模传递-表面嵌入制备导电抗黏附泡沫材料及强化油水分离性能研究

Oils adhere to the surface of sponge causing surface fouling, the reduction of oil/water separation efficiency and the difficulty of sponge recycling during oil/water separation. To solve this problem, this project investigates the development of electrical conductive anti-adhesion sponge and its synergetic effects on enhancing oil/water separation. To fulfil this object, mold transfer-surface embedding is utilized to construct super-wetting sponge with electrical conductive micro/nano hierarchical structure through embedding polymer modified electrical conductive nano materials. The mechanism on adjusting the formation of homogenously nano coating on the matrix via embedding the conductive nanaomaterials (e.g. Ag and graphene) is explored. The effects of nano coating on wettability, electrical conductivity and mechanical properties are extensively studied. Furthermore, the synergetic effects of hydrophobicity and electrical conductivity on anti-oil-adhesion and the enhancement of oil/water separation efficiency are profound studied. These studies are aming to solve the problems that the nano coating is easy to be peeled-off and the mechanism of the electrical induced Joule-heating effects on oil-sponge interface and the improvement of anti-oil-adhesion. By carrying out these studies, this project is going to reach the objectives of the ease of fabrication of anti-oil-adhesion oil/water separation sponge, continuous and high efficient of oil/water separation and improving the stability of the sponge in oil/water separation.

含油废水的排放，造成严重的环境污染。泡沫材料因具有孔隙率高、吸附比大、易操作等优点而被广泛用于油水分离，然而其在油水分离过程中存在抗油黏附性差、分离效率低和循环稳定性差的缺点，限制了油水持续高效分离。针对此问题，本项目提出模传递-表面嵌入的方法，在模传递过程中将有机物改性的导电纳米材料嵌入泡沫表面，构建具有微纳层级结构的导电超疏水抗黏附泡沫材料。围绕这一思路，本项目拟开展Ag、石墨烯等导电纳米材料嵌入方式对泡沫材料耐久性调控机理的研究；探索嵌入纳米材料对疏水性、导电性和机械性能的影响规律；揭示疏水性及电致焦耳热协同抗黏附机理及其对不同油水混合物强化分离的作用机制。本项目的实施有助于实现耐久性抗黏附油水分离泡沫材料的简易制备和对油水分离循环稳定性的提高，为含油废水的工程化处理提供理论基础和数据支撑。

油品及疏水性有机污染物的泄漏与排放造成了严重的水污染和生态破坏，如何实现油/水有效分离引起世界各国的广泛关注。泡沫材料具有润湿性、较大的孔隙率和吸附比，能够吸收液体，从而简化油水分离程序提高分离效率。然而，其易被油（尤其是粘度大的油类）污染造成网孔堵塞，导致短时间内分离通量急剧下降甚至分离失效，难以重复使用。目前解决由粘附主要是在商业海绵或自组装海绵上构建超浸润表面、水化层、热效应抗粘附。然而，纳米材料的使用会导致海绵硬度增加、弹性降低，无法挤出吸附油类，造成循环性能下降。此外，商业海绵和自组装海绵孔径较大，难以调控，影响使用范围。基于此本项目开展了以下研究工作：一、针对油水分离通量和选择性矛盾难以解决的问题，开展了浸润性和孔径协同效应对油水分离效率的影响，膜超亲水（WCA=0°）时，水的分离效率接近100%；膜亲水（0°<WCA<60°）时，水分离效率随接触角增加先减小后增加；膜疏水（接近90°-100°）时，不具有分离效果；而膜为疏水/超疏水（WCA>120°）时，油的分离效率增至99.5%。二、模传递-表面嵌入制备疏水-机械耐久性石墨烯-PDMS海绵，在PDMS海绵表面嵌入石墨烯获得机械弹性高、耐久性强的PDMS海绵，海绵的吸附容量在400%~1500%之间。三、模传递-表面嵌入调控环氧树脂海绵机械弹性-耐久性机制，通过引入醚键环氧树脂由硬变软，再次通过模传递-表面嵌入La2O3纳米颗粒提高了海绵的弹性和耐久性，海绵油水分离效率大于95%，10次循环使用分离效率稳定且通量达到2800 L·m-2·h-1以上。四、Ag NWs/Ag flakes表面嵌入调控PDMS海绵导电性及油水分离性能，调控改变银的用量实现不同导电性，通过电致焦耳热效应使油滴迅速滑落导电表面。本项目基于模传递-表面嵌入的方法，解决了纳米材料修饰海绵造成的硬度增加、弹性降低的矛盾，并通过嵌入纳米材料提高浸润性。