Preparation and application of gold and silver nanoparticles immobilized on Aspergillus niger

近年来受日益增长的“绿色化学”概念和环境保护意识的驱动，利用微生物还原法制备金属纳米颗粒已成为一种新颖且环境友好的纳米材料制备方法。目前有关微生物还原法的研究大多采用的是活菌体，还原过程所得的纳米颗粒主要形成于胞内，影响到纳米颗粒后续利用，而利用微生物干/死菌体还原所得的金属纳米颗粒则在胞外或菌体表面上形成，有利于获得菌体负载的金属纳米颗粒。该负载型金属纳米颗粒具有易于分离回收的特性，可望作为一种新型材料在多相催化等领域得以应用。本论文以工业上广泛应用的黑曲霉菌为生物吸附、还原材料，系统研究了其对贵金属离子(金、银)的生物吸附、生物还原特性，进而制备出黑曲霉菌体负载的金、银纳米材料，分别考察菌体负载金纳米材料对染料还原的催化性能以及菌体负载银纳米材料的抗菌性能，并借助于TEM、EDS、XRD、XPS、FTIR和AAS等技术对所得纳米材料进行表征，对其结构与应用性能进行关联。主要研究内容和结果归纳如下： 首先，以黑曲霉干菌体作为生物吸附剂，对其吸附Au(III)离子的影响条件、吸附热力学、吸附动力学进行了系统的研究，并对吸附机理进行了较为深入的分析。结果表明，黑曲霉菌对Au(III)离子的吸附性能对溶液pH值具有一定的依赖性，其最佳pH值为2.0～3.0；20℃下吸附过程分为2个阶段进行，分别对应于Au(III)离子还原前和还原后的吸附，而30℃、40℃和60℃下吸附过程均无明显分段现象；当Au(III)离子初始浓度小于233.32mg•L–1时，吸附量几乎不受温度的影响，而当初始浓度大于367.94mg•L–1时，升温明显促进了吸附量的提高。黑曲霉菌对Au(III)离子的吸附等温线可用Langmuir方程很好地模拟，20℃、30℃、40℃和50℃时Au(III)离子饱和吸附量分别为185.19mg•g–1、202.02mg•g–1、235.85mg•g–1和277.78mg•g–1。热力学函数Gibbs自由能变、吸附焓变和吸附熵变的计算结果表明，黑曲霉菌对Au(III)离子的吸附过程是一自发的吸热和熵增过程。其吸附动力学可用准二级速率方程描述，吸附活化能为55.71kJ•mol–1。黑曲霉菌吸附Au(III)离子的主要作用机制是静电引力、络合作用和氧化还原作用，菌体表面的酯基、羧基、羟基和氨基等均是键合Au(III)离子的主要官能团，其中以羟基的贡献最大，而氨基的贡献相对较小。 其次，利用黑曲霉干菌体对Au(III)离子的吸附还原特性制备了AuNPs/黑曲霉菌催化剂，考察了HAuCl4溶液初始pH值、反应温度、HAuCl4浓度、反应时间和菌体表面基团预处理等催化剂制备条件，以及染料种类、NaBH4用量、催化剂浓度等催化反应条件对染料催化还原性能的影响，并对所得AuNPs/黑曲霉菌催化剂进行了表征。结果表明，AuNPs/黑曲霉菌对6种染料均具有高的催化还原性能，其表面同时存在Au0、Au+和Au3+金物种，其中氧化态Auδ+在催化剂中的含量和组成(Au+/Au3+)对催化剂活性影响显著。对于MB催化还原反应，催化剂较优制备条件为：2.0g•L–1的黑曲霉菌粉与pH值为5、浓度为23.64～94.56mg•L–1的HAuCl4溶液在30℃下反应48～72h。在上述条件下制得的催化剂，当MB与NaBH4物质的量的比为1:100、催化剂浓度为55.6mg•L–1时，50～70s可将2×10–4mol•L–1MB完全还原。随着NaBH4用量的增加，MB还原反应速率迅速增大；随着催化剂浓度的增大，MB还原反应速率先逐渐增大后几乎不变。AuNPs/黑曲霉菌催化剂对MB的催化还原性能在重复使用2次后明显降低，对于GTL则重复使用9次后活性未明显降低。 最后，利用黑曲霉干菌体吸附还原银氨离子制备了AgNPs/黑曲霉菌复合材料，以E.coli为测试菌株评价该复合材料的抗菌性能，通过银释出实验考察该复合材料的稳定性，研究了反应温度与pH值对还原过程和所得复合材料的抗菌性能及稳定性的影响，并对所得AgNPs/黑曲霉菌进行了表征。结果表明利用黑曲霉干菌体还原制得的AgNPs/黑曲霉菌复合材料，AgNPs以粒度为6.9～8.2nm的近球形颗粒形式均匀分布在黑曲霉菌体表面，银负载量为3.7%～5.0%。反应温度从30℃提高至60℃有利于提高菌体银负载量，所得AgNPs粒径增大；反应pH值从9.5提高至11.5有利于提高反应速率，而菌体银负载量和AgNPs的粒径则差异不大。该复合材料对E.coli具有较好的抗菌性能，其MIC为217～434mg•L–1(以菌粉总质量表示)；500mg•L–1的复合材料(银负载量为3.8%)在10min内能完全杀死106cfu•mL–1E.coli，且重复使用5次后，其抗菌性能未有明显下降；该复合材料的抗菌性能主要与AgNPs粒度大小有关，AgNPs的粒径越小其抗菌性能越强。银释出实验结果表明，AgNPs/黑曲霉菌复合材料中AgNPs与菌体结合牢固，单位质量复合材料释放出Ag+的量为1.7～6.8mg•g–1(占总质量分数的3.4%～18.4%)，提高反应温度和反应pH值后Ag+的释出均减少。Currently, increasing “green chemistry” concept and environmental awareness necessitate the development of environmental benign nanoparticles synthesis. As a result, the bioreduction method based on microorganisms has emerged as novel and environmental benign approach to synthesize metal nanomaterials in recent years. However, current studies on the miroorganism-mediated synthesis were focus on the living microorganism and most of the as-synthesized nanoparticles were intracellular, resulting in the difficulties in subsequent processing and applications. In contrast, the nanoparticles synthesized by inactive miroorganism were extracellular or located on the cell surface. These metal nanoparticles immobilized on cell surface can be easily recovered and applied as a novel material for heterogeneous catalytic reactions etc. This study aims at the characteristic of biosorption and bioreduction of Au(III) and Ag(I) by Aspergillus niger(A. niger), which has been widely used in industry. