Interfacial engineering of graphene oxide immobilization on polylactic acid substrates through surface modification

Abstract Graphene oxide (GO) exhibits strong adsorption capability for dye removal, but its practical utilization remains constrained by aggregation and poor recoverability in aqueous systems. In this study, GO was immobilized onto biodegradable polylactic acid (PLA) through an interfacial engineering strategy. PLA substrates were first activated by alkaline etching to increase surface roughness and energy, followed by 3‑aminopropyltriethoxysilane (KH550) silanization to enhance interfacial adhesion. GO was then deposited onto the modified PLA via ultrasonic-assisted coating. The as-prepared composite was systematically characterized using SEM, FTIR, Raman spectroscopy, and XRD, confirming successful GO immobilization. Stability tests demonstrated that the composite retained 93.7% and 81.5% of its initial GO loading in aqueous and acidic environments after 13 days, respectively. Methylene blue (MB) adsorption experiments revealed kinetics following the pseudo-second-order model with adsorption equilibrium reached within approximately 60 min. The adsorption data were well described by the Langmuir isotherm model, yielding a maximum adsorption capacity of 197.21 mg·g −1 , indicative of monolayer adsorption. After six adsorption–desorption cycles, the composite retained 75.2% of its initial adsorption capacity, indicating satisfactory reusability. This work developed a surface-engineered GO–PLA composite through an effective surface modification strategy, generating a stable and reusable material whose functional performance was validated by the adsorption experiments.