Repurposing Quality-Downgraded Fluorinated Carbon Nanotubes as Eco-Additives in Microgel Composites for Sustained Water Release

While significant efforts have been made to recycle metals like lithium or cobalt for sustainable development in the battery industry, the reuse of other high-value materials, such as fluorinated carbon nanotubes (FCNTs), remains underexplored. This study introduces a novel, eco-friendly method to repurpose quality-downgraded FCNTs (QD-FCNTs) as effective nano-additives in polyacrylamide (PAAm) microgel composites for water retention applications. Because QD-FCNTs are rich in surface defects, by employing a mild surface treatment with a low dosage of organic electron donor N,N,N′,N′-tetramethyl-p-phenylenediamine, we enhanced the hydrophilicity of QD-FCNTs without additional energy input or a large quantity of harmful chemicals. This treatment significantly improved the interaction between QD-FCNTs and PAAm microgels, leading to a 55% increase in water retention time compared to the composites made of untreated QD-FCNTs. Our findings present a sustainable approach to extending the lifecycle of FCNTs, contributing to the circular economy and offering practical solutions for potential water management in agriculture and environmental technologies.