Treumann Svantje, Torkzaban Saeed, Bradford Scott A, Visalakshan Rahul M, Page Declan
CSIRO Land and Water, Glen Osmond, SA 5064, Australia.
CSIRO Land and Water, Glen Osmond, SA 5064, Australia.
J Contam Hydrol. 2014 Aug;164:219-29. doi: 10.1016/j.jconhyd.2014.06.007. Epub 2014 Jun 20.
It is essential to understand the mechanisms that control virus and bacteria removal in the subsurface environment to assess the risk of groundwater contamination with fecal microorganisms. This study was conducted to explicitly provide a critical and systematic comparison between batch and column experiments. The aim was to investigate the underlying factors causing the commonly observed discrepancies in colloid adsorption process in column and batch systems. We examined the colloid adsorption behavior of four different sizes of carboxylate-modified latex (CML) microspheres, as surrogates for viruses and bacteria, on quartz sand in batch and column experiments over a wide range of solution ionic strengths (IS). Our results show that adsorption of colloids in batch systems should be considered as an irreversible attachment because the attachment/detachment model was found to be inadequate in describing the batch results. An irreversible attachment-blocking model was found to accurately describe the results of both batch and column experiments. The rate of attachment was found to depend highly on colloid size, solution IS and the fraction of the sand surface area favorable for attachment (Sf). The rate of attachment and Sf values were different in batch and column experiments due to differences in the hydrodynamic of the system, and the role of surface roughness and pore structure on colloid attachment. Results from column and batch experiments were generally not comparable, especially for larger colloids (≥0.5μm). Predictions based on classical DLVO theory were found to inadequately describe interaction energies between colloids and sand surfaces.
了解控制地下环境中病毒和细菌去除的机制对于评估粪便微生物污染地下水的风险至关重要。本研究旨在明确提供批量实验和柱实验之间的关键系统比较。目的是研究导致柱系统和批量系统中胶体吸附过程中常见差异的潜在因素。我们在广泛的溶液离子强度（IS）范围内，通过批量实验和柱实验，研究了四种不同尺寸的羧酸盐改性乳胶（CML）微球作为病毒和细菌替代物在石英砂上的胶体吸附行为。我们的结果表明，批量系统中胶体的吸附应被视为不可逆附着，因为发现附着/分离模型不足以描述批量实验结果。发现不可逆附着阻断模型能够准确描述批量实验和柱实验的结果。发现附着速率高度依赖于胶体尺寸、溶液离子强度以及有利于附着的砂表面积分数（Sf）。由于系统流体动力学的差异以及表面粗糙度和孔隙结构对胶体附着的作用，批量实验和柱实验中的附着速率和Sf值不同。柱实验和批量实验的结果通常不可比，尤其是对于较大的胶体（≥0.5μm）。发现基于经典DLVO理论的预测不足以描述胶体与砂表面之间的相互作用能。
