The fashion industry's reliance on dyes contributes significantly to environmental pollution, which disturbs the ecological balance. To address this issue, we used ZnO/Mg combined with activated carbon (AC) at various concentrations (0.1g, 0.5g, and 1g), which were synthesized via sol-gel and mechanical alloying processes. The analysis of X-ray diffraction shows reduced crystallite size, with d-spacing change ( d ) for ZnO/Mg/AC (0.5g) and ( d ) for ZnO/Mg/AC (1g), respectively. The results of the IR spectrum indicated the main vibrations is MgO and Zn-O bonds at wave numbers 673cm-1 and 467cm-1. It was found that ZnO/Mg/AC (1g) shows high degradation performance : 86.15% as a consequence of reduced crystallite size: 22.67nm, decreased skin depth: 0.002cm, widening of optical phonon vibration ( ): 252cm-1 and increased : 4.6eV as a function AC variation. Moreover, the finding of high photocatalytic performance 80% for 0.25mLMB dissolved in 250mL distilled water is obtained from all composites. Based on these results, ZnO/Mg/AC shows potential as a photocatalyst to solve the MB waste problem.