Silver nanoparticles tolerant bacteria from sewage environment

Silver nanoparticle (SNP) is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar growth kinetics to that without nanoparticles. A reduction in the amount of exopolysaccharides was observed after SNPs – B. pumilus culture supernatant interaction. The Fourier transform infrared spectroscopy (FT-IR) peaks for the exopolysaccharides extracted from the bacterial culture supernatant and the interacted SNPs were almost similar. The exopolysaccharide capping of the SNPs was confirmed by UV-Visible, FT-IR and X-ray di raction analysis. The study of bacterial exopolysaccharides capped SNPs with E. coli, S. aureus and M. luteus showed less toxicity compared to uncoated SNPs. Our studies suggested that the capping of nanoparticles by bacterially produced exopolysaccharides serve as the probable mechanism of tolerance.     

Mechanism of Cd（II） adsorption by macrofungus Pleurotus platypus

The mechanism of Cd(II) uptake by the dead biomass of macrofungus Pleurotus platypus was investigated using di erent chemical and instrumental techniques. Sequential removal of cell wall components of the biosorbent revealed that structural polysaccharides play a predominant role in the biosorption of Cd(II). The adsorption kinetics fitted well with the pseudo second-order model suggested that the adsorption of Cd(II) on P. platypus involved a chemisorption process. Transmission electron microscopy of the cadmium exposed biomass confirmed the deposition of the metal mainly in the cell wall. Fourier transform infrared spectroscopic analysis of the metal loaded biosorbent confirmed the participation of –OH, –NH and C–O–C groups in the uptake of Cd(II). Energy dispersive X-ray analysis of the biosorbent before and after metal uptake revealed that the main mechanism of adsorption was ion-exchange. The e ectiveness of CaCl2 in the desorption of cadmium perhaps suggested the exchange of Ca2+ with Cd(II).     

板栗内皮对水溶液中镉的吸附研究

采用生物吸附法去除水体重金属污染具有重要的现实意义.本文以板栗内皮为吸附剂,研究了溶液pH值、反应时间、吸附剂投加量对水溶液中镉的吸附量与去除率的影响;通过模型拟合、离子交换实验、电镜扫描（SEM）和红外光谱（FTIR）分析,对吸附机理进行了探讨.结果表明：板栗内皮是一种理想的镉吸附剂,适应pH值范围宽（3～6）,达到...     

红外分光光度法测定水中石油类探讨

对红外分光光度法测定水中石油类进行了探讨,通过减少四氯化碳使用量,用玻璃纤维滤膜代替玻璃砂芯漏斗过滤脱水,对样品进行实验分析,结果能保证分析的准确度,表明该方法具有可操作性。     

固体进样一土壤中总有机碳的测定

本文阐述了固体直接进样…非色散红外吸收法测定土壤中总有机碳（TOC）的含量。所谓固体进样就是对土壤样品进行直接测定,省略了繁杂的消解过程并降低消解过程中易挥发性物质的损失,优点在于准确度高,精密度好,大大提高了分析效率,是一种值得推广的方法。     

Observation of the nighttime nitrate radical in Hefei, China

Observation of nighttime nitrate radical (NO3) was performed by using long path differential optical absorption spectroscopy (LP-DOAS), on the outskirts of Hefei, China. The time series of NO3 and supporting parameters were simultaneously measured for a week (31 May-7 June 2006). The results indicated that the average concentration of NO3 was 15.6 pptv with an average lifetimes of 96 s, whereas, NO3 production rates varied from 8×105/(cm3·s)to 2.98×107/（cm3·s）. Furthermore, the calculated N2O5 concentration averaged at 380 pptv. Analysis of data indicated that direct sinks were probably dominating the NO3 loss process during this campaign. Finally, the results were compared with other campaigns in the boundary layer.     

修饰作用对面包酵母细胞形貌及其吸附Cu2+性能的影响比较

分别采用无水乙醇、氢氧化钠修饰面包酵母,并将修饰前后的菌样用于含 Cu2 废水的吸附研究.通过扫描电镜、Zeta 电位仪和红外光谱仪对吸附前后菌样进行了检测分析.结果显示,化学修饰作用使菌细胞不同程度地发生形变,使其个体减小、表面粗糙且细胞粘连,以及 Zeta电位改变,同时菌样的红外光谱吸收峰强度、波数也发生变化甚至有新特征吸收谱线产生.这表明,修饰作用不仅改变了酵母细胞的外形结构、表面电荷,而且提高了菌表面有机官能团的数量及吸附活性,其中 NaOH 修饰作用还使菌细胞中羰基更加暴露.在吸附Cu2 的过程中,菌样表面羧基、羰基、羟基、氨基、酰胺基、磷酰基等官能团发挥了重要作用.     

废胶粉裂解产物分析

废旧轮胎裂解后产生的固体(废胶粉)和液体物质(油)可以有很多用途,例如可以用于防水改性沥青、防水材料等方面.当前,对废胶粉的利用研究越来越多,但是对胶粉本身的结构研究却很少.本文利用紫外分析、高效液相分析、液相色谱质谱分析、红外分析等方法,对裂解油进行了分析研究;利用热重分析、红外分析对废胶粉进行了研究.实验结果表明胶粉和油的分解都分三个过程,两者的成分很多都相同.在胶粉和油中都含有大量的长链烃,根据液相色谱质谱得出的数据对分解产物进行了初步的推理判断.     

红外光谱技术应用的进展

对红外光谱(IR)分析技术的研究进展和应用现状进行综述,叙述了漫反射、衰减全反射、连用技术、傅立叶红外光谱仪的研制进展和红外光谱技术在医药、化工、环境等方面的应用.