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) supported on A. niger were fabricated via reduction of Au(III) ([AuCl4]–) and Ag(I) ([Ag(NH3)2]+) by dry biomass of A. niger. Catalytic activity of AuNPs/A. niger and antimicrobial activity of AgNPs/A. niger composite were evaluated respectively. A variety of techniques, such as TEM, EDS, XRD, XPS, FTIR and AAS were employed to characterize the composites and study the relationship between the performance and structure of the composites. The main contents and some successful results have been listed as following. Firstly, the biosorption potential of A. niger for Au(III) was investigated. The biosorption mechanism, as well as the parameters influencing the biosorption of Au(III) and thermodynamics and kinetics was systematically studied. The results indicated that Au(III) biosorption was pH-dependent and the favorable pH value was about 2.0–3.0. Au(III) biosorption involved two stages corresponding to periods before and after Au(III) reduction at 20 ºC. The biosorption capacity was hardly affected by temperature at lower initial Au(III) concentrations(367.94 mg•L–1). Au(III) biosorption was found to fit the Langmuir model well and the maximum Au(III) uptake capacity was 185.19 mg•g–1, 202.02 mg•g–1, 235.85 mg•g–1 and 277.78 mg•g–1 at 20 ºC, 30 ºC, 40 ºC and 50 ºC, respectively. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes were calculated, revealing the biosorption process was spontaneous and endothermic and entropy increased. The biosorption process was found to conform to the pseudo-second-order rate kinetics and the obtained activation energy was 55.71 kJ•mol–1. The biosorption of Au(III) by A. niger mainly depended on electrostatic forces, complexation and redox. FTIR characterization illustrated that the functional groups such as ester, amino, carboxyl and hydroxyl might be responsible for the interaction between Au(III) and A. niger biomass and the hydroxyl groups were found to play the key role. Secondly, AuNPs/A. niger catalyst was synthesized by dry biomass of A. niger. The catalytic activity of AuNPs/A. niger towards the reduction of various dyes in the presence of NaBH4 was evaluated. The effect of catalyst preparation parameters including pH value of HAuCl4, catalyst preparation temperature, concentration of HAuCl4, catalyst preparation time and pretreatment of the function groups of biomass, and the effect of catalytic reaction conditions including dye species, dosage of NaBH4 and concentration of catalyst on the catalytic performance were investigated, respectively. The results indicated that AuNPs/A. niger was an efficient catalyst for catalytic reduction of six organic dyes. The characterization results of catalysts indicated that gold species on the catalysts existed in the form of Au0, Au+ and Au3+. The catalytic performance of