Utilization of biodegradable chitosan-derived sponges as oil retainers

An innovative approach of chitosan-derived biodegradable sponges with high sorption capacity, excellent recyclability, and inherent oleophilic properties have been developed for the first time to remove the crude oil polluting the environment. Chitosan-nitrogen mustard ionic carbonate-beta-cyclodextrin (CH-NMIC-CD), chitosan-nitrogen mustard ionic carbonate (CH-NMIC), and chitosan (CH) sponges with macropores were prepared using tripolylphosphate (TPP) by adopting subsequent lyophilization. Detailed characterization such as FTIR, TGA, XRD, and SEM has been done to confirm the formation, stability, crystalline nature, and morphology of the prepared sponges. The FTIR spectra confirmed the successful incorporation of NMIC in CH-NMIC-CD and CH-NMIC and the presence of beta-CD in the (CH-NMIC-CD). It was found from the TGA results that the presence of beta-CD makes the sponge CH-NMIC-CD stable. SEM analysis showed the morphology of the sponges found to be highly porous with interconnected macropores. The oil absorption capacity was 12.30 g(oil)/g(ns) higher for the sponge CH-NMIC-CD followed by CH-NMIC and CH. The sponges showed reusability excellently even after consecutive sorption-desorption separation cycles for five times. Moreover, the sponges were completely biodegraded within 25 days. The finding holds a promising future to use CH-NMIC-CD sponges in pollutant entrapment particularly in the removal of crude oil and allied area.