乙醇废水的超临界水氧化处理工艺研究

研究了以超临界水氧化法（SCWO）处理乙醇废水的工艺过程，实验表明，一氧化碳和二氧化碳分别是反应中间产物和最终，550℃，25MPa,停留时间大于15s时，SCWO能将乙醇完全氧化为二氧化碳，达到稳彻底处理的目的，随停留时间增大，湿度升高，乙醇的去除率增大，而压力和氧气浓度的变化对过程没有显著影响。     

Pr-N共掺杂TiO2光电催化降解孔雀石绿动力学

以溶胶-凝胶法制备的Pr-N共掺杂TiO2催化剂为电极,在光电催化反应器中,研究了光电催化降解孔雀石绿的动力学过程.结果表明,孔雀石绿氧化降解速率与溶液的初始浓度、pH、外加电压及反应的温度有关,在初始浓度为10～30 mg.L-1、pH为3～8、电压1～5 V、温度为298～338 K的实验范围内,反应的氧化降解符合一级反应动力学模型且模型值与实验值吻合良好.模型中反应的初始反应活化能Ea为11.99 kJ.mol-1,说明反应较易进行;pH的反应级数1.634 7,远远高于电压的级数0.850 2及初始浓度的级数0.123 8,表明通过控制pH可有效地提高光电催化的氧化降解速率.     

新农药硫肟醚在有机溶剂中的光解

以紫外灯为光源,对硫肟醚在甲醇、丙酮、正己烷和二甲苯等有机溶剂中的光解反应动力学及降解机理进行了初步研究.结果表明,硫肟醚在4种有机溶剂中的紫外光解反应符合一级动力学规律,在4种溶剂中反应速率常数分别为1·14×10-1(正己烷)、8·90×10-2(甲醇)、2·46×10-2(二甲苯)和4·51×10-3min-1(丙酮),硫肟醚的降解半衰期分别为6·08,7·79,28·18和153·86min.通过对硫肟醚光解产物进行分离和LC-MS鉴定,初步推出在紫外光辐射下硫肟醚在有机溶剂中的降解主要涉及到硫肟醚分子的肟醚键(CNOC)断裂、甲硫键(C—S—CH3)光氧化、脱氯反应和光异构化作用等途径.     

正丁醛与氯原子反应的动力学和机理研究

在室温和一个大气压下,利用气相色谱和气质联用研究了氯原子与正丁醛的光化学反应,获得了该反应的反应速率常数k2=(1 19±0 10)×108m3·mol-1·s-1;该反应的主要产物是:丙醛、乙醛、CO和CO2.结合这些主要产物以及它们的产率对氯原子与正丁醛反应的机理进行了探讨,获得了氯原子在正丁醛的—CHO、α位、β位和γ位摘氢份额分别为44%,25%,20%和11%.     

Fenton试剂氧化降解腐殖酸动力学

研究了Fenton试剂氧化降解腐殖酸废水的过程及动力学.结果表明,Fenton法能通过氧化和混凝作用有效去除腐殖酸,其中氧化降解速率主要与Fenton试剂投量、腐殖酸初始浓度和初始pH值有关,且氧化作用主要发生在反应前60 min.在pH为4.0,[Fe2+]0为5～40 mmol.L-1,[H2O2]0为40～120 mmol.L-1,[HS]0为250～1 000 mg.L-1,温度为278～318 K的实验范围内,反应初始阶段腐殖酸的氧化降解符合表观反应动力学模型.模型值与实验值吻合良好,说明该反应动力学模型能较好地描述Fenton氧化降解腐殖酸过程.Fenton氧化降解腐殖酸的初始反应活化能Ea为14.9 kJ.mol-1,说明反应较易进行.动力学模型的反应总级数为2.34,其中H2O2的反应分级数(0.86)高于Fe2+的分级数(0.47),表明H2O2浓度比Fe2+浓度对Fenton氧化降解反应的影响大.     

