A green 3D scaffolds based on chitosan with thiol group as a model for adsorption of hazardous organic dye pollutants

Water contamination is an increasing global concern due to deterioration of water quality. Chitosan and its derivatives are one of the most promising and applicable bio-sorbents for dye adsorption. This study investigated the adsorption properties of novel 3D scaffolds prepared with chitosan using modifiers with thiol group (or thiomers) for wastewater treatment. These thiomers were produced by the covalent conjugation of thiol moieties (cysteine) to chitosan (ChiCys), mediated by a zero-length crosslinker. Porous 3D scaffolds were tested for methyl orange and methylene blue adsorption. The results demonstrated high thiolation (ChiCys = 500 +/- 39 mu mol g(-1)). The prepared scaffolds showed a hierarchal interconnected 3D porous structure and chemical stability suitable for use as bio-sorbents. Moreover, they presented cytocompatibility using in vitro bioassays. These scaffolds demonstrated high adsorption efficiency (over 90%) and maximum uptake (305 +/- 2 mg g(-1)) at pH = 7.0 for methyl orange (100 mg L-1). The adsorption was well fitted to a pseudo-second-order kinetics and Langmuir equations. Thus, for the first time, thiomer 3D-scaffolds were produced by combining green bio-sorbent behavior for organic dyes, which offers an innovative strategy for the treatment of contaminated water bodies.