AuNPs/A. niger was closely related to the content and composition (Au+/Au3+) of Auδ+. For MB reduction, the optimal catalyst preparation condition was 2.0 g•L–1 A. niger powder reacted with 23.64–94.56 mg•L–1 HAuCl4 at pH=3 and 30 oC for 48–72 h. When the concentration of NaBH4 was 100 times to that of MB and the concentration of catalyst was 55.6 mg•L–1, MB with an initial concentration of 2×10–4 mol•L–1 could be completely reduced within 50–70 s. The reaction rate of MB reduction process can be enhanced with the increase dosage of NaBH4. With the increase of catalyst concentration, the reaction rate increase gradually and then remain almost the same. Furthermore, for the reduction of CR, the AuNPs/A. niger showed excellent reusability for 9 successive cycles with no obvious decrease in catalytic effects. However, for the reduction of MB, the catalytic rate of the catalyst decreased significantly after 2 times’ reuse. Finally, AgNPs/A. niger composites were fabricated via the reduction of [Ag(NH3)2]+ by dry biomass of A. niger. The antimicrobial property of AgNPs/A. niger composites was evaluated and the representative E. coli was used as the tested strain. The immobilization efficiencies of silver ions and AgNPs in the composites were confirmed by silver leaching experiments. The effects of temperature and pH value on the bioreduction process and the antimicrobial activity and the stability of the composites were studied. AgNPs/A. niger composites were also systematically characterized. The results showed that AgNPs with 6.9–8.2 nm were well dispersed on the cell surface and the Ag loadings were 3.7%–5.0%. Although increasing the reaction temperature from 30 oC to 60 oC resulted in the increase of the silver loading, the size of the as-synthesized AgNPs became larger at the same time. The increase of pH value from 9.5 to 11.5 accelerated the reaction and shortened the reaction time (from 144 h to 24 h), whereas no significant effects were observed on the Ag loading and the size of AgNPs. The AgNPs/A. niger composites exhibited excellent antimicrobial activity against E. coli and the minimal inhibitory concentration (MIC) was 217–434 mg•L–1 (based on the weight of AgNPs/ A. niger). The AgNPs/A. niger composite showed fast and long-lasting bactericidal activity toward E. coli. The composite with the concentration of 500 mg•L–1 (3.8% Ag loading) can fully kill 106 cfu•mL–1 E. coli after 10 min of incubation and bactericidal activity can be kept even after five rounds’ recycle. The antimicrobial activity of the composite was found to be mainly depended on the size of AgNPs and smaller size exhibited better antimicrobial activity. The release of AgNPs and Ag+ from the AgNPs/A. niger composites was also investigated. The results suggested that the as-prepared AgNPs were supported firmly on A. niger and the release of Ag+ was 1.7–6.8 mg per gram of AgNPs/A. niger. Furthermore, increasing the reaction temperature or the pH value led to the decrease of Ag+ release.学位：工学博士院系专业：海洋与环境学院_环境工程学号：2262008015014

