Visible light induced photo catalytic degradation of dyes is an inviting approach in wastewater treatment techniques. In this study, silver loaded alumina was synthesized by immobilization of Ag nanoparticles on Al2O3 by facile green method with Azadirachta indica leaves extract and characterized by different advanced techniques. The prepared Ag-Al2O3 particles were tested as photo catalyst on degradation of methylene blue under visible irradiation. Ag-Al2O3 showed improved photo catalytic performance on photo degradation of methylene blue. The deposition of Ag enhanced the photo catalytic activity of Al2O3 from 35 to 95% degradation of methylene blue. Effect of various parameters on catalytic activity were investigated. Curve Expert computer program was used for kinetics analyses of the data according to Langmuir-Hinshelwood and Eley-Rideal mechanism. A 100 mg L-1 solution (50 mL) completely degraded in 120 min of reaction duration at 50 degrees C over 0.1 g of 3% Ag-Al2O3 as catalyst. 0.01, 0.06 and 0.08 min(-1) were calculated as average rate constants at 30, 40 and 50 degrees C respectively. 25.7 kJ mol(-1) was calculated as average activation energy. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.