09/02/2024
By Susan D'Amore
Indian Institute of Science Education and Research, Pune, India
Presentation: A Novel Cellulosic Porous Biomass: Structure, Properties and Applications
Wednesday, Sept. 11, 2024
3 to 5 p.m.
Southwick Hall 240
Aeschynomene aspera, commonly known as Shola, is a dried milky-white shrub of the Aeschynomene genus and grows in the wild in the wetlands of the Bengal estuaries and marshy areas of Assam, Orissa, and Bangladesh. It is a light, soft, spongy material that has been utilized for centuries by native artisans of Bengal to create decorative items commonly used in
social and religious ceremonies. Visually, it resembles expanded polystyrene but is superior in malleability, texture, luster, and sponginess.
The unique and intriguing color, texture, and feel of the Shola pith set us of on an exploration of the physical, structural and chemical properties of this abundantly available biomass and explore potential applications that uniquely exploit its physicochemical properties. The Shola pith, the pure white inner stem is rich in amorphous cellulose, possesses an exquisite
three-dimensional hierarchical architecture and is a 3D porous scaffold designed by nature. The pith consists of about 70% cellulose as the main chemical component which is much higher than what is found in other lignocellulosic sources. In addition, the pith has about 12% hemicellulose, 2-3% pectin, 10% lignin, 2.5% wax, and 2% protein as other chemical components.
The Shola pith exhibits super-hydrophobicity with a water contact angle of ~135˚ on the surface of the pith while oil droplets instantly spread on the surface, indicating excellent hydrophobic–oleophilic properties. Studies reveal that Shola pith exhibits
a fast and high sorption capacity of 40-60 g/g for various oils and organic liquids. Silicone oil shows a sorption capacity of about 166 g/g. Shola pith can also efficiently separate oil from an oil-in-water emulsion. This behavior is unprecedented in natural sorbents.
In a related study, we have extended a recently reported mechanochemical catalytic approach to oxidation of tertiary carbon-hydrogen bonds (ACS Catalysis, 2024, https://doi.10.1021/acscatal.4c00775; https://cen.acs.org/synthesis/c-h-activation/
Mechanochemical-reaction-oxidizes-CH-bonds/102/ web/2024/05) to the oxidation of whole biomass to generate spherical carboxyl-functional nanocellulose. We demonstrate the feasibility of a one-step solvent free process for the preparation of oxidized cellulose spherical nanoparticles (~90 nm) starting from the whole biomass without any chemical pretreatment.
Normally nanocellulose is prepared by a three-step process involving acid-assisted steam explosion followed by alkali treatment and chemical oxidation using TEMPO. The mechanochemically oxidized cellulose nanospheres is water dispersible and
show expected properties such as a stabilizer in a Pickering emulsion and surface activity as detergents
for dewetting oil and removing stains from fabrics.
For more information, please contact susan_damore@uml.edu