A Review on Advances in the Use of Raw and Modified Agricultural Lignocellulosic Residues in Mono- and Multicomponent Continuous Adsorption of Inorganic Pollutants for Upscaling Technologies.

Using raw and modified lignocellulosic residues as bioadsorbents in continuous adsorption is challenging but it marks significant progress in water treatment and the transition to a bio-based circular economy. This study reviews the application of bioadsorbents in fixed-bed columns for treating water contaminated with inorganic species, offering guidance for future research. It evaluates chemical modifications to enhance adsorptive properties, explores adsorption mechanisms, and analyzes bioadsorbent performance under competitive adsorption conditions. Analysis of adsorption data included evaluation of adsorption capacity in mono- and multicomponent solutions, regeneration, reuse, bed efficiency, and disposal of spent bioadsorbents. This enabled assessing their scalability to sufficiently high levels of maturity for commercialization. In multicomponent solutions, selectivity was influenced by the characteristics of the bioadsorbents and by competitive adsorption among inorganic species. This affected adsorption performance, increasing the complexity of breakthrough curve modeling and controlling the biomaterial selectivity. Models for mono- and multicomponent systems are presented, including mass transfer equations and alternatives including "bell-type" equations for overshooting phenomena and innovative approaches using artificial neural networks and machine learning. The criteria discussed will assist in improving studies conducted from cradle (synthesis of new biomaterials) to grave (end use or disposal), contributing to accurate decision making for transferring the developed technology to an industrial scale and evaluating the technical and economic feasibility of bioadsorbents.