MSLA-Fabricated PEGDA-HEMA/Chitosan Hybrid Monoliths for Efficient Congo Red Adsorption

Abstract

This study demonstrates the fabrication of PEGDA-HEMA/chitosan hybrid monoliths by masked stereolithography (MSLA) as sustainable structured adsorbents for Congo Red (CR) dye removal from aqueous solution. Chitosan was incorporated into PEGDA-HEMA photopolymer resin to introduce accessible functional sites while preserving the three-dimensional (3D) lattice. FESEM-EDX confirmed chitosan distribution and amine groups on the monolith surface, whereas FTIR suggested dye binding through hydrogen bonding, electrostatic attraction, and possible π-π interactions. Batch adsorption studies at pH 3, analyzed using a design-of-experiment (DOE) approach to obtain regression equations for removal efficiency ( R% ) and adsorption capacity ( q e ) as functions of dosage, temperature, and initial concentration. A single lattice dose and 40˚C gave the highest removal (96%, q e = 2.01 mg/g), while increasing initial concentration from 10 to 50 ppm raised q e from 1.28 to 3.35 mg/g despite fluctuating removal efficiency. Results indicate that R% and q e are governed by distinct mechanism, offering a basis for optimizing PG-HM/CS in continuous-flow applications.