Synthesis and Characterisation of Zinc/Aluminium-Layered Double Hydroxide-L-Phenylalanate Nanocomposites Using Ion Exchange Method

Abstract

This study was conducted to synthesise Zn/Al-layered double hydroxide-ʟ-phenylalanate (Zn/Al-LDH-LP) nanocomposite via ion exchange method. The synthesised nanocomposite was characterised using PXRD, FTIR, CHNS, ICP-OES, TGA/DTG and FESEM. The PXRD patterns of the Zn/Al-LDH-LP nanocomposite demonstrate an expansion of interlayer spacing, with a value of 15.8 Å, hence, indicates the successful intercalation of the drug ʟ-phenylalanate into the interlayer gallery of the Zn/Al-layered double hydroxide. The intercalation was also confirmed by the FTIR study which show the appearance of peaks in the FTIR spectra of Zn/Al-LDH-LP that represents the alkyl C-H stretch, N-H stretch, antisymmetric and symmetric stretching of COO‾ group. CHNS analysis showed that Zn/Al-LDH-LP nanocomposite contained 37.89% carbon (w/w) and the loading percentage of LP in the Zn/Al-LDH-LP nanocomposite is 57.91% (w/w). The result obtained from the FTIR spectroscopy, CHNS elemental analyser and ICP-OES shows that the Zn/Al-LDH-LP nanocomposite was composed of both Zn/Al-LDH and ʟ-phenylalanate, thus confirmed the occurrence of the intercalation. The thermogravimetric analysis shows that the Zn/Al-LDH-LP nanocomposite possesses better thermal stability than the pristine ʟ-phenylalanine, and occurred in four stages at maximum temperature of 152°C, 242°C, 311°C and 427°C with weight losses of 8.2%, 6.8%, 8.7% and 52.9%, respectively. The chemical formula for Zn/Al-LDH-LP nanocomposite was proposed as [Zn0.71Al0.29(OH)2][C6H5CH2(NH2)COO ‾ ]0.29.1.33H2O. This study demonstrates that the ZLH-LP nanocomposite can be synthesised using the ion exchange method.