Adsorption of Azo Dyes by a Novel Bio-Nanocomposite Based on Whey Protein Nanofibrils and Nano-clay: Equilibrium Isotherm and Kinetic Modeling

Abstract

Excessive discharge of hazardous azo dyes into aquatic ecosystem is a global environmental concern. Here, we develop a green approach to remediate dye pollutions in water by fabricating an easy separable bio-nanocomposite, based on whey protein concentrate, its nanofibrils and montmorillonite nano-clay. Nanofibrils lead to a uniform dispersion of montmorillonite in the whey protein matrix and also reinforce the nanocomposite. The adsorption efficacy was monitored in a batch system, using cationic dyes (Chrysoidine-G, Bismarck brown-R), reactive dyes (reactive black-5, reactive orange-16), acid dyes (acid red-88, acid red-114), and direct dyes (direct violet-51, Congo red). This nanocomposite adsorbed different dye classes, cationic dyes quicker (>82%, after 4 h) and reactive dyes slower. Then, the effect of dye concentration, contact time and adsorbent dose on Chrysoidine-G adsorption was explored. The adsorbent showed a high removal (>93%) for a wide concentration range of Chrysoidine-G. Equilibrium adsorption parameters were reasonably fitted with a linear (Nernst) isotherm model, while kinetic data were fitted with pseudo-second-order and intra-particle diffusion models. To characterize the nanocomposite, we used SEM, FT-IR, XRD and BET techniques. We conclude that this nanocomposite is a green adsorbent with potential use for wastewater treatment and related purposes.HighlightsWe produced a novel bio-nanocomposite using whey nanofibrils and MMTNanofibrils help disperse MMT particles uniformly in the WP matrixThe adsorbent’s performance was compared to the adsorbents in absence of MMT and nanofibrilsThis composite adsorbs cationic, anionic, direct and reactive azo dyes with different kineticsAdsorption isotherms and kinetics are studied in detailAbstract Figure

A Facile Review on the Sorption of Heavy Metals and Dyes Using Bionanocomposites

“…A green technique was used to create a BNC-based protein concentrate; its nanofibrils and montmorillonite nanoclay (WPF/MMT) were employed for the removal of cationic dye (Chrysoidine-G (CG), Bismarck brown-R (BBR)), acid dyes (acid red-88 (AC88), acid red-114 (AR114)), direct dyes (direct violet-51 (DV51), congo red (CR)), and reactive dyes (reactive black-5 (RB5), reactive orange-16 (RO16)). It was observed that the BNCs sorbed the CG cationic dye much faster than the other dye type, and with a greater than 93% removal efficiency for a wide concentration range of CG dye, while the PSO and the linear Nerst models best depict the sorption of these dyes to the BNCs [21].…”

“…Protein-based sorbents have distinct advantages over traditional polysaccharide-based adsorbents like CLL, chitosan (CS), and lignin due to their structural and chemical diversity. Furthermore, certain proteins can self-assemble and transform into highly organized nanofibrils that can withstand high temperatures and salt concentrations and have strength and stiffness similar to steel and silk [21].…”