Dissolved silica is a major concern for a variety of industrial processes owing to its tendency to form complex scales that severely deteriorate system performance. In this work, we present a pretreatment technology using a Joule-heated sponge to rapidly remove silica from saline waters through adsorption, thereby effectively mitigating silica scaling in subsequent membrane desalination processes. The adsorbent sponge is fabricated by functionalizing two-dimensional layered double hydroxide (LDH) nanosheets on a porous, conductive stainless-steel sponge. With the application of an external voltage of 4 V, the Joule-heated sponge achieves 85% silica removal and 95% sponge regeneration within 15 min, which is much more efficient than its counterpart without Joule-heating (360 min for silica adsorption and 90 min for sponge regeneration). Material characterization and reaction kinetics analysis reveal that electrostatic interactions and “memory effect”-induced intercalation are the primary mechanisms for silica removal by the LDH nanosheets. Moreover, Joule-heating reduces the boundary layer resistance on nanosheets and facilitates intraparticle diffusion of dissolved silica, thereby increasing silica removal kinetics. Joule-heating also enhances the release of silicate ions during the regeneration stage through exchange with the surrounding anions (OH^– or CO₃^2–), resulting in a more efficient sponge regeneration. Pretreatment of silica-rich feedwaters by the Joule-heated sponge effectively reduces reverse osmosis membrane scaling by amorphous silica scale, demonstrating great potential for silica scaling control in a broad range of engineered processes.

中文翻译：

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用于快速去除水中二氧化硅的焦耳加热层状双氢氧化物海绵

溶解二氧化硅是各种工业过程的主要关注点，因为它倾向于形成复杂的结垢，严重降低系统性能。在这项工作中，我们提出了一种预处理技术，使用焦耳加热海绵通过吸附从盐水中快速去除二氧化硅，从而有效地减轻后续膜脱盐过程中的二氧化硅结垢。吸附海绵是通过在多孔导电不锈钢海绵上对二维层状双氢氧化物 (LDH) 纳米片进行功能化来制造的。外加 4 V 电压后，焦耳加热海绵在 15 分钟内实现了 85% 的二氧化硅去除和 95% 的海绵再生，这比没有焦耳加热的海绵（二氧化硅吸附 360 分钟和 90海绵再生的分钟）。材料表征和反应动力学分析表明，静电相互作用和“记忆效应”诱导的嵌入是 LDH 纳米片去除二氧化硅的主要机制。此外，焦耳加热降低了纳米片上的边界层电阻并促进了溶解二氧化硅的颗粒内扩散，从而增加了二氧化硅去除动力学。焦耳加热还通过与周围阴离子（OH 从而增加二氧化硅去除动力学。焦耳加热还通过与周围阴离子（OH 从而增加二氧化硅去除动力学。焦耳加热还通过与周围阴离子（OH^–或 CO ₃ ^2– )，从而实现更有效的海绵再生。用焦耳加热海绵对富含二氧化硅的给水进行预处理，有效地减少了反渗透膜因无定形二氧化硅水垢而产生的水垢，这在广泛的工程过程中展示了二氧化硅水垢控制的巨大潜力。