Horseman Thomas, Lin Shihong
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States.
ACS Environ Au. 2022 May 31;2(5):418-427. doi: 10.1021/acsenvironau.2c00011. eCollection 2022 Sep 21.
Mineral scaling is a phenomenon that occurs on submerged surfaces in contact with saline solutions. In membrane desalination, heat exchangers, and marine structures, mineral scaling reduces process efficiency and eventually leads to process failure. Therefore, achieving long-term scaling resistance is beneficial to enhancing process performance and reducing operating and maintenance costs. While evidence shows that superhydrophobic surfaces may reduce mineral scaling kinetics, prolonged scaling resistance is limited due to the finite stability of the entrained gas layer present in a Cassie-Baxter wetting state. Additionally, superhydrophobic surfaces are not always feasible for all applications, but strategies for long-term scaling resistance with smooth or even hydrophilic surfaces are often overlooked. In this study, we elucidate the role of interfacial nanobubbles on the scaling kinetics of submerged surfaces of varied wetting properties, including those that do not entrain a gas layer. We show that both solution conditions and surface wetting properties that promote interfacial bubble formation enhances scaling resistance. In the absence of interfacial bubbles, scaling kinetics decrease as surface energy decreases, while the presence of bulk nanobubbles enhances the scaling resistance of the surface with any wetting property. The findings in this study allude to scaling mitigation strategies that are enabled by solution and surface properties that promote the formation and stability of interfacial gas layers and provide insights to surface and process design for greater scaling resistance.
矿物结垢是一种发生在与盐溶液接触的浸没表面上的现象。在膜脱盐、热交换器和海洋结构中，矿物结垢会降低工艺效率并最终导致工艺故障。因此，实现长期抗结垢有利于提高工艺性能并降低运营和维护成本。虽然有证据表明超疏水表面可能会降低矿物结垢动力学，但由于处于卡西 - 巴克斯特润湿状态的夹带气体层的有限稳定性，长期抗结垢能力受到限制。此外，超疏水表面并非对所有应用都可行，但具有光滑甚至亲水表面的长期抗结垢策略往往被忽视。在本研究中，我们阐明了界面纳米气泡对具有不同润湿特性的浸没表面（包括那些不夹带气体层的表面）结垢动力学的作用。我们表明，促进界面气泡形成的溶液条件和表面润湿特性都会增强抗结垢能力。在没有界面气泡的情况下，结垢动力学随着表面能的降低而降低，而大量纳米气泡的存在会增强具有任何润湿特性的表面的抗结垢能力。本研究中的发现暗示了通过促进界面气体层形成和稳定性的溶液和表面特性实现的结垢缓解策略，并为提高抗结垢能力的表面和工艺设计提供了见解。
