Surface functionalization of 3D-printed cellulose-polyamide composite filter for heavy metal removal

The development of 3D-printed cellulose-based materials for water treatment remains limited due to the infusible nature of cellulose and its insolubility in common solvents. Moreover, existing strategies to modify cellulose for this purpose are often complex. In this work, a simple approach was employed to fabricate cellulose-polyamide composite filters using selective laser sintering (SLS) 3D printing technology, followed by functionalization with citric acid for application in heavy metal removal. The developed 3D-printed filters, named CA/3D-MCC, were characterized using FTIR, SEM, Zeta potential, TGA, and XPS. The citric acid-functionalized filters demonstrated selective adsorption of Pb(II) from a multimetal solution, with adsorption behavior fitting both the Langmuir isotherm and pseudo-second-order kinetic models. The maximum adsorption capacity for Pb(II) was 19.82 mg/g at an optimal pH of 5.5 with equilibrium attained within 4 h. The CA/3D-MCC filters were successfully reused and regenerated over five cycles, maintaining removal efficiencies between 70–82 %. The adsorption process was driven by carboxyl and hydroxyl groups, through a combination of electrostatic interactions and coordination between the adsorbate and 3D-printed adsorbents. Additionally, the filter showed practical application in flow-through column systems. Overall, this work presents a simple approach for creating 3D-printed cellulose-based materials for water purification and wastewater treatment applications.