Fereducer反应强化直流电晕自由基簇射治理苯

为强化直流电晕自由基簇射对含苯废气的去除,采用Fereducer反应进行实验研究.将含Fereducer试剂的电极气引入反应器中,在苯浓度分别为953mg/m³和63mg/m³时,其去除率提高了21%和4.2%.电极气(O₂、H₂O)的存在对苯的脱除起了不同程度的促进作用,最高可达89.6%.苯的初始浓度较低时脱除效率较高,但高浓度下的绝对去除量较大.     

脉冲放电等离子体治理甲苯废气放大试验研究

应用脉冲放电等离子体技术,在线板式反应器内对低浓度甲苯废气的治理进行放大试验.采用闸流管开关脉冲电源,其最大输出功率1kW,最大脉冲电压峰值100kV. 试验规模4～16m³·h^-1. 试验考察了峰值电压、重复频率、进口浓度和处理气量对甲苯去除率的影响.结果表明:峰值电场强度在9～12kV·cm^-1范围内增加,甲苯去除率相应明显提高;当处理气量为4 m³·h^-1、脉冲电压峰值69kV、进口浓度1 180mg·m^-3、重复频率300pps时, 甲苯的去除率可达88%;反应器的能量利用率在16g·(kW·h)^-1左右;甲苯的降解产物主要是CO₂和H₂O,还有少量CO. 结合甲苯去除率与能量密度、甲苯进口浓度的关系,建立反应器动力学模型,获得甲苯的反应速率常数为0.00356 L·J^-1. 为进一步优化放大反应器设计及与电源匹配提供了基础数据.     

非热等离子体结合CuO催化剂或Ca(OH)2吸收剂去除氮氧化物

采用非热等离子体结合催化或现场化学吸收的2种方法来去除气流中的NO_x.结果表明,非热等离子体结合催化,反应器内的CuO催化剂能有效地促进NO的还原反应;相对于催化还原NO而言,脉冲电晕作用下能有效地降低NO催化还原的反应温度.当催化剂为CuO,脉冲电压为18kV,反应温度为200℃,还原剂为1%CO及NO进口浓度为719 mg/m³条件下,NO的去除率达到了100%.非热等离子体结合现场化学吸收方法,是一种在常温下从气流中净化氮氧化物的有效方法,NO的去除率远远高于反应器内没有吸收剂的情况.可以认为反应器内的Ca(OH)₂吸收剂通过与NO的氧化产物NO₂或NO₃的吸收反应促进了NO的去除.当反应器内有Ca(OH)₂吸收剂存在时,在脉冲电压为18kV,O₂浓度为2%及NO进口浓度为1 050 mg/m³条件下,NO的去除率达到了100%.     

生物沸石反应器在微污染水源水处理中的应用

首次利用生物沸石反应器去除微污染水源水中的 NH₃^- N、NO^-₂ - N、Mn、有机物、色度、浊度等 .经长期运行测试 ,生物沸石反应器对 NH₃^- N平均去除率可达 93%,对 NO^-₂ - N的平均去除率为 90 %,对有机物可去除 32 %,并提出了反应器的最佳过滤速度为 8～10 m/h,最佳填料填充高度为 600～800 mm.生物沸石反应器具有和生物活性炭、生物陶粒一样的性能 .该技术为微污染水源水质净化提供了一种新材料 ,新途径 .     

DBD技术脱除恶臭气体H2S和CS2的可行性

采用DBD技术脱除工业废气中的H₂S和CS₂.12kV的电压下,分压为4kPa的H₂S,放电5s,去除率接近100%;分压为1.33kPa的CS₂,放电15s,其去除率可达80%.H₂S和CS₂的去除率都随其浓度的增加而下降.在实验室研究的基础上,设计了废气处理量为420m³/h、流速为10m/s的DBD净化装置,进行了实际含H₂S和CS₂的工业废气净化研究,H₂S去除率可达89%,能量消耗为5.2W·h/m³.结果表明DBD技术对于处理含硫恶臭工业废气,具有实际应用价值.     

