The Oxidation of Nanocellulose from Oil Palm Empty Fruit Bunch (OPEFB) by TEMPO/NaClO/NaBr

One of the largest biomass wastes in Indonesia is oil palm empty fruit bunch (OPEFB), which produces thousands of tons of waste in a year. The value of biomass can be upgraded to nanocellulose-based adsorbents. Cellulose is extracted through three processes: delignification, bleaching, and hydrolysis. In this study, nanocellulose was oxidated with TEMPO (2,2,6- tetramethylpiperidine-1-oxyl radical)/NaClO/NaBr at pH 10 in a temperature room. The influence of oxidizer (NaClO 2, 4, 6, 8, and 10 mmol/gram) and catalysator (NaBr 25, 50, 100, 150, 200 mg/gram) in the formation of carboxylate groups and reaction time was studied. After the pretreatment process, cellulose content in the final product reached 61.8% with a crystallinity index of 58%. With lengths ranging from 127.4 nm to 512 nm and a diameter of less than 20 nm, nanocellulose is classified as cellulose nanofiber. Conductometry titration is used to find the carboxylate group formed on the nanocellulose surface. The highest carboxylate groups were found in 1,600 mmol/gram by adding 20 mmol/gram NaClO. As the addition of oxidants, degradation of nanocellulose occurred, which was indicated by a decrease in nanocellulose weight and shifting of function groups. All the reaction processes happened below 25 minutes, increasing the reaction rate by adding more than 50 mg/gram NaBr.