Preparation of Watersoluble Nanosilver Powder by Microorganism Reduction and Its Application in Catalysis and Antibiosis

纳米材料由于其维度降低而产生许多特殊的物理和化学性质，成为当今材料科学研究的一个热点。金属离子的生物吸附与生物还原由于其在环境保护、纳米材料制备等方面的潜在应用前景也成为近年来各国学者广泛开展的科研领域。本论文以筛选自金银矿区的气单胞菌(Aeromonassp.)SH10、棒状杆菌(Corynebacteriumsp.)SH09、地衣芽孢杆菌(Bacilluslicheniformis)R08等为主要实验菌株，利用微生物细胞丰富的有机官能团，研究在一定条件下快速还原银盐或银氧化物，并利用生物质对还原出来的银单质颗粒可提供修饰、包裹保护作用，制备得到稳定的生物质银溶胶，并尝试揭示还原的可能机理，...Nanostructured materials are capable of giving unique physicochemical properties and therefore they have been attracting increasing attention. Biosorption and bioreduction of metal ions have been receiving growing attention due to its potential applications in the fields of environment protection, nanomaterial synthesis, etc. Several strains were used to investigate the silver bioreduction in this...学位：工学硕士院系专业：化学化工学院化学工程与生物工程系_化学工程学号：20033300

Studies on mechanisms of silver biosorption by Aeromonas SH10

［中文文摘］以气单胞菌SH10为生物吸附材料,从静电吸附作用、离子交换作用、络合作用、沉淀作用几方面研究了SH10吸附Ag+过程可能存在的作用机制.结果表明,气单胞菌SH10吸附银离子依赖于静电吸附作用;吸附Ag+前后溶液中Na+、K+、Mg2+浓度的变化较小,说明吸附过程中离子交换不明显;SH10表面的羧基、氨基和脂类基团经化学屏蔽后,对Ag+的吸附量明显下降,结合红外光谱分析结果,确定酰胺基CO-NH为SH10与银离子发生络合作用的主要官能团;电镜扫描结果表明,SH10在吸附过程中可以和Ag+形成沉淀沉积在细胞表面.［英文文摘］The study on mechanisms of metal biosorption is helpful to improve the biosorption ability of organism. Mechanisms of silver biosorption by Aeromonas SH10 were discussed from several aspects such as electrostatic adsorption, ion exchange, complexation and deposition. Results showed that silver biosorption by SH10 didn't mainly depend on ion exchange duo to only slight increase of the contents of Na~+, K~+, Mg~ 2+ in solution after biosorption, while electrostatic adsorption was found to be responsible for biosorption. Adsorptive capacity of silver ion decreased distinctly after functional groups such as carboxyl, amino and lipid groups on SH10 cell wall were chemicallymodified, respectively. Combined with FTIR spectra, amino groups were confirmed to be the main active groups that could combine with silver ion. SEM illustrated precipitation could take place on the cellwall of SH10.国家自然科学基金(No.20376067

Study on mechanisms of silver biosorption by laminaria japonica

生物吸附金属作用机制的研究,有助于提高生物吸附剂的吸附能力。文章以前期优选出的对银具有较强吸附能力的海带为生物吸附材料,从静电吸附作用、离子交换作用、络合作用、沉淀作用几方面研究了其吸附Ag+过程可能存在的作用机制。结果表明:海带吸附银离子不依赖于静电吸附作用;吸附Ag+前后溶液中Na+、K+、Mg2+质量浓度的变化说明吸附过程中存在离子交换机制;海带表面的羧基、氨基和脂类基团经化学屏蔽后,对Ag+的吸附量明显下降,结合红外光谱分析结果,确定酰胺基CO—NH和离子化羧基COO-为海带与银离子发生络合作用的主要官能团;电镜结果表明海带在吸附过程中可以和Ag+形成沉淀沉积在细胞表面。The study on mechanisms of metal biosorption is helpful to improve the biosorption ability of organism.Mechanisms of silver biosorption by Laminaria japonica were discussed from several aspects such as electrostatic(adsorption,) ion exchange,complexation and deposition.The results show that silver biosorption by Laminaria(japonica) doesn′t depend on electrostatic adsorption,while ion exchange is responsible for biosorption because of(increase) of the mass concentration of Na~+,K~+,Mg~(2+) in solution before and after biosorption.Adsorptive capacity of Ag~+ distinctly decreases after functional groups such as carboxyl,amino and lipid groups in Laminaria japonica cell wall are chemically modified respectively.Combined with FTIR spectra,carboxyl and amino groups are(confirmed) to be the main active groups which can combine with silver ion.Precipitation can take place on the cell wall of Laminaria japonica through SEM characterization.国家自然科学基金资助项目(20376067

STUDY ON THE PHYSIC-CHEMICAL PROPERTIES OF BIOSORPTION OF SILVER BY LAMINARIA JAPONICA

[中文文摘]以海带(Laminariajaponica)干粉为吸附剂,研究了海带吸附Ag+的物理化学特性。结果表明:海带对Ag+有很强的吸附能力,最大理论吸附量可达273mg/g干重。该吸附在20~40℃范围内是一个不依赖于温度的快速过程;对溶液的pH值有较宽的适应范围;海带浓度在0.5~4.0mg/L范围内,海带对Ag+的吸附量与海带粉的浓度成反比;起始Ag+浓度在10~800mg/L的范围内,海带对Ag+的吸附量与起始Ag+浓度成正比。吸附等温线符合Langmuir模型。TEM观察结果表明,海带能够将Ag+还原成Ag0。海带可用于从含Ag+的强酸废液中回收Ag+,当废液中Ag+浓度为121.9mg/L时,其回收率可达98.3%。[英文文摘]Biosportion of heavy metals is an effective technology for the treatment of industrial wastewater. In this paper, dried biomass of Laminaria japonica was used as biosorbent for Ag+. The physic-chemical properties of biosorption of silver by Laminaria japonica were studied.The results showed that Laminaria japonica had relatively strong ability of adsorbing Ag+, and its theoretical maximum uptake capacity was 273mg/g dry biomass. Ag+ biosorption by Laminaria japonica was a rapid and temperature (20~40℃) independent process. In the range of pH value from 2 to 6, biosorptive process was unrelated to pH, and even in strong acid solution (pH<1) Laminaria japonica still showed a high efficiency for Ag+ uptake. During the process of biosorption, pH value of solution rose from 5.5 to 6.4, which suggested that ion exchange might be one of the biosorptive mechanisms. Ag+ adsorption followed Langmuir model. The biosorptive capacity (q) of Ag+ decreased with increase of biomass concentration (Cb) (0.5~4.0g/L), and rose with increase of initial Ag+ concentration (Ci) (10~800mg/L). TEM observation indicated that the Ag+ ions could be reduced to Ag0 particles by Laminaria japonica.Moreover, Laminaria japonica could be used to recover Ag+ from strong acid wastewater, and the biosorptive efficiency (E) reached 98.3%. As the Ag+ concentration (Ci) was 121.9mg/L. The result indicated that Laminaria japonica was suitable for the development of effective biosorbent for the removal and recovery of silverfrom wastewater.国家自然科学基金(20376067); 中国石油化工股份有限公司项目