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生物矿化针铁矿吸附废水中铬的实验研究   总被引:6,自引:0,他引:6  
在静态条件下,利用生物矿化针铁矿对含铬模拟废水进行吸附实验研究。结果表明,生物矿化针铁矿对质量浓度在5mg/L以下的含Cr2O7^2-,Cr^3 模拟废水均具有较好的去除效果,平均去除率达94%,出水达到“污水综合排放标准”(GB8978—1996);其吸附符合Langmuir与Freundlich模型。  相似文献
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Biomineralization, biosilicification in particular (i.e. the formation of biogenic silica, SiO2), has become an exciting source of inspiration for the development of novel bionic approaches following “nature as model”. Siliceous sponges are unique among silica forming organisms in their ability to catalyze silica formation using a specific enzyme termed silicatein. In this study, we review the present state of knowledge on silicatein-mediated “biosilica” formation in marine sponges, the involvement of further molecules in silica metabolism and their potential application in nanobiotechnology and medicine. Werner E. G. Müller dedicated this study to Prof. Vera Gamulin (Rudjer Boskovic Institute, Zagreb, Croatia) in honour of her unique contributions in molecular evolution.  相似文献
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Extant monoplacophorans (Tryblidiida, Mollusca) have traditionally been reported as having an internal nacreous layer, thus representing the ancestral molluscan condition. The examination of this layer in three species of Neopilinidae (Rokopella euglypta, Veleropilina zografi, and Micropilina arntzi) reveals that only V. zografi secretes an internal layer of true nacre, which occupies only part of the internal shell surface. The rest of the internal surface of V. zografi and the whole internal surfaces of the other two species examined are covered by a material consisting of lath-like, instead of brick-like, crystals, which are arranged into lamellae. In all cases examined, the crystallographic c-axis in this lamellar material is perpendicular to the surface of laths and the a-axis is parallel to their long dimension. The differences between taxa relate to the frequency of twins, which is much higher in Micropilina. In general, the material is well ordered, particularly towards the margin, where lamellae pile up at a small step size, which is most likely due to processes of crystal competition. Given its morphological resemblance to the foliated calcite of bivalves, we propose the name foliated aragonite for this previously undescribed biomaterial secreted by monoplacophorans. We conclude that the foliated aragonite probably lacks preformed interlamellar membranes and is therefore not a variant of nacre. A review of the existing literature reveals that previous reports of nacre in the group were instead of the aragonitic foliated layer and that our report of nacre in V. zografi is the first undisputed evidence of nacre in monoplacophorans. From the evolutionary viewpoint, the foliated aragonite could easily have been derived from nacre. Assuming that nacre represents the ancestral condition, as in other molluscan classes, it has been replaced by foliated aragonite along the tryblidiidan lineage, although the fossil record does not presently provide evidence as to when this replacement took place.  相似文献
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李哲  张欢  张秀芳  周野  吴迪  李明堂 《环境科学学报》2017,37(10):3687-3695
有机肥的大量使用使得菜田土壤重金属含量呈快速的累积趋势,对蔬菜安全生产构成了严重的威胁.本文从长期施加鸡粪猪粪等农家肥的大棚蔬菜根际土壤中筛选出了一株能降解尿素释放碳酸根,进而通过生物矿化作用固结重金属的细菌,系统发育分析和生理生化特征表明该菌株为氧化木糖无色杆菌,将其命名为LAX2.菌株LAX2可在含尿素的培养基中快速生长,所产脲酶的活力可达140 U·mL-1,发酵液的pH可达9.06.菌株LAX2可耐受浓度高达115 mg·L-1的铜离子.X-射线衍射分析(XRD)、傅里叶红外光谱分析(FTIR)、扫描电子显微镜(SEM)和能谱(EDS)分析表明菌株LAX2可通过生物矿化作用形成微球形的Cu2(OH)2CO3,其直径可达2 μm.菌体细胞吸附、生物矿化和化学沉淀对溶液中Cu2+的去除率分别为93%、85%和72%.菌株LAX2对土壤中有效态Cu的固定作用呈现适应-快速-慢速3个阶段,培养5、10和30 d后土壤有效态Cu的含量分别下降了52.3%、73.7%和87.4%.与菌体细胞吸附和化学沉淀相比,生物矿化作用固定的Cu对短期内的淹水和反复冻融具有很强的抗性作用.以上结果表明菌株LAX2可通过生物成矿作用形成性质较稳定的碳酸铜矿物,在土壤铜污染修复方面具有重要的应用价值.  相似文献
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Removal of Pb2 + and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb2 + and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb2 + and biodegradation of acephate. In the present study, both Pb2 + and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions. Batch experiments were conducted to study the influence of pH, interaction time and Pb2 + concentration on the process of removal of Pb2 +. At the temperature of 25°C, the maximum removal of Pb2 + by B.subtilis FZUL-33 was 381.31 ± 11.46 mg/g under the conditions of pH 5.5, initial Pb2 + concentration of 1300 mg/L, and contact time of 10 min. Batch experiments were conducted to study the influence of acephate on removal of Pb2 + and the influence of Pb2 + on biodegradation of acephate by B.subtilis FZUL-33. In the mixed system of acephate–Pb2 +, the results show that biodegradation of acephate by B.subtilis FZUL-33 released PO43 +, which promotes mineralization of Pb2 +. The process of biodegradation of acephate was affected slightly when the concentration of Pb2 + was below 100 mg/L. Based on the results, it can be inferred that the B.subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination.  相似文献
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