The development of nanoadsorbents for remediation of polluted water in order to obtain clean and healthy water quality has been carried out, namely the incorporation of Chitosan (K)-Magnetic (M)-Activated Carbon (K) materials. The activated carbon used is the result of the synthesis of banana peel waste nanocrystals, while the magnetic is Fe3O4. The method used in this study is an experimental method with coprecipitation through several stages, namely (1) magnetic synthesis of Fe3O4 by thecoprecipitation method, (2) preparation of chitosan solution, (3) synthesis of activated carbon nanocrystals from banana peel waste by the milling process, (4) merger of the three materials, and (5) characterization with SEM/EDX, XRD, FTIR, BET, PSA, TGA, and AAS to test the performance of the material against polluted water.The study found that 210 minutes was the optimal time for the heavy metal ions Fe, Mn, Zn, and Pb to adsorption.The best sample was sample S4 with a ratio of 1:2:2 with adsorption for Zn 92.43%, Fe 95.44%, Mn 89.54%, and Pb 84.38%. For the heavy metal ions: Mn 5624 mg/g, Fe 5849.4 mg/g, Zn 4894.22 mg/g, and Pb 468.2 mg/g, the Langmuir model was used. The adsorption kinetics showed that the reaction order for Pb, Mn, Zn, and Fe ions varied with pseudo-first order and pseudo-second order. CMC nanoadsorbents are effective in remediating the water contaminated with heavy metals, such as Pb, Mn, Zn, and Fe, meeting the environmental health quality standards for water media for sanitation hygiene purposes.