A novel environmentally friendly nanocomposite aerogel based on the semi-interpenetrating network of polyacrylic acid into Xanthan gum containing hydroxyapatite for efficient removal of methylene blue from wastewater

Eco-friendly nanocomposite aerogels were prepared as adsorbents for the removal of a model pollutant (methylene blue, MB) from water. These aerogels were comprised of hydroxyapatite (HA) nanoparticles embedded within a polymer matrix consisting of a semi-interpenetrating network of xanthan gum (XG) and polyacrylic acid (PAA). Microscopy and BET analysis showed that the aerogels formed had a nanofibrous porous microstructure with a surface area of 89 m2/g. Rheological analysis showed that the aerogels were viscoelastic materials whose elasticity increased with increasing HA concentration (up to 5 w/w%). The aerogels were effective at removing MB from water, exhibiting an adsorption capacity of 130 mg/g after 200 min. The binding of the MB to the aerogels was mainly attributed to hydrogen bonding and electrostatic attraction. A reusability test showed that the MB removal efficiency of over 86% was preserved after 10 cycles of adsorption-desorption. These results suggest that our nanocomposite aerogels may be useful for the efficient removal of anionic pollutants from wastewater and water supplies due to their ease of synthesis, cost-effectiveness, good mechanical properties, high thermal stability, and good adsorption performance.