Pratiwi, D., Udaibah, W., & Kustomo, K. (2021). Synthesis of Hydrochar Cassava peels with hydrothermal carbonization method and applications as hard water softener. Journal of Natural Sciences and Mathematics Research, 7(1), 34-43. doi:https://doi.org/10.21580/jnsmr.2021.7.1.11283