UV/H2O2液相氧化净化烟气中NO的实验研究

采用UV/H₂O₂液相氧化技术净化气体中的NO,通过正交实验和单因素实验,研究了H₂O₂浓度、温度、初始pH值、NO浓度、光照条件、O₂含量和气体流量等因素对NO去除率的影响.结果表明,UV/H₂O₂液相氧化体系对NO有良好的净化效果,可以获得80%左右的NO去除率, 温度、H₂O₂浓度和初始pH值对NO去除率具有不同程度的影响,温度和H₂O₂浓度对NO去除率影响较大.单因素实验结果表明, 当H₂O₂浓度为0.2 mol/L、初始pH值为6～7时NO去除率较高;溶液中H₂O₂浓度过高或过低、溶液过酸或过碱均会抑制·OH的产生而不利于NO的去除;净化NO的最佳反应温度为40 ℃,低于一般湿法脱硝温度(50 ℃);NO的去除率随紫外光辐射强度和O₂含量的增加而升高;同时,NO的去除也受气液传质面积和气液传质系数的控制.     

厌氧氨氧化菌的培养与推流式反应器氨厌氧工艺

采用推流式固定化絮体生物反应器培养出高活性的厌氧氨氧化(ANAMMOX)红色颗粒污泥.在稳定运行后,反应器的NH₄⁺-N和NO₂^--N去除率皆大于98%,TN平均去除率为86%,NO₃^--N的生成率约为14%,TN去除负荷达2.56kg/(m³·d).同时考察了进水基质比例对反应器性能的影响,并用扫描电镜观察了颗粒结构.     

2种MSW好氧生物反应器型填埋方式的对比实验

在系统分析现有MSW生物反应器型填埋方法优缺点基础上,对其改进,将强制通风好氧和渗滤液循环2种方式有机结合组成新的反应器(称之为反应器A) ,与只有强制通风好氧的反应器(称之为反应器B)作对比.实验过程中对2反应器中NH₃、CH₄、CO₂、pH、温度、电导率及沉降进行控制和监测,对渗滤液中Fe³⁺和NH₄⁺进行监测与分析,研究2种MSW好氧生物反应器对所填垃圾降解及所产生渗滤液中COD、Fe³⁺和NH₄⁺的去除效果,探讨两者对所填埋垃圾降解和渗滤液中所测参数去除机理,从而得出反应器A比反应器B对垃圾和渗滤液有更好的降解和去除效果.     

臭氧/纳米TiO2催化氧化去除水中微量硝基苯的研究

在悬浮颗粒搅拌混合反应器中,研究了臭氧/纳米TiO₂催化氧化去除水中微量硝基苯的性能,结果表明,纳米TiO₂催化臭氧化去除硝基苯较单独臭氧氧化有明显的提高,反应20min硝基苯的去除率提高了44%.实验中分别考察了纳米TiO₂热处理温度、催化剂投量、臭氧投量、硝基苯初始浓度、pH值对臭氧/纳米TiO₂催化氧化去除硝基苯的影响.发现550℃烧结得到的纳米TiO₂表现出最好的催化臭氧化活性,在较低的臭氧投量与催化剂用量条件下,硝基苯的去除率可达到56.57%;增大臭氧或者硝基苯的初始浓度,硝基苯的去除率随之提高;但是改变催化剂投量,硝基苯的去除效果几乎不受影响;中性或碱性pH环境利于纳米TiO₂催化臭氧化反应的进行.通过研究叔丁醇对纳米TiO₂催化臭氧化反应的影响,证明反应遵循羟基自由基(·OH)反应机理.     

单级自养脱氮工艺氨氮去除途径研究

以SBBR单级自养脱氮系统的污泥为对象,采用不同的人工模拟废水为反应器进水,通过批式试验的方式研究了单级自养脱氮系统内的中间产物及氮素平衡情况,并探讨了氨氮的去除途径.结果表明,以仅含氨氮的人工模拟废水为进水,在未投加有机碳源的条件下,系统内62％的氨氮被转化为NO^-₂、NO^-₃、NH₂ＯH、N₂Ｈ₄、NO、NO₂、N₂Ｏ和N₂等一系列氮化合物,其中N₂占90.07％.单级自养脱氮系统内的氨氮是由多种途径去除的.4.5％的氨氮是在吹脱等物化作用下去除的,不超过3.73％的氨氮是通过传统的硝化反硝化途径去除的,53.77％的氨氮是由自养脱氮途径去除的,自养脱氮反应起主要的脱氮作用,且自养脱氮反应可以通过2条代谢途径来实现.但在足够NO₂存在并且缺氧的条件下,单级自养脱氮系统内的出水氨氮浓度与空白反应器相当,NH⁺₄并没有被亚硝化单胞菌以NO₂为电子受体氧化为NO^-₂和N₂等化合物而得以去除,可能是因为系统内不存在该类型的亚硝化功能菌.     

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.     

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.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

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

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Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.