菌株Acinetobacter sp.C-2对酸性红GR的脱色研究

近年来,生物法处理染料废水已成为国内外的研究热点。文章实验室通过梯度驯化,从土壤中分离筛选得到一株能有效脱色磺基化偶氮染料酸性红GR的菌株C-2,根据16S rDNA基因序列分析鉴定为Acinetobacter sp.。采用表面响应法(Response Surface Methodology,RSM)对菌株C-2脱色酸性红GR的主要影响因素进行了优化,实验结果表明最优条件为:接种量17.5 g/L,酸性红GR初始浓度100 mg/L,酵母粉浓度2.50 g/L,果糖浓度3.00 g/L。在该条件下,14 h内脱色率可达99%。同时,利用Haldane方程对菌株的脱色动力学进行拟合,最大脱色速率vmax、亲和常数Ks和抑制常数Ksi分别为328.33 mg/(g.h)、309.69 mg/L和1 365.83 mg/L,并且经计算,最佳脱色速率和GR浓度分别为105.91 mg/goh、650.37 mg/L。研究结果表明菌株C-2具有较高的偶氮染料脱色活性,用于实际染料废水的生物修复具有较好的应用前景。     

丹东凤凰山山上与山下降水酸度迥异原因分析

采用分段监测的方法研究了辽宁丹东凤凰山垂直高度上的降水酸度及组分特征,并利用后向气流轨迹与分段离子相关性叠加分析的方法,对山上与山下降水酸度的差异成因进行了分析。结果表明：凤凰山4次降水中,pH值山上均低于山下,总离子浓度山上均低于山下,说明近地面大气污染物对酸雨起到一定的中和作用;山上降水酸度主要受大气远距离传输影响,山下降水酸度受本地源和远距离传输的共同作用。     

膜载纳米Pd/Fe双金属颗粒脱氯一氯乙酸的研究

通过涂敷法、共混法和化学接枝法制备了PVDF-PAA膜、PVDF·TiO2-PAA膜和PVDF-g-AA膜3种新型载体膜,分别负载纳米钯/铁双金属颗粒后对一氯乙酸进行还原脱氯实验并通过SEM以及红外吸收光谱(FT-IR)对3个体系进行表征。结果发现,与传统的Pd/Fe纳米悬浮颗粒体系相比,膜载纳米双金属颗粒体系的脱氯效率更高,并且PVDF-PAA膜、PVDF·TiO2-PAA膜和PVDF-g-AA膜3种膜负载的纳米钯/铁双金属颗粒在120min内对10mg/L的一氯乙酸的脱氯效率分别是:56.33%、71.01%和75.51%。     

蚌埠市区酸雨污染特征分析及控制对策

利用2008年至2012年蚌埠市区降水监测数据,综合分析蚌埠市区酸雨污染时空、季节、化学组分的变化特征、变化趋势及其成因,致酸前体物、气象因素等与酸雨污染的关系,同时针对蚌埠市区酸雨污染提出几点治理措施和建议。     

模拟酸雨对福州平原稻田土壤真菌群落结构及多样性影响

酸雨已成为全球农业、环境和生态领域关注的重要问题之一.为了探讨酸雨对稻田土壤真菌多样性的影响,了解真菌群落结构变化与酸雨胁迫之间的关系.本文以福州平原稻田为试验场所,根据福州市近年来的酸雨成分,配置不同酸度的模拟酸雨,计算出喷淋量,并于水稻秧苗移栽后每隔7 d喷淋一次酸雨,直至水稻收割.当水稻收获时,采集土壤样品分析不同酸度模拟酸雨处理下早、晚稻土壤真菌群落组成及其丰度.结果表明:①模拟酸雨处理改变了稻田土壤真菌的相对丰度、多样性及群落组成,且不同处理中真菌的优势菌属及相对丰度也具有差异;②早稻3个模拟酸雨处理组均使稻田土壤真菌多样性降低,在晚稻生长期,pH=2.5和pH=3.5处理使稻田土壤真菌多样性降低,而pH=4.5处理则使真菌多样性显著升高;③模拟酸雨处理使Paranamyces、刺座霉属(Volutella)、镰刀菌属(Fusarium)的相对丰度显著降低,同时也出现了少量Monographella、Hygrocybe、Acremonium等对照组中不存在的菌属;④早、晚稻pH=4.5处理组与对照组之间真菌的物种多样性及群落结构差异均最大;⑤环境因子能够影响土壤中真菌的相对丰度并改变土壤碳组分,其中,真菌Westerdykella(韦斯特壳属)的相对丰度与稻田土壤电导率(EC)呈显著负相关(p0.01),Psilocybe的相对丰度与稻田土壤微生物量碳(MBC)呈显著正相关(p0.01).     

