共查询到19条相似文献,搜索用时 31 毫秒
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碳酸岩矿化菌诱导碳酸钙晶体形成机理研究 总被引:14,自引:0,他引:14
选用碳酸盐矿化菌(芽孢杆菌系), 分别研究了不同浓度细菌液、细菌体及其分泌物对碳酸钙晶体形成的影响. 研究表明, 细菌液浓度越高, 控制碳酸钙晶体形貌作用越显著; 细菌体为碳酸钙结晶提供异相成核点而对形貌并没有实质影响; 细菌分泌物可诱导出球形、纺锤形等多种形态亚稳态球霰石; 在微生物环境的长期作用下可形成有机-无机复合碳酸钙硬质膜. 通过对电导率测定结果和碳酸钙红外图谱分析得出, 生物有机质分子链的极性基团(COOH, C=O等)与Ca2+产生静电、配位等一系列作用, 调控晶体的生长. 本研究对于微生物诱导碳酸钙的工程性应用, 如混凝土微裂缝修复、古建筑表面防护处理、微纳米碳酸钙颗粒制备等具有一定指导意义. 相似文献
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本文以一株海洋菌株Bacillus sp.Q72的胞外液为还原体系,实现了Se(Ⅳ)到纳米硒(SeNPs)的生物转化。利用FTIR、UV-Vis、XRD、SEM、TEM、XPS、拉曼光谱、粒度分析等对生物合成SeNPs的理化性质进行了研究,随后考察了SeNPs的抗菌活性和细胞毒性。结果表明,菌株Bacillus sp.Q72胞外液生物合成的SeNPs为球型,平均粒径为187.6nm,其表面包覆着蛋白质、核酸等生物大分子。SeNPs对金黄色葡萄球菌和铜绿假单胞菌均表现出较好的抑菌活性,同时具有较低的细胞毒性。利用细菌胞外液生物合成纳米硒,避免了利用菌体直接还原在分离过程中的繁琐操作,为SeNPs的生物合成提供了新方法。 相似文献
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采用动电位扫描法、电化学交流阻抗法和表面分析方法研究了假单胞菌的加入对A3钢在枝孢霉菌溶液中腐蚀行为的影响. 结果表明, 假单胞菌的存在影响了A3钢在枝孢霉菌体系中阳极的反应过程, 假单胞菌与枝孢霉菌混合体系(简称假-枝混合菌体系)中A3钢的自腐蚀电流小于枝孢霉菌单种菌体系, A3钢的腐蚀速率减小;随着浸泡时间的延长, 从第7天开始, A3钢电极在假-枝混合菌体系中的阻抗值较之同样浸泡天数的枝孢霉菌单种菌体系的阻抗值大, 假单胞菌的存在抑制了枝孢霉菌对A3钢的腐蚀. SEM结果表明, A3钢在枝孢霉菌和假-枝混合菌体系中均发生了点蚀,枝孢霉菌单菌体系中A3 钢的点蚀坑大而深, 假-枝混合菌体系中的点蚀坑与枝孢霉菌体系相比小而浅. 相似文献
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研究了添加分枝杆菌(Mycobacterium sp.)、假单胞菌(Pseudomonas sp.)和混合菌(分枝杆菌和假单胞菌)对多环芳烃(PAHs)污染土壤中细菌群落结构的影响.采用DGGE研究土壤细菌群落结构及多样性的变化,通过测序鉴定细菌种类.研究结果表明:投加微生物能够改变土壤细菌群落结构的组成,促进或加强了有PAHs降解能力的菌株如假单胞菌、如微杆菌(Micrococcus sp.)的出现;投加微生物改变了土壤中的细菌多样性指数,分枝杆菌处理组的多样性指数变化稍大.研究结果为PAHs污染土壤的修复理论与技术进一步发展奠定理论基础,也为PAHs污染土壤修复中微生物的选择提供依据. 相似文献
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以葡聚糖为模板控制合成文石型碳酸钙 总被引:9,自引:0,他引:9
依据生物矿化的基本原理,在动态条件下以葡聚糖为模板,采用仿生的方法控制合成了具有独特形貌并含有少量葡聚糖的碳酸钙复合材料.用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、傅里叶变换红外吸收光谱(FTIR)和电导率测定等手段对所得的复合碳酸钙进行了形貌与结构表征.结果表明,所得CaCO3为文石晶型,外貌类似菜叶.进一步的研究发现,在CaCO3结晶过程中葡聚糖与CaCO3之间存在超分子相互作用,并讨论了这种作用的可能机理. 相似文献
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用FT-IR、XRD、SEM和TGA等研究了4种不同模拟体系中胆红素钙晶体的成核与生长情况,考察了生物大分子和CO2对胆红素钙的成核与结晶等的影响。结果表明,水溶液中胆红素钙很难结晶形成晶体结构,但在暴露大气中的葡聚糖水溶液模拟体系中则形成了含质量分数为12%碳酸钙的胆红素钙/碳酸钙复合晶体。在此过程中,CO2气体促进了碳酸钙晶体的形成,碳酸钙晶体不同晶面的选择吸附性能和葡聚糖分子的含O功能团为胆红素钙的成核提供了有效位点和定向调控作用,共同模板作用诱导调控了在2θ为19.8°、21.8°有强衍射峰的胆红素钙晶体的形成。晶态胆红素钙具有明显的热分解温度,而处于非晶态时则无此种现象。 相似文献
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Xiuzhen Zhang Anjian Xie Fangzhi Huang Yuhua Shen 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(3):515-520
The morphogenesis and growth process of calcium carbonate on the cellulose acetate/polyvinyl pyrrolidone (CA/PVP) blend films in the presence of L-aspartic acid was carefully investigated. The results showed that the concentration of L-aspartic acid, the initial pH value of reaction solution and temperature turned out to be important factors for the control of morphologies and polymorphs of calcium carbonate. Complex morphologies of CaCO3 particles, such as cubes, rose-like spheres, twinborn-spheres, cone-like, bouquet-like, etc. could be obtained under the different experimental conditions. The dynamic process of formation of rose-like sphere crystals was analyzed by monitoring the continuous morphological and structural evolution and components of crystals in different crystal stages. This research may provide a promising method to prepare other inorganic materials with complex morphologies. 相似文献
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该文以更加接近生物矿化的方法研究了蔗糖/精氨酸体系对碳酸钙晶体取向、形貌和晶型的控制作用.XRD 分析表明,在蔗糖/L-精氨酸混合体系中合成的晶体主要为碳酸钙的球霰石晶型及少量的方解石型,在单独的蔗糖或L-精氨酸溶液中基本是球霰石晶型.SEM分析表明,蔗糖和L-精氨酸均可诱导形成特殊形貌的碳酸钙.实验结果表明,蔗糖/精... 相似文献
