Investigation of Methylene Blue Adsorption Behavior of Polyurethane, Iron Oxide, and Zeolite‐Based Hybrid Composites

ABSTRACT In this study, the methylene blue adsorption efficiency of the hybrid composite containing polyurethane, zeolite, and iron oxide was clarified. A melamine‐based polyurethane was prepared via a straightforward two‐step process and then mixed with zeolite and iron oxide nanoparticles to obtain composite materials. The mixing procedure involved dispersing zeolite and iron oxide nanoparticles in a suitable solvent under ultrasonic agitation, followed by gradual incorporation into the polyurethane matrix with continuous stirring to ensure uniform distribution and strong interfacial bonding. The structures of the materials were characterized through techniques such as Fourier transform‐infrared (FT‐IR), X‐ray powder diffractometer (XRD), thermogravimetry (TG), and Scanning electron microscopy (SEM). XRD results demonstrated that the particle size of Fe 3 O 4 and PU‐Fe‐5Z nanoparticles was calculated as 7.63 ± 4.51 and 12.85 ± 4.79 nm, respectively. A series of experiments was conducted to optimize the adsorption process, including variations in initial pH (3–11), temperature (30°C–50°C), contact time (0–100 min), adsorbent dose (0–100 mg), and initial dye concentration (20–100 mg/L). The Langmuir isotherm findings showed that the maximum adsorption capacity ( q max ) of the polyurethane–iron oxide composite containing 5% zeolite (PU‐Fe‐5Z) for methylene blue was 208.3 mg g −1 within 120 min at pH 7.0 and 50°C. Moreover, the nature of the adsorption of methylene blue onto the adsorbents was spontaneous, and it was characterized by mounted randomness.