蒽醌染料中间体催化强化偶氮染料生物脱色

考察了醌还原菌群利用6种蒽醌染料中间体对偶氮染料生物脱色的催化强化作用.结果表明,溴氨酸(1-氨基-4-溴蒽醌-2-磺酸, BAA)的催化强化效果最好;游离态菌群以BAA作为氧化还原介体可催化强化多种偶氮染料的生物脱色,其中对酸性大红3R脱色的适宜条件为pH 6～9之间;外加葡萄糖浓度400～600 mg/L;BAA浓度19～34.2 mg/L,染料起始浓度≤900 mg/L.在此条件下,最大脱色率约为95%、达到最大脱色率的时间<7 h.同时发现,投加氧化还原介体BAA浓度为38～57mg/L时,固定化菌群降解酸性大红3R(180 mg/L)的最大脱色率在14 h内达到93%;在不补加BAA的情况下,固定化菌群经7次循环使用后,脱色率仍保持在85%以上.     

酸性偶氮染料还原产物强化偶氮染料生物脱色

考察醌还原菌群利用酸性偶氮染料的生物还原产物对偶氮染料生物脱色的强化作用.结果表明,酸性红B 等酸性偶氮染料的还原产物作为氧化还原介体可以强化多种偶氮染料的生物脱色.当酸性红B 还原产物浓度为0.2mol/L 时,其对活性艳红KE-3B 最佳脱色pH 值为7~11,在4~40℃范围内脱色率随温度上升而提高.根据高效液相色谱-质谱对酸性红B 还原产物的分析结果,推测起氧化还原介体作用的物质是2-氨基-4-磺酸基-1-萘酚     

酵母Candida krusei对合成染料的脱色

通过筛选实验,从土壤中新分离到1株对活性艳红K-2BP具有明显脱色效果的酵母菌株Y-G-1,经鉴定为克鲁斯假丝酵母Candida krusei.该菌株对含活性艳红K-2BP起始浓度为200mg/L的培养基,最大脱色率为99%,达到最大脱色率的时间是12h.克鲁斯假丝酵母的最佳接种量应不低于5%(体积分数),培养基最适pH在4～9之间,氮源(NH₄)₂SO₄浓度不低于0.1%,相对应的碳源葡萄糖浓度不低于0.5%.对脱色机理的研究表明,该菌株对活性艳红K-2BP的去除属于降解脱色.此外,该菌株对另外9种染料(50mg/L)的脱色率在62%～96%之间.其中,对偶氮染料弱酸艳红B、活性黑KN-B和活性红M-3BE的脱色率都达到了90%以上,对三苯甲烷染料(酸性媒介漂蓝B)的脱色率达到了93%.表明克鲁斯假丝酵母在染料废水的处理上可能具有较好地应用潜能.     

高盐条件下染料酸性橙7的生物降解特性

对偶氮染料废水厌氧-好氧生物处理中的高盐度抑制生物活性和芳香胺自氧化问题,通过多种强化策略,考察了NaCl为100g/L时酸性橙7(AO7)的生物降解特性.结果表明,加入葡萄糖(0.5g/L)、蛋白胨(1g/L)和酵母粉(0.5g/L)有利于高盐条件下AO7的生物降解.进水中加入酸性红B对AO7的脱色有加速作用.耐盐污泥中加入蒽醌形成的蒽醌-污泥自固定化体系可以促进AO7脱色,当蒽醌浓度为100mg/L时,AO7最大脱色率约为92%.以活性炭毡作为生物载体,厌氧和好氧体系均可实现稳定运行,且体系污泥沉降性良好,脱色速率达26.67mg/(L×h),且可有效抑制脱色中间产物1-氨基-2-萘酚的好氧自氧化,使COD去除率始终保持在90%以上.     

介体厌氧催化活性艳红K-2BP脱色及构效特性研究

研究了筛选出的4种结构相似的醌类氧化还原介体对活性艳红K-2BP厌氧脱色的促进作用,并分析了介体促进效果与其化学结构活性相关性. 在35℃中温厌氧条件下,采用间歇批量实验法,测定不同体系中介体催化活性艳红K-2BP脱色效果.结果表明,①结构相似的醌类氧化还原介体蒽醌(AQ)、1,5-二氯蒽醌(1,5-AQ)、1,8-二氯蒽醌(1,8-AQ)和1,4,5,8-四氯蒽醌(1,4,5,8-AQ),均促进活性艳红K-2BP脱色,反应速率提高了1.4～3倍;②当醌类介体投加浓度为4 mmol·L^-1,活性艳红K-2BP染料浓度为300 mg·L^-1时,促进作用由大到小的顺序为:1,8-AQ>1,5-AQ>AQ>1,4,5,8-AQ;③ 当活性艳红K-2BP染料浓度为300 mg·L^-1时,1,8-AQ促进效果最佳且脱色速率常数随1,8-AQ浓度的增加而增加呈线性关系;④介体促进效果与介体取代基团数量、位置和电子共轭效应相关.本研究初步建立了氧化还原介体定性/定量构-效关系数学模型,探究和完善非水溶性氧化还原介体催化强化理论体系.     

