微生物降解重油的初步研究

丛石油污染的土壤中筛选出一株假单胞菌,考察了其对重油的降解效果。降解18d,重油的降解率达到42．8％,饱和烃、芳香烃、胶质、沥青质的降解率分别为42．95％,43．85％,44．5％,5．55％;质量浓度2．5g／L的表面活性剂Tween-80可使重油的18d降解率达到51．0％;弱碱性条件有利于重油的生物降解;生物泥浆法处理重油污染的土壤,1kg土壤中重油质量100g,降解45d,重油的降解率达到38．85％。     

土壤氰化物污染生物修复技术研究进展

综述了植物修复、微生物修复和生物联合修复等土壤氰化物污染生物修复技术的降解机理、降解途径及降解影响因素的研究进展,探讨了氰化物生物修复技术的发展趋势和应用前景。指出基于提高修复时效和针对土壤复合污染类型的多技术融合研究、基于提高微生物耐受性和降解效率的菌株固定化及菌根真菌-植物联合技术研究以及基于工程化应用为导向的现场试验研究是未来研究的重点领域,为土壤氰化物污染的综合治理和修复提出了新思路。     

生物刺激与生物强化联合修复柴油污染土壤

从柴油污染土壤中筛选分离出一株高效降解柴油的菌株CY-1,考察了自然衰减修复、生物刺激修复、生物强化修复以及生物刺激-生物强化联合修复等4种修复方法对土壤中柴油的降解能力及降解过程中几种土壤微生物酶活性的变化。实验结果表明:该菌为假单胞菌属;采用生物刺激-生物强化联合修复初始柴油质量分数为2.70%的柴油污染土壤,经过31 d的降解,柴油质量分数降至1.09%,柴油去除率达59.6%;经生物刺激-生物强化联合修复,土壤脱氢酶活性和荧光素二乙酸酯水解酶活性最高;通过生物刺激处理可使土壤脲酶活性和磷酸酶活性达到最高。     

重金属污染土壤生物毒性的发光菌法测定及评价

向土壤中人为投加重金属污染物,制备了重金属含量不同的一系列污染土壤,对土壤重金属浸提条件进行了探究,并应用明亮发光杆菌T3（Photobacterium phosphoreum T3）对单一Cu、Cd和Pb污染及Cu-Cd和Cu-Pb复合重金属污染土壤的生物毒性进行了测定。实验结果表明,土壤重金属的最佳浸提剂为0.1 mol/L HCl溶液,最佳浸提时间为2.0 h。在单一重金属污染条件下：Cu表现出低浓度促进生长、高浓度抑制生长的双重生物效应,而Cd和Pb则表现出浓度与生物毒性的正相关性;3种重金属污染土壤的毒性强弱顺序为Cd>Pb>Cu。在复合重金属污染条件下,由于重金属之间的相互作用,污染土壤的生物毒性增强。     

石油污染土壤的生物修复技术研究

通过实验室选择性富集培养,从大庆石油污染土壤中获得了能以大庆原油为碳源快速生长的石油降解菌。采用该降解菌对原油污染土壤进行了原位生物联合修复实验。接入降解菌的处理单元分别种植大豆、碱草或加入蓬松剂,与空白试样作对比。各处理单元石油污染土壤中石油烃含量初始值为2228．25mg／kg（以1kg干土计）。经过135d的生物联合修复,石油烃降解率达63．65％-83．26％。     

高效石油烃降解菌的筛选及其对原油污染土壤的修复

从陕北原油污染土壤中筛选出7株高效石油烃降解菌,其中黄杆菌属CC-2、不动细菌属SC-5、假单胞菌属SC-6表现出较强的石油烃降解能力。通过单因素试验和正交试验考察总石油烃(TPH)降解效果的影响因素,得出各因素对TPH降解率影响程度的大小次序为:溶液p H降解温度降解菌接种量摇床转速,且在降解菌接种量为7%(φ)、溶液p H为7、降解温度为30℃、摇床转速为150 r/min的最适处理条件下,菌株SC-6的TPH降解率可达61.23%。原油污染土壤生物修复实验结果表明:高效石油烃降解菌的投加有利于土壤TPH降解率和酶活性的提高;"菌株SC-6+营养剂"组修复处理42 d后的TPH降解率可达57.59%。     

氰化物污染土壤微生物修复方法初步研究

利用经过筛选和驯化的降氰菌处理氰化物污染土壤,实现氰化物的降解和去除,据此建立降氰菌修复含氰土壤的新方法。结果表明,降氰菌处理效果快速有效,经过3 d生物培养,氰化物降解率达到31.2%;随着培养时间延长,微生物群落代谢能力发生变化,在第3~8 d氰化物降解率增长缓慢,在第8 d达到33.3%。通过降氰菌种资源的筛选和应用,为氰化物污染土壤的修复提供了清洁、经济、有效的技术思路。     

