UiO-66-NH2/guanidine-functionalized chitosan: A new bio-based reusable bifunctional adsorbent for removal of methylene blue from aqueous media.

Methylene Blue (MB) is a common pollutant found in industrial wastewater, and its removal is crucial to ensure environmental sustainability. Due to MOFs have high surface area, tunable pore size distribution, and excellent adsorption capacity, in the current study, Uio-66-NH2@Cs-ISo-Gu nanohybrid was prepared through soluthermal method and then was used to remove MB dye. The results displayed that dye optimal adsorption by Uio-66-NH2@Cs-ISo-Gu nanohybrid occurred in the first 40 min, pH = 8, and low dye concentrations. Also, with increasing temperature, the amount of adsorption has decreased, which indicated the adsorption process would be exothermic. Based on the results, the Uio-66-NH2@Cs-ISo-Gu nanohybrid has a surface area of 120.9 m2.g-1 and a type IV isotherm. Also, the Freundlich isotherm and pseudo-second order models had the best agreement with the experimental data. The maximum adsorption capacity for this nanohybrid was 178.571, 153.846, and 135.135 mg.g-1 at 25 °C, 45 °C, and 65 °C temperatures, respectively, which could be successfully used as an excellent adsorbent in treatment of wastewater. However, further research is needed to understand the underlying adsorption mechanism and optimize the process for efficient removal of MB from contaminated water sources.