CMC固定化烟曲霉活菌体小球中活性染料的解吸研究

考察了吸附在CMC(羧甲基纤维素纳)固定化烟曲霉活菌体小球中活性艳蓝KN-R和活性艳红K-2BP的解吸,并在此基础上提出了吸附-回收染料的技术思路。结果表明:pH值为12.0的75%乙醇对CMC固定化烟曲霉活菌体小球中的活性艳红K-2BP和活性艳蓝KN-R的解吸效果较好。30min内,对CMC固定化烟曲霉活菌体小球中的活性艳蓝KN-R和活性艳红K-2BP的解吸率分别为60.8%和50.4%。CMC固定化烟曲霉活菌体小球中的活性艳红K-2BP的解吸动力学符合一级指数衰减模型。CMC固定化烟曲霉活菌体小球能重复利用三次以上。     

CMC固定化灭活烟曲霉小球对活性艳蓝KN-R的吸附机理——吸附平衡、动力学和扩散传质过程

考察了羧甲基纤维素钠(CMC)固定化灭活烟曲霉小球吸附活性艳蓝KN-R的吸附平衡、吸附动力学和扩散传质过程.结果表明:CMC固定化灭活烟曲霉小球对活性艳蓝KN-R的吸附较易进行,吸附等温线能较好地用Langmuir模型和Freundlich模型来描述,而且用Langmuir模型更好,最大单分子层吸附量为66.7mg·g-1.吸附动力学很好地符合准二级动力学模型.小球内部扩散过程用Weber-Morris模型拟合的结果反映小球内部扩散过程是其吸附控制步骤,且染料从小球液相边界层向小球表面的扩散过程亦不能忽略.用外部传质模型Mathews and Weber (M & W)模型和Frusawa and Smith(F & S)模型分别计算得到的外部传质速度的表征值β1S值均小于0.1 h-1.初始染料浓度越大,染料从液相到固相的外部传质速度越慢,而在小球内部越易扩散.     

固定化烟曲霉吸附染料后的解吸平衡及动力学研究

对羧甲基纤维素钠(CMC)固定化灭活烟曲霉小球中的2种活性染料的解吸剂进行了选择,并对其解吸平衡和解吸动力学进行了研究.结果表明,pH值为12.0的75%乙醇溶液对吸附在CMC固定化灭活烟曲霉小球中的活性艳蓝KN-R和活性艳红K-2BP的解吸效果较好;一级指数衰减方程能很好地描述对2种活性染料的解吸动力学;解吸平衡数据均可以用Freundlich等温模型来拟合.     

Na-CMC固定化烟曲霉对活性艳蓝KN-R的吸附脱色研究

采用羧甲基纤维素钠(Na-CMC)固定化烟曲霉对活性蒽醌染料活性艳蓝KN-R吸附脱色.通过批式吸附实验探讨了吸附体系的pH值、温度、供氧条件、盐度,固定化小球的粒径、接种量等对吸附脱色效率的影响.结果表明,适合于固定化小球吸附脱色的吸附体系的pH值在弱酸或碱性(4.3～9.0)范围内,不调pH值时(pH=4.3),48h的吸附率为94.5%,pH值为6～9时,48 h的吸附率在98%以上;固定化小球的最佳脱色温度为40℃,该温度下24h的吸附率达94.4%;氧充足情况下(摇床转速调节为50r·min-1)的吸附体系较静止状态能显著提高吸附脱色率;固定化小球脱色过程中能承受一定的盐度,NaCl浓度为0.1%时,吸附脱色效果最好;盐度为2.5%时,48h的吸附率降低至68.4%;粒径为2.0～3.85mm的固定化小球对活性艳蓝KN-R的吸附率相差不大;接种量为3.0%时的吸附脱色效果最好,24h对活性艳蓝KN-R的吸附率达91.0%.在烟曲霉生长期内,固定化小球吸附脱色动力学符合一级动力学方程.     

丝瓜瓤固定无花果曲霉吸附活性艳蓝KN-R的脱色研究

利用植物载体丝瓜瓤对无花果曲霉(Aspergillus ficuum)进行固定,并对活性艳蓝KN-R进行脱色研究探讨了固定化菌体的菌龄、pH、温度、菌量对染料脱色的影响.比较了固定化菌体与菌丝球对活性艳蓝KN-R的脱色效果,研究了该固定化菌体的重复利用和动力学实验,并进行了实际废水的脱色研究.结果表明,最佳脱色条件为菌龄3d,温度33℃,pH为6.0,菌量对染料脱色的影响依次为2%＞1%＞0.5%;固定化菌体对活性艳蓝KN-R的脱色效果优于菌丝球,且它对实际染料废水的脱色率均达80%以上;丝瓜瓤固定无花果曲霉对不同初始浓度(25～186mg·L-1)活性艳蓝KN-R的脱色过程遵循二级动力学方程;经6次重复利用后的该固定化菌体,其脱色率仍达80.79%.     

