*2.1. Materials*

Nata de coco (BC pellicles) was collected from a local market, in Cilegon (Banten, Indonesia) region. Sodium hydroxide, NaOH, hydrochloric acid, HCl, and ethanol, C2H5OH were obtained from Thermo Fischer Scientific. Metal chlorides MnCl2, FeCl3.6H2O were purchased from Merck Indonesia (Jakarta, Indonesia). Commercial Microcrystal Cellulose, MCC was purchased from Sigma-Aldrich (Saint-Quentin, France) and Commercial Nanocrystal Cellulose, NCC from CelluForce, QC, Canada. All the reagents and chemicals are used as a laboratory grade without further purification. Demineralized water (conductivity of 0.06 mScm−1) produced by a purification chain was used for all experiments.