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A novel and simple method for preparing tubular structure agglomerates of calcium carbonate (CC-tube) is described. Calcium chloride and sodium carbonate aqueous solutions were used as reactants separated by a collodion film (a nitrocellulose material) in aqueous solution. The effects of the concentrations of calcium chloride and sodium carbonate aqueous solutions on the morphology and phase structure of the as-obtained samples were investigated. The CC-tube growth was prevented with the increase of reactant concentration from 0.5 to 1.0 mol•L-1. Compared with Na2CO3 aqueous solution, it is favourable to grow calcite crystals in CaCl2 aqueous solution. The products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron- microscopy. 相似文献
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本文研究了二维琼脂凝胶圆盘体系中碳酸钙分形结构的形成过程,发现随着反应时间的增加,碳酸钙的形态经过了细小颗粒-枝晶结构-分形结构的转变过程,该分形结构实际上是由纳微米级碳酸钙晶粒聚集而成的。增加琼脂和反应物的浓度,碳酸钙微晶的形貌和尺寸发生了变化,呈现立方体与球形,由其构成的分形结构的尺寸也随着改变,但碳酸钙的晶型均为方解石型,无明显变化。二维凝胶体系中碳酸钙分形结构的形成主要与琼脂极性基团提供成核位点、多糖的网络结构、沉淀剂离子扩散受限有关。 相似文献
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The influence of the primary structures of plant (Canavalia ensiformis) and bacterial (Bacillus pasteurii) ureases on the precipitation of calcium carbonate polymorphs in solutions of calcium salts and urea at room temperature was investigated. Despite a similar catalytic function in the decomposition of urea, these ureases exerted different influences on the crystal phase formation and on the development of unusual morphologies of calcium carbonate polymorphs. Spherical and uniform vaterite particles were precipitated rather than calcite in the presence of Bacillus urease, while the presence of Canavalia urease resulted in the precipitation of calcite only. Vaterite particles were shown to be built up of nanosized crystallites, proving the importance of nanoscale aggregation processes on the formation of colloidal carbonates. Reduction of the concentration of Bacillus urease in the reacting solution results in the formation of calcite crystals with a more complex surface morphology than the ones obtained by Canavalia urease. These differences may be explained by dissimilarities in the amino acid sequences of the two examined ureases and their different roles in nucleation and physicochemical interactions with the surface of the growing crystals, during the precipitation processes. This study exemplifies the diversity of proteins produced by different organisms for the same function, and the drastic effects of subtle differences in their primary structures on crystal phase formation and growth morphology of calcium carbonate precipitates, which occur as inorganic components in a large number of biogenic structures. 相似文献
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Supersaturation control in aragonite synthesis using sparingly soluble calcium sulfate as reactants 总被引:2,自引:0,他引:2
Sparingly soluble calcium salts were studied as reactants in the synthesis of needle-like precipitated calcium carbonate (PCC). The morphology and aspect ratio of the PCC particles were characterized with SEM. Polymorphs and crystal size were characterized using X-ray diffraction. The counterions of the sparingly soluble salts influenced the growth kinetics of PCC as well as the polymorphism and morphology of product particles. Either chrysanthemum-like or needle-like aragonite can be synthesized from calcium sulfate and sodium carbonate depending on the supersaturation and synthesis conditions. Low concentration and slow addition rate of sodium carbonate solution were favorable to the formation of aragonite. Addition of sodium sulfate to the reaction system (calcium chloride and sodium carbonate) promoted the formation of aragonite and decreased the crystal size of aragonite due to the decrease of supersaturation and adsorption of sulfate ion. Too much added sodium sulfate, however, did not further increase the aragonite fraction. An optimal temperature for the formation of aragonite was found to be ca. 60 degrees C. Slow dissolution kinetics of sparingly dissoluble salt also is very important for controlling PCC polymorphism and morphology. 相似文献