Activated carbon photocatalyst with high surface area has been synthesized and modified with iron oxide nanoparticles by microwave heating technique. The surface-modified microporous activated carbons were characterized by BET surface area and XRD analysis. Degradation experiments were conducted in batch mode with the variables such as contact time (0-120min), photocatalyst dosage (0.01-0.2g/L), initial solution concentration (50-150mg/L), and solution pH (2-10). The iron oxide-modified activated carbon (3-Fe-MAC) was found to be more active compared to the free iron oxide nanoparticles and pristine activated carbon for methylene blue (MB) degradation. Kinetic studies on the photocatalytic degradation of MB using zeros, linear regression data suggested that the degradation followed first-order kinetics. The optimal conditions for the degradation of MB dye were 75min, 100ppm dye concentration, neutral pH, and 0.13mg/L of 3-Fe-MAC dosage.