A one-step FeCl3-facilitated carbonization/activation of a new precursor, namely Vicia faba L. Peels (VFPs), was developed to synthesize a novel microporous magnetic activated carbon (MMAC) for efficient elimination of methylene blue dye (MB) from wastewater and dibenzothiophene (DBT) from model fuel. The typical MMAC was produced using a 1.5:1 FeCl3:VFPs impregnation ratio at 750 °C for 90 minutes, with a 10 °C/min heating rate. This adsorbent was characterized using various techniques (XRD, FESEM, EDX, N2 adsorption-desorption, and VSM) to assess its crystallinity, morphology, texture, and magnetic properties. The BET surface area of the produced MMAC was 1224.80 m2/g, with a mean pore diameter of 1.91 nm. The VSM measurements confirmed the magnetic features of the resulting adsorbent, with a magnetization of 0.085 emu/g. The superior elimination of MB from its aqueous phase (200 mg/L) using the resulting MMAC reached 99.30% with 0.15 g of MMAC at 30 °C for 50 minutes and a pH of 9.0. At the same time, the maximum removal of the sulfur compound from the model (200 mg/L) amounted to 97.93 % using 0.35 g of the MMAC at 30 °C for 40 minutes. The adsorption of both contaminants from their liquid phases was better described by the Langmuir isotherm and the pseudo-2nd-order kinetic model than by other models. The maximum adsorptive capacity for MB was 331.50 mg/g compared with 31.83 mg/g for DBT at the typical working variables. Under typical experimental conditions, desulfurization of real oil fuel amounted to 62.22%. At the same time, the elimination of MB from its solutions in river and well waters was, respectively, 91.04% and 80.12 %. Reusability of the studied pollutants over the regenerated adsorbent under the optimal working conditions exhibited an elimination performance of both contaminants above 90%. In conclusion, using agricultural solid waste for the eco-friendly preparation of novel adsorbents promotes sustainability and effective waste management.