水热解过程对提质褐煤液体产物的影响

对来自内蒙古的白音华褐煤进行了一系列水热解实验,分析不同温度和初始水煤浆浓度对水热解产物过滤出的液体的影响.分析了液体中TOC、COD、BOD5、总氮、氨氮、Cl-、SO42-的含量以及溶液的pH值.结果显示,水热解温度对于废液中的碳和氮含量影响较大,水热解温度从200℃增加到350℃时,水热解温度的升高,碳和氮分别增加了20多倍和30多倍;初始水煤浆浓度对Cl-和SO42-的含量影响较大,随着初始水煤浆浓度的升高, Cl-和SO42-逐渐增多.水热解温度应低于350℃, 初始水煤浆浓度应综合考虑设备材质来选择.     

聚吡咯改性生物炭对氟的吸附特性研究

以聚吡咯(PPy)改性芦苇-底泥生物炭(LB)制备了一种特异性吸附阴离子的吸附剂材料(LB/PPy)并实现水体中氟离子的高效去除.通过扫描电镜(SEM)、X射线光电子能谱(XPS)、孔径分析仪(BET)和傅里叶红外光谱(FTIR)对LB/PPy材料进行结构表征,并通过批量吸附实验探究LB/PPy对氟离子的吸附动力学和关键影响因素,最终揭示了该材料对氟离子的特异性吸附机理.PPy增加了LB材料的比表面积及表面官能团丰度,赋予其较高的吸附容量及特异性吸附阴离子性能.LB/PPy对氟离子的吸附动力学过程均符合准二级动力学模型,吸附过程同时存在物理吸附和化学吸附作用,但主要以化学键合为主;40℃时,达到最大吸附容量,为45.34mg/g,温度增加,吸附容量提升.该材料去除氟离子的最适p H值范围为8～10,具有高效的吸附效果,在多离子混合存在下仍能够保证对氟离子良好的特异性吸附能力,具有极高的应用价值.     

不同构型富氮生物炭对Pb (II)和Cr (VI)的作用机制

为了明确不同构型富氮生物炭对重金属的作用机理,本研究以玉米秸秆为生物质,通过尿素改性结合高温热解制备了3种不同氮构型的富氮生物炭（以吡咯氮为主的Pr-NBC、吡啶氮为主的Pd-NBC和石墨氮为主的Gp-NBC）,考察其对典型重金属的作用行为.吸附动力学和吸附等温线等实验结果显示：富氮生物炭对Pb （II）和Cr （VI）的吸附均以化学吸附为主,且存在明显的差异;对Pb （II）的吸附容量与溶液离子强度成正比,吸附可能以形成内层络合物为主,对Cr （VI）的作用则包含吸附和还原两个过程;对两种重金属的吸附容量受pH影响较大,静电吸引作用可能是主要驱动力.吸附前后的材料表征显示：富氮生物炭主要通过静电吸引作用、阳离子交换、沉淀作用和阳离子-π键作用吸附Pb （II）,通过静电吸引作用吸附Cr （VI）,同时能将Cr （VI）还原为Cr （III）.不同构型氮与重金属作用机理存在差异,其中,石墨氮主要通过与Pb （II）形成阳离子-π键作用促进吸附,吡咯氮和吡啶氮具有还原性,可将Cr （VI）转化为Cr （III）,实现减毒.因此,在考察自然环境中富氮生物炭对重金属的作用机制时,应当充分考虑氮构型的影响.     

利用水华微藻生物质去除水中Cr(Ⅵ)离子的研究

将野生水华微藻生物质作为吸附材料去除水中Cr(Ⅵ)离子。实验发现温度对去除效率没有显著影响,而pH值和Cr(Ⅵ)离子去除率呈严格负相关。在微藻吸附剂浓度为5.0 g/L、温度25℃、pH值5.0和初始Cr(Ⅵ)离子浓度30.0 mg/L条件下,经过2次吸附可以将水中Cr(Ⅵ)离子降低到0.45 mg/L,去除率达到98.5%。进一步分析表明,溶液中Cr(Ⅵ)浓度随着吸附时间逐步下降,Cr(Ⅲ)浓度会随着吸附时间逐步上升,逐渐接近总Cr浓度,这表明吸附过程中微藻生物质会将部分Cr(Ⅵ)还原成Cr(Ⅲ)。本研究表明,野生水华微藻生物质是一种低成本的吸附材料,可以用于去除废水中Cr(Ⅵ)离子。     

铝酸钙渣处理含氟废水研究

用铝酸钙渣吸附去除废水中的氟离子,试验了焙烧温度、初始氟离子浓度和接触时间对氟离子去除的影响,并作了吸附等温线。结果表明,最佳焙烧温度为800℃,吸附平衡时间为40min,最大吸附容量为12.0mg/g,吸附等温线符合B.E.T模型。因此,用铝酸钙渣处理含氟废水经济可行。     

基于环境因子的异养硝化菌Providencia rettgeri strain YL脱氮性能研究

初步研究了不同温度、pH值、摇床转速和C/N环境因子对Providencia rettgeri strain YL菌株脱氮作用的影响。研究结果表明:Providencia rettgeri strain YL菌株在以葡萄糖和氯化铵为碳氮源的培养基中,温度为35℃,pH为7,摇床转速为120r/min,C/N=10时具有最佳的脱氮效果。     