The Pollution Control of Polycyclic Aromatic Hydrocarbons and the Research Prospect of Bioremediation

该文介绍了多环芳烃的形成机理和在环境中的污染现状 ;讨论了多环芳烃环境污染的控制途径、微生物降解机理和生物修复的方法 ,并对其它生物在多环芳烃生物修复中的作用进行了讨论The paper introduces the forming mechanism of PAHs and the current status of pollution in the environment,and discusses the pathway of controlling the PAHs pollution,the mechanism of microbial degradation and the method of bioremediation,and also approaches the role of other biology in the bioremediation repair of PAHs.国家自然科学基金 ( 30 0 70 15 7);; 教育部科学技术研究重点项目基金 ( 99180 )资

气候变化问题多学科协同机制实践研究

由于不合理的人类活动，全球气候正呈现以变暖为主要特征的变化。气候变化及其导致的各种环境事件已经严重影响到人类社会的可持续发展，成为当今国际社会所共同面对的挑战。相关学科基于本学科的研究领域 与研究范畴开展了卓有成效的研究。文章以社会学、伦理学、哲学为视角，横向梳理了相关学科对气候变化问题介入的原因、气候变化问题的认知及相关的研究成果，并进行评述。综合分析和探讨了气候变化问题研究中学科间研究对象、研究目的、研究方法的区别与联系，提出以学科间的自组织系统来研究气候变化问题的观点，进行学科间的跨界交流与探讨，探讨学科间的协调，关注气候变化问题的文化内涵，构建多学科间的研究范式，促进学科间的有机交流与融合，以推进气候变化的减缓与适应行动。</p

Assay of biotoxicity of polycyclic aromatic hydrocarbons by Microtox test.

利用Microtox 技术检测5 种多环芳烃化合物生物毒性结果表明,二甲亚砜配制的测试液中萘、菲及荧蒽均对发光细菌具有一定生物毒性,且随浓度的增大而增强,相同浓度下毒性菲> 萘;测试液中当萘浓度小于其溶解度时即产生100%的抑光率,萘EC50为4.32mg/ L ,而菲及荧蒽浓度近其溶解度时所产生的最大抑光率分别为< 50 %和15 %左右;芘及蒽最大浓度时则对发光细菌无生物毒性显示。表明Microtox 技术可有效检测低环化合物萘的生物毒性,但对高环化合物( ≥3 环) 的检测因受其低水溶性的限制而灵敏度降低,利用二甲亚砜获取多环芳烃污染物提取液的生物毒性主要与低分子化合物萘及菲有关。国家自然科学基金项目(30070157) 、福建省教育厅基金项目(KB 0316) 和福建省泉州市科技计划重点项目(Z200234) 共同资

Microtox技术检测多环芳烃生物毒性的研究

利用Microtox技术检测 5种多环芳烃化合物生物毒性结果表明 ,二甲亚砜配制的测试液中萘、菲及荧蒽均对发光细菌具有一定生物毒性 ,且随浓度的增大而增强 ,相同浓度下毒性菲 >萘 ;测试液中当萘浓度小于其溶解度时即产生 10 0 %的抑光率 ,萘EC50 为 4 .32mg/L ,而菲及荧蒽浓度近其溶解度时所产生的最大抑光率分别为 <5 0 %和15 %左右 ;芘及蒽最大浓度时则对发光细菌无生物毒性显示。表明Microtox技术可有效检测低环化合物萘的生物毒性 ,但对高环化合物 (≥ 3环 )的检测因受其低水溶性的限制而灵敏度降低 ,利用二甲亚砜获取多环芳烃污染物提取液的生物毒性主要与低分子化合物萘及菲有