凹凸棒石/氧化锌纳米复合材料对亚甲基蓝的吸附性能

采用化学沉淀法在凹凸棒石的表面负载纳米氧化锌合成了凹凸棒石/氧化锌(ATP/ZnO)纳米复合材料.同时,研究了亚甲基蓝在纳米复合材料上的吸附行为,并从热力学和动力学角度探讨了吸附作用机理.吸附实验表明:纳米复合材料对亚甲基蓝有优异的吸附能力;纳米复合材料对亚甲基蓝的吸附热力学符合Langmuir等温吸附方程,最大吸附量可达110.50mg·g-1,吸附焓变为18.69kJ·mol-1,吸附自由能变为-33.06～-22.74kJ·mol-1,吸附熵变约为146J.mol-1.K-1,是一个自发的吸热过程;纳米复合材料对亚甲基蓝的吸附动力学符合准二级动力学方程,速率常数随着溶液初始浓度的提高而下降.     

蜜环菌漆酶对蒽醌类染料的脱色条件优化

利用蜜环菌发酵所得的漆酶,直接对印染工业中常见的两种蒽醌类染料活性艳蓝KN-R和活性艳蓝X-BR进行催化脱色实验,得出了最佳脱色条件.结果表明,活性艳蓝KN-R最适脱色温度为30℃,最适染料浓度为80 mg.L-1,最适酶量为0.25U.mL-1,最适pH值为5,在最优条件下活性艳蓝KN-R最高脱色率达90%以上.活性艳蓝X-BR的最适脱色温度为30℃,最适染料浓度为50 mg.L-1,最适酶量为0.5 U.mL-1,最适pH值为4,在最优条件下活性艳蓝X-BR最高脱色率达70%以上.本研究利用蜜环菌粗漆酶液直接对印染工业中常见蒽醌类染料进行脱色,结果表明蜜环菌粗漆酶液具有良好的脱色效果,蜜环菌漆酶在印染工业染料废水脱色方面具有潜在的应用价值.     

应用青霉菌BX1活体吸附水中活性艳蓝KN-R

研究了染料高效吸附菌(青霉菌BX1)的生长条件及其对活性艳蓝KN-R的吸附特性为避免染料对其生长的毒害,本研究将菌体培养及其对染料的吸附分离.结果表明,青霉菌BX1生长分3个阶段:孢子活化、线性生长和菌体自解.菌体生长的最佳温度为30℃,最优碳源依次为淀粉＞木糖＞蔗糖＞麦芽糖＞葡萄糖＞乳糖,最佳pH值为4.0用培养48h的活菌体吸附水中的100mg/L的活性艳蓝KN-R,120min脱色率达93.7%,20℃时菌体(以干菌重计)对染料的最大饱和吸附量为159mg/g.     

酶法原位制备过氧乙酸对活性艳蓝KN-R氧化脱色的工艺

利用过水解酶催化合成过氧乙酸,过氧乙酸原位氧化活性艳蓝KN-R脱色.在单因子试验的基础上,通过正交优化试验确定活性艳蓝KN-R的最佳脱色条件为:在5 m L反应体系中,最适p H 5.0,加酶量为20 U·反应-1,乙酸乙酯对过氧化氢的摩尔比率为40∶1和活性艳蓝KNR的浓度为80 mg·L-1.在此条件下反应6 h后,活性艳蓝KN-R的脱色率为81.11%,24 h后的脱色率为91.96%.在50倍放大试验中,该工艺24小时的脱色率为84.55%.     

固定化青霉菌吸附活性艳蓝KN-R的脱色研究

利用植物载体玉米芯对青霉菌X5进行了固定化研究.通过正交试验确定载体固定化真菌的最优条件,考察了pH值、温度、盐浓度、葡萄糖浓度对菌株脱色的影响.结果表明,菌量为8g/L,载体大小为1/3×1cm²×π×1cm,载体个数为15个,摇床转速为100r/min条件下玉米芯能够有效地固定菌体,固定化菌对染料脱色的最佳温度为30℃,pH值为3.0,葡萄糖浓度为10g/L,盐度对脱色有一定的影响,在最优条件下,固定化菌对活性艳蓝KN-R脱色率达到95%以上.固定化菌对活性艳蓝脱色符合二级动力学方程,生物吸附过程较好地符合Freundlich吸附模型,固定化菌体重复利用5次后,脱色率仍达73.51%.     

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.     

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.