Surface cationization of cellullose via Fenton oxidation for remedying dye contaminants: Adsorption performance and mechanism

Targeted modification of cellulose corresponds to the physicochemical characteristics of dyes is advantageous to increase its adsorption capacity, but which is still exclusive. Here, a Fenton oxidation system was applied to fabricate microcrystalline cellulose (MCC) supported iron (Cel@Fe). Physicochemical property analysis elucidated that the incorporation of Fe nanoparticles tuned the surface charge for oxidized MCC. The carboxyl groups from partial oxidation of MCC could chelate Fe 2+ or Fe 3+ ions, forming [cellulose-Fe ion (H 2 O) x ] complexes. Polyaromatic 1,9-dimethylmethylene blue (DMB) and acid yellow 79 (AY79) were used as the modeling dyes to evaluate the adsorption capacity of cationized Cel@Fe. With a theoretical maximum adsorption capacity of 255.1 mg/g for AY79 on [email protected] and 79.2 mg/g for DMB on MCC, adsorption matched the pseudo second order ( R 2  = 0.999) and the Langmuir isotherm ( R 2  = 0.999) models for both dyes. The adsorption for AY79 on Cel@Fe was found to be primarily dependent on electrostatic interactions, atomic non-covalent interactions (Fe O), and steric effect, according to the reduced density gradient (RDG) Gaussian density functional theory (DFT) calculation. This work presents a promising strategy to synthesize cationized and sinkable cellulose adsorbent for efficient decontamination of wastewater containing dyes.