In this study, lignocellulose, nano-cellulose (NC), and silica were extracted from the agricultural by-products peanut shell (PS), rice husk (RH), and sugarcane bagasse (SB) using an ultrasound-assisted chemical method. Ball milled PS, RH, and SB powders were hydrolyzed with 0.1 M HCl followed by an alkaline hydrogen peroxide solution (AHPS) treatment at 50oC for 1 h in an ultrasonic bath to dissolve lignin and silica. Lignin in AHPS was precipitated with acid coagulation and recovered using centrifugation. For silica extraction, the supernatant was concentrated and capping agents (CTAB and n-butanol solution, 1:1) were added before oven drying. The dried silica was further treated in a furnace at 700oC for 2 h to obtain pure white silica powder. For the synthesis of NC, undissolved cellulose collected from the AHPS treatment was washed several times with deionized water until neutral pH was achieved. The samples were transferred into ultrasonic vessels containing 1% H2O2 and NC was collected after ultrasonic irradiation at 20 kHz for 1 h. The thermal and morphological properties of NC and silica obtained were evaluated using XRD, FE-SEM, EDS, Raman, and TGA. XRD analysis showed that the highest degree of NC crystallinity (65%) was obtained from SC followed by RH (53%) and PS (43%). The FE-SEM results showed that the NC fibers range from 100 nm to 200 nm. Similarly, crystalline silica was obtained from RH and amorphous silica from SC and PS. FE-SEM results showed that silica particles were spherical and ranging from 20 nm to 50 nm. Thermal analysis results indicated that NC from RH was the most heat-stable in terms of onset temperature (275oC) compared to SC (250oC) and PC (240oC). The method used in this study may be an effective technique for extracting lignocellulose and silica from agricultural by-products for the comprehensive utilization of biomass.

Synthesis of nano-cellulose and silica from agricultural waste: A comprehensive utilization of biomass

2019 Spring National Meeting

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