Hypothesis

The effective separation and recovery of oils from water is important for the protections of ecosystems and the environment. Polymeric porous monoliths have been demonstrated as attractive absorbents for oil/water separation. However, the recyclability was mainly realized by squeezing, combustion, or centrifugation, which may restrict in elastic materials, destroy the adsorbates or need special apparatus. Thus it is desirable to developing monoliths with controllable oil absorption and desorption.

Experiments

A series of “smart” monoliths with pH-induced switchable wettability were fabricated by high internal phase emulsion (HIPE) polymerization and epoxide ring-opening for the incorporation of amine groups. The resultant monoliths and their wettabilities were examined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), nitrogen adsorption/desorption and contact angle analysis, respectively. The oil separation efficiency and recyclability were evaluated.

Findings

The monoliths with macroporous structure can undergo switchable wettability under reversible pH stimulation. As an absorbent, the monoliths not only separated and recovered organic solvents and oils (including crude oil) from aqueous mixtures through a reversible and recyclable absorption and desorption process upon alternating the pH between 7.0 and 1.0, but also continuously expulsed oils from water surfaces in a continuous manner with the aid of external driving pressures. Moreover, the monoliths also allowed the effective separation of surfactant-free and surfactant-stabilized oil-in-water emulsions with high separation efficiency.

中文翻译：

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具有pH诱导的可切换润湿性的大孔整料，用于可回收油的分离和回收

假设

从水中有效分离和回收油类对保护生态系统和环境非常重要。聚合物多孔整料已被证明是用于油/水分离的有吸引力的吸收剂。然而，可回收性主要是通过挤压，燃烧或离心来实现的，这可能会限制弹性材料，破坏被吸附物或需要特殊的设备。因此，希望开发出具有可控的吸油和脱油的整料。

实验

通过高内相乳液（HIPE）聚合和环氧基开环并引入胺基，制备了一系列具有pH诱导的可切换润湿性的“智能”整料。分别使用傅立叶变换红外光谱（FTIR），扫描电子显微镜（SEM），氮吸附/脱附和接触角分析来检查所得的整料及其润湿性。评价了油分离效率和可回收性。

发现

具有大孔结构的整料在可逆的pH刺激下可以进行可切换的润湿性。作为吸收剂，整料不仅在pH值介于7.0和1.0之间变化时，通过可逆和可循环的吸收和解吸过程从水性混合物中分离和回收有机溶剂和油类（包括原油），而且还连续不断地将油类从表面上排出。在外部驱动压力的作用下连续地进行。此外，整料还允许以高分离效率有效地分离不含表面活性剂的和表面活性剂稳定的水包油型乳液。