用1-(2-吡啶偶氮)—2-萘酚改性硅胶富集天然水中痕量铜

用螯合剂改性硅胶富集和分离痕量金属铜离子已有报道。本文报道了用吸附1-(2—吡啶偶氮)-2-萘酚(PAN)的改性硅胶(PAN-SG)富集并测定天然水中痕量Cu~(2+)的工作。 实验部分 1.试剂和仪器 Cu~(2+)标准溶液(1.018mg/ml,0.500mg/ml);PAN的乙醇溶液(3.407×10~-_3mol/L,2.5×10~(-3)mol/L);Britton-Robison(B.R.)缓冲液(0.02mol/L,pH1.8     

化学发光法检测空气中NO_2研究

以0.2%的三乙醇胺水溶液作为二氧化氮吸收液,将空气中二氧化氮转化为亚硝酸盐,进而测出空气中二氧化氮的浓度。通过实验发现,进样方式、载流速度、硫酸浓度、溴酸钾浓度和酸性铬蓝K的浓度对该体系的发光强度都有影响,确定了体系的最优条件,建立了标准曲线,亚硝酸根的浓度在6.0×10-9～1.0×10-5mol/L范围内分段有很好的线性关系,检出限为8.5×10-11mol/L。对1.0×10-8mol/L和1.0×10-6mol/L的亚硝酸根进行11次平行测定,相对标准偏差分别为1.8%和2.2%。用该方法对氧化剂实验室空气中的二氧化氮含量进行了检测并进行标准加入和回收实验,回收率在95%～104%之间,该法可用于大气环境中的NO2测定。     

报废汽车内饰件塑料浮选技术研究

报废汽车内饰件塑料品种复杂、难以分选,为此,以分离汽车内饰件中4种主体塑料——PP(聚丙烯)、ABS(丙烯腈-丁二烯-苯乙烯)、PC(聚碳酸酯)、PVC(聚氯乙烯)为目标,利用实验室自制浮选设备,考察了浮选液流量、溶气罐压力、润湿液浓度等因素对浮选效果的影响. 结果表明:当溶气罐压力为0.22 MPa、浮选液流量为10 L/min、润湿液中ρ(单宁酸)为15 mg/L时,一级浮选PP、ABS、PC、PVC效果达到最佳,其中PP和ABS为上浮料,二者上浮率分别为100%和98.63%;PC和PVC为下沉料,二者下沉率分别为98.95%和100%. 当溶气罐压力为0 MPa、浮选液流量为6 L/min、润湿液中ρ(单宁酸)为10 mg/L时,二级浮选完全分离PP/ABS;当溶气罐压力为0.24 MPa、浮选液流量为10 L/min、润湿液采用10 mg/L单宁酸和10 mmol/L癸二酸二丁酯时,二级浮选分离PC/PVC效果达到最佳,PC上浮率为92.87%,PVC下沉率为91.41%. 通过二级浮选分离,PP、ABS、PC、PVC的最终分离率分别达到100%、98.63%、92.87%和91.41%,显示出该二级浮选工艺在报废汽车内饰件塑料分选方面具有较为广阔的应用前景.      

吸附溶出伏安法同时测定水中痕量铅和锌

本文报告了同时测定痕量铅和锌的一种新方法.在0.01mol/LHAC-0.01mol/LNAC-1.2×10~(-5)mol/L乙醛酸缩氨基硫脲(GATSC)中,Pb-GATSC和Zn-GATSC络合物均产生非常灵敏的络合吸附波,峰电位分别是-0.63V和-0.82V(VS·SCE).峰电流和Pb、Zn的浓度分别在1.0×10~(-8)～3.0×10~(-7)mol/L和3.O×10~(-8)～8.O×10~(-7)mol/L范围内成直线关系,铅的检出限是2.0×10~(-9)mol/L,锌的检出限是8.0×10~(-9)mol/L.这一方法已被用于测定水中痕量铅和锌,结果令人满意.     

[Bmim]PF_6溶剂浮选UV-Vis检测水中四环素类抗生素

建立了一种分离/富集的新体系——离子液体气浮溶剂浮选,该体系集离子液体萃取和气浮溶剂浮选优势于一体,以离子液体1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF)6和乙酸乙酯(EA)混合溶剂为浮选溶剂,以稀土金属离子La(Ⅲ)或Ce(Ⅲ)为捕集剂,分离/富集了水中的四环素类抗生素,并用紫外-可见分光光度法测定其总含量,线性范围分别为0.0～34μg/L、0～23.0μg/L,表观摩尔吸光系数分别为ε390=1.92×105L/(mol·cm),ε380=1.15×105L/(mol·cm)。实测了鱼塘水样,加标回收率为84.06%～106.15%,RSD3.31%。研究结果表明:该方法灵敏度高、选择性好、富集倍数大、污染小,适用于环境水样中痕量四环素类抗生素的分离分析。     

