活性炭对两种生物染料脱色效果的实验研究

以颗粒状活性炭为吸附载体,对两种单体生物染料进行脱色吸附实验研究。通过实验确定出最佳优化条件：活性炭用量80g/L,溶液pH值约为5、5,溶液最佳温度为35℃,搅拌速度为150rpm／min,此时染料脱色率可达98％以上;在几种条件实验过程中,将两种染料进行对比发现：红色染料脱色率一般都比绿色染料脱色率高,而且前者一般比后者反应较敏感。同时,从活性炭的表面结构方面探讨吸附脱色机理,为活性炭深度处理印染废水的研究可提供一定的科学依据。     

污泥灰对模拟染料废水的吸附研究

以南京市江心洲污水处理厂污泥为原料热解制得污泥灰,并将其用于吸附直接耐酸大红4BS和活性艳红K-2BP模拟染料废水.考察了吸附剂投加量、吸附时间、温度和pH值对吸附效果的影响,并对其吸附动力学特征进行了探讨.结果表明,反应温度、吸附时间和吸附剂投加量对吸附效果有影响,而废水pH变化则不会引起脱色率的较大改变.室温下,4BS和K-2BP的最佳污泥投加量分别为3g·L-1、10g·L-1.4BS在最佳反应条件（反应时间为25min,反应温度为40℃）下,脱色率可达93%;K-2BP在最佳反应条件（反应时间为150min,反应温度为40℃）下,脱色率约为73%.     

固定化蛋白酶对废水中蛋白质的水解效果与机理

采用吸附方法将蛋白酶固定于活性炭、大孔树脂和硅胶载体上,分别研究了3种载体蛋白酶固定化效果,酶活性以及对淀粉加工黄浆废水中蛋白质的水解效果.批次试验结果表明,3种载体蛋白酶固定效果分别为:硅胶20.31%,大孔树脂37.85%,活性炭61.95%;酶活性最高时pH均为5.5;酶活性分别为3.6mg/min、21.48mg/min和18.68mg/min .水解后,大孔树脂和活性炭固定酶的水解产物氨基酸总量分别较水解前增加21.26倍和14.6倍;产物中检出1 6种氨基酸,较水解前增加2种.以大孔树脂为载体构建固定化酶反应器进行连续进水试验,结果表明:进水中蛋白质浓度明显影响反应器的水解效果,当其蛋白质浓度与反应器的酶浓度匹配时(500mg/L) ,反应器能获得80 %蛋白质水解率和36.1%有机物水解酸化率.挥发性水解产物组成以乙醇和乙酸为主,分别占50.3%,33.3%.为乙醇型水解.     

粉状活性炭的再生技术

一、试验方案的选择 1.味精脱色粉炭的特性粉状活性炭用于味精精制工序中主要为了脱去味精粗品中色素,在脱色过程中活性炭除了吸附谷氨酸钠溶液中的色素、铁和其它金属离子外,其表面还会附着谷氨酸钠、蛋白质等胶体以及氨基酸和菌种等。用于粉状活性炭脱除味精脱色时,其吸附负荷比污水处理的废炭高5～8倍,属于高负荷运行,废炭的     

活性氧化镁处理高氟水的试验研究

文章以活性氧化镁作为吸附剂进行了降氟试验,通过pH-3C型酸度计考察了氧化镁投入量、pH值、温度和反应时间等因素对降氟效果的影响,并做了正交试验得到了最佳反应条件。实验结果表明,活性氧化镁降氟效果的最优化条件为：氧化镁的用量为0.30 g、反应时间为40 min、溶液的pH值为7.0、反应温度为40℃,产率为83.56%。此外与活性氧化铝作为吸附剂的降氟效果相比,其降氟效果要明显强于活性氧化铝。     

镁铝双氢氧化物用于染料废水脱色的研究

以氯化铝、氯化镁、氨水等为原料,合成了镁铝双氢氧化物正电溶胶(MADH).以水溶性染料模拟废水为研究对象,检验了MADH对染料废水的脱色效果,并对其脱色机理进行了探讨. 结果表明,MADH对活性染料、酸性染料和直接染料等阴离子型染料具有明显的脱色效果.在足量MADH存在的条件下,废水脱色率可达99%以上,最佳pH为6～9,最佳反应时间为10 min.温度升高不利于吸附过程的进行,其饱和吸附容量为327～2 113 mg/g.MADH用于实际印染工业废水处理,脱色率和CODCr去除率同样较高.脱色机理为MADH对染料的化学吸附作用.MADH对阳离子型染料的去除效果较差.      

