Extraction and characterization of nanocellulose from three types of palm residues

Abstract

Carbon footprint and nonrenewability are among the motives to mitigate dependence on oil resources. On the other hand, palm trees exceeded 100 million around globe, which poses enormous amount of biowastes to get exploited per annum. Moreover, nanocellulose is emerging as efficient low cost material, which shows increasing versatility throughout time. In this investigation we will attempt to extract nanocellulose from palm wastes (fronds, leaves, and coir), and characterize them. Dry biomass was pulped by being subjected to 10% (wt/wt) NaOH alkaline treatment at 160 °C for 2 h. Pulped non-bleached biomass underwent acidic hydrolysis by mechanical stirring in 20% H2SO4 (v/v) and heating to 120 °C for 30 min. After filtration, neutralization, and centrifugion, resultant particles were characterized to assess their morphology, size, particle charge, existing chemical groups, and crystallinity. For the three types of palm residues, our preparation technique was successful to isolate lignin containing nanocellulose particles. However, coir was more recalcitrant to acidic hydrolysis than fronds and leaves. Our palm residues yielded 42–82 nm spherical particles, and zeta potential ranging between −11 and −19 mV. Crystallinity was higher after pulping, and lower after hydrolysis, which suggests promotion of amorphous content of cellulose. Lignin-containing nanocellulose prepared in this study initiates promising horizon especially in heavy metal (cations) removal from water in environmental applications and sustained drug delivery for medical applications.

Keywords

• Nanocellulose
• Lignin containing
• Acidic hydrolysis
• Palm
• Residues
• Valorization