<p>A BiMgFeO₄/activated carbon (BiMgFeO₄/AC) composite was synthesized via a glycine-assisted self-combustion method and evaluated as an adsorbent for the removal of methyl orange (MO) and methyl green (MG) from aqueous solutions. The structural and textural properties were investigated using SEM, FTIR, XRD, and N₂ adsorption–desorption analyses. SEM observations revealed a porous microstructure favorable for dye diffusion, while BET analysis confirmed a mesoporous structure with an average pore diameter of 7.54 nm. FTIR analysis confirmed the presence of characteristic metal–oxygen bonds and surface functional groups and XRD patterns evidenced the presence of Fe₃O₄, MgO, and Bi₂O₃ phases, confirming the successful formation of the composite. Adsorption experiments examined the effects of temperature, contact time, initial dye concentration, and adsorbent dose. Equilibrium data were well described by both Freundlich and Langmuir isotherm models. The maximum adsorption capacities reached 196.08 mg g⁻¹ for MO and 192.31 mg g⁻¹ for MG at 298 K. Kinetic studies showed that the adsorption process followed a pseudo-second-order model and reached equilibrium within 120 min. Weber–Morris intraparticle diffusion and Boyd models revealed distinct mass-transfer mechanisms for the anionic (MO) and cationic (MG) dyes. Thermodynamic parameters confirmed that adsorption was spontaneous and exothermic, governed predominantly by physical interactions. Overall, the BiMgFeO₄/AC composite shows good adsorption performance for dye removal, offering a promising strategy for wastewater remediation.</p> Graphical abstract <p></p>