Garbage to Nanocellulose: Quantitative Isolation and Characterization of Steam-Treated Carboxymethyl Holocellulose Nanofibrils from Municipal Solid Waste

• Published in: ACS sustainable chemistry & engineering Vol. 11; no. 7; pp. 2727 - 2736
• Main Authors: Patterson, Gabriel D., McManus, James D., McSpedon, Dane, Nazneen, Saira, Wood, Delilah F., Williams, Tina, Hart-Cooper, William M., Orts, William J.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 20-02-2023
• Subjects: municipal solid waste; holocellulose nanofibrils; steam autoclaving; carboxymethylation; waste management
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.2c05236

Municipal solid waste (MSW) is a major source of greenhouse gas emissions unless its carbons are sequestered into higher-value products. This study focuses on isolating organic solids and cellulose-rich fibers from MSW via high-pressure steam treatment and converting the fibrous, prepulped materials from wastepaper, packaging materials, cardboard, etc., into value-added cellulose nanofibrils. Chemical–mechanical defibrillation of steam-treated municipal solid waste was optimized using heterogeneous and nonregioselective carboxymethyl etherification coupled with shearing by blender, thus transforming a heterogeneous mix of MSW into homogeneous carboxymethyl holocellulose nanofibrils without the use of conventional pretreatments of crude cellulosic feedstock. These carboxymethylated, hemicellulose-coated, cellulose nanofibrils were isolated quantitatively at >95% yield with widths 3–8 nm, thicknesses 1–3 nm, and lengths up to 1000 nm. We posit that this advancement of combining an inexhaustible, global supply of waste cellulose, large-scale steam autoclaving pretreatment, and an industrially relevant carboxymethylation process could unlock the higher potential of sustainable cellulosic nanomaterials for a circular economy.