A facile strategy to simultaneously increase surface roughness and reduce surface energy for the preparation of water-repellent, recyclable and self-cleaning expanded perlite

Abstract

Although expanded perlite with abundant sources and low cost has been widely used in a diverse of different fields, it still requires multi-step processing to prepare desired functional materials, leading to complicated experimental procedures. And imparting new functionalities to expanded perlite with simple and effective methods remains a challenge. In this paper, a novel facile chemical vapor deposition method of in situ growing polysiloxane nanofilaments to simultaneously increase surface roughness and reduce surface energy is developed to prepare a water-repellent, recyclable and self-cleaning large granular expanded perlite (LGEP). Self-generation of surface roughness by low surface energy polysiloxane nanofilaments changes the surface wettability of the LGEP from hydrophilicity to hydrophobicity, showing an excellent water-repellent behavior. Relying on the imparted water repellency, the prepared LGEP can selectively remove organic solvents from water, and still maintain a stable sorption capacity after 15 consecutive cycles of sorption and desorption, holding a good recyclability. The prepared LGEP also exhibits an exceptional self-cleaning ability to remove surface particulate pollutants, which can provide a new design idea to synthesize perlite-based functionalized materials. These outstanding properties contribute to a broad range of the practical application of expanded perlite.