Synthesis and characterization of L-Arginine modified silica by sol-gel method prepared rice hull ash

Abstract

The synthesis of L-arginine modified silica using 3-glycidoxypropyl-trimethoxysilane (GPTMS) as linking agent has been done through sol-gel process. Sodium silicate (Na2SiO3) from rice hull ash (RHA) as the silica source precursor, L-arginine solution 0.9 M with various volume ratios and the linking agent were mixed to form a gel labelled SiO2(RHA)-Arg. The synthesis was successfully carried out in the form of bone white solids. Furthermore, SiO2(RHA)-Arg were characterized using Fourier transform infrared (FTIR) spectrophotometer, elemental analyser, thermogravimetric analyser (TGA) and 29Si-NMR. FTIR spectra of SiO2(RHA)-Arg shows two new peaks at 1672 and 1583 cm-1 confirming NH2 and C=O groups, respectively. Elemental analysis indicates that the mol ratio of GPTMS: L-arginine is 5: 1. TGA analysis explains that the ratio of SiO2: GPTMS: Arg is 5:5:1. The analysis of 29Si-NMR indicate that the silica binds two molecules of GPTMS. The results of SiO2(RHA)-Arg characterization show that silica atom binds two molecules of GPTMS, and every molecule of GPTMS binds five L-arginine molecules.