Department of Soil and Water Sciences, China Agricultural University, Beijing, 100193, PR China.
Department of Earth Sciences, Memorial University St. John's, Newfoundland and Labrador, A1B 3X5, Canada.
Water Res. 2019 May 15;155:204-213. doi: 10.1016/j.watres.2019.02.022. Epub 2019 Feb 22.
The stability and transport of clay colloids in groundwater are strongly influenced by colloid interactions with dissolved organic matter (DOM). Protein is an important DOM component that is ubiquitous in natural water, reclaimed water, and soil solutions. To date, the interactions between clay colloids and proteins have not been fully studied. The objective of this study was to examine the effect of bovine serum albumin (BSA), a representative protein, on the stability, aggregation, and transport of kaolinite colloids under neutral pH conditions. Hydrodynamic diameter and ζ-potential measurements, stability tests, and column transport experiments were performed in salt solutions with a range of ionic strengths and different BSA concentrations at pH 7. Additionally, BSA-kaolinite colloid interactions were studied using TEM and batch adsorption experiments. The experimental results showed that BSA prevented colloid aggregation and increased the stability and transport of colloids, especially at high ionic strength, even though the charges of kaolinite colloids were less negative in the presence of BSA. Theoretical calculation of the interaction energies indicated that XDLVO theory, in which the steric force is considered due to BSA adsorption, could correctly quantify the interaction energies in the presence of BSA. This study demonstrated that the role of protein needs to be determined in order to better predict the overall effect of DOM on particle aggregation and transport in the soil environment.
粘土胶体在地下水中的稳定性和迁移性受到胶体与溶解有机质（DOM）相互作用的强烈影响。蛋白质是 DOM 的一个重要组成部分，在天然水、再生水和土壤溶液中普遍存在。迄今为止，粘土胶体与蛋白质之间的相互作用尚未得到充分研究。本研究的目的是在中性 pH 条件下，研究牛血清白蛋白（BSA）——一种代表性蛋白质对高岭石胶体稳定性、聚集和迁移的影响。在 pH 值为 7 的盐溶液中，在不同的 BSA 浓度和一系列离子强度下，进行了水动力直径和 ζ-电位测量、稳定性测试和柱传输实验。此外，还使用 TEM 和批量吸附实验研究了 BSA-高岭石胶体相互作用。实验结果表明，BSA 可防止胶体聚集，增加胶体的稳定性和迁移性，尤其是在高离子强度下，尽管在 BSA 存在下，高岭石胶体的电荷变得更负。相互作用能的理论计算表明，由于 BSA 的吸附，考虑了空间力的 XDLVO 理论可以正确量化存在 BSA 时的相互作用能。本研究表明，需要确定蛋白质的作用，以便更好地预测 DOM 对土壤环境中颗粒聚集和迁移的总体影响。