Design of POCT quality management system based on the Internet of things

目的设计基于物联网的POCT质量管理系统以规范POCT质量管理。方法分析POCT质量管理存在的问题,以便携式血糖仪为例,从数据采集、传输、服务器; 管理存储等各环节设计POCT物联网质量管理系统。结果设计了基于物联网和医疗云为基础的POCT质量管理系统,该系统可实现POCT操作人员与设备管理; ,实时进行质量控制数据监控与报告管理,并方便管理者分析所管辖区域的POCT全程质量问题。结论设计的基于物联网的POCT质量管理系统具有理论可行性; 。Objective To design a POCT quality management system based on the; Internet of things so as to standardize POCT quality management. Methods; The existing problems in POCT quality management were analyzed. Taking; portable blood glucose meters as an example,the quality management; system of POCT-Internet of things was designed based on the all aspects; of data acquisition,transmission, server management and storage,etc.; Results The POCT quality management system based on the Internet of; things and medical cloud technology was designed. The system could; implement the management of POCT operators and devices,monitor the; realtime quality control data and reports,and facilitate the; administrators to analyze the quality problems in the whole process of; POCT management. Conclusion The designed POCT quality management system; based on the Internet of things has the theory feasibility.厦门市第二批青年创新创业人才计

Relevant relationship between IUD and endometrial polypus

目的:研究宫内节育器(InTrAuTEruS dEVICE,Iud)与子宫内膜息肉的相关性。方法:统计2004年5月--2007年5月在厦门大学附属中山医院行宫腔镜取环并经病理检查确诊Iud合并子宫内膜息肉病例,分析Iud与子宫内膜息肉的相关敏感因素。结果:1357例宫腔镜取环者Iud合并子宫内膜息肉285例,占21%,患者对金属皮带扣或金饰物过敏,经阴道分娩和人工流产且中位子宫患者的发病率较高,息肉好发于Iud的周围。放环时间15年以上,Iud变形、下移和长锈斑的比例均较高。结论:放置Iud且有息肉形成高危因素的患者应及时行宫腔镜检查,并行诊刮术或子宫内膜息肉电切术、取环术。Objective:To study relevant relationship between IUD and endometrial polyps(EMP).Methods:The cases who removed IUD and EMP by hysteroscopic operation and diagnosed by pathological examination were analyzed in Xiamen Zhongshan Hoapital from may 2004 to may 2007,and the related factors of IUD and EMP were analyzed.Results:of 1357 cases who removed IUD by hysteroscopic operation,the cases who had EMP was 21%(285/1357).EMP growed around IUD in cases whose uteri were middle position.Vaginal labor and artificial abortion and allergic to metal including the metal buckle and gold ornaments were high risk factors.Conclusion:The cases with IUD who had risk factors of endometrial polypus formation need do hysteroscopic operation and remove IUD

Progress in functional separator materials for lithium-ion batteries

隔膜是锂离子电池四大关键材料之一,随着锂离子电池在电动汽车、储能等领域的应用不断延伸,对隔膜的性能要求越来越高.本文从安全和电化学性能等角度论述了近年来无机陶瓷改性功能隔膜、聚合物改性功能隔膜及其他功能性隔膜的相关研究进展,并对功能性隔膜的发展提出展望,为从事相关研发的工作者提供一些借鉴.As the application of Li-ion batteries has been expanding from consumer electronics to industrial usage including electric vehicles and energy storage, the separator, which is a critical component of a Li-ion battery, has gained much more attention to improve its performance.This paper reviews the research progress of ceramic coater separators, polymer modified separators and other functional separators from the viewpoint of the Li-ion battery safety and electrochemical performance.Furthermore, the paper also brings on the future prospect of functional separators which provides some references for the development of this area.国家高技术研究发展计划重大项目(2012AA110404); 中航工业产学研合作创新工程专项研究计划(cxy2011XD27)资