固定化蒽醌对偶氮染料生物降解促进作用研究

采用非水溶性蒽醌固定化技术对偶氮染料生物降解促进作用进行了研究,对比了海藻酸钙,聚乙烯醇-硼酸,聚乙烯醇-海藻酸钙和琼脂4种固定化技术,探讨了溶解氧对脱色过程的影响和固定化蒽醌系统脱色广谱性.研究结果表明,固定化蒽醌可提高多种偶氮染料生物厌氧脱色速度1.5～2倍和降低偶氮染料脱色过程氧化还原电位-10～-15 mV;经4次循环使用后,其加速作用仍保持在90%以上;固定化蒽醌微生物系统具有很强抗氧冲击能力.     

东方伊萨酵母YP-1对染料活性艳红K-2BP的脱色

利用含染料的选择性培养基从土壤中分离出一株对活性艳红K-2BP有明显脱色效果的酵母菌株YP-1,经鉴定为东方伊萨酵母Issatchenkia orientalis.结果表明,该酵母菌对￡400mg/L的活性艳红K-2BP有较好的脱色效果.对于活性艳红K-2BP起始浓度为100mg/L的培养基,该菌株可在12h达到99%以上的最大脱色率,其最佳接种量为10%(体积分数),最适pH值在3~9之间,氮源(NH4)2SO4的浓度30.02%,碳源葡萄糖的浓度30.2%.脱色机理研究结果表明,该酵母对活性艳红K-2BP的去除是先吸附后生物降解.此外,该菌株对初始浓度为200mg/L的偶氮染料活性黑KN-B的脱色率也可达99.5%.     

酵母Candida krusei对合成染料的脱色

通过筛选实验,从土壤中新分离到1株对活性艳红K-2BP具有明显脱色效果的酵母菌株Y-G-I,经鉴定为克鲁斯假丝酵母Candida krusei．该菌株对含活性艳红K-2BP起始浓度为200mg／L的培养基,最大脱色率为99％,达到最大脱色率的时间是12h．克鲁斯假丝酵母的最佳接种量应不低于5％（体积分数）,培养基最适pH在4～9之间,氮源（NH4）2S04浓度不低于0．1％,相对应的碳源葡萄糖浓度不低于0．5％．对脱色机理的研究表明,该菌株对活性艳红K-2BP的去除属于降解脱色．此外,该菌株对另外9种染料（50mg／L）的脱色率在62％～96％之间．其中,对偶氮染料弱酸艳红B、活性黑KN-B和活性红M-3BE的脱色率都达到了90％以上,对三苯甲烷染料（酸性媒介漂蓝B）的脱色率达到了93％．表明克鲁斯假丝酵母在染料废水的处理上可能具有较好地应用潜能．     

Al-Cu双金属体系对活性艳红X-3B的脱色研究

以典型偶氮染料活性艳红X-3B为模型污染物,采用测定染料去除率、TOC去除率、苯胺生成量的方法及添加EDTA的对照试验,考察Al-Cu双金属体系对偶氮染料废水的脱色机理和脱色动力学.结果表明,在近中性条件下处理30min后脱色率就可达到83%左右;处理120min后脱色率高达96.4%,其中约为34%的色度去除是由于活性艳红X-3B被还原为苯胺,约为20%和30%的色度去除是由于铝离子混凝和铝刨花表面吸附.染料废水脱色是一个先大量吸附再进行内电解还原逐步降解的过程,铝离子的絮凝-吸附作用能有效促进色度的去除.脱色反应可视为表观一级反应,提高反应温度可以加快脱色速率.     

染料脱色菌的筛选及对活性艳红X-3B的脱色研究

从广州某印染厂生化处理池的活性污泥中筛选到三株对活性艳红X-3B具有高效脱色作用的真菌,其中菌株HMX-3的脱色能力最强。考察了培养时间、温度、培养方式、pH值以及染料浓度对HMX-3脱色能力的影响。结果表明,菌株HMX-3对150mg/L X-3B的24h脱色率达65.8%,经60h可使其完全脱色;HMX-3对活性艳红X-3B脱色的最适温度为25℃~35℃,最佳pH值为6~8,且振荡培养较静置培养条件下的脱色率高;随染料浓度的增加,脱色率降低,但对于400mg/L的X-3B在72h时的脱色率可达86.7%。     

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.     

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.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

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.