Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, School of Polymer Science and Engineering , Qingdao University of Science and Technology , Qingdao 266042 , P. R. China.
ACS Appl Mater Interfaces. 2019 Oct 9;11(40):36638-36648. doi: 10.1021/acsami.9b11277. Epub 2019 Sep 26.
Given the complexity and diversity of actual oily sewages, developing multifunctional separation materials with features of high separation efficiency and low energy consumption for separating diverse oil/water emulsions is urgently needed, yet it remains a formidable challenge till now. Herein, a superior graphene/poly(vinyl alcohol) Janus aerogel (J-CGPA), showing an intriguing three-dimensional (3D) hierarchical architecture (a dense skin-layer and a larger internal cell network) and desirable asymmetric wettability, was exploited via a simple direct freeze-shaping technique and subsequent mussel-inspired hydrophilic modification. Benefiting from the controlled unilateral decoration of dopamine, the resultant aerogels displayed completely opposite superwettability on two antithetic sides, i.e., one side is highly hydrophobic (water contact angle (WCA), 143°), whereas the other side is superhydrophilic. On the basis of the favorable 3D hierarchical structure and binary cooperative superwetting properties, the Janus aerogels achieved a remarkable switchable separation performance for both highly emulsified oil-in-water and water-in-oil emulsions as well as stratified oil/water mixtures accompanied with outstanding separation efficiencies. Particularly, an ultrahigh permeation flux of 1306 L m h along with a high rejection efficiency of 99.7% was acquired solely under the driving of gravity (<1 kPa), which is 1-2 order of magnitude higher than that of pioneering two-dimensional Janus polymeric/inorganic membranes recently reported. Moreover, together with robust reusability, this novel 3D Janus aerogel indicates a promising practical application for high-performance oily wastewater remediation.
鉴于实际含油污水的复杂性和多样性，开发具有高效分离效率和低能耗特点的多功能分离材料，用于分离各种油/水乳液，是当务之急，但迄今为止，这仍然是一个巨大的挑战。在此，通过一种简单的直接冷冻成型技术和随后的贻贝启发的亲水改性，开发了一种优异的石墨烯/聚乙烯醇 Janus 气凝胶（J-CGPA），其具有引人注目的三维（3D）分层结构（致密的皮层和更大的内部细胞网络）和理想的不对称润湿性。得益于多巴胺的受控单侧修饰，所得气凝胶在两个相对的面上表现出完全相反的超润湿性，即一侧具有高疏水性（水接触角（WCA），143°），而另一侧具有超亲水性。基于有利的 3D 分层结构和二元协同超润湿特性，Janus 气凝胶实现了对高度乳化的水包油和油包水乳状液以及分层油/水混合物的显著可切换分离性能，同时具有出色的分离效率。特别是，在重力（<1 kPa）的驱动下，仅获得了 1306 L m h 的超高渗透通量和 99.7%的高去除效率，比最近报道的开创性二维 Janus 聚合物/无机膜高 1-2 个数量级。此外，这种新型 3D Janus 气凝胶还具有强大的可重复使用性，表明其在高性能含油废水处理方面具有广阔的应用前景。
