Synthesis of novel ZnAl2O4/Al2O3 nanocomposite by sol–gel method and its application as adsorbent

• Published in: Journal of sol-gel science and technology 2021-07, Vol.99 (1), p.158-168
• Main Authors: Saffar, A., Ahangar, H. Abbastabar, Salehi, Shahriyar, Fekri, M. H., Rabbani, A.
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Aluminum oxide; Ceramics; Chemistry and Materials Science; colloids; Composites; Crystallization; Differential thermal analysis; etc.; fibers; Glass; Heat treatment; Inorganic Chemistry; Materials Science; Methylene blue; Morphology; Nanocomposites; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Nano-structured materials (particles; Sol-gel processes; Specific surface; Surface area; Surface chemistry; Synthesis; Zeta potential
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-021-05559-1

In this research, ZnAl 2 O 4 /Al 2 O 3 nanocomposites with different ZnAl 2 O 4 (30, 50, and 70 wt.%) were successfully prepared in one step by sol–gel method and utilized for the removal of methylene blue (MB). The structural properties of nanocomposites were investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), FTIR analysis, Zeta potential, and BET. The obtained results showed the synthesized nanocomposites by sol–gel method were amorphous and heat treatment at 700 °C led to the crystallization of zinc aluminate spinel. The maximum MB removal (70%) was obtained under o9 ptimal conditions such as initial concentration of MB (10 mg/L), pH of solution (8.5), the amount of adsorbent (0.05 g), type of adsorbent (70 wt.% ZnAl 2 O 4 /Al 2 O 3 nanocomposite). The average size of zinc aluminate crystals in the maximum amount of zinc aluminate in the composite (70 wt.%) was calculated to be 27 ± 1 nm and its morphology changed from sheet to mass. The specific surface area of the nanocomposite was calculated to be 70 m 2 /g. The kinetics of adsorption was fitted with the pseudo-second order model. Highlights ZnAl 2 O 4 /Al 2 O 3 nanocomposites with different ZnAl 2 O 4 were synthesized in one step by sol–gel method. The specific surface area of Al 2 O 3 –70 wt.% ZnAl 2 O 4 nanocomposite was calculated to be 70 m 2 /g. The highest adsorption efficiency MB (72%) was obtained from 10 mg/L initial solution.