While the presence of organic macromolecules (or foulants) can exacerbate silica scaling of membranes, the effects of the types and physicochemical properties of macromolecules on silica scale formation remain poorly understood. We herein use a quartz crystal microbalance with dissipation monitoring to investigate the kinetics of silica mass deposition on sensors coated by lysozyme, bovine serum albumin (BSA), humic acid, or alginate. Our results show that deposited silica mass resulting from heterogeneous nucleation of monosilicic acid cannot be explained by the free energy barrier to nucleation but instead linearly correlated to the hydration energy of the macromolecule-covered surfaces. The most silica heterogeneous nucleation occurs on the most hydrophilic alginate-coated surface, which is likely due to the favorable interaction between silicic acid and alginate via hydrogen bonding and chemical reactions. For the deposition of silica aggregates formed from bulk nucleation, the deposited silica mass is the highest on the BSA-coated surface, consistent with the greatest adhesion force between BSA and silica measured using force spectroscopy. Finally, silica scaling on macromolecule-coated surfaces is promoted by calcium ions, and the deposition of silica is mostly irreversible upon rinsing with water.

中文翻译：

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有机高分子涂层表面二氧化硅垢的形成机制

虽然有机大分子（或污染物）的存在会加剧膜的二氧化硅结垢，但大分子的类型和物理化学性质对二氧化硅结垢形成的影响仍然知之甚少。我们在此使用带有耗散监测的石英晶体微量天平来研究二氧化硅质量沉积在由溶菌酶、牛血清白蛋白 (BSA)、腐殖酸或藻酸盐涂层的传感器上的动力学。我们的结果表明，单硅酸异相成核导致的沉积二氧化硅质量不能用成核的自由能势垒来解释，而是与大分子覆盖表面的水合能线性相关。大多数二氧化硅异质成核发生在最亲水的藻酸盐涂层表面，这可能是由于硅酸和藻酸盐之间通过氢键和化学反应的有利相互作用。对于由本体成核形成的二氧化硅聚集体的沉积，沉积的二氧化硅质量在 BSA 涂层表面上最高，这与使用力谱测量的 BSA 和二氧化硅之间的最大粘附力一致。最后，钙离子促进了高分子涂层表面上的二氧化硅结垢，并且二氧化硅的沉积在用水冲洗后大多是不可逆的。