热解温度对污泥基生物炭结构特性及对重金属吸附性能的影响

鉴于污泥基生物炭作为重金属吸附剂的研究还缺乏足够的数据,为探讨不同热解温度对生物炭结构性质及其对水体重金属吸附能力的影响,在缺氧条件下于300~900℃范围内以城市污泥为原料制备生物炭,利用元素分析、比表面积测定、电位测定和红外光谱分析等方法对生物炭的理化性质和结构特征进行表征,并选用900℃生物炭进行了吸附重金属Pb、Cr和Cd的试验研究.结果表明:① 300~900℃缺氧条件下制备的生物炭产率为44.39%~69.41%,污泥呈弱酸性（pH为6.35）,热解后的生物炭呈碱性（pH为7.7~10.58）.② 900℃生物炭中w（H）、w（N）大幅降低,分别比干污泥中减少89.50%和77.16%,而w（C）降低29.22%,固碳作用显著.热解后生物炭比表面积明显增大,700和900℃生物炭比表面积分别达到58.48和87.55 m2/g,最佳制备温度为700~900℃.③ 热解后的生物炭具有大量极性基团,热解温度越高,酸性基团越少,碱性基团含量增多.④ 热解作用使生物炭zeta电位升高,吸附能力增强.⑤ 900℃生物炭吸附Pb、Cr和Cd的最佳pH为7~8,对Pb、Cr和Cd的最大吸附量分别为2.38、2.48和1.16 mg/g.⑥ 各因素对生物炭吸附重金属的影响顺序,对于Pb和Cr表现为生物炭投加量>热解温度;对于Cd,表现为生物炭投加量>pH.研究显示,污泥基生物炭对Pb、Cr的吸附能力高于Cd,影响生物炭吸附行为的主导因子为生物炭投加量,影响Pb和Cr吸附的次要因子为生物炭热解温度,而影响Cd的次要因子为pH.生物炭吸附重金属的主要机理是离子交换吸附、络合反应、表面沉淀和竞争性抑制作用.      

粘土吸附水中氟离子的研究

研究了粘土和明矾去除饮用水中氟离子的机理,探讨了pH值、溶液温度、氟离子浓度和吸附时间对粘土吸附饮用水中氟离子的影响.结果表明,粘土对饮用水中氟离子具有较好的吸附效果,是较为理想的饮水除氟材料.     

木棉生物炭对水体中Cr(Ⅵ)的吸附特性和机制研究

选取木棉为原材料,在不同温度下制备成生物炭.实验考察了溶液初始pH、不同热解温度及生物炭投加量对吸附效果的影响,并利用吸附动力学、吸附等温线及SEM-EDS、FTIR、XPS、Zeta电位等手段研究木棉生物炭对水溶液Cr（Ⅵ）的吸附特性及吸附机理.结果表明,热解温度为400℃,固液比为2∶1,pH=2.0时,木棉生物炭对水溶液中Cr（Ⅵ）的吸附效果最好.吸附动力学和吸附等温线结果显示,颗粒内扩散方程和Langmuir模型更能较好地拟合吸附过程.由Langmuir模型可以看出,400、550、700℃热解温度下制备的木棉生物炭对水溶液中Cr（Ⅵ）的最大吸附量分别为25.325、20.602、19.616 mg·g^-1.FTIR和Zeta结果表明,木棉生物炭主要通过官能团络合和静电吸附作用去除水溶液中Cr（Ⅵ）.XPS分析结果显示,生物炭表面大部分Cr（Ⅵ）被还原为Cr（Ⅲ）,其中,Cr（Ⅵ）占比为26.6%,Cr（Ⅲ）占比为73.4%.研究表明,木棉生物炭作为去除水溶液中Cr（Ⅵ）的吸附剂具有较大的应用潜力.     

水合氧化镧吸附除磷的试验研究

以开发新型高效除磷吸附剂材料为目的,以金属水合氧化物MeH(metal hydrate)为试验对象,对所选材料进行了吸附除磷性能评价.通过对多种水合金属氧化物吸附除磷性能的比较研究,发现水合氧化镧LaH(lan-thanum hydrate)具有优异的除磷吸附容量,其吸附容量大约为参照物粉末活性氧化铝的十几倍.该吸附剂的吸附容量随pH值变化显著,在pH=3附近达最大值;吸附等温线较符合Langmuir方程;进行了抗无机阴离子干扰能力测试,给出了干扰离子的影响顺序;该吸附剂对正磷酸根的去除性能优越,但对聚磷酸根的去除效果不理想.试验结果表明,水合氧化镧在平衡吸附容量、pH适应范围等方面与参照物活性氧化铝相比较,具有优异的性能.     

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.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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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.     

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.     

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.     

Sorption of 1-naphthol by plant cuticular fractions

The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.     

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.     

Seed selections for crystallization of calcium phosphate for phosphorus recovery

Seed induces and promotes the crystallization of calcium phosphate, and acts as carrier of the recovered phosphorus （P）. In order to select suitable seed for P recovery from wastewater, three seeds including Apatite （AP）, Juraperle （JP） and phosphate-modified Juraperle （M-JP） were tested and compared. Batch and fixed-bed column experiments of seeded crystallization of calcium phosphate were undertaken by using synthetic wastewater with 10 mg/L P phosphate. It shows that AP has bad enduring property in the crystallization process, while JP has better performance for multiple uses, and M-JP is a hopeful seed for P recovery by crystallization of calcium phosphate.