In this work, agro-industrial wastes such as sugarcane bagasse and orange peel were used for obtaining activated carbons through phosphoric acid activation in order to propose them as adsorbent materials during the production of carbon foam or filters for wastewater treatment applications. A two-step process was carry out to obtain activated carbons; the first step consisted of a simple physical activation at high temperature 400 °C to reach raw material decomposition; followed by acid activation at temperature of 500 °C. The effect of concentration of acid media (45, 65 and 85 wt.%) was analyzed in terms of the thermal stability, sorption, textural and structural properties. Surface area increases with the concentration of activation media, which is ranging from 114.08-355.52 m² g-1, 49.54-228.90 m² g-1 for sugarcane bagasse and orange peel, respectively. Fourier transform-infrared spectra showed the presence of functional C-O-P group, which confirmed with the thermal stability of the samples. The produced carbon foams showed a two-level cell structure with bubble and bar-like structures that increase the pore quantity in the carbon foams.