微生物水泥力学性能和耐久性的可持续应用研究进展

微生物沉淀技术涉及土木、生物、环境等多学科,是利用微生物自身代谢活动中矿化行为诱导碳酸钙快速沉淀的一种方法,本文介绍了微生物矿化作用及胶结过程,并从力学性能和耐久性等方面进行详细阐述,为土木工程的可持续应用研究提供了合理的建议。     

环境变化对微生物活性及矿化的影响

微生物诱导碳酸钙沉积（MICP）技术因具有低能耗、低污染等环境友好性优势成为文物保护、水处理、混凝土修补加固等领域的研究热点。MICP的矿化效果受多因素的制约与影响。本文开展了环境温度、pH值等因素对细菌生长和微生物矿化的影响研究。结果表明,环境温度不超过40℃时对菌液脲酶活性影响不大,42.5~45℃时6h后脲酶活性急剧降低,超过45℃时30min后菌液浓度及脲酶活性均大幅下降,直至失活;pH值越大,脲酶活性衰减越明显,pH≥11时脲酶活性急剧下降,大量的细菌不能承受高碱性环境进一步分解死亡。MICP技术在30℃时碳酸钙产量最高,在pH值为11~13的环境中细菌很难生长繁殖,碳酸钙生成量较低。     

青海强盐渍粉砂土MICP的有效性探索

在极端环境中发现原生高产脲酶微生物并开展岩土体的固强研究,是岩土体微生物矿化研究的一个热点和难点.该文在青海柴达木地区的强盐渍土中发现一种新型原生高产脲酶微生物,在强盐环境中,试验该微生物的盐耐受性和矿化性能,开展被加固土体力学强度试验.结果表明:在强盐渍环境下,该新型微生物脲酶活性保持在3.02U～5.03U.在强盐...     

巴氏芽孢八叠球菌及相关微生物的生物矿化的分子机理与应用

巴氏芽孢八叠球菌是迄今为止所知的利用尿素降解进行生物矿化的最为高效的微生物系统之一,基于其碳酸钙生物矿化形成的"超强能力",巴氏芽孢八叠球菌已经被成功地应用于沙石、土壤等生物固化中,成为一种全新的、具有极大潜力的生物建筑辅助技术,被称为"生物水泥"。由于巴氏芽孢八叠球菌分离自土壤,没有病原性并具有极好的环境友好性。近年来,其应用领域被拓展到环境治理乃至健康医疗领域,成为全新的研究热点。然而,与应用研究相比,人们对巴氏芽孢八叠球菌生物矿化背后的分子机理还知之甚少。因此,这里针对迄今为止国内外对于巴氏芽孢八叠球菌生物矿化相关的分子机理的研究进行分析介绍,在此基础上综述了包括建工、环境、及医疗健康领域在内的巴氏芽孢八叠球菌的应用,希望能够促进对于该球菌矿化的研究。     

MICP技术对水泥基材料的改性研究

利用微生物在新陈代谢过程中发生的矿化作用,进行诱导形成碳酸钙,称之为微生物诱导碳酸钙沉积(MICP),它是一种新颖的环境友好型生物技术。在总结国内外相关资料的基础上,介绍了MICP的矿化行为及其影响因素,分析了MICP在改性水泥基材料方面的研究情况,并指出了MICP技术在水泥基材料应用中亟待解决的关键问题。     

微生物用于海洋混凝土裂缝自修复的研究进展

微生物矿化技术修复混凝土有了初步的发展,已有的研究主要是把细菌加入普通混凝土中研究对其的修复作用。从微生物的选择、固载物质的选择、修复效果的表征方面以及用于修复的混凝土方面综述了微生物用于混凝土裂缝修复的研究现状,为进一步的研究方向提出了建议。     

水泥基材料中微生物矿化机理及理论模型研究

采用菌液浸泡法,研究了微生物矿化对水泥基材料的防护增强作用,分析了营养成分对微生物生长及矿化行为的影响,并结合微观测试结果,探讨了水泥基材料中微生物的矿化机理。结果表明,菌液浸泡后水泥试件强度显著提高,其中硫铝酸盐水泥基体与微生物矿化的适应性更好。水泥基材料中微生物的矿化遵循矿物成核作用的物理化学规律,硫铝酸盐水泥基体中,大量白色棱形颗粒状和花瓣状方解石型碳酸钙依附于水泥石基面定向排列生长;硅酸盐水泥基体中的方解石型碳酸钙呈团簇状覆盖于水泥石基面。菌液营养成分会影响微生物的矿化效率,当菌液中尿素浓度≤10 g/L时,随浓度的增大,微生物矿化强度提高;当钙离子浓度为2 mmol/L时,微生物的矿化强度最大。     

