胶团强化超滤处理含镍废水

胶团强化超滤(MEUF)是一种高效分离水中金属离子的技术。以无机陶瓷膜为媒介,采用胶团强化超滤法处理含镍废水,考察膜孔径,表面活性剂十二烷基硫酸钠(SDS)浓度、镍离子浓度、pH值等因素对胶团强化超滤过程的影响。实验结果表明:膜孔径、SDS浓度、pH值对镍离子截留率有显著影响。当废水温度为20℃,操作压力为0.15 MPa,膜孔径为20 nm,SDS浓度为6.0 mmol/L时超滤效果最好;在此条件下,镍离子的截留率达99.25%,膜通量为89.65 L/(m2.h)。     

胶束强化超滤处理阿特拉津的研究

常规处理工艺并不能有效去除水中的环境内分泌干扰物质。研究采用十二烷基硫酸钠(SDS)为表面活性剂对阿特拉津进行增溶,并采用聚砜超滤膜和SDS胶束强化超滤处理阿特拉津。考察了SDS浓度、操作压力、无机盐、β-环糊精和烷基多苷(APG)等因素对工艺的影响。结果表明,胶束强化超滤对阿特拉津的去除率可达80%以上,无机盐、β-环糊精、APG和SDS的复配可以提高阿特拉津的去除率。     

O3/H2O2降解阿特拉津影响因素研究

摘要采用O3/H2O2,氧化去除水中内分泌干扰物阿特拉津,考察了反应条件及水质对去除的影响,并对反应机制进行了初步探讨。阿特拉津初始浓度2mg/L,投量为7．5mg/L的O3,单独氧化去除率为27．2％;相同O3投量下,控制H2O2/O,摩尔比为0．75,5min阿特拉津的去除率最高可达96．5％;pH值为7．5～8．5,温度在25～40℃的范围内,都维持了较高的去除率,表明H2O2/O3,体系对阿特拉津的去除效果良好,降解速度快,反应条件温和。0．5mg/L的腐殖酸,对阿特拉津的去除影响不大,腐殖酸浓度为1、2和5mg/L时,平均去除率分别为63．4％、50．7％和30．2％;碳酸氢钠的浓度为50和200mg/L时,去除率分别为88．1％和73．8％,说明水质对阿特拉津的去除影响较大。叔丁醇的浓度为5和20mg/L时,阿特拉津的去除率分别降低到44．7％和27．5％,去除率随自由基抑制剂叔丁醇增加而降低,说明H2O2/O3降解阿特拉津主要为该体系产生的羟基自由基的贡献。     

固相好氧反硝化同步去除水中硝酸盐和阿特拉津可行性研究

研究了利用固相好氧反硝化同步去除水中硝酸盐和阿特拉津的可行性。通过释碳性能的比较得出淀粉基颗粒是适宜的反硝化碳源,在间歇式实验中,初始硝态氮浓度为55~60 mg/L时,平均反硝化速率为7.03 mg/(L·h),能有效去除水中的硝酸盐。当水中阿特拉津浓度低于10 mg/L时,对好氧反硝化脱氮没有影响,浓度增加至20 mg/L,对反硝化有抑制作用。在好氧反硝化条件下,阿特拉津初始浓度分别为0.1,1 mg/L时,24 h后去除率分别为93%和94.8%,阿特拉津的去除主要通过吸附作用。     

电解法回收胶团强化超滤(MEUF)浓缩液中的Cd2+

胶团强化超滤是基于表面活性剂的双亲分子结构特性去除水中金属离子的新方法.重金属离子废水经胶团强化超滤处理后的浓缩液中含有高浓度的重金属离子,需进一步处理.采用电解法回收胶团强化超滤浓缩液中的Cd2+,考察了电极种类、电压、电解时间、pH、SDS与Cd2+浓度比等5个条件对电解效率的影响.研究发现,表面活性剂对电解有一定的阻化作用.实验得到最佳条件为:不锈钢(阳极)-石墨(阴极),U为2.8 V,电解时间为100 min,pH为4,[SDS]/[Cd2+]=5([SDS]=8.5 mmol/L恒定).在此条件下,浓缩液中的Cd2+的回收率达到了50.26%.     

