Iron (Fe) pollution in Indonesian waters frequently exceeds health thresholds, necessitating the development of efficient biomass-based adsorbents, such as tuna bone. This study aims to analyze the characteristics of yellowfin tuna bone (Thunnus albacares) activated carbon activated with phosphoric acid (H3PO4) and its effectiveness as an iron (Fe) adsorbent. The research methods included preparation, carbonization at 300°C, and chemical activation using various H3PO4 concentrations (3M, 5M, and 7M) for 24 hours. Activated carbon characterization was conducted through moisture content, ash content, iodine absorption tests, and SEM-EDS analysis. Fe adsorption tests were performed at concentrations of 5, 10, and 20 ppm using Atomic Absorption Spectrophotometry (AAS). The results indicated that increasing H3PO4 concentration decreased ash content and enhanced iodine absorption. Activation with 7M H3PO4 yielded the best characteristics, featuring an ash content of 0.53%, an iodine absorption of 716.99 mg/g, and a porous surface morphology. In adsorption testing, the 7M activated carbon was most effective at a high Fe concentration (20 ppm) with an efficiency of 61.52% and an adsorption capacity of 2.46 mg/g. Further research may focus on optimizing adsorption parameters such as pH, contact time, temperature, and adsorbent mass, as well as using FTIR analysis to identify the functional groups present in the adsorbent.
Copyrights © 2026