Soils are a host to several micro-organisms which are responsible for various biogeochemical processes prevailing in the geoenvironment. Such processes have been utilized to alter engineering properties of the coarse-grained soils viz., sands, such as strength, liquefaction potential and permeability. One of such processes, which has been explored by several researchers, is Biogenic Calcite Precipitation (BCP) in the coarse-grained soils. Though the impact of biogenic calcite (BC) on engineering behaviour of sands has been dealt with in great detail, the mechanism of calcite ‘growth’ on their surface, which primarily depends on biosorption (i.e. attachment of bacterial cells), has not been investigated and/or discussed in detail. It should be noted that biosorption would strongly depend upon the overall surface characteristics of the sand grains, apart from their chemico-mineralogical characteristics. Unlike fine-grained soils, where the bacteria-soil interaction is being investigated extensively by researchers, the above-referred studies on sands have been pretermitted, largely. With this in view, an attempt has been made to investigate the mechanisms associated with the interaction of bacterial cells with sand grains and BC substrates, which is a precursor for the biogeochemical processes such as BCP, bioremediation and biological degradation of soils. Highlighting the role of key factors in bacterial cell-sand interactions, a conceptual model has been proposed for the growth of biogenic calcite around a sand grain. Such a fundamental study, conducted by employing Atomic Force Microscopy and Extended Derjaguin-Landau-Verwey-Overbeek (ExDLVO) theory, provides an insight into the biosorption on sands and BC.

中文翻译：

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砂土中生物吸附和生物方解石沉淀的研究

土壤是几种微生物的宿主，这些微生物负责地球环境中普遍存在的各种生物地球化学过程。此类过程已被用于改变粗粒土壤（即沙子）的工程特性，例如强度、液化潜力和渗透性。几位研究人员已经探索了其中一种过程，即粗粒土壤中的生物方解石沉淀 (BCP)。虽然生物方解石 (BC) 对砂土工程行为的影响已经得到了详细的处理，但其表面方解石“生长”的机制，主要取决于生物吸附（即细菌细胞的附着），尚未得到研究和/或详细讨论。需要注意的是，生物吸附除了它们的化学矿物学特征外，这将在很大程度上取决于砂粒的整体表面特征。与细粒土壤不同，细粒土壤中细菌与土壤的相互作用正在被研究人员广泛研究，上述对沙子的研究在很大程度上是预先考虑的。有鉴于此，已尝试研究与细菌细胞与沙粒和 BC 基质相互作用的相关机制，沙粒和 BC 基质是生物地球化学过程（如 BCP、生物修复和土壤生物降解）的前体。强调关键因素在细菌细胞-沙相互作用中的作用，已经提出了一个概念模型，用于围绕沙粒生长的生物方解石。如此基础的研究，在沙子和 BC 上的生物吸附。