Sustainable nanoarchitectonics of cellulose-derived spherical activated carbon for efficient uremic toxin removal in pharmaceutical applications

• Cellulose-derived spherical carbons (SACs) synthesized via steam activation. • SAC100 achieved 2334 m 2 g −1 area and 762 mg g −1 indole uptake, exceeding Kremezin®. • High selectivity retained for α-amylase and β-aminoisobutyric acid. • Cellulose-derived SACs provide sustainable, biocompatible CKD therapy option. Activated carbon adsorbents are essential in pharmaceutical applications for removing uremic toxins in chronic kidney disease (CKD) patients. However, commercial petroleum-based products such as AST-120 (Kremezin®) require high dosages (2 g, three times daily) and face limited patient compliance. In this study, spherical activated carbons were synthesized from renewable microcrystalline cellulose via direct carbonization and steam activation under optimized conditions. The resulting materials retained uniform spherical morphology and exhibited hierarchical pore structures. The smaller-precursor carbon exhibited a BET surface area of 2,334 m 2 g −1 , high carbon purity (96.3 %), and superior adsorption performance, achieving an indole uptake of 762.2 mg g −1 , exceeding that of Kremezin® (637.1 mg g −1 ). It further showed enhanced selectivity, retaining 81.3 % of α-amylase and 91.7 % of DL-β-aminoisobutyric acid in solution. Selectivity indices reached up to 95.28, indicating effective discrimination between toxins and essential biomolecules. These findings highlight the potential of cellulose-derived spherical carbons as high-performance, biocompatible alternatives for oral adsorbent therapies. Their enhanced adsorption capacity, reduced non-specific interactions, and sustainable origin support their applicability in next-generation CKD treatment platforms, potentially contributing to improved patient compliance.