Adsorption of Hexavalent Chromium Ions from Aqueous Solutions Using Chitosan/Urotropin Magnetic Nanocomposite

In the pursuit of substantially augmenting the adsorption efficiency of hexavalent chromium (Cr(VI)) from aqueous solutions, a pioneering and eco-friendly chitosan/urotropin magnetic nanocomposite (CUMNC) has been synthesized. The fabricated nanocomposite is characterized using various analytical techniques, XRD, FTIR, AFM, SEM, EDX, TGA, and BET. The BET analysis results verified the mesoporous structure with a high surface area of 365 m2 g-1 and a high pore volume 0.3782 cm3 g-1. The adsorption process of Cr(VI) onto the CUMNC adsorbent was conducted through a batch technique, involving the systematic variation of key parameters, including pH, concentration, contact time, and temperature. Langmuir and pseudo-second-order nonlinear models were found to be the best-fit models to predict isotherms and kinetics of adsorption, respectively. The highest adsorption capacity of 151.51 mg/g was achieved under the optimum conditions, which included a 0.1 g adsorbent dosage, 30 mg/L Cr(VI) concentration, resulting in a removal percentage of 91.7%, at a pH value of 9.0 for 200 min. In conclusion, the CUMNC nanocomposite has proven to be a highly efficient adsorbent material, exhibiting effectiveness in both acidic and alkaline environments as well as easy regeneration, low cost, and environmental friendliness.