Yusmartini, Eka Sri, et al. “Characterization and Adsorption Effectiveness of Coconut Shell-Activated Carbon Fe₃O₄ As Novel-Adsorbent on Copper Removal from Wastewater”. Global Journal of Engineering and Technology Research, vol. 1, no. 04, Dec. 2025, pp. 193-8, https://doi.org/10.65150/EP-gjetr/V1E4/2025-05.