Fabrication and Characterization of Sulfonated Carbon Materials and Chitosan-Derived Functioned Carbon via Schiff’s Base Process for Separation Purposes

Abstract

The Schiff bases reaction is applied to form various functioned carbon structures using renewable carbon from waste sources, Chitosan, 4-Amino-3-hydroxy-napthalene-1-sulphnic acid, and dimethyl amino benzaldehyde as starting materials. The formed functioned carbons were characterized by TEM, FTIR, XRD, and surface area analysis to assess their morphology, structure, porosity, and surface functional groups. In addition, the chromatographic-based thermodynamic analysis is applied to evaluate the surface energy and thermodynamic parameters during the separation of hydrocarbon species. Results indicated the formation of various carbon structures in convex-like shapes with diameters between 600 nm and 1500 nm, including side-building edges of diameter between 100 nm and 316 nm. The formed functioned carbon surfaces are rich with O-H, N=C, C=C, C=O, and C=S groups, as indicated by the FTIR. The function carbons are named carbon coated with Chitosan-derived covalent organic layer (C@Chitosan-COL) as well as Schiff’s base-derived sulfonated carbon (Schiff’s-C-S) in relation to the applied starting materials. The chromatographic-based thermodynamic analysis showed that the entropy changes of adsorption (ΔSA) increased with increasing chain length demonstrating less random movement and higher adsorption in both materials. The fabricated C@Chitosan-COL and Schiff’s-C-S showed an efficient separation of hydrocarbon mixture including n-Nonane, n-Decane, n-Undecane, and n-Dodecane.