离子交换树脂对高浓度氨氮废水的吸附研究

采用D707、D708两种不同类型的离子交换树脂对高浓度氨氮废水进行吸附处理研究,分析了不同的吸附条件及等温吸附模型对吸附效果的影响.静态吸附实验表明:NH+4的吸附率随树脂投加量的增大而增加,在非碱性条件下树脂对NH+4的吸附率随p H的升高而增加;恒速振荡时间达到90 min以上时两种树脂可吸附平衡,当p H为7时,D707、D708树脂对NH+4的吸附容量分别达到196.1、217.4 mg·g-1;D707、D708树脂对NH+4的吸附属吸热过程,随温度的升高树脂对NH+4的吸附率逐渐增大,在298 K温度下D707、D708树脂吸附NH+4的表观吸附活化能Ea分别为54.67和34.46 k J·mol-1,吸附过程为液膜扩散主控制;树脂对NH+4吸附符合Langmuir吸附等温式;使用2 mol·L-1H2SO4对树脂进行解吸,脱附率达到98%以上,重复实验3次吸附率基本不变.     

对硝基酚在超高交联吸附树脂NDA-701上的脱附行为研究

通过碱当量选择、脱附动力学以及固定床吸附-脱附实验,研究了对硝基酚在自制的超高交联吸附树脂NDA-701上的脱附行为,考察了2个温度下不同碱当量比(MNaOH/4-NP)对树脂脱附率的影响;研究了3个脱附温度和3种MNaOH/4-NP值情况下NDA-701的脱附动力学性能;考察了NDA-701的固定床吸附性能和不同脱附...     

大孔树脂对柠檬黄吸附行为的研究

用三种大孔树脂NDA-7、NDA-99和ND-900作为吸附剂,对水溶液中柠檬黄进行吸附,探讨了温度、盐含量和pH值对不同类型树脂吸附行为的影响。实验结果表明,三种树脂对柠檬黄的吸附均符合Freun-dlich公式,在相同温度下,三种树脂对柠檬黄的吸附量大小顺序为ND-900〉NDA-99〉NDA-7;降温和减小溶液初始pH值均有利于三种树脂对柠檬黄的吸附;盐分对三种树脂的吸附效果均有严重的负效应,但是随着盐含量的增加,三种树脂对柠檬黄的吸附曲线又表现出不同的变化趋势。     

复合功能树脂吸附处理2-氨基吡啶生产废水的研究

采用中和法对2-氨基吡啶生产废水进行预处理,然后采用NDA-88复合功能吸附树脂固定床工艺对预处理过的废水进行动态吸附和脱附.实验结果表明,NDA-88树脂对2-氨基吡啶的吸附量为150.1 mg/g.每个周期处理废水30 BV(床体积),前12 BV出水COD由2 800mg/L降至100mg/L以下,后18BV出水...     

NDA-150 树脂对垃圾渗滤液生物处理出水的吸附

以NDA-150 树脂为吸附剂,研究了该树脂对垃圾渗滤液生物处理出水中有机物的吸附特性.结果表明,该树脂的吸附率受溶液的pH值影响较大,其最优pH 值为2.0.静态吸附动力学显示,树脂初期吸附速度较快,24h 内可使最终出水的COD 满足直排标准(<100 mg/L);72h基本达到吸附平衡.吸附过程符合Freundlich 方程,吸附放热,且为促进吸附过程.动态吸附脱附试验表明,1.000gNDA-150 树脂的COD 吸附量为175.6mg/g 树脂,且脱附峰比较集中,当NaOH 脱附液体积为120mL 时,有机物脱附率为99.8%.     

螯合型离子交换树脂在起爆药生产废水中的应用研究

采用螯合型离子交换树脂对起爆药生产废水中的重金属离子进行了动态吸附研究,探讨了流速、温度、初始浓度等因素对动态吸附、脱附的影响,并确立了适宜的工艺条件。实验结果表明:D418离子交换树脂处理K.D起爆药生产废水中的铅离子,吸附、脱附性能稳定。上批次20mL低浓度的脱附液套用于下批次的脱附,树脂的脱附率保持稳定。适宜工艺条件为:吸附流速60mL/h,吸附温度313K,脱附流速30mL/h,脱附温度室温,脱附剂3mol/L的硝酸,用量50mL。采用离子交换树脂工艺处理起爆药生产废水中的金属离子,不仅具有较高的处理效率,同时可以避免二次污染的产生,进行回收利用,因此是一种较好的处理起爆药生产废水中重金属离子的方法。     

UiO-66对废水中二氯苯氧乙酸的吸附特性

以Ui O-66型金属有机框架为吸附剂,研究了时间、p H值和温度对自制金属有机框架Ui O-66吸附2,4-D性能的影响.结果表明,Ui O-66的吸附平衡时间为24 h;初始溶液最佳p H值为4.0;Ui O-66上的平衡吸附量随温度的升高而增加,实验最佳温度应控制在30℃.Ui O-66对2,4-D的吸附符合Langmuir吸附模型;吸附动力学符合拟二级模型;颗粒内扩散过程是吸附速率控制步骤;热力学计算结果显示ΔG0、ΔH0、ΔS0,由此判断吸附是自发、吸热、熵增加的化学过程.本实验表明,Ui O-66在去除农业废水中2,4-D领域有实际应用的潜力.     

离子交换树脂处理铜冶炼废水中Cu(Ⅱ)的研究

为了探究铜冶炼废水中Cu2+的处理方法,本文选用D851型离子交换树脂处理废水中的Cu2+,通过离子交换树脂静态吸附实验确定了该树脂的最佳使用条件,最佳反应时间为60min,最佳反应温度为35℃,最佳反应p H值为5.5。     

改性壳聚糖的制备及其对水中酞酸酯的吸附

以柠檬醛化学改性壳聚糖,制备柠檬醛交联壳聚糖树脂。采用红外光谱(IR)、X射线衍射(XRD)、扫描电镜(SEM)、比表面测定及孔径分析方法表征柠檬醛交联壳聚糖树脂的结构。在25℃,pH为7条件下,考察柠檬醛交联壳聚糖树脂对3种酞酸酯(PAEs)邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二丁酯(DBP)和邻苯二甲酸2-乙基己酯(DEHP)的吸附性能,剖析吸附机理。研究结果表明,壳聚糖对DMP、DEHP和DBP的吸附容量分别为92、113和87 mg/g,而柠檬醛交联壳聚糖树脂对DMP、DEHP和DBP的吸附容量分别为147、166和190 mg/g,柠檬醛交联壳聚糖树脂对3种PAEs的吸附效果明显提高,吸附动力学均满足一级动力学方程。经吸附剂再生实验,柠檬醛交联壳聚糖树脂对PAEs的脱附率达到96.5%~97.1%,可重复使用。     

硅藻土吸附处理铜离子废水的研究

本文以硅藻土为吸附剂,静态处理含铜废水,探讨了硅藻土用量、吸附时间、初始p H值、反应温度和污染物初始浓度对废水处理效果的影响,结果表明:在污染物浓度为60mg/L,硅藻土用量为5 g/L、吸附时间为30 min、p H值为5、温度为25~35℃时,铜离子去除率可达62%。在30℃及p H等于5时,最大吸附量为13.831 mg/g,符合Langmuir方程。     

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.     

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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