Biogenic silica-based microparticles obtained as a sub-product of the nanocellulose extraction process from pineapple peels

Loading...
Thumbnail Image
Date
2018-07-10
Journal Title
Journal ISSN
Volume Title
Publisher
San Carlos, Costa Rica
Abstract
La sílice en los tejidos de las plantas se ha incorporado como un componente para mejorar las propiedades mecánicas y como una barrera física para los materiales compuestos. La cáscara de la piña presenta micropartículas en forma de rosetas que podrían estar asociadas a sílice biogénica. En este estudio, se muestra por primera vez que las micropartículas a base de sílice se co-purifican durante el proceso de extracción de nanocelulosa de piña (Ananas comosus). Esto muestra que la biomasa vegetal podría ser una fuente poco apreciada, no solo para la nanocelulosa, sino también para un subproducto muy valioso, micropartículas de 10 µm de sílice biogénica tipo roseta. El rendimiento de recuperación obtenido fue de 7,2% en peso; con respecto a su peso inicial sólido. Debido a su tamaño y morfología, las micropartículas tienen aplicaciones potenciales como refuerzo en adhesivos, compuestos de polímeros, en el campo biomédico, e incluso como fuente de sílice para fertilizantes. Silica in plant tissues has been suggested as a component for enhancing mechanical properties, and as a physical barrier. Pineapples present in their shell and bracts rosette-like microparticles that could be associated to biogenic silica. In this study, we show for the frst time that silica-based microparticles are co-purifed during the extraction process of nanocellulose from pineapple (Ananas comosus). This shows that vegetable biomass could be an underappreciated source, not only for nanocellulose, but also for a highly valuable sub-product, like 10µm biogenic rosette-like silica-based microparticles. The recovery yield obtained was 7.2 wt.%; based on the dried initial solid. Due to their size and morphology, the microparticles have potential applications as reinforcement in adhesives, polymer composites, in the biomedical feld, and even as a source of silica for fertilizers.
Description
The nanocellulose extraction process from pineapple peels was previously described by the authors, and a diagram of the process is shown in Supplementary Fig. S1. Briefy, the ground pineapple peels were incubated in NaOH to remove the lignin and hemicellulose, then bleached in NaClO, before incubating in HCl to hydrolyze the cellulose and to obtain microcellulose. Between each step, the product was thoroughly rinsed with water until neutral pH, and the solid was recovered by centrifugation at 13000 rpm. In the final step, the material was hydrolyzed with H2SO4 to obtain NCC. Two fractions of particles were separated from this acid solution by centrifugation at 2500 rpm; the supernatant containing mainly particles in the nanometer range and the precipitate containing the micrometer solid fraction and insoluble materials. The precipitate was mainly BRMS. To purify the BRMS of cutin and NCC residues as well as remove the carbon-based materials surrounding the particles, the solid was incubated with a second H2SO4 solution. Sulfuric acid solutions of 65, 30, 15 and 2 wt.% were tested between 30 minutes and 4 hours at 55 °C (1 g of precipitate/10 ml of H2SO4 solution) to determine the lowest acid concentration needed to disperse the carbon derivatives in the solution. The second H2SO4 acid step was applied to partially depolymerize the cutin bound to polysaccharides19. Finally, the product was separated from the liquid viscous phase by centrifugation at 2500 rpm and rinsed several times with deionized water. For FTIR analysis, the cutin derivatives were separated from NCC by phase separation at 13000 rpm.
Keywords
EXTRACCIÓN DE NANOCELULOSA, MICROPARTÍCULAS BIOGÉNICAS A BASE DE SÍLICE NONOCELULOSA, SÍLICE, SÍLICE BIOGÉNICA, CÁSCARA DE PIÑA, PIÑA, NANOCELULOSA DE PIÑA
Citation
https://www.nature.com/articles/s41598-018-28444-4