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1.
采用投加预处理烟束曲霉(Aspergillus fumisynnematus)死菌体的方法去除含铬废水中的Cr(Ⅵ).考察了不同溶液初始pH值、Cr(Ⅵ)初始浓度、死菌体投加量及温度条件下,CTAB预处理烟束曲霉死菌体对Cr(Ⅵ)还原速率和总Cr的平衡吸附率的影响,并根据红外光谱分析初步探讨了CTAB预处理烟束曲霉死菌体与Cr的相互作用机理.结果表明:CTAB预处理烟束曲霉死菌体对总Cr有良好的吸附效果,在30℃.150 r·min-1,pH 2.0的条件下,在100mL浓度20gg·L-1的Cr(Ⅵ)溶液中投加0.5 g CTAB预处理烟束曲霉死菌体,2h内总Cr最大吸附率达到了72%,约为原死菌体总Cr吸附率的2倍,但反应达到平衡后的总Cr吸附率下降到30%左右.吸附平衡后的解吸实验结果表明Cr(Ⅵ)几乎全部被还原为Cr(Ⅲ).在实验pH值范围内,pH值越低、Cr(Ⅵ)初始浓度越小、预处理死菌体投加量越大以及温度越高,越有利于Cr(Ⅵ)的还原;pH值越高、Cr(Ⅵ)初始浓度越小、预处理死菌体投加量越大以及温度越低,对总Cr的平衡吸附率越大.预处理死菌体与Cr的相互作用主要是氨基和羧基与不同形态Cr的吸附作用以及菌体对Cr(Ⅵ)的还原作用.  相似文献   

2.
利用小型EGSB反应器培养的硫酸盐还原颗粒污泥进行Cr(Ⅵ)去除实验,考察硫酸盐还原颗粒污泥对Cr(Ⅵ)的去除特性及对总Cr的平衡吸附并进行吸附等温式拟合.结果表明,颗粒污泥对Cr(Ⅵ)的去除是物理、化学及生物过程共同作用的结果,主要包括了还原及吸附作用.颗粒污泥对Cr(Ⅵ)的去除作用与环境因素、颗粒污泥的化学组成和结构的完整程度等密切相关.对Cr(Ⅵ)的去除速率随颗粒污泥投加量及Cr(Ⅵ)初始浓度的增加而提高;提高振荡速度和温度均可提高Cr(Ⅵ)的去除效率及对总Cr的吸附速率,但当振荡速度达到150r·min-1时或温度达到40℃时颗粒污泥会出现结构的离散并降低总Cr的平衡吸附量;pH值越低颗粒污泥对Cr(Ⅵ)的去除效率就越高,但颗粒污泥表面的硫化物在pH值为酸性时会转化成H2S气体逸出,并因此影响对总Cr的吸附效率.颗粒污泥对总Cr的最大吸附量为6.84mg·g-1,其对总Cr的吸附过程符合Langmuir吸附等温式.  相似文献   

3.
采用磷酸酸化处理米糠,使用改性米糠处理含铬废水,以吸附率为评价指标,考察了吸附剂添加量、pH值、反应时间、温度及溶液Cr(Ⅵ)初始质量浓度等主要因素对吸附率的影响。实验结果表明,酸改性米糠对含铬废水具有较优异的吸附效果,最大吸附率可达到81.3%;pH值为影响吸附率的最重要因素,pH值等于2时,吸附剂对Cr(VI)吸附效果最好;米糠用量、反应时间和溶液初始Cr(Ⅵ)浓度分别为17.5 g/L,90 min,30 mg/L时吸附效果最佳。  相似文献   

4.
分别考察了YSQ-2菌丝球活体、菌丝球死菌体及死菌体粉末3种菌体对溶液中Cr(Ⅵ)的去除过程。实验结果表明3种YSQ-2菌体均能在48 h内完全去除溶液中的Cr(Ⅵ),对Cr(Ⅵ)的去除效率排序为:死菌体粉末菌丝球死菌体菌丝球活体;3种YSQ-2菌体均能有效吸附溶液中的Cr,对Cr的吸附效果排序为:菌丝球活体菌丝球死菌体死菌体粉末,48 h后的平衡吸附率分别为32.2%、23.0%和11.4%。对解吸实验表明3种菌体所吸附的Cr的形态均为Cr(Ⅲ)。菌体对Cr的吸附效率与溶液中的Cr(Ⅵ)浓度有密切关联,在其他条件不变的情况下,溶液中Cr(Ⅵ)浓度越高,菌体对Cr的吸附效果会相对越好。  相似文献   