微波诱导氧化处理雅格素红BF-3B150%染料废水的研究

以颗粒活性炭为催化剂 ,建立了微波诱导氧化工艺 ,对雅格素红BF 3B15 0 %染料废水进行了有效处理 .分别考查了废水初始浓度、微波功率、微波辐照时间、活性炭粒径、活性炭用量和废水pH值对废水处理效果的影响 .该工艺对稀释 10 0倍后的实际废水 (原水COD为 2 82 4 0mg·L-1)最佳处理工艺条件为 :微波辐照时间 6min、微波辐射功率 6 5 0W、活性炭用量为 8g、活性炭粒径 2 0目以下 ,微波诱导催化氧化在酸性条件下比在碱性条件下的处理效果要好 .在此工艺条件下 ,废水脱色率达99 6 %、COD去除率达 96 8% .微波辐射雅格素红染料废水脱色表观反应动力学研究表明 ,该反应近似一级反应 ,动力学常数为 0 735 1min-1,半衰期为 0 94min .微波诱导氧化、活性炭吸附和单纯微波辐射 3种不同工艺的对比实验表明 ,微波诱导氧化工艺具有明显的优越性 ,且不会对环境造成二次污染     

水热炭化对吸附处理染料废水产生的废活性炭的再生效果

为实现废粉末活性炭的循环利用,采用水热炭化对吸附处理染料废水产生的废粉末活性炭进行再生,考察了水热炭化再生温度、再生时间、初始pH和再生次数等因素对废粉末活性炭再生效果的影响.结果表明:将320℃的水热条件下反应8 h得到的再生粉末活性炭用于吸附处理染料废水,色度去除率在95%左右,废粉末活性炭再生率可超过60%,且酸性条件下更有利于活性炭再生.经过5次吸附再生循环,废粉末活性炭再生率为55.54%,再生率仅下降6.06%.红外光谱分析结果表明,新粉末活性炭、废粉末活性炭和再生粉末活性炭的官能团种类基本一致;表面官能团Boehm滴定测定结果显示,再生粉末活性炭表面碱性基团含量降低、酸性基团含量增加.由于升温改变了废粉末活性炭的吸附平衡,有机物从其表面脱附,部分有机物在再生液中降解;此外,废粉末活性炭表面不易挥发和脱附的有机物在高温高压下炭化所得的产物能进一步吸附有机物,因此导致了废粉末活性炭的再生.研究显示,水热炭化对废粉末活性炭有较好的再生效果,具有实际应用价值.      

改性麦糟吸附水中酸性湖蓝A和碱性湖蓝BB实验研究

采用AlCl_3改性麦糟和Na OH改性麦糟分别处理酸性湖蓝A和碱性湖蓝BB,研究了不同pH、吸附剂投加量、时间和温度对吸附效果的影响。结果表明:改性麦糟对酸性湖蓝A吸附反应的最佳条件在室温下,初始染料色度为500倍,溶液pH为3,吸附剂投加量5 g/L,反应时间30 min,脱色率达93%;改性麦糟对碱性湖蓝BB吸附反应的最佳条件在室温下,初始染料色度为500倍,溶液pH为9,吸附剂投加量3 g/L,反应时间30 min,脱色率达99%。且吸附过程符合准二级动力学模型,其相关系数均在0.999以上。实验处理后废水色度在50倍以下,水质达到《污水综合排放标准》(GB8978-1996)一级标准。     

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。     

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.     

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.     

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.     

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.     

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.     

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.     

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

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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.     

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.