(634c) Conversion of Lignocellulosic Biomass to Highly Functional Micro- and Nano-Materials for Water Treatment

An important pillar of sustainable development is the preparation of functional materials derived from renewable resources. Nevertheless, facile methods to convert lignocellulosic biomass into value-added, highly functional micro- and nanomaterials remain limited. Here, we evaluate the potential of a sustainable method to convert a variety of lignocellulosic biomass into highly charged products. We show how the sequential oxidation of both delignified (e.g., softwood pulp and cotton) and untreated (e.g., corncob and tomato peel) lignocellulosic sources yield three distinct products, including nanoparticles, fully solubilized polymers, and microproducts, bearing up to 6 mmol of carboxylate groups per gram, which is ~500% beyond the theoretical charge content of cellulose nanocrystals (CNC). The main difference among the products was the type of nanoparticles: delignified sources yielded hairy cellulose nanocrystals, whereas lignin nanoparticles were formed from the untreated sources. As a proof-of-concept for the applications of these materials, we use carboxylated cotton microproducts to remove ~ 92.5 mg of neodymium (Nd) per gram from a dilute Nd solution in less than 5 min and recover approximately 64% of it via pH adjustment. This work may provide new opportunities for the conversion of a wide array of lignocellulosic biomass into highly functional biocolloids with the highest charge density ever reported for advanced sustainable applications.