导数示波极谱法测定农药中的三氯乙醛

本文报导用导数示波极谱法直接测定农药中微量三氯乙醛的方法。实验结果表明,三氯乙醛在0.010mol/L NH_4Cl、5.00×10~(-4)mol/L EDTA和2.00×10~(-6)mol/L四乙基溴化铵组成的底液中,于滴汞电极上产生灵敏的峰电流。峰电位为-1.55V(Vs·S·C·E·)。检测下限为3.00×10~(-7)mol/L;浓度在3.00×10~(-7)～1.00×10~(-3)mol/L范围内与峰电流呈良好的线性关系。     

聚酰胺复合纳滤膜去除水中PFOS的研究

利用聚酰胺复合纳滤膜去除水中的PFOS,在0.6MPa操作压力条件下过滤12h,研究PFOS浓度、离子种类、总离子强度以及海藻酸对PFOS截留效果的影响.结果表明,随着PFOS浓度增大其截留率也随之升高;溶液总离子强度越大,PFOS截留率越高,当过滤进行到12h时,溶液总离子强度为150mmol/L时,PFOS的截留率比溶液总离子强度为10mmol/L时仍高2.1%;溶液中加入1mmol/L Ca²⁺时PFOS的截留效果优于加入1mmol/L Na⁺时的效果;并且随着二价离子浓度的增加,截留率上升,过滤结束时,Ca²⁺浓度为3mmol/L的条件下PFOS的截留率约为97.5%,高于1mmol/L Ca²⁺存在时PFOS的截留率（95%）;海藻酸存在时PFOS的截留率显著增高,尤其在1mmol/L钙离子存在条件下,过滤12h后PFOS的截留率仍可达到95%以上,但海藻酸会导致膜污染的发生从而引起膜通量下降.     

重组基因酵母法研究酞酸酯类化合物的类雌激素作用

为了检测五种酞酸酯类化合物的类雌激素活性,采用重组人雌激受体α、相关效应元件以及β-半乳糖苷酶报告基因酵母分别测定17β-雌二醇(E)2、邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二辛酯(DOP)、邻苯二甲酸丁苄酯(BBP)单独作用时诱导酶活并计算其EC50。通过各化合物与E2的EC50的比以及最大β-半乳糖苷酶活性来比较酞酸酯类化合物的类雌激素活性。五种酞酸酯类化合物的实验浓度范围为1.0×10-3~1.0×10-11 mol/L。结果表明,DEP(1×10-7~1×10-9 mol/L)、DBP(1×10-6~1×10-9 mol/L)、BBP(1×10-3~1×10-6 mol/L)具有明显的类雌激素活性,诱导的最大酶活分别为:1.515、0.832 2、1.669,而DMP和DOP并未检出明显的类雌激素活性。DEP、DBP、BBP与E2的EC50的比分别为8.85×10-2、2.54×10-2、8.82×10-6。说明DEP、DBP在低浓度就表现出类雌激素活性,而BBP在较高浓度才表现出类雌激素活性。     

光助Fenton反应降解水溶性染料曙红Y脱色研究

对水溶性染料曙红Y使用Fenton试剂结合光催化氧化降解褪色的过程进行了研究,对该反应的4种主要影响因素加以分析:染料浓度、Fenton试剂用量、光源、初始pH值。经过系列的研究分析得出了曙红Y降解的最佳降解条件,并对Fenton试剂光催化氧化反应机理进行了初步探讨。实验结果表明:太阳光照射能有效地促进曙红Y的降解褪色(脱色率大于95%),明显缩短褪色时间,节约氧化剂的用量。当Fe2+浓度在3.50×10-5~7.19×10-5mol/L之间以及H2O2的摩尔量为染料摩尔量的50~100倍时,太阳光光照能有效地促进0.10 g/L以下浓度的曙红Y的降解。     

沉淀浮选法回收废液中稀土的实验研究

依据沉淀浮选法的基本原理,提出了从废酸中回收RE_2O_3的方法.用Na_2SO_4作沉淀剂,与RE~(3+)形成溶解度小的RE_2(SO_4)_3·xNa_2SO_4·yH_2O复盐;用月桂胺作捕收剂浮选回收,RE_2O_3的回收率达98％以上。用(NH_4)_2SO_4作沉淀剂分离废酸中的Ca~(2+),去除率达99％,从而使浓度为2mol/L的HCl废酸能循环使用。     

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.     

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.     

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.     

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.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.