Napitupulu, M., Walanda, D.K., Natakusuma, Y., Basir, M. and Mahfudz 2018. Capacity of Adsorption of Cadmium (II) Ion by Bio-charcoal from Durian Barks. Journal of Surface Science and Technology. 34, 1-2 (Jun. 2018), 30–36. DOI:https://doi.org/10.18311/jsst/2018/11055.