Preparation of magnetic MnFe₂O₄-Cellulose aerogel composite and its kinetics and thermodynamics of Cu(II) adsorption

In this paper, a MnFe₂O₄-Cellulose magnetic composite aerogel (MnCA) with high adsorption capacity was fabricated by in situ incorporating MnFe₂O₄ to regenerated cellulose hydrogel matrix, followed by CO₂ supercritical drying. A green synthetic strategy was performed by using renewable cellulose materials, environmentally benign cellulose solvents and facile synthetic conditions. The results showed that the obtained magnetic cellulose aerogel had a continuous and tiered three dimensional network with interconnected fibrils of about 30 nm in width, which was similar to those of cellulose aerogel prepared from NaOH/urea solution via CO₂ supercritical drying. Meanwhile, they had high specific surface areas of 236–288 m²/g and total pore volume of 0.55–0.88 cm³/g. In addition, the hybrid aerogel showed superparamagnetism with maximum saturation magnetization reaching up to 18.53 emu/g. The magnetic nanocomposite aerogel could be used for biological and environmental applications. The adsorption test showed that MnCA had rapid adsorption rate and excellent adsorption ability of removing heavy metal ions in aqueous solution which could attain to 63.3 mg/g within 100 min. Moreover, all the composite aerogels exhibited good reusability and could be easily reused from the water after adsorption.