Fenton氧化—微生物法降解土壤中石油烃

以长期被苯系物污染的活性污泥为菌源,采用液相“诱导物-中间产物-目标污染物”驯化模式驯化出专性混合石油降解菌群,并将其用于Fenton氧化—微生物法处理模拟石油污染土壤。高通量测序结果表明,产黄杆菌属（Rhodanobacter）、分支杆菌属（Mycobacterium）和根瘤菌属（Rhizobiales）为主导菌属。实验结果表明：接种混合菌群后降解50 d,土样的总石油烃（TPH）去除率较土著菌提高了13.4~20.5百分点;对于TPH含量（w）分别为4%,8%,11%的土样,Fenton氧化的最佳H₂O₂加入量分别为3,4,4 mol/L（Fe²⁺加入量0.04 mol/L）,TPH总去除率分别可达88.8%,65.0%,47.7%,较单独Fenton氧化或单独微生物法均有很大程度的提高,且缩短了降解时间,增加了土壤有机质。     

稻草秸秆生物炭对土壤中重金属Cd和Pb的固化稳定化机制

以500℃下制备的稻草秸秆生物炭为土壤修复剂,通过60 d的培养实验研究了Cd-Pb复合污染土壤的固化稳定化修复过程,并运用元素分析、FTIR等方法对生物炭的基本性质进行了表征.表征结果显示,稻草秸秆生物炭呈碱性,比表面积较大,拥有较好的芳香性,不易在环境中降解.实验结果表明,施加稻草秸秆生物炭后,污染土壤中的Cd有效...     

黑麦草-不动杆菌组合体系对石油污染土壤的生物强化修复

以盆栽实验为基础,研究了植物（黑麦草,Lolium perenne L）-微生物（不动杆菌,Acinetobacter sp.）组合体系对石油污染土壤的修复效果。实验结果表明：在总石油烃含量为4 420.18 mg/kg、脱氢酶活性为230.52 μg/（g·d）、苯酚毒性当量浓度（TEQphenol）为1 633.21 mg/L的初始条件下,强化组总石油烃降解率最高为53.08%,是对照组的1.60倍;土壤的脱氢酶活性达到637.73 μg/（g·d）,是对照组的10.64倍;石油污染土壤的生物毒性大幅降低, TEQphenol最终降低至171.08 mg/L。说明该组合体系对石油污染土壤具有很好的修复作用,且微生物对土壤中有毒物质的降解起主要作用。     

高级氧化技术处理水中人工甜味剂的研究进展

介绍了几个国家在地表水、污水处理厂进出水等水环境中检测出的人工甜味剂的含量,简介了人工甜味剂对人体的危害,综述了基于臭氧氧化和紫外光照射的高级氧化技术处理水中人工甜味剂的研究进展,剖析了人工甜味剂的降解产物和降解路径以及在降解过程中的矿化效果和毒性变化,对后续的研究方向进行了展望。     

Fenton法氧化降解聚乙烯醇的机制

为深入了解Fenton法氧化降解聚乙烯醇（PVA）的机制,通过考察反应过程中COD、BOD5、总有机碳及pH等随反应时间的变化,研究了聚乙烯醇Fenton氧化降解过程的特点,结果表明,当PVA被Fenton试剂氧化时,可生成大量CO2,同时生成酸性中间产物。进一步分析认为,当Fenton试剂中H2O2不足景时PVA氧化的中间产物以醛为主,而当H2O2足量时醛会被继续氧化生成有机酸,最终COD去除率达到80％。     

Biodegradation of Slow-Release Fertilizers (Methyleneureas) in Soil

The biodegradation of urea and condensation products thereof (ureaforms or methyleneureas), their nitrification, and their influence on the respiratory rate of soil was studied over periods of up to 100 days. The total methyleneurea content of the soil was determined after its acidic extraction, using a convenient colorimetric assay, and an HPLC protocol was established to analyze for specific components of methyleneureas. Urea, unfractionated methyleneureas, and hot-water soluble methyleneureas were rapidly metabolized to ammonium, which accumulated to high concentrations and was consequently oxidized to nitrate; an accumulation of nitrite was observed during urea but not during methyleneurea degradation. Hot water-insoluble methyleneureas were degraded much more slowly, and ammonium formed from these compounds was oxidized to nitrate without being released in significant amounts. These results suggest that the use of methyleneureas of optimized composition with regard to their water solubility may help to resolve problems such as the toxicity of ammonia to plant growth as well as nitrogen loss by leaching of nitrate, denitrification and volatilization.     

