Functional regulation of polymer aerogels by graphene doping and peptide nanofiber-induced biomineralization as sustainable adsorbents of contaminants

Abstract

As a green sustainable inorganic material, hydroxyapatite (HA) has potential application in water purification. Aerogel materials with 3D structure have great advantages in the field of adsorption due to their low density and large specific surface area. In this work, peptide nanofibers (PNFs) with a motif-designed peptide sequence are synthesized via molecular self-assembly, and are then bound to the surface of graphene oxide (GO) nanosheets through π–π conjugation and provided active sites for nucleation and growth of HA crystals during the subsequent biomineralization process. The hybrid aerogel cross-linked between polyvinyl alcohol (PVA) and GO has a regular pore structure, and the mineralization process promotes functional regulation of aerogels. The mineralized PVA/PNF/GO–HA hybrid aerogels show good adsorption performance for Pb²⁺, and the saturated adsorption capacity can reach 113.88 mg g⁻¹ when Pb²⁺ is 400 mg L⁻¹ (pH = 5, 25 °C). At the same time, the adsorption effect of the PVA/PNF/GO–HA hybrid aerogel on MB is also obvious, and the adsorption capacity reaches 234.85 mg g⁻¹ when the methylene blue (MB) concentration is 500 mg L⁻¹ (pH = 7, 25 °C). In addition, the hybrid aerogel has better stability in water, which is convenient for recovery after adsorption. Finally, the fabricated hybrid aerogels are evaluated for their sustainability using the Ranking Efficiency Product (REP) method. This study facilitates the design and synthesis of nanohybrid aerogels through biomimetic synthesis with highly sustainable applications in water purification.