Challenges and advances in nanocellulose-based adsorbents for dye removal: mechanisms and future directions

The rapid growth of the textile industry has led to a sharp increase in dye-filled wastewater, posing a significant environmental concern. Adsorption is a promising method for dye removal, but traditional adsorbents often fall short due to limited capacity, lack of sustainability, and low selectivity. Nanocellulose-based materials have shown great potential, with some achieving high adsorption capacities, such as 3429.23 mg/g for Congo Red on cellulose-based aerogel and 2282.3 mg/g for malachite green on magnetic nanocellulose-based adsorbents. These adsorbents follow various adsorption models, including Langmuir and Freundlich isotherms, and kinetic models such as the pseudo-second-order model indicating strong interactions with target dyes. This review thoroughly examines nanocellulose-based adsorbents, exploring their types, properties, and preparation methods. This review analyses dye interactions, including factors influencing adsorption, and provides an in-depth look at adsorption kinetics, isotherms, and thermodynamics. Also, this review aims to clarify the true potential of nanocellulose-based adsorbents for dye removal, summarizing recent advancements while identifying research gaps and future directions to support further development in this field.