Department of Polymer Materials and Chemical Engineering, School of Materials Science and Engineering, East China Jiaotong University, Nanchang, Jiangxi 330013, PR China.
Department of Polymer Materials and Chemical Engineering, School of Materials Science and Engineering, East China Jiaotong University, Nanchang, Jiangxi 330013, PR China.
J Colloid Interface Sci. 2019 Jan 15;534:183-194. doi: 10.1016/j.jcis.2018.09.021. Epub 2018 Sep 7.
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.
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.
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.
有效分离和回收水中的油对于保护生态系统和环境非常重要。聚合物多孔整体材料已被证明是用于油水分离的有吸引力的吸收剂。然而，可回收性主要通过挤压、燃烧或离心来实现，这可能会限制弹性材料，破坏吸附物或需要特殊设备。因此，开发具有可控吸油和解吸性能的整体材料是可取的。
通过高内相乳液（HIPE）聚合和环氧化物开环反应，制备了一系列具有 pH 响应性可切换润湿性的“智能”整体材料，以引入胺基。分别采用傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、氮气吸附/解吸和接触角分析对所得整体材料及其润湿性进行了测试。评估了油分离效率和可回收性。
具有大孔结构的整体材料可以在可逆 pH 刺激下经历可切换的润湿性。作为一种吸收剂，该整体材料不仅可以通过在 7.0 和 1.0 之间交替 pH 值来实现有机溶剂和油（包括原油）从水混合物中的可逆和可回收吸收和解吸过程，而且还可以在外力驱动压力的帮助下连续地从水面上连续地排出油。此外，该整体材料还可以有效地分离无表面活性剂和表面活性剂稳定的油包水乳液，具有较高的分离效率。
