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Chitosan is a bio-based polyelectrolyte with high potential for wastewater treatment. Chitosan can remove anionic dyes by adsorption but it has low performance in the removal of cationic dyes. In this work, we report the synthesis of chitosan-based graft-copolymers using gamma radiation. Acrylic acid and poly(ethylene glycol) were grafted successfully onto chitosan applying a radiation dose of 12 kGy at a dose rate of 8 kGyh-1. The grafted-copolymers have improved adsorptive properties for the removal of basic dyes reaching a maximum adsorption capacity higher than 300 mgg-1. The Lanmguir’s isotherm model described satisfactorily the interaction between the grafted copolymers and basic dyes. Freundlich’s isotherm model described the adsorption of anionic dye acid orange 52. The grafted copolymers removed successfully textile dyes from wastewater of the dyeing process. The best results were obtained in the removal of direct and basic dyes. Further, poly(ethylene glycol) grafted on the copolymer conferred better swelling behavior making easy the separation of the adsorbent after dye removal. The results showed that the adsorbent materials synthesized by radiochemical graftcopolymerization are more efficient than the beads, composite materials, and blends of chitosan.

Graft polymerization induced by ionizing radiation is a powerful tool in materials science to modifying the physical properties of polymers. Chitosan is a biocompatible, biodegradable, antibacterial, and highly hydrophilic polysaccharide. In this work, we report the obtaining of amphiphilic polymers through graft polymerization of acrylic monomers (methyl acrylate, t-butyl acrylate, and hexyl acrylate) onto chitosan. The polymerization reaction was carried out by simultaneous irradiation of monomers and chitosan using a gamma radiation source of 60Co. The formation of Langmuir films of amphiphilic polymers was studied at the air-water interface through surface pressure versus main molecular area isotherms (Π-A) and hysteresis cycles of compression and decompression. Finally, it was analyzed the transferring of Langmuir films towards solid substrates to obtaining Langmuir-Blodgett films with potential application as an antibacterial coating. The microstructure of the Langmuir-Blodgett films was characterized by AFM microscopy observing a regular topography with roughness ranging between 0.53 and 0.6 μm.