Investigation of the ozonolysis of ethylenebisdithiocarbamate-fungicides in model solutions

A study of the effectiveness of ozonation for the removal of nabam (disodium ethylenebisdithiocarbamate) from aqueous solutions was carried out. Nabam is the parent compound of a commonly used group of fungicides. The process of nabam degradation was followed in terms of several parameters such as nabam concentration, chemical oxygen demand (COD), sulphate ion concentration as a measure of the relative degree of mineralization of nabam, and the pH value of the solution. Ozonation accelerates the decomposition of nabam with the formation of sulphates and nitrates as final products. The intermediate decomposition products of nabam are more resistant to degradation by ozone than the parent compound. The amounts of ozone which are used in wastewater treatment plants for disinfection may be sufficient to remove both nabam and its decomposition products, at a low level of contamination, but if the concentration of nabam is too high the intermediate decomposition products can still be present. Lowering the pH of the medium favours the oxidation of nabam.     

Mechanism of Microbial Degradation of Slow-Release Fertilizers

Methyleneureas are condensation products of urea and formaldehyde of different molecular mass and solubility; they are used in large amounts both as resins, binders, and insulating materials for industrial applications, as well as a slow-release nitrogen fertilizer for greens, lawns, or in bioremediation processes. In the present study, the microbial breakdown of these products was investigated. The nitrogen was released as ammonia and urea, and the formaldehyde released immediately oxidized via formiate to carbon dioxide. The enzymatic mechanism of metabolization of methyleneureas was studied in microorganisms isolated from soil, which were able to use these compounds as the sole source of nitrogen for growth. A strain of the Gram-negative bacterium Ralstonia paucula (formerly Alcaligenes sp. CDC group IVc-2) completely degraded methylenediurea and dimethylenetriurea to urea, ammonia, formaldehyde, and carbon dioxide. The enzyme initiating this degradation (methylenediurease) was purified and turned out to be different from the previously described enzyme from Ochrobactrum anthropi with regard to its regulation of expression and physicobiochemical properties. Fungal degradation of methyleneureas may occur via the formation of organic acids, thus leading to a nonenzymatic degradation of methyleneureas, which are unstable under acidic conditions.     

Emission of Volatiles from Polymers — A New Approach for Understanding Polymer Degradation

Emission of low molar mass compounds from different polymeric materials was determined and the results from the volatile analysis were applied to predict the degree of degradation and long-term properties, to determine degradation rates and mechanisms, to differentiate between biotic and abiotic degradation and for quality control work. Solid-phase microextraction and solid-phase extraction together with GC-MS were applied to identify and quantify the low molar mass compounds. Volatiles were released and monitored at early stages of degradation before any matrix changes were observed by e.g. SEC, DSC and tensile testing. The analysis of volatiles can thus also be applied to detect small differences between polymeric materials and their susceptibility to degradation. The formation of certain degradation products correlated with the changes taking place in the polymer matrix, these indicator products could, thus, be analysed to rapidly predict the degree of degradation in the polymer matrix and further to predict the long-term properties and remaining lifetime of the product.     

多溴联苯醚降解和分析研究进展

介绍了多溴联苯醚(PBDEs)在环境中的分布情况,综述了近年来国内外对PBDEs测定方法以及化学催化降解、生物降解和热解等PBDEs降解技术的研究进展,并对PBDEs研究的未来发展方向进行了展望。     

Synthesis of3H- polyethylene and its use for fate studies on degradable plastics

Determining the fate of xenobiotic materials in the environment can be aided by the use of radioactive isotope technology. Previous research on the degradation of polymers such as polyethylene (PE) was aided by the utilization of radiotracers. In order to study the environmental fate of degradable (PE/starch) plastics, we synthesized³H-labeled PE. Results of soil incubation studies indicate that only minimal degradation of the PE component, as indicated by the production of water-soluble metabolites, occurred during 2 years of incubation in soil. Despite the minimal degradation, the³H label did not allow for detection of the degradation products. In addition, the³H-PE was particularly useful for tracing the fate of degradable plastics after consumption by terrestrial isopods. The detection of aqueous-soluble radioactivity in isopod frass was used to indicate degradation of the plastic film.     

十溴联苯醚环境修复技术的研究进展

介绍了溴代阻燃剂十溴联苯醚（BDE-209）环境修复技术的研究进展。从光降解、零价铁降解、生物降解3个方面对BDE-209的降解机理和降解后的产物进行了介绍。BDE-209经光照、厌氧微生物、零价铁的脱溴作用后,降解成低溴代联苯醚产物;好氧微生物利用低溴代联苯醚作为生长碳源,将其在酶的作用下开环降解,进入三羧酸循环或彻底分解成CO₂和H₂O。提出应采用多种方法协同作用,更有效地降解多溴联苯醚化合物。