天然高分子吸附剂研究——羧甲基交联壳聚糖树脂的合成及吸附特性

以壳聚糖为原料，经乙二醇双缩水甘油醚交联后，与氯乙酸反应，合成了羧甲基交联壳聚糖树脂，并研究了其对Ｃｕ＾２＋、Ｎｉ＾２＋，Ｃｏ＾２＋的静态吸附性能，结果表明，该树脂对上述３种金属离子均具有良好的吸附性能，其吸附容量分别达２．２５，１．９８和１．８１ｍｍｏｌ·ｇ＾－１。     

改性壳聚糖重金属生物质吸附剂的制备及表征

为改善壳聚糖的耐酸性及对Pb(Ⅱ)的吸附容量,将壳聚糖与丙烯酰胺接枝,再与戊二醛进行交联,制备出了壳聚糖改性聚合物(G-CAM)。研究了制备条件对接枝率和接枝效率的影响,结果表明,在T=70℃;单体浓度(m壳聚糖:m丙烯酰胺)为1:3;引发剂浓度为0.10g;接枝反应时间为4h时,可制得较为满意的接枝壳聚糖产物。对交联剂的用量通过耐酸性实验和Pb2+吸附实验进行了考察,结果表明,当m壳聚糖:m丙烯酰胺=1:3(m壳聚糖=1g)时,交联剂戊二醛的加入量为0.6mL,得到的产物制备成的吸附剂不但有较好的耐酸性,而且对Pb(Ⅱ)吸附效果最佳。经吸附剂再生实验,G-CAM对Pb(Ⅱ)的吸附量变化幅度小于1%,可重复使用。     

羧基淀粉接枝聚合物的制备及其在重金属离子废水处理中的应用

本文研究了玉米淀粉经环氧氯丙烷交联制成高交联淀粉后,以Ge~(4+)为引发剂,把丙烯腈接枝到高交联淀粉上,通过碱皂化作用将腈基转化为羧基制备羧基淀粉接枝聚合物(ISC)的方法。并研究了ISC在含重金属离子废水处理方面的应用。     

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。     

壳聚糖接枝共聚物在污泥脱水中的应用研究

以壳聚糖为原料,通过接枝共聚反应分别合成壳聚糖-AM-DMDAAC,壳聚糖-AM,壳聚糖-AA三种不同类型的天然改性高分子絮凝剂.对活性污泥脱水性能的研究结果表明,与其它两种壳聚糖接枝共聚物相比,壳聚糖-AM-DMDAAC阳离子型接枝共聚物是适合污泥脱水的良好絮凝剂.对于100 mL污泥,当污泥pH值为6.00,投药量为20 mg/L,真空度0.05 MPa下,阳离子型壳聚糖接枝共聚物真空抽滤1 min的滤液体积可达到70 mL,抽滤 5 min 后,可将污泥含水率从95.4%降低到86.4%,脱水效果优于其它几种常用的污泥脱水剂.     

壳聚糖乙酸酯冠醚对金属离子的吸附性能研究

利用壳聚糖Ｃ２位上活泼氨基与苯甲醛进行反应,制得了Ｓｃｈｉｆｆ碱苯甲醛壳聚糖（简称ＣＴＢ）,再将合成的二苯并１６－冠－５氯代乙酸酯冠醚接枝到ＣＴＢ上,得到壳聚糖－苯并１６－冠－５乙酸酯冠醚（简称ＴＣＢＣ）,使其在酸性条件下脱去苯甲醛,制得壳聚糖－二苯并１６－冠－５－乙酸酯冠醚（简称ＣＴＣＥ）。经元素分析、红外光谱分析表征了其结构。并研究了ＣＴＢＣ和ＣＴＣＥ对Ｐｂ＾２＋、Ｃｕ＾２＋、Ｃｒ＾３＋、Ｎｉ     

交联改性壳聚糖的制备及其对Ni2+的吸附性能

以壳聚糖为原料,甲醛为预交联剂,戊二醛为交联剂,通过反相乳液聚合法制备了改性壳聚糖吸附剂.通过正交试验考察了交联反应条件对改性壳聚糖吸附Ni2+性能的影响,得出的最佳交联条件为:甲醛用量1 mL,反应温度70℃,戊二醛用量2 mL,反应时间2h.在最佳条件下制备的交联壳聚糖对Ni2+的吸附量达1.98 mmol/g.对吸附Ni2+后的交联壳聚糖分别用0.1 mol/L盐酸和0.1 mol/L氢氧化钠溶液进行脱附,结果表明用0.1 mol/L氢氧化钠溶液脱附效果较好.     

诺氟沙星吸附剂生物炭-壳聚糖复合微球的制备优化

为了提高生物炭-壳聚糖复合微球对NOR（诺氟沙星）的吸附能力,以复合微球对NOR的吸附量为指标,考察了生物炭与壳聚糖质量比、壳聚糖脱乙酰度、戊二醛用量、交联时间、交联速率及生物炭热解温度对复合微球吸附NOR的影响,并由均匀试验确定复合微球的最佳制备条件.结果表明,生物炭与壳聚糖质量比、壳聚糖脱乙酰度、戊二醛用量、交联时间、交联速率及生物炭热解温度对复合微球吸附NOR具有明显影响.制备复合微球的关键影响因素是生物炭热解温度、戊二醛用量和交联速率.吸附NOR的复合微球最佳制备条件:生物炭热解温度为300℃、生物炭与壳聚糖质量比为5:1、壳聚糖脱乙酰度为77%、戊二醛用量为80 mL、交联速率为150 r/min、交联时间为3 h.此时,复合微球对NOR的吸附量为9.51 mg/g,且具有较高的耐酸溶性和机械强度.研究显示,复合微球能够高效吸附NOR,并且吸附后容易分离,具有修复水体污染的潜力.      

端烯丙基苯并15-冠-5接枝壳聚糖对金属离子的吸附性能

将３’－端烯丙基苯并１５－冠－５和４’－端烯丙基苯并１５－冠－５接枝到壳糖或交联壳聚糖上,合成了４种新新型的壳聚糖冠醚,并研究了这４种壳聚糖冠醚对Ｐｄ＾２＋、Ｃｕ＾２＋、Ｈｇ＾２＋的静态吸附性能。结果表明,这４种吸附剂对Ｐｄ＾２＋具有良好的吸附性能,并能在Ｃｕ＾２＋和Ｈｇ＾２＋共存的条件下选择吸附Ｐｄ＾２＋。     

铅模板交联壳聚糖对Pb(Ⅱ)的吸附性能

研究了脱乙酰度、粒度和溶液pH值等因素对壳聚糖吸附铅离子性能的影响,得到了最佳吸附条件为壳聚糖脱乙酰度100%和溶液pH值6.5.在该条件下,壳聚糖与铅离子作用后,用戊二醛交联,然后用盐酸洗脱铅离子,合成了铅交联壳聚糖模板树脂.探讨了交联剂量对交联壳聚糖吸附性能的影响以及铅模板交联壳聚糖对金属离子的吸附性能.结果表明,在CHO/NH₂为0.75:1时合成交联壳聚糖树脂对铅离子有最大吸附量,并且该树脂对铅离子和铜离子有较高的选择性,在酸性条件下不会发生软化和溶解,重复使用性良好.     

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.