MnO2 nanoflakes/cellulose nanofibre aerogel fabricated via ultrasonication for high-performance water desalination

Abstract

MnO₂ nanoflakes/cellulose nanofibre aerogel (MCNF) has been fabricated via the methods of redox reaction and ultrasonication. The SEM and TEM images demonstrate that the core–shell structure of ultrathin MCNF, possessing a 3D structure, was successfully obtained via ultrasonic control. Nitrogen adsorption analysis shows that the MCNF composites have a larger specific surface area compared with that of CNF, due to the inserted CNF inhibiting the aggregation of MnO₂. The desalination capacity was evaluated by an adsorptive experiment, involving several ions (Ca²⁺, Mg²⁺, Na⁺ and sea water) in aqueous solution. MCNF exhibited excellent desalination behaviour towards ions in sea water, depending on both the strength of the efficient positive ionic charge and ionic radius. More interestingly, the regenerated MCNF after initial HCl and subsequent KOH treatment could be repeatedly used after ten adsorption/desorption cycles without obvious degradation of the performance. Moreover, with high desalination efficiency and reusability, and ease of separation, the aerogel is a candidate for desalination in practical applications.