Microwave-assisted preparation and adsorption performance of activated carbon from biodiesel industry solid reside: Influence of operational parameters

► Highlight the renewable use of biodiesel industry solid residue. ► Evaluate the effects of impregnation ratio, microwave power level and radiation time. ► Short activation time of 7 min and low chemical impregnation ratio of 1:1. ► High BET and Langmuir surface area of 1372 and 2058 m2/g, respectively. ► Monolayer adsorption capacity of 395.30 mg/g for methylene blue and carbon yield of 73.78%.