Gallic acid-loaded montmorillonite nanostructure as a new controlled release system: Fid-Bau Portal

Gallic acid-loaded montmorillonite nanostructure as a new controlled release system

Rabiei, Morteza / Sabahi, Hossein / Rezayan, Ali Hossein

Abstract A new controlled release system was obtained by mimicking the process of forming clay-phenol nanostructure in soil by aqueous dispersion. The nanostructure was prepared using gallic acid (GA) as a guest and impure and unmodified montmorillonite (Mt) as the clay host. The experiment was performed at two pH levels, 3 and 7. XRD, FTIR, TGA and UV–Visible analyses showed that GA adsorption was higher at pH3 (33%) compared to pH7 (20%). TGA analysis showed that Mt/GA nanocomposites prepared at pH7 lost 73% and one of pH3 lost 47% of their absorbed GA at 370–780°C, respectively. Free GA lost only 28% of its mass at 370–780°C and 72% at 260°C. These results suggest the existence of a stronger linkage between absorbed GA at pH7 compared to pH3. Correlation coefficient between temperature and GA released from nanocomposite formations at pH7 (r=0.99.5), pH3 (r=0.96) and from free GA (r=0.88) also confirmed this hypothesis. The pattern of GA release from Mt at PBS 0.1M, shows that Mt/GA nanostructure can be presented as a new controlled release system.

Graphical abstract Display Omitted

Highlights • FTIR, TGA and UV-Visible analyses showed that GA adsorption was higher at pH3 (33%) compared to pH7 (20%). • TGA analysis showed that Mt/GA produced at pH7 and 3 lost 73% and 47% of their absorbed GA at 370-780°C, respectively. • These results suggested the existence stronger linkage between intercalated GA at pH7 compared to pH3. • Correlation coefficient between temperature and GA released from nanocomposites also confirmed this hypothesis. • The pattern of GA release from Mt, shows that Mt/GA nanostructure can be presented as a new controlled release system.