Nitrate Removal Performance of Different Granular Adsorbents Using a Novel Fe-Exchanged Nanoporous Clinoptilolite
Shamin Hosseini Nami, Seyed Borhan Mousavi
Abstract
High Resolution Image Download MS PowerPoint Slide The primary purpose of this investigation is to assess the nitrate removal efficiency of the two diverse synthesized beads from natural clinoptilolite modified with iron cations (Fe/Clin). Beads were prepared utilizing nanoporous Fe/Clin by employing alginate (A) and chitosan (Ch). X-ray diffraction, Fourier transform infrared, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, and Brunauer–Emmett–Teller methods were operated to scrutinize the clinoptilolite, Fe/Clin, Fe/Clin-A-bead, and Fe/Clin-Ch-bead. A comprehensive batch adsorption investigation was performed using both synthesized specimens to determine the effective parameters. The effects of pH, bead dosage, and time were assessed. The optimum removal rates of 86.13 and 88.79% were computed for Fe/Clin-A-bead and Fe/Clin-Ch-bead at the optimized dosage and pH. Moreover, the best nitrate removal performance was at 4 and 3 g/L for Fe/Clin-A-bead and Fe/Clin-Ch-bead, respectively. The removal rates of 2, 3, 4, and 5 g/L of Fe/Clin-A-beads were 78.80, 82.40, 86.13, and 87.45%, respectively. On the other hand, Fe/Clin-Ch-beads had better removal performance at the measured range. The removal rates of 2, 3, 4, and 5 g/L of Fe/Clin-Ch-beads were 83.35, 88.79, 89.50, 92.25, and 90.04%, respectively. The optimal adsorption time for Fe/Clin-A-bead and Fe/Clin-Ch-bead was 75 and 60 min, respectively. Both beads’ isotherms were investigated using Langmuir, Freundlich, and Dubinin–Radushkevich (D-R) isotherms. The maximum adsorption using Langmuir and D-R isotherms was 24.39 and 7.06 mg/g for the alginate bead and 36.63 mg/g and 10.93 mg/g for the chitosan bead, respectively. The kinetics of both beads were also studied utilizing Lagergren first-order, pseudo-second-order, and intraparticle diffusion. The kinetic model of both beads was best described by the pseudo-second-order.