Surface Deposition of Juglone/FeIII on Microporous Membranes for Oil/Water Separation and Dye Adsorption

Deposition of dopamine and tannic acid has received great attention in the fields of surface and interface science and technology. The deposition behaviors of various metal-phenolic systems have been investigated, and it is generally accepted that at least one catechol group is essential to the formation of the coatings. Herein, we report a novel and effective surface-coating system based on the coordination complexes of Fein ions with a natural product juglone that contains only one phenolic hydroxyl. We investigated the deposition behaviors of this novel system on various substrates. Microporous polypropylene membrane modified with juglone/Fe-III coatings is superhydrophilic and underwater superoleophobic, showing high separation efficiency and good reusability for various oil/water emulsions. In addition, the modified membrane can adsorb anionic dyes and selectively remove them from dye mixtures with high efficiency. We further demonstrated that the coating is a result of the synergetic effect of juglone/Fe-III coordination and Fe-III hydrolysis. This work not only provides new insights into surface deposition systems but also expands the polyphenol family for surface coatings of multifunctional materials.