3D-printed chitosan/polylactic acid-based antimicrobial cups for toxic metal adsorption from water

Abstract

This work presents fabrication of eco-friendly, 3D printable, antimicrobial composites that capture toxic heavy metal ions from contaminated water bodies. Chitosan, a biopolymer having heavy metal chelating sites was incorporated into polylactic acid (PLA), a 3D printable, biodegradable thermoplastic matrix. Using the heat-press method, a series of composites was prepared by altering the wt% of chitosan. Using moderately polluted water, the composites were subjected to Pb^2 + , Cu²⁺, and Cd²⁺ adsorption at ambient temperature and neutral pH. The 30 and 60 wt% chitosan (C) loaded composites (30 C/PLA and 60 C/PLA) reduced Pb²⁺ below the environmental protection agency (EPA) recommended action level (AL) before 5 min. The 60 C/PLA reduced Cu²⁺ below EPA-AL within 30 min. All the composites adsorbed the metal ions significantly higher than neat PLA, the control. Reusability studies for Pb²⁺ removal with the 30 C/PLA indicated that ca 96 % of the original Pb²⁺ adsorption efficiency could be achieved even after the fifth regeneration cycle. Moreover, 30 C/PLA and 60 C/PLA indicated inhibition zones for Escherichia coli, a bacterium that could live in water. No inhibition zone was detected with the control. In addition, the 10, 20, and 30 C/PLA were successfully 3D printed into cup-like shapes. Ultimate compressive strength, toughness, and Young’s modulus of the 3D printed 30 C/PLA cups were significantly higher than that of the control. An object with complex geometry was also successfully 3D printed using the 30 C/PLA composite. As per the overall results, this is the first work to report a 3D printable eco-friendly antimicrobial material (30 C/PLA) that reduces toxic Pb²⁺ below EPA-AL before 5 min while retaining ca 96 % of the original Pb²⁺ adsorption efficiency even after the fifth cycle. The approach lays a foundation for future development of cost-effective, eco-friendly water filtration devices with free-standing complex geometries via 3D printing.