改性稻草秸秆对低浓度含油污水的吸附去除研究

对改性稻草秸秆吸附去除低浓度含油污水的效果进行了研究,稻草秸秆改性采用磷酸活化后高温改性。对其改性温度条件进行了优化,结果表明稻草秸秆最佳改性温度为500℃。考察了改性稻草的投加量和粒径,含油污水的盐度和温度等条件对低浓度含油污水吸附去除效果的影响。当改性稻草投加量为0.8 g/L时,对60 mg/L的含油污水中原油的去除率达到89.5%;原油的吸附去除效果随着样品粒径变小吸附能力提高,在盐度为15‰~30‰,温度为10~35℃,改性稻草秸秆对低浓度含油污水具有较好的吸附去除效果。改性稻草秸秆对低浓度含油污水的吸附过程符合准二阶动力学模型。     

改性材料在石油污染水体中的应用

研究了溶液中硬脂酸改性磁铁矿的改性条件,确定了改性时间、温度、改性剂用量等。对改性磁铁矿进行了活化指数、吸油量、透水时间等的测定,并通过红外图谱及扫描电镜图谱的分析,探讨了改性及吸附机理。     

硬脂酸和硅烷偶联剂KH570对氧化钙疏水改性研究

为开发事故情况下高浓度毒性有机物污染土壤快速固化/稳定化材料,本文以氧化钙(Ca O)为基材,硬脂酸和硅烷偶联剂KH570为两种改性剂,采用湿法工艺对Ca O粉体进行表面疏水改性,探讨不同工艺条件对改性效果的影响,并对改性后Ca O的形态和结构进行表征.结果表明,硬脂酸改性氧化钙的最佳工艺条件为:硬脂酸添加质量分数5%,改性温度30℃,改性时间30 min;KH570改性Ca O的最佳工艺条件为:KH570添加量0.02 m L·g-1Ca O,改性时间40 min.改性后Ca O的接触角均大于90°.傅里叶红外和扫描电镜分析表明,两种改性剂均以化学吸附的方式包覆在Ca O表面,达到了表面疏水改性的目的.     

改性核桃壳对石油烃类物质的吸附试验研究

为了研究改性制备核桃壳对石油烃吸附程度,以化学改性制备核桃壳为吸附剂,考察了溶液p H值、时间和温度对改性核桃壳吸附石油烃效果的影响。结果表明:当温度为298 K,p H为7.0,0.2 g改性核桃壳吸附处理100 m L浓度为60 mg/L的柴油溶液,80 min后吸附量最大,可达到12.57 mg/g。该吸附过程符合准二级动力学方程,其相关系数达到0.9999。在3种温度(298,308,318 K)条件下的吸附等温曲线更符合Freundlich模型。通过热力学计算证实,该吸附过程是吸热的、自发的过程,一定程度上的升温有助于石油烃的吸附。     

巯基改性玉米秸秆对水中Cu(Ⅱ)的吸附特性

采用巯基乙酸改性玉米秸秆(MACS)为吸附剂,研究不同影响条件下其对Cu(Ⅱ)的吸附特性.结果表明,当振荡速率为250r/min、吸附温度为40℃、吸附时间为60min、水样初始pH值为6.0时,吸附去除效果最佳,Cu(Ⅱ)去除率可达97.94％.准二级动力学可准确描述MACS对Cu(Ⅱ)的吸附过程,在吸附温度为45℃...     

改性钢渣对镉离子吸附特征的研究

对比不同的改性方法,研究改性钢渣对镉离子去除的效果,并对改性前后钢渣吸附性能进行比较。通过考察粒径、投加量、处理时间、镉溶液初始浓度等因素对吸附效果的影响,拟合吸附等温曲线。实验结果表明,高温活化改性钢渣效果最佳,当改性1.5 h,温度为800℃时镉离子去除率达到最高为94%。在室温条件下,在100 m L含镉溶液(镉离子初始浓度10 mg/L)中,投加1 g粒径为0.15~0.9mm的钢渣,振荡30 min后吸附达到最佳。高温改性钢渣对镉离子的吸附过程符合Freundlich方程,相关系数为0.998 4。     

有机污染物吸附特性最佳条件的确定

以兰州市柳沟河水质为研究对象,分析确定污水中有机污染物吸附特性的最佳条件。以污水中的活性炭吸附量和COD去除率为指标,优选吸附剂活性炭的预处理方法,采用单因素法分别研究污水pH、活性炭粒度、吸附温度、吸附时间及震荡强度得出吸附特性最佳条件,即为活性炭用量0.3g,污水p H值8.0,活性炭粒度20目,吸附温度30℃,吸附时间1.5h,震荡强度100r/min。     

油墨的疏水聚团磁种分选试验研究

疏水性的磁铁矿作为磁种被用于废纸脱墨。磁铁矿表面吸附有一层油酸钠和硬脂酸而具有了疏水性。用煤油使油墨与磁种发生聚团,然后采用磁选法实现油墨的去除。文章探索油墨与磁种之间疏水聚团的工艺条件。研究结果表明,磁种用量3g/L、煤油用量0.3125g/L、pH=9、搅拌时间45min、温度45℃为最佳工艺参数,此条件下油墨在磁性产品中的回收率达94.99%。     

原煤吸附净化含油污水的实验研究

通过室内模拟研究了各因素对原煤吸附净化含油污水的影响,并探讨了利用原煤吸附净化含油污水的可行性.研究表明,当吸附温度为20℃,pH为5,吸附时间为10 min,煤粒径为3 mm,投加浓度为0.075 g·mL-1时,原煤吸附除油的效果最佳,稳定性最好.结果同时表明,在最佳条件下,Langmuir方程可以较好地描述低浓度重质油在阳泉烟煤上的吸附过程,且可判知该反应较易发生,可使油组分的去除率达52.28%以上,出水均符合排放要求.研究结果为含油污水的治理提供了科学依据.     

改性贻贝壳对亚甲基蓝的吸附去除研究

对改性贻贝壳吸附去除亚甲基蓝的效果进行了研究,考察了改性温度、吸附剂投加量、溶液盐度、吸附剂粒径、吸附温度等条件对亚甲基蓝吸附去除效果的影响。在200~1 060℃条件下对贻贝壳进行了温度改性优化,结果表明,最佳改性温度为550℃。当改性贻贝壳投加量为0.6 g/L时,对亚甲基蓝的去除率达到87%;亚甲基蓝的吸附去除效果随着贻贝壳粒径变小吸附能力略有上升,当粒径小于60目时,吸附能力趋于稳定,对亚甲基蓝的去除率在90%左右;盐度对吸附效果影响较大,亚甲基蓝去除效果受离子强度效应影响随盐度的增加先减小后增大最后到达稳定;而吸附温度对改性贻贝壳的吸附能力的影响较小。     

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.     

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.     

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.     

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.     

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.     

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.