Nanocellulose from Rice Husk and Sugarcane Bagasse: Measurement, Reporting, and Functional Interpretation

Converting rice husk and sugarcane bagasse into nanocellulose requires measurements that distinguish material recovery, composition, surface chemistry, and application performance. This critical review examines 41 selected studies, including 23 with extractable numerical examples and 18 used for contextual interpretation. A recorded Scopus search dated 22 September 2026 informs the source documentation, but retrospective selection and inconsistencies between the available inventories prevent an exhaustive systematic-review claim. Nine studies underwent targeted full-text checks, and two further full articles were checked during revision; 12 numerical examples remain dependent on abstracts and metadata. Descriptive synthesis preserves study-specific denominators, methods, and comparators. In bagasse, increasing NaClO from 9 to 12 mmol g−1 increased nanofibrillation from 85% to 86%, without increasing carboxyl content or modulus. CNC loading increased EPDM tensile strength from 2.68 to 10.82 MPa at 8 phr, followed by a decline at 10 phr. Succinylated CNCs adsorbed 184.2 mg g−1 Pb2+ and 157.1 mg g−1 Cd2+ at the reported concentration of 280 ppm. These observations support within-study interpretation, rather than feedstock ranking. An operational framework distinguishes directly comparable, conditionally comparable, and non-comparable measurements. Life-cycle, cost, and service-performance evidence further shows why a laboratory improvement does not establish an environmental or economic advantage.