基于微生物矿化技术的再生粗骨料改性方法研究

再生粗骨料高吸水率的特点限制了其在实际工程中的高附加值应用。基于微生物矿化技术改性再生粗骨料,旨在提出一种环境友好型改性方法。首先研究骨料改性过程中氯离子的去除,其次需减少氨氮副产物的排放,然后对比分析再生骨料类型对改性效果的影响,最后优选出一种高效低耗的改性方法。结果表明:采用无氯培养基,可实现改性过程的无氯要求;通过添加人造沸石,可减少氨氮副产物的排放;采用4次先浸泡-后喷洒工艺的骨料改性效果最佳;从微生物黏附、矿化反应、孔隙填充3个阶段分析了微生物矿化技术改性再生粗骨料的整个过程。     

微生物矿化沉积改善再生骨料性能的研究进展

对国内外目前所研究的再生骨料强化技术、矿化沉积技术的研究进行了比较系统的综述;对微生物矿化沉积技术应用于改善再生骨料性能进行分析;并通过对不同处理方式进行试验对比研究,初步分析选择先浸菌后喷淋的处理方式作为利用微生物矿化沉积技术来改善再生骨料性能的最优处理方式。     

微生物抑尘剂的研制方法探讨

基于微生物矿化技术,研制了经济高效的绿色环保型微生物抑尘剂,通过筛选在建筑扬尘颗粒环境中具有优异矿化性能的微生物菌株,从微生物抑尘剂的制备方法、性能测试方法以及规模化应用等方面展开探讨,以期对微生物抑尘剂的研制及推广应用提供借鉴作用。     

Biological process of soil improvement in civil engineering:A review

The concept of using biological process in soil improvement which is known as bio-mediated soil improvement technique has shown greater potential in geotechnical engineering applications in terms of performance and environmental sustainability.This paper presents a review on the soil microorganisms responsible for this process,and factors that affect their metabolic activities and geometric compatibility with the soil particle sizes.Two mechanisms of biomineralization,i.e.biologically controlled and biologically induced mineralization,were also discussed.Environmental and other factors that may be encountered in situ during microbially induced calcite precipitation(MICP) and their influences on the process were identified and presented.Improvements in the engineering properties of soil such as strength/stiffness and permeability as evaluated in some studies were explored.Potential applications of the process in geotechnical engineering and the challenges of field application of the process were identified.     

微生物岩土技术的研究进展

岩土体中存在着大量的微生物,这些微生物的活动对岩土体的物理、力学性质有一定的影响。微生物岩土技术,是将微生物反应加以控制和利用,来解决岩土工程中的问题。在近十年里,微生物岩土技术逐渐成为岩土工程研究界的一个热门课题,并取得了很大的进展。从原理和应用两个角度对这一领域的研究进行归类和分析。从微生物反应原理的角度来说,微生物岩土技术所利用的微生物过程包括微生物矿化作用,微生物产气泡过程,以及微生物膜生长过程等。从实际应用的角度来说,微生物岩土技术的应用领域包括岩土体加固、防渗,砂土液化防治,土体抗侵蚀,污染土治理等。此外,还对微生物岩土技术的实施方法特点,监测和检测技术,以及环境影响进行了介绍。     

微生物岩土技术及其应用研究新进展

微生物岩土技术主要是利用自然界广泛存在的微生物的代谢功能,与环境中其他物质发生一系列生物化学反应,改变土体的物理力学及工程性质,从而实现环境净化、土壤修复、地基处理等目的。微生物岩土技术作为岩土工程领域新的分支逐渐成为一个热门研究方向,近年来,许多学者已经开展了相关研究。为了促进该领域更加全面深入的基础研究,指导微生物技术在岩土工程中更切合实际的推广与应用,对环境岩土工程领域涉及的几种主要微生物种类、相关生物化学反应过程以及微生物作用机理进行详细的介绍与总结,并对微生物岩土技术在土体加固、岩土体抗渗封堵、金属污染土修复等方面的相关研究及应用进行了总结与评述。     

自修复混凝土技术的现状与发展

自修复混凝土（SHC）技术是一种新型混凝土修补技术,利用混凝土中添加的自修复剂或微生物等使得混凝土中的裂缝自行愈合,从而延长混凝土使用寿命,减少环境污染和资源浪费。本文介绍了自修复混凝土技术的原理、发展、研究热点及未来的趋势和应用前景。     

基于混菌产电微生物燃料电池的最新研究进展

混菌微生物燃料电池(MFC)是直接利用环境中多种微生物附着于阳极而产电的方式,相对于纯菌MFC的前期菌种培养和富集,混菌电池的启动不仅省时且更节约成本,同时其抗环境冲击的能力也更强,电池稳定性更高。介绍了混菌MFC的最新研究现状,详细讨论了产电微生物的种类、电子传递机制、影响混菌MFC产电效能的主要因素,以及目前存在的问题等,并指出了混菌MFC的未来研究重点和方向。     

