Additive manufacturing of graphene oxide-functionalized polylactic acid (PLA) adsorbent for diuron removal

The presence of emerging contaminants, such as diuron, in water bodies demands the development of efficient treatment technologies. In this scenario, adsorption stands out for its high efficiency, especially with the use of graphene oxide (GO), a nanomaterial with exceptional adsorptive capacity for organic compounds. Although adsorption with graphene oxide (GO) is highly promising due to its high chemical affinity, the difficulty in recovering the powdered nanomaterial generates risks of secondary contamination. As a technological solution, this study proposes the immobilization of GO in a polylactic acid (PLA) matrix through Fused Granular Fabrication (FGF) additive manufacturing, aiming to combine high adsorptive performance with ease of handling. Four compositions (0.25 to 1.50% w /w of GO) were developed and characterized. The incorporation of the nanomaterial acted as a nucleating agent, increasing the crystallinity of PLA from 13.25% up to 46.62%, in addition to improving thermal stability. The composite with 0.50% GO exhibited the best mechanical balance (stiffness and strength). In the diuron removal tests, the sample with 0.25% GO stood out for its technical and economic efficiency, reaching over 70% removal and a capacity of 25.08 mg g −1 (pH 3; 2 h). The kinetics followed the Pseudo-First-Order model, and the equilibrium fitted the Sips isotherm (R 2 = 0,99 e 0,97, respectively), indicating a physisorption mechanism. The results confirm that the FGF technology overcomes the separation limitations of GO, providing structural stability to the composite. The material proves to be highly viable for water treatment, and future studies in fixed-bed systems are recommended to optimize operational parameters.