Hydrogel beads based on sodium alginate and quince seed nanoparticles for the adsorption of methylene blue

Abstract

In this paper, bioadsorbents containing sodium alginate and quince seed nanoparticles were prepared using the ionotropic gelation method for the adsorption of methylene blue. The structural characterization of the bioadsorbents and nanoparticles was performed by using Fourier Transform-Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), thermogravimetric (TG), and Brunauer-Emmett-Teller (BET) analysis. Cationic dye (methylene blue, MB) was used for the adsorption studies and some operational parameters such as initial pH solution, temperature, contact time, initial dye concentration, and adsorbent dose were optimized. The pseudo-first, and second order kinetics, Langmuir, and Freundlich isotherm models were used to analysis of the experiment results. The findings showed that the experimental results were fitted to the pseudo-second order kinetic and Langmuir isotherm models. The highest methylene blue adsorption capacity was obtained as 192.3 mg/g at 60 °C in the presence of sodium alginate bioadsorbent containing 5.0% quince seed nanoparticles at pH 7. The thermodynamic parameters (ΔG°, ΔH°, and ΔS°) were also calculated, and the MB adsorption on the bioadsorbents was performed as spontaneous and exothermic due to the negative value of the ΔG° and ΔH°.