Nanosilica from shakhotaka and bamboo leaf biomass waste: extraction, characterization, and as a stationary phase for application in chromatographic separation

Abstract

Shakhotaka and bamboo leaves agricultural biomass from Lampang Province, Thailand, is considered a potential renewable source for silica due to its abundance status. The preparation and characterization of nanosilica from shakhotaka and bamboo leaf biomass waste were the main objectives of this investigation. Shakhotaka (X = K) and bamboo (X = B) leaf biomass waste were converted into nanosilica using three acid (1 M HCl) pretreatment techniques: refluxing for 1 h (X-Rf-800), stirring for 12 h (X-H12-800), and stirring for 24 h (X-H24-800) before thermal combustion at 800 °C for 5 h under an air atmosphere. The optimal nanosilica yield of K-Rf-800 and B-Rf-800 was based on leaf dry weight, which was found to be around 28 and 30%. Fourier transform infrared (FTIR) spectroscopy showed the hydrophilic silanols on its surface and siloxane groups of the produced nanosilica, and X-ray diffraction (XRD) patterns revealed the presence of an amorphous nanosilica combined with a small semicrystalline phase. According to the Brunauer–Emmett–Teller (BET) analysis and the transmission electron microscopy (TEM) images of the K-Rf-800 and B-Rf-800 nanosilica, the mesoporous size was 13 nm, the surface areas were 69.06 and 56.84 m²/g, and non-spherical particle sizes ranged from 23 to 40 nm. With a reusability of at least five times, the resulting nanosilica could potentially be utilized as stationary phases in microcolumn chromatography to separate the green chlorophyll and yellow carotene pigments from Anethum graveolens leaves when compared to commercial SiO₂, according to the results of the separation factor value.