水下超疏油/油下超疏水材料的设计与制备及按需油水分离性能研究

The underwater superoleophobic and underoil superhydrophobic material is the effective way to realize on-demand separation of oil/water mixtures. However, the underwater superoleophobicity and underoil superhydrophobicity are the two contradictory wetting properties, which was due to the underwater superoleophobicity often require material’s intrinsic water contact angle to be the smaller the better, while, the underoil superhydrophobicity require the material’s intrinsic water contact angle to be the higher the better. Up to now, such materials are rarely reported at home and abroad. In the project, it is envisaged that the wettability of a surface could be effectively managed by controlling the proportion of the hydrophobic and hydrophilic nanoparticles that deposited onto that surface for achieving controllable preparation of underwater superoleophobic and underoil superhydrophobic materials. Then, the wetting properties of the smart filter materials will be reversibly switched between the underwater superoleophobicity and underoil superhydrophobicity by prewetting the filter materials with water or oils. Therefore, the immiscible oil/water mixtures and oil/water emulsions could be separated in on-demand and effective way, according to the condition whether the density of water is larger than oil or not and the type of emulsions no matter water is the continuous phase or dispersed phase. Moreover, the effect of wettability and the reversible transition wettability of the as-prepared materials on their oil/water separation will be analyzed comprehensively. Base on this, the principal design criteria of such materials and regulation rule in the preparation process, the mechanism of wettability being reversed between underwater superoleophobicity and underoil superhydrophobicity and the mechanism of oil/water separation will be elucidated systematically. Above all, the achievements of this project would establish the theoretical and technical foundation for preparation and design of underwater superoleophobic and underoil superhydrophobic materials and on-demand oil/water separation.

水下超疏油/油下超疏水材料是实现油水混合物按需分离的有效途径。然而，水下超疏油和油下超疏水是两种相互矛盾的浸润性质，水下超疏油要求材料本征水接触角越低越好而油下超疏水则要求水接触角越高越好。迄今为止，该材料的制备在国内外鲜有报道。本项目拟通过控制基底表面所沉积亲水、疏水颗粒的比例来达到对其表面浸润性的有效调控，实现水下超疏油/油下超疏水材料的可控制备。然后利用水或油预润湿诱导其浸润性在水下超疏油和油下超疏水之间可逆转换，从而根据非乳化油水混合物中油和水密度的相对大小及油水乳液的乳化类型，实现油水混合物的按需分离。同时对所制备材料的浸润性能及可逆转换浸润性能对油水分离性能的影响进行详细分析。在此基础上，揭示该材料的构建原则及制备过程中的调控规律，阐明浸润性在水下超疏油和油下超疏水之间可逆转换的调控机制，明确油水分离机理，这将为水下超疏油/油下超疏水材料的制备及按需油水分离奠定理论和技术基础。

随着生产生活中含油污水的大量排放和海上原油泄漏事故的频繁发生，如何快速高效的对含油污水进行分离已经成为关系人民生活、经济发展与环境安全的重要课题。水下超疏油/油下超疏水材料是实现油水混合物按需和高效分离的有效途径。本项目在制备一系列超疏水、水下超疏油和水下超疏油/油下超疏水油水分离材料的基础上，利用“中庸之道”，通过牺牲部分水下超疏油或油下超疏水性能获得同时具有水下超疏油/油下超疏水性质的表面。采用简单的液相反应将低表面能物质十八烷基三氯硅烷等接枝在凹凸棒、二氧化钛和黄土等无机微纳米颗粒表面得到超疏水颗粒，然后利用一步喷涂法喷涂上述亲水和疏水无机颗粒的混合物，通过控制滤膜基底表面所喷涂凹凸棒、二氧化钛和黄土等亲水、疏水颗粒的比例来达到对其表面浸润性的有效调控，实现了水下超疏油/油下超疏水油水分离材料的普适性制备。然后利用水或油预润湿诱导其浸润性在水下超疏油和油下超疏水之间可逆转换，从而根据非乳化油水混合物中油和水密度的相对大小及油水乳液的乳化类型，实现了各类油水混合物 (甚至包括水和原油混合物)的按需和高效分离，分离效率在99.6 %以上。同时对所制备材料的浸润性能及可逆转换浸润性能对油水分离性能的影响进行详细分析。在此基础上，揭示了水下超疏油/油下超疏水油水分离材料的构建原则及制备过程中的调控规律，阐明了浸润性在水下超疏油和油下超疏水之间可逆转换的调控机制，提出了油水乳液强化分离的“捕获-聚集-脱离”分离机制，为水下超疏油/油下超疏水材料的制备及各类油水混合物的按需和高效分离奠定了理论和技术基础。这一系列工作发表以Journal of Materials Chemistry A, Chemical Engineering Journal, Journal of Membrane Science, ACS Applied Materials & Interfaces, Green Chemistry等为代表的国际知名期刊SCI论文18篇，连续3年入选英国皇家化学会“Top1%高被引中国作者”榜单(2018-2020年度)，受美国化学会邀请撰写油水分离相关英文专著1章，申请国家发明专利5件，其中授权2件，培养硕士研究生9名，在第六届国际仿生工程大会等做分会场邀请报告9次。