Preparation and characterization of chitosan graphene oxide nanocomposite for the removal of 17-β-estradiol sulfate from water: kinetics, thermodynamics and simulation studies

The presence of 17-β-estradiol sulfate residue in water is of great concern due to its hazardous nature (endocrine disruptor and carcinogen). For this, chitosan was used with graphene oxide to prepare chitosan graphene oxide nanocomposite. This material was characterized and used as an adsorbent for the removal of 17-β-estradiol sulfate residue in water. This adsorbent showed a rapid, efficient, and environmentally friendly method of 17-β-estradiol sulfate removal from water. The optimal conditions for maximum removal were 93.6% (4.68 mg/g) with 2500 µg/L of 17-β-estradiol sulfate, 30 min of agitation, 0.50 g/L of graphene oxide chitosan nanocomposite, a pH of 7.0, and temperature of 25 °C. The thermodynamic parameters confirmed the spontaneity and exothermic nature of the 17-β-estradiol sulfate uptake process. The kinetic study revealed a first-order reaction, with the mechanism of uptake attributed to liquid film diffusion. The supra-molecular interaction between β-estradiol and graphene oxide chitosan nanocomposite was elucidated, highlighting the pivotal role of two hydrogen bonds with binding affinities of −6.80 and −7.03 kcal/mole for the first and second hydrogen bonds. This method is speedy, efficacy, and environmentally friendly; making it applicable for the removal of β-estradiol from water in diverse water systems.