武汉市饮用水中阿特拉津及降解产物浓度特征

为了解武汉市政水厂水源水和出厂水中阿特拉津及降解产物的浓度水平和去除率,该文采用超高效液相色谱-串联质谱法,对10家市政水厂在丰水期和枯水期采集的水源水和出厂水中的阿特拉津及降解产物进行检测,检测物质分别为阿特拉津(ATZ)、异丙基阿特拉津（DIA）、二丁基阿特拉津(DEA)、二氨基氯代阿特拉津（DACT）和羟基阿特拉津(OH-ATZ)。研究结果显示,水源水中ATZ的浓度中位数是37.2 ng/L,降解产物浓度依次为DEA(5.88 ng/L)、OH-ATZ(5.07 ng/L)、DIA(3.12 ng/L)和DACT(1.26 ng/L),阿特拉津及降解产物在汉江水中的含量是长江水的3～5倍。水源水和出厂水中DIA和DEA在丰水期7月浓度较高,而DACT在枯水期5月浓度较高。经过常规水处理工艺流程后,ATZ几乎未被去除,DIA和DACT出现去除率负增长,建议在常规水处理工艺中增加颗粒活性炭和臭氧等工艺,以降低饮用水中阿特拉津及降解产物的浓度。     

强化反硝化条件下地下水中阿特拉津的生物降解研究

利用所筛选的(从吉林市农药厂下水污泥中分离得到)实验菌种A1,在强化反硝化的厌氧条件下进行阿特拉津的降解实验研究,研究结果表明:降解的最适条件为pH=7,温度为20℃,NO_3~-浓度为30mg/L(当阿特拉津浓度为29.89mg/L时),菌的初始接种量为5.6×10~6个/mL。模拟温度为10℃的地下水环境,21天内菌对阿特拉津的降解率可以达到65.7%,虽然低于好氧条件下83.6%的降解率,但不需要向地下水中通氧,从而可降低处理成本。     

SDS、SDBS胶团强化超滤Cu~(2+)的比较

采用模拟含Cu2+废水,以阴离子表面活性剂SDS和SDBS胶团强化超滤分离Cu2+(Cu2+固定为0.6 mmol/L),通过对渗透通量、渗透浓度、去除率、富集率的比较,从而得出SDS、SDBS分离效果的优劣.结果表明,添加SDS的渗透通量始终高于SDBS[其中SDS平均渗透通量为29.92 L.(m2.h)-1,而SDBS只有16.55 L.(m2.h)-1],渗透浓度始终低于SDBS,当渗透液Cu2+浓度接近为0时,SDBS、SDS所需浓度分别为2 mmol/L和6 mmol/L.SDS的Cu2+去除率和平均富集率高于SDBS(SDS平均去除率为85.06%,平均富集率为4.18;SDBS对应值分别为69.05%,4.05).此外,SDS自身的平均富集率也高于SDBS(SDS为3.89,SDBS为3.13).由此可见,SDS比SDBS更适合去除Cu2+.     

水中除草剂阿特拉津的测定

采用二氯甲烷液液萃取-氮吹浓缩-丙酮定容去除干扰物,用气相色谱检测水中的阿特拉津,根据保留时间定性,外标法定量.本方法适用于水中阿特拉津的残留量分析,最低检测浓度为4.51×10-2 μg∕L.     

海藻酸钠强化超滤含铜废水

聚合有机物强化超滤技术因具有操作压力低、膜通量大且截留效果好的优点,而受到了广泛的关注.文章研究了天然有机物海藻酸钠强化超滤去除模拟含铜废水的特性及影响因素,试验结果表明,当海藻酸钠投加量为100 mg/L.pH=6.0,温度为25℃,Cu2+初始浓度为10mg/L时,MWCO(截留分子量)为4 kDa.6 kDa,1...     

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.     

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.     

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.     

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.     

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.     

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.     

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.