镉和酸雨对苦楝幼苗细胞膜透性及渗透调节物质含量的影响

采用盆栽法研究了3个梯度模拟酸雨(p H=5.6、4.5、3.5)和不同剂量Cd2+(0、30、60、90、120、150、180 mg·kg~(-1))单一及复合处理,对苦楝(Melia azedarach L.)幼苗生长、质膜透性和主要渗透调节物质含量的影响.结果表明,p H=4.5和30 mg·kg~(-1)Cd2+复合处理对苦楝生物量的积累和幼苗的生长具有一定促进作用;p H=4.5和低剂量Cd2+(≤60 mg·kg~(-1))单一及复合处理下,株高和干重变化不显著(p0.05),叶色、叶绿素含量、相对电导率和丙二醛含量也无明显变化;而强酸雨(p H=3.5)和高剂量Cd2+(≥90 mg·kg~(-1))处理下,叶片发黄卷曲,叶绿素含量下降,相对电导率和丙二醛含量增大,且酸雨和Cd2+复合处理较单一酸雨和单一Cd2+处理毒害作用更明显,表现为复合叠加效应;随酸雨强度和Cd2+剂量的增加,可溶性糖含量下降,可溶性蛋白和游离脯氨酸含量先升后降,二者峰值均出现在p H=4.5和60 mg·kg~(-1)Cd2+处理,且Cd2+剂量≤120 mg·kg~(-1)时,各酸雨梯度下可溶性蛋白和脯氨酸含量均高于CK.综上认为,在Cd2+剂量≤60 mg·kg~(-1)、酸雨p H≥4.5的区域,苦楝可以正常生长且保持较大生物量,可将其作为Cd污染典型酸雨区的绿化和修复树种.     

餐厨垃圾发酵制备生物燃料丁醇的研究

餐厨垃圾含丰富有机质,是潜在的廉价优质生物质资源;丁醇是继乙醇后的一种极具潜力的新型生物燃料。探索了以餐厨垃圾糖化液为原料,通过微生物发酵制取生物燃料丁醇。首先从实验室现有5株产丁醇梭菌中,优选出Clostridium beijerinckii NCIMB 8052作为丁醇生产菌,并考察在未添加任何营养物质,且不调节pH的条件下(简称非调控状态),以糖化液作为底物进行丁醇发酵的可行性。结果表明:非调控状态发酵的丁醇产量仅为5.96 g/L,并产生"酸崩"抑制;添加0.3%(w/V)Ca CO_3提高了糖化液pH缓冲能力,可解决"酸崩"问题,并将丁醇产量、总溶剂产量及丁醇生产速率分别提高了57.8%、53.1%和90.6%。这证明餐厨垃圾做为原料用于燃料丁醇生产是完全可行的。     

重庆市渝中区20年酸雨污染变化趋势及成因分析研究

以重庆市渝中区降雨及大气监测数据为基础,对重庆市渝中区近二十年酸雨污染的变化趋势、降水中化学成分变化进行分析,并从致酸源、地理因素、气象因素等方面探讨了重庆市渝中区酸雨污染的主要成因.结果表明:重庆市渝中区酸雨污染不仅来自于本区,还受外区输入性污染影响,特殊的地理环境和不利的大气扩散条件加重了酸雨污染的程度;近年来降雨pH总体上升,酸雨污染有所减轻;酸雨污染由煤烟型污染向石油型污染转变.     

Effects of simulated acid rain on root growth of Cunninghamia lanceolata and Schima superba saplings planted in acidified soil

Results from pot culture (with one-year old Cunninghamia lanceolata and Schima superba) are described. It was found that the biomass production and elongation of C. lanceolata was seriously inhibited at pH 2.0 rain, but for S. superba, was not affected markedly. When pH values of experimental rain were higher than 2.0, the root growth of both species was not adversely affected. Aluminium had already accumulated to some degrees in the roots of both trees, and started to affect the root growth of C. lanceolata at pH 2.0 rain. The soil chemistry was also examined. Increased acidity of experimental rain increased the leaching of Ca and Mg. The Al/Ca mol ratio increased from 0.3 to 0.9 in top soil, and in rhizosphere to 1.5 when the pH values of simulated acid rain were 4.5 to 2.0. In this experiment, NO₃- fertilization effect was discovered.     

Polycyclic aromatic hydrocarbon in rain and street runoff in Amman, Jordan

Concentrations of polycyclic aromatic hydrocarbons(PAHs) were determined in the rain and street runoff samples from two sites in the vicinity of Amman City during the pluvial period 1999--2000. The results showed that elevated levels of PAHs were detected in the city center(site 1 ) than the residential area( site 2) and that the levels were higher in street runoff than rain samples of the same sites. The highest concentration of PAHs in both street runoff and rain samples were observed in the first rainy month( November 1999) which indicated a wash out effect of PAHs originating from vehicular emission accumulated during the long dry summer season before sampling. Within the investigated cold winter seasons, fluctuations in PAHs concentration were observed. The variation was attributed to the fossil combustion for heating purposes and to intervals between rainfalls: as the longer the intervals between rains were, the higher the PAH concentration were. Removal of PAHs from the atmosphere through precipitation over the investigated period varied with time and places depending on the amount of rainfall where higher rainfall removed higher amount of PAHs from the almosphere. The amount of PAHs washed out through precipitation was estimated to be around 14.8 mg/m^2 and 21.1 mg/m^2 for sites 1 and 2 respectively.