一株双酚A降解菌的筛选、鉴定及其生长、降解条件

从沈阳北部污水处理厂曝气池活性污泥中驯化、分离及筛选得到一株以双酚A为唯一碳源的高效降解菌株D-17,通过菌体形态、生理生化反应特性及16S r DNA基因测序分析对其进行了鉴定,并研究了该菌株的生长及双酚A降解条件。菌种鉴定结果表明,该菌为乙酸钙不动杆菌(Acinetobacter calcoaceticus)。实验结果表明:该菌株的生长及降解双酚A的最适条件为溶液pH 7.0,接种量10%,摇床转速150 r/min,降解温度30℃,降解时间5d;当双酚A初始质量浓度为60 mg/L时,双酚A降解率达52.62%;投加蛋白胨后,双酚A降解率提高至57.15%。     

The co-occurrence network patterns and keystone species of microbial communities in cattle manure-corn straw composting

Environmental Science and Pollution Research - Microbes often form complex ecological networks in various habitats. Co-occurrence network analysis allows exploring the complex community...     

LUCC及气候变化对李仙江流域径流的影响

为揭示李仙江流域LUCC和气候变化对径流变化的影响，基于SWAT模型，通过设置不同情景，定量分析了不同土地利用类型和气候要素对流域内径流的影响，并结合RCP4.5、RCP8.5两种气候情景对流域未来径流的变化进行了预估。结果显示：(1) SWAT模型在李仙江流域径流模拟中具有很好的适用性，可以用SWAT模型进行流域的径流模拟，率定期的模型参数R2、Ens分别达到0.74、0.73，验证期的模型参数R2、Ens分别达到0.63、0.63；(2) 单一土地利用情景显示，将农业用地转化为林地或草地，均会导致流域径流量的减少，而将林地转化为草地则会引起流域径流量的增加，农业用地、林地、草地三者对径流增加贡献顺序为农业用地＞草地＞林地。(3) 2006~2015年间李仙江流域的LUCC引起的月均径流增加幅度小于气候变化引起的月均径流减少幅度，李仙江径流的变化由气候变化主导。(4) 在RCP4.5和RCP8.5两种气候情景下，2021~2050年间李仙江流域径流均呈减少趋势，减少的速率分别为3.6和2.15亿m³/10 a，这与1971~2015年间，流域实测径流减速为6.7亿m³/10 a的变化趋势一致，但这两种情景下，径流的减少趋势有所降低，分别为1971~2015年减速的53.7%、32.1%。     

改性沸石对二级生化出水中氨氮的吸附特性

采用氯化钠联合高温对天然斜发沸石进行改性,通过批次实验探究改性沸石吸附氨氮特性。结果表明:氯化钠浓度为0.8 mol·L~(-1),焙烧温度为300℃条件下,氨氮去除效果最佳;改性沸石在氨氮初始浓度为8mg·L~(-1),投加量为10 g·L~(-1),反应时间为120 min的条件下,去除率可达71%,相比天然沸石提高23.1%。通过扫描电镜(SEM)、X射线能谱(EDS)、比表面积(BET)、X射线衍射(XRD)和傅里叶光谱(FT-IR)考察改性前后沸石组成特征以及化学键的变化,可以看出,改性机制可去除孔道杂质及Na~+置换沸石中金属阳离子;氨氮吸附过程满足拟二级动力学方程(R~2=0.986),Langmuir等温线模型拟合结果 (R~2=0.998)优于Freundlich模型(R~2=0.839),且改性沸石最大吸附容量为5.94 mg·L~(-1)。热力学计算结果表明,沸石对氨氮的吸附过程是一个自发、吸热、熵增过程。上述结果表明,改性沸石能够有效地对污水厂二级生化出水中氨氮进行深度处理。     

Effects of Inorganic Antiseptic on the Properties of Zein-Based Active Films

Zein, one of corn processing byproducts, has excellent film-forming ability. However, zein does not have intrinsic antibacterial or antioxidant activity which limits its direct applicability as active food packaging material. In the present study, the rod-shaped micro-sized ZnO crystals were incorporated into zein films to construct zein-based active films as active packaging material with antibacterial property. The morphologies, structural analysis and sizes of ZnO crystals were analyzed by field emission scanning electron microscope and X-ray diffraction. Prepared zein films were evaluated for ZnO loading and distribution. Furthermore, antibacterial activities on Gram-negative bacteria and Gram-positive bacteria were tested by using the disc diffusion method. Lastly, the stability of zein-based active films under the different storage temperature and humidity was investigated. The results showed that zein based-active films had well mechanical properties, stability and antibacterial activities, which were related to the sizes of ZnO crystals in films.     

臭氧监测仪实验室校准及稳定性测试

以国内监测系统在用的臭氧校准仪为二级传递标准对臭氧监测仪开展了实验室校准,通过计算单次校准所得校准曲线的斜率和截距,符合中国相关标准中关于臭氧监测仪的校准指标:多点校准所得校准曲线的斜率为0.95~1.05,截距为-5~5 nmol/mol。进一步对2台臭氧监测仪进行了稳定性测试,12个月内臭氧监测仪的斜率变化为0.976 05~1.008 42,截距变化为-0.669 00~0.577 93 nmol/mol,臭氧监测仪的斜率、截距均符合臭氧监测仪校准指标的要求。稳定性测试表明,TF 49i型臭氧监测仪和EC 9810型臭氧监测仪经校准后均可用于实验室内臭氧标准传递比对工作。实验中臭氧监测仪更换臭氧涤除器、仪器零件后校准曲线的斜率均有明显变化,建议更换耗材后需采用高浓度臭氧对臭氧监测仪进行饱和并再次校准。     

Methyl siloxanes in road dust from a large silicone manufacturing site in China: implications of human exposure

Environmental Science and Pollution Research - Methyl siloxanes are becoming increasingly prevalent in the environment because of their extensive use in various consumer products. Little is known...     

A grey-relation-based method (GRM) for thermogravimetric (TG) data analysis

Journal of Material Cycles and Waste Management - Thermogravimetric analyzer was applied to analyze 22 solid materials and their mixtures at a heating rate of 10 K min−1...     

基于对数模糊优先规划法的火灾风险评估

随着城市化进程的推进,每年都有大量的火灾事故发生,造成大量的人员伤亡和财产损失,为了避免事故发生或者减少伤亡损失,火灾风险评估是一种有效的方法之一。基于层次分析法,提出了对数模糊优先规划法进行火灾风险评估。首先以地下车库火灾风险评估为例,参考相关文献和专家意见,建立了地下车库火灾风险评价指标体系;然后利用对数模糊优先规划法计算各个评价指标的权重,然后根据专家打分获得评语集,结果所计算的权重集,可以得到地下车库的火灾风险评估结果为"良好"。最后,进行讨论了火灾风险评估的方法的有效性,并与层次分析法对比,对数模糊优先规划法可以使得决策者更加自信和舒适,并且决策结果更加合理。