Optimizing cellulose nanofiber composite for Co2+ ions recovery from lithium-ion battery wastes and removal from wastewater: A green environmental solution

Abstract

In this study, we have introduced an advanced composite material that combines the remarkable properties of cellulose nanofibers (CNFs) with a tailored surface to enable the concentration, spectrophotometric detection, removal of Co2+ ions from wastewater samples and recovery of Co2+ ions from lithium-ion battery waste. CNFs, known for their eco-friendly nature and exceptional surface characteristics, serve as an ideal substrate for immobilizing the (3,3′-((1E,1′E)-((4-nitro-1,2-phenylene) bis(azaneylylidene)) bis(methaneylylidene)) bis(2-hydroxybenzoic acid) (NAMH) chromophoric ligand. The resulting CNFs-NAMH composite displays extraordinary sensitivity to Co2+ ions in aqueous solutions, achieving an impressive limit of detection (LOD) as 0.87 ppb. This exceptional sensitivity allows for straightforward visual detection with the naked eye.A noteworthy feature of the CNFs-NAMH composite is its rapid and distinct color change in approximately a minute upon exposure to varying concentrations of Co2+ ions. Moreover, this composite demonstrates high efficiency in removing Co2+ in polluted wastewater samples and recovering Co2+ ions from lithium-ion batteries, with a high efficiency of up to 79.5 % for Co2+ ions recovery from lithium-ion batteries and removal efficiency of 97.35 % for Co2+ from wastewater samples. This capability addresses critical environmental concerns associated with wastewater treatment and lithium-ion battery waste and provides a practical and sustainable approach for reclaiming valuable Cobalt ions.