5.
谢翼飞  李旭东  李福德 《环境科学》2009,30(4):1060-1065
研究了硫酸盐还原菌(SRB)生成的生物硫铁纳米材料(纳米硫铁)的特性及其在高浓度含铬废水处理中的应用.采用透射电镜(TEM)、X-射线衍射(XRD)和X-射线光电子能谱(XPS)等测试方法对纳米硫铁特性进行分析,考察了pH、温度、投加量对纳米硫铁处理高浓度含铬废水影响,并与传统含铬废水处理方法进行了效果比较.结果表明,纳米硫铁材料粒径长为45~80 nm,长宽比10~15,其铁硫原子比为1.07~1.11,主要组分为无定形态硫化亚铁(amorphous FeS)和四方硫铁矿(mackinawite).反应体系pH、温度、投加量是影响纳米硫铁去除Cr(Ⅵ)的主要因子,pH越低,温度越高,纳米硫铁投加量越大,对Cr(Ⅵ)的去除速率越快.其中pH值对Cr(Ⅵ)的去除影响最大,在pH=3、 25℃、纳米硫铁与Cr(Ⅵ)摩尔比为1.17/1时,10 min即可使Cr(Ⅵ)浓度0.03 mol/L的废水达标排放.此外,纳米硫铁较市售分析纯硫化亚铁具有处理时间短、投加量少等优点;较传统生物处理(SRB法)具有污泥量少和出水COD低等优点.  相似文献   

6.
该文通过沉淀法制备了FeS,并利用SEM及XRD对其表征,通过批实验进行了FeS去除水中Cr(Ⅵ)的研究,主要考察了温度、pH、FeS投加量及初始Cr(Ⅵ)浓度对Cr(Ⅵ)去除效率的影响。结果表明:Cr(Ⅵ)的去除效率随着温度的升高以及溶液pH值的降低而升高;当Cr(Ⅵ)为30mg/L时,FeS的最佳投加量为0.2g/L。FeS与Cr(Ⅵ)的反应符合假一级反应动力学模型,表观活化能为21.78kJ/mol。  相似文献   

7.
磁性壳聚糖微球吸附水中As(Ⅲ)的实验研究   总被引:2,自引:0,他引:2  
文章主要考察实验室制得的乙二胺改性磁性壳聚糖微球对毒性高,迁移能力强的A(sⅢ)去除效果。通过单因素实验研究了pH值、吸附时间、A(sⅢ)溶液初始浓度和吸附剂投加量对磁性壳聚糖微球吸附除A(sⅢ)效果的影响。实验结果表明在pH值为2,吸附时间为90 min,磁性壳聚糖微球投加量为0.4 g时,对初始浓度为10 mg/L,体积为100 mL的A(sⅢ)溶液去除率达到96.96%,吸附后溶液中A(sⅢ)浓度仅为0.304 mg/L,低于我国污水综合排放标准中砷含量标准值。磁性壳聚糖微球的解吸实验表明,吸附剂解吸4次后,对A(sⅢ)的去除率仍达到95%以上,吸附性能稳定,具有较好的可重复利用性。因此,磁性壳聚糖微球是一种去除低浓度含砷废水非常有效的材料。  相似文献   

