含酚废水提供了科学依据。     

金刚烷胺模拟废水Fenton 氧化及其中间产物分析

采用Fenton试剂氧化法处理模拟金刚烷胺废水,研究不同反应条件下Fenton试剂对金刚烷胺的去除效果,确定反应的最佳条件.结果表明:当反应温度为常温(23 ～ 25℃),pH为4,H2O2投加量为3 000 mg/L,H2O2与Fe2+的质量比为1.28时,处理含金刚烷胺浓度为500 mg/L废水,CODCr去除率为...     

电Fenton法处理染料废水的研究

采用电Fenton法预处理染料废水,对影响COD及色度去除率的各种因素,包括内电解反应的初始pH值、铁的投加量、铁炭投加比,Fenton试剂氧化处理过程中初始pH值、H2O2的投加量及投加方式、反应时间等进行了研究。结果表明,内电解反应的最佳条件为：pH值为3.0,铁的投加量为25g/L,Fe/C为1：1.3;Fenton试剂氧化处理染料废水的最佳条件为：H2O2投加量为30mmol/L,pH值为内电解出水pH值（pH值为4.0左右）,反应时间为50min。COD去除率可达58%,色度去除率可达95%以上。     

Fe-cyclam/H2O2体系催化降解罗丹明B机制

传统的利用Fenton反应处理染料废水的方法pH适用范围窄、需大量亚铁盐的持续投加,限制了其应用.工作中成功制备了桥连四氮杂环十四烷铁配合物(Fe-cyclam),在较宽的pH范围(2～7)内都能活化H_2O_2降解罗丹明B,且在低催化剂条件下(50μmol·L~(-1)),对罗丹明B的降解效果优于Fenton反应.该体系能快速降解罗丹明B、酸性红88、酸性橙Ⅱ、活性红24、中性红等多种染料,并对偶氮类染料有较高的选择性.Fe-cyclam的稳定性良好, 3次循环降解后,罗丹明B的去除效率依然保持在90%以上.淬灭实验证明该过程为非自由基主导的降解过程,并通过电子顺磁共振(EPR)中捕获到高价铁-氧活性中间体Fe~V-oxo的生成.本工作证明了基于Fe-cyclam/H_2O_2体系能高效地降解废水中染料,具有较高的应用潜力.     

微电解/Fenton法预处理炼油碱渣的实验

采用铁碳微电解/Fenton试剂组合工艺对炼油碱渣废水混凝沉淀处理后出水,进行降解研究。实验结果表明:pH值为3,废水与铁碳填料的体积比为2∶1,微电解反应时间2 h,曝气的条件下,废水的处理效果最好,COD的去除率超过42.5%。Fenton试剂处理微电解反应出水的最佳操作条件是:pH值在2～3之间、反应时间2.5 h、Fe2+浓度为800 mg/L左右、H2O2浓度为0.25 mol/L,在此条件下,Fenton试剂处理微电解处理后的炼油碱渣废水COD平均去除率为63.8%以上,微电解/Fenton工艺对COD的总去除率在79.2%左右,可生化性由0.16提高到0.56。     

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.