Cellulose nanofiber aerogel-encapsulated GO@LDH nanocomposite for effective simultaneous removal of copper(II) and chromium(VI) contaminants

This work engineered an innovative cellulose nanofibrils aerogel-immobilized graphene oxide (GO)/magnesium–aluminum layered double hydroxide (LDH) nanostructure (LDGC) for the effective simultaneous sequestration of Cu(II) and Cr(VI) ions in aqueous solution. The composite was synthesized through a facile physical encapsulation method, combining the high porosity of cellulose nanofiber (CNF) aerogels with the multifunctional adsorption sites of GO@LDH. Structural analysis demonstrated that LDGC possessed a markedly increased specific surface area (43.78 m 2 ·g −1 ) relative to its constituent materials, coupled with a high density of oxygen-functionalized moieties conducive to heavy metal coordination. Batch adsorption studies revealed outstanding simultaneous removal performance (85 mg·g −1 for Cu(II) and 88 mg·g −1 for Cr(VI) in binary-component systems), representing 318% and 161% improvement compared to single-ion conditions, respectively. Kinetic analyses aligned with the pseudo-second-order model (R 2  > 0.99), suggesting predominant chemisorption mechanisms. The composite maintained > 93% efficiency after 4 regeneration cycles and showed strong resistance to common interfering ions (Ca 2 ⁺/SO 4 2 ⁻ increased adsorption by 92–105%). This work provides a sustainable strategy for simultaneous heavy metal removal, addressing critical challenges in wastewater treatment through rational design of multifunctional nanocomposites.