Recent advances in lignocellulose-derived nanomaterials for sustainable wastewater remediation

Heavy metal contamination in wastewater poses a critical global environmental challenge due to the persistence, toxicity, and bioaccumulative behaviour of these pollutants. Despite significant progress in wastewater treatment technologies, developing efficient, cost-effective, and sustainable methods for heavy metal removal remains a critical concern. In this context, lignocellulose-derived nanomaterials have emerged as renewable, eco-friendly alternatives to conventional adsorbents, supporting the global transition toward sustainable water treatment solutions. This review provides a comprehensive overview of the synthesis, modification, and functionalization of lignocellulose-based nanomaterials, with particular focus on nanocellulose and nanolignin, and their application in heavy metal remediation. The adsorption behaviour of these materials is critically analyzed in terms of mechanisms, kinetics, isotherm models, and thermodynamic parameters. Due to their high surface area, abundant functional groups, and tunable chemistry, nanoscale cellulose and lignin exhibit excellent affinity and adsorption capacity toward diverse heavy metal ions. Recent developments in nanocellulose-based membranes and filtration systems for efficient separation and purification of contaminated wastewater are discussed. Various reactor configurations, including batch, continuous-flow, fixed-bed, and fluidized-bed systems, are evaluated for adsorption efficiency, scalability, and operational feasibility. Progress in process optimization and reactor integration for large-scale applications is also highlighted. Moreover, the techno-economic feasibility, commercialization potential, limitations, and future research directions of lignocellulose-derived nanomaterials are critically assessed. Collectively, these materials represent a sustainable and versatile platform for next-generation wastewater treatment, directly supporting SDG 6 (Clean Water and Sanitation) and contributing to SDGs 12 and 13 by promoting innovation, resource efficiency, and climate-resilient solutions.