层控贱金属矿床的生物成矿作用

着重讨论层控贱金属矿床的生物成矿作用及其有关的地质特征。以我局勘查过的矿床为例,对该类矿床的地质特征、找矿意义、成矿机制、可能的矿床成因进行了探讨,从而得出找矿标志、找矿方法和思路     

Microbial interactions with tributyltin compounds: detoxification, accumulation, and environmental fate

While inorganic forms of tin are of relatively low toxicity towards microorganisms, the more lipid-soluble organotins can be highly toxic. Generally, trisubstituted (R3SnX) organotins are more toxic than di- (R2SnX2) and monosubstituted (RSnX3) compounds; the anion (X) apparently having little influence on toxicity. However, many microorganisms exhibit resistance to organotins, a phenomenon of relevance to the environmental cycling of organotins and also to novel biological methods of treatment. Organotin degradation can involve the sequential removal of organic moieties to yield less toxic derivatives, e.g. debutylation of tributyltin compounds to di- and monobutylins. Such degradation is known to take place in bacteria, algae and fungi, and this provides one route for detoxification. In addition, microorganisms are capable of accumulating tributyltin compounds, and this is another mechanism of removal from solution. The high lipid solubility of organotins ensures cell penetration and association with intracellular sites, while cell wall components also play an important role. Of the fungal wall components, melanin pigments are capable of TBT binding, and the addition of melanin to growing cultures can remove toxicity; melanised strains are also more sensitive than albino strains of the same species. To date, little attention has been paid to the biotechnological exploitation of these interactions for the degradation of tributyltin or its removal from solution. This paper describes some interactions of microorganisms (bacteria, cyanobacteria, microalgae, and fungi) with tributyltin compounds, with particular reference to toxicity, bioaccumulation and detoxification. Such processes should receive due consideration in any environmental management programme.     

Tropospheric H2 budget and the response of its soil uptake under the changing environment

Molecular hydrogen (H₂) is an indirect greenhouse gas present at the trace level in the atmosphere. So far, the sum of its sources and sinks is close to equilibrium, but its large-scale utilization as an alternative energy carrier would alter its atmospheric burden. The magnitude of the emissions associated with a future H₂-based economy is difficult to predict and remains a matter of debate. Previous attempts to predict the impact that a future H₂-based economy would exert on tropospheric chemistry were realized by considering a steady rate of microbial-mediated soil uptake, which is currently responsible of ~ 80% of the tropospheric H₂ losses. Although soil uptake, also known as dry deposition is the most important sink for tropospheric H₂, microorganisms involved in the activity remain elusive. Given that microbial-mediated H₂ soil uptake is influenced by several environmental factors, global change should exert a significant effect on the activity and then, assuming a steady H₂ soil uptake rate for the future may be mistaken. Here, we present an overview of tropospheric H₂ sources and sinks with an emphasis on microbial-mediated soil uptake process. Future researches are proposed to investigate the influence that global change would exert on H₂ dry deposition and to identify microorganisms involved H₂ soil uptake activity.     

Recent developments in photocatalytic water treatment technology: A review

In recent years, semiconductor photocatalytic process has shown a great potential as a low-cost, environmental friendly and sustainable treatment technology to align with the “zero” waste scheme in the water/wastewater industry. The ability of this advanced oxidation technology has been widely demonstrated to remove persistent organic compounds and microorganisms in water. At present, the main technical barriers that impede its commercialisation remained on the post-recovery of the catalyst particles after water treatment.This paper reviews the recent R&D progresses of engineered-photocatalysts, photoreactor systems, and the process optimizations and modellings of the photooxidation processes for water treatment. A number of potential and commercial photocatalytic reactor configurations are discussed, in particular the photocatalytic membrane reactors. The effects of key photoreactor operation parameters and water quality on the photo-process performances in terms of the mineralization and disinfection are assessed. For the first time, we describe how to utilize a multi-variables optimization approach to determine the optimum operation parameters so as to enhance process performance and photooxidation efficiency. Both photomineralization and photo-disinfection kinetics and their modellings associated with the photocatalytic water treatment process are detailed. A brief discussion on the life cycle assessment for retrofitting the photocatalytic technology as an alternative waste treatment process is presented. This paper will deliver a scientific and technical overview and useful information to scientists and engineers who work in this field.     

玻璃镀膜与微相处理法(微法)镀膜技术

该文简要介绍了玻璃的表面镀膜、微相处理法玻璃镀膜技术,分析了影响玻璃镀膜的因素和玻璃表面镀膜技术经济性、环保安全性及玻璃镀膜发展的前景。