Iron or Fe is classified as a metal that has low toxicity, but if the concentration exceeds the quality standard, it can potentially cause pollution to the environment. This study aims to make activated carbon from rubber seed coat shells as an adsorbent for artificial Fe liquid waste using Fe2(SO4)3. 05 grams of activated carbon was activated using a ratio of 2:1, 3:1, 4:1 (NaOH: charcoal), and then an FTIR test was carried out to see the characteristics of the activated carbon. Measurement of Fe concentration using UV-VIS spectrophotometry, with various concentrations of 1, 1.5, 2, 2.5, 3, 4, 6, and 10 mg/L. After that, an analysis of the effect of contact time with the addition of activated carbon as an adsorbent for heavy metal Fe liquid waste was carried out, using variations of 05, 10, 15, 20, 30, 45, 90, and 120 minutes. An analysis of the effect of Fe concentration, with various concentrations of 10, 20, 30, 40, and 50 mg/L. Obtained from the linear equation of the calibration curve y = 0.0679x - 0.0013 with a correlation coefficient of 0.9996. The results of the third FTIR test showed that the ratio of NaOH and carbon activators did not change significantly. The functional groups that appeared were O-H, C=O carboxylate, C-C-C, aromatic C-H, aromatic C=C, C-O, and Si-O. Activated carbon 2:1, 3:1, and 4:1 have an absorption percentage of 86.72%, 89.45% and 96.37%. The greatest absorption efficiency is at a ratio of 4:1, optimum at 90 minutes. Sample 2:1 has an adsorption capacity of 0.163 mg/g, sample 3:1 of 0.259 mg/g, and 4:1 of 1.340 mg/g. The greatest adsorption capacity of activated carbon is at a ratio of 4:1, adsorption occurs physically (Freundlich) with a multilayer layer.Iron or Fe is classified as a metal that has low toxicity, but if the concentration exceeds the quality standard, it can potentially cause pollution to the environment. This study aims to make activated carbon from rubber seed coat shells as an adsorbent for artificial Fe liquid waste using Fe2(SO4)3. 05 grams of activated carbon was activated using a ratio of 2:1, 3:1, 4:1 (NaOH: charcoal), and then an FTIR test was carried out to see the characteristics of the activated carbon. Measurement of Fe concentration using UV-VIS spectrophotometry, with various concentrations of 1, 1.5, 2, 2.5, 3, 4, 6, and 10 mg/L. After that, an analysis of the effect of contact time with the addition of activated carbon as an adsorbent for heavy metal Fe liquid waste was carried out, using variations of 05, 10, 15, 20, 30, 45, 90, and 120 minutes. An analysis of the effect of Fe concentration, with various concentrations of 10, 20, 30, 40, and 50 mg/L. Obtained from the linear equation of the calibration curve y = 0.0679x - 0.0013 with a correlation coefficient of 0.9996. The results of the third FTIR test showed that the ratio of NaOH and carbon activators did not change significantly. The functional groups that appeared were O-H, C=O carboxylate, C-C-C, aromatic C-H, aromatic C=C, C-O, and Si-O. Activated carbon 2:1, 3:1, and 4:1 have an absorption percentage of 86.72%, 89.45% and 96.37%. The greatest absorption efficiency is at a ratio of 4:1, optimum at 90 minutes. Sample 2:1 has an adsorption capacity of 0.163 mg/g, sample 3:1 of 0.259 mg/g, and 4:1 of 1.340 mg/g. The greatest adsorption capacity of activated carbon is at a ratio of 4:1, adsorption occurs physically (Freundlich) with a multilayer layer.