Preparation and characterization of silica from rice husk ash as a reinforcing agent in whey protein isolate biocomposites film

Abstract

This research focused on extracting silica (SiO2) from rice husk ash (RHA) to eliminate the problem of local disposal from the rice mill industry. Here, the various potassium hydroxide (KOH) composition was proposed to identify SiO2 characteristic, which is crucial to the particle size. The resulting SiO2 was applied as a filler in whey protein isolate (WPI) biocomposite films. SiO2 was synthesized from the RHA by carrying out a KOH solution, then separated from the extracted SiO2 using hydrochloric acid (HCl). Fourier transform infrared spectroscopy, X-ray diffractometer, scanning electron microscopy, and dynamic light scattering were used to characterize all the SiO2 material. It was found that the yield of SiO2 was 2.85%, 4.63%, 7.32%, 15.63%, and 27.42%, severally. When the concentration of KOH was 1 N, 1.5 N, 2 N, 2.5 N, and 3 N, the crystallinity was 20.53% to 55.20%. Besides, the particle size ranged from 2.61 to 0.14 µm and the particle distribution from 2.09 to 1.56 µm. The tensile strength and elongation of WPI biocomposite film using 5% SiO2 were 14.12 MPa and 30.70%, respectively. It can be summarized that SiO2 is the potential to be used as a filler agent in biocomposite film.