气液膜接触器分离混合气中CO2过程研究

建立了膜接触器吸收CO2 ,溶液热再生连续循环实验装置 ,评价了疏水性PP(聚丙烯 )微孔膜 ,MDEA(N 甲基二乙醇胺 )溶液及添加活化剂PZ(哌嗪 )的活化MDEA溶液吸收CO2 传质过程。结果表明 :在溶液浓度 2 5mol L ,气速0 5～ 3 0L min,液速 15～ 15 0mL min时 ,总传质系数Kov为 1 0× 10 - 5～ 3 6× 10 - 5m s(MDEA) ,1 6× 10 - 5～ 4 5×10 - 5m s(MDEA +PZ)。采用阻力层无因次关联方程模型预测Kov值 ,计算值和实验值符合较好。基于模型和实验结果 ,将PZ的吸收行为作为溶液的活化作用 ,在计算Kov值时 ,考虑活化作用因素并归结于化学增强因子E中 ,模型能更好地预测实验结果。实验证明在单一醇胺组份MDEA中添加少量PZ能提高总传质系数Kov值     

CuO/γ-Al2O3脱硫动力学研究

研究了CuO/γ-Al2O3脱硫剂脱除烟气中SO2的反应动力学。采用浸渍法制备了CuO/(γ-Al2O3)为0.12g/g脱硫剂,X-射线衍射(XRD)表明CuO呈亚单层状态分布。0.12gCuO/g(γ-Al2O3)脱硫剂硫化反应的等压吸附表明,在100～300℃、300～550℃、550～800℃范围内,SO2的吸附性质分别为物理吸附、化学吸附、化学脱附。针对化学吸附过程,提出了Langmuir反应动力学模型。计算得到SO2的反应级数为1级,活化能Ea为19.98kJ/moL,指前因子K0为9.97×10-5s-1.Pa-1。模型检验显示Langmuir反应动力学模型可以很好地描述CuO/(γ-Al2O3)为0.12g/g脱硫剂硫化过程中CuO与SO2的反应。     

相对速率法测氯原子与一系列低碳醇的反应速率常数

在 2 92± 1K温度和 1 0 1× 10 5Pa压力下 ,以丙烷为参照物 ,采用相对速率方法测定了一系列醇与氯原子在气相中的反应速率常数 ,这些醇与氯的反应速率常数分别为 (单位 :10 7m3·mol-1·s-1) :甲醇k1=3 2 9,乙醇k2 =6 14,正丙醇k3=8 97,异丙醇k4 =4 0 0 ,正丁醇k5=11 7,异丁醇k6=12 5 ,叔丁醇k7=2 0 5 ,正戊醇k8=15 8,异戊醇k9=12 3     

杂多化合物脱硫化氢动力学研究

在双搅拌、无浓度梯度气液反应器中考察了磷钼杂多化合物吸收H2S过程的宏观动力学行为.结果表明,吸收剂浓度提高,脱硫效果增强,当磷钼酸钠浓度超过6.25×10-3mol/L后,单一与复配体系对H2S的吸收速率均趋恒定.从工业操作角度来看,6.25×10-3mol/L是适宜的操作浓度温度提高,吸收效果略有降低,但变化幅度不大,实际操作温度可选择常温;进气H2S浓度提高,吸收效果增强.两种脱硫体系中,以复配体系脱硫性能为优.实验测得25℃下反应器中H2S的气、液相传质系数分别为:kGH-2S =8.201×10-10kmol/(m2.s.Pa),kLH-2S=3.440×10-4m/s.吸收反应对磷钼酸钠及硫化氢的反应级数分别为0.339与1.055.     

负载型TiO2光电催化降解孔雀石绿的动力学研究

以钛酸四丁酯(TBOT)为钛源,硝酸镧为镧源,尿素为氮源,采用溶胶-凝胶法合成了La-N共掺杂的TiO2光催化剂,并探究了其对孔雀石绿氧化降解的性能.结果表明该反应遵循一级动力学,得到动力学模型;其中外加偏电压的反应分级数(0.935 8)高于pH的反应分级数(0.611 9)以及初始浓度的反应分级数(0.335),表明外加偏电压对反应的影响最大.模型值与实验值吻合良好(R2为0.910～0.996 1),说明该反应动力学模型能较好地描述光电催化降解孔雀石绿过程.     

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.     

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.     

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.     

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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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.     

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.