Synthesis of a new magnetic nanocomposite hydrogel based on poly(vinyl acetate-co-maleic anhydride)/melamine for efficient dye removal

In this work, we fabricated a novel magnetic nanocomposite hydrogel based on poly(vinyl acetate- co-maleic anhydride)/melamine. A simple one-pot method was applied to fabricate the nanocomposite, and its adsorption capacity was investigated using Congo red (CR) dye. Then, the effects of a variety of parameters such as adsorbent dosage, solution pH, initial dye concentration, and contact time on the efficiency of the adsorbent were evaluated. The optimal adsorption of CR on the adsorbent was observed at pH 5 with 10 mg adsorbent and 10 mg L−1 initial dye concentrations where the adsorption efficiency reached above 90%. The Langmuir model was applied for fitting the adsorption isotherm of CR obtained on the proposed nanocomposite hydrogel, and it was observed that the adsorption process most probably followed a pseudo-second-order kinetic model. The obtained results showed that the proposed nanocomposite adsorbent could be used in water treatment. It was characterized with different techniques including X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, vibrating sample magnetometer, and energy dispersive X-ray.