8.
壳聚糖-钇多孔微球对Cr(Ⅵ)的吸附性能与机理分析   总被引:1,自引:0,他引:1       下载免费PDF全文
以壳聚糖和Y2(OH)5NO3为原料通过乳液交联法制备了壳聚糖-钇(Ch—Y)复合微球,通过扫描电镜、透射电镜、X射线衍射、红外光谱等方法对其表面形貌、结构进行了表征.探讨了溶液的pH值、反应时间、投加量、离子初始浓度对其吸附性能的影响.研究结果表明,壳聚糖-钇(Ch—Y)复合微球在pH值为3的酸性环境中对Cr(Ⅵ)保持了较高的吸附能力,吸附容量为52.39mg·g-1,其吸附行为符合Langmuir吸附等温模型;通过吸附机理的研究,发现壳聚糖-钇(Ch—Y)对Cr(Ⅵ)吸附是化学吸附静电吸附协同氧化Cr(Ⅵ)离子作用来实现的.  相似文献   

9.
为了有效提高水中Cr(Ⅵ)和Cr(Ⅲ)去除效果,将高分子絮凝剂二硫代羧基化羟甲基聚丙烯酰胺(DTMPAM)和三氯化铁(FeCl3)进行复配应用到含铬废水的处理中,通过絮凝实验法分别考查了DTMPAM复配FeCl3前后对含Cr(Ⅵ)水样和含Cr(Ⅲ)水样的去除性能.结果表明,DTMPAM在pH值分别为3.0、4.0、5.0时,单独投加DTMPAM对含Cr(Ⅲ)水样中Cr(Ⅲ)的去除效果均不太理想,Cr(Ⅲ)的最高去除率分别为23.80%、41.11%、42.38%;FeCl3的投药顺序和浓度对DTMPAM复配FeCl3去除水样中Cr(Ⅲ)具有较大影响,按照先投加FeCl3后调节pH值再投加DTMPAM进行絮凝的投药顺序,且FeCl3浓度为60 mg·L-1时,含Cr(Ⅲ)水样中Cr(Ⅲ)的最高去除率可达到99.55%.单独投加DTMPAM对含Cr(Ⅵ)水样中Cr(Ⅵ)具有良好的去除效果,而对总Cr的去除效果较差,当pH值为3.0、DTM...  相似文献   

10.
采用投加烟曲霉菌丝球方法去除水中的富里酸,研究了pH值、吸附时间、不同富里酸初始浓度、温度、以及菌丝球的投加量对烟曲霉菌丝球吸附富里酸的影响,并利用傅里叶红外光谱技术(FTIR)分析了烟曲霉菌丝球与富里酸的吸附官能团的相互作用。结果表明:烟曲霉菌丝球对富里酸有较好的吸附效果,在最佳pH 4时对富里酸的吸附量为9.49 mg/g;吸附时间10 min时,存在吸附量突降现象,45 min时对富里酸的吸附量最大,随后稍降低至不变。随着富里酸初始浓度的增大,烟曲霉菌丝球对富里酸的吸附量也随着增大。但随着烟曲霉菌丝球的投加量的增大,对富里酸的吸附量逐渐减少。吸附过程中,烟曲霉中的氨基与富里酸分子中的羧基发生了一定的化学作用,同时与羟基等基团形成氢键,为吸热过程。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels (behavior, sublethal, lethal). In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints (acute, chronic, behavioral). Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In the present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.  相似文献   

17.
Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.  相似文献   

18.
RemovalofheavymetalsfromsewagesludgebylowcostingchemicalmethodandrecyclinginagricultureWuQitang,NyirandegePascasie,MoCehuiF...  相似文献   

19.
UNITANK is a biological wastewater treatment process that combines the advantages of traditional activated sludge process and sequencing batch reactor, which is divided into Tank A, B and C. In this study, the sludge distribution and its impact on performance of UNITANK were carried out in Liede Wastewater Plant (WWTP) of Guangzhou, China. Results showed that there was a strong affiliation between Tank A and B of the system in sludge concentration distribution. The initial sludge concentration in Tank A could present the sludge distribution of the whole system. The sludge distribution was mainly influenced by hydraulic condition. Unsteady sludge distribution had an impact on variations of substrates in reactors, especially in decisive reactor, and this could lead to failure of system. Settler could partially remove substrates such as COD and NO3-N, but there was adventure of sludge deterioration. The rational initial sludge concentration in Tank A should be 4000-6000 mg/L MLSS.  相似文献   

20.
Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.  相似文献   

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