Nouveaux adsorbants préparés par activation chimique des schistes bitimineux marocains par l’acide phosphorique : influence des conditions expérimentales sur les propriétés des adsorbants

New adsorbents were prepared from Moroccan oil shale of Tarfaya (layer R3) by chemical activation with phosphoric acid. The objective was to investigate different factors that control the activation process, in order to determine the optimum conditions of preparation. The examined factors were holding time in the oven, pre-processing and atmosphere (N-2/air). The impact of the different factors was investigated by determining the yield of adsorbent and the maximum capacity of adsorption for methylene blue. Due to the existence of numerous factors, a two-level factorial design was used to find the most influential factors and their mutual interactions. The results of this study yielded the following classification of the factors: atmosphere, pre-processing, activation temperature and holding time in the oven. The best properties were found for a particular combination of the chosen parameters: temperature and activation time equal to 250 degrees C and 2 hours, respectively, in air. The adsorption capacity for methylene blue and specific surface area (SBET) of this adsorbent were 500 mg/g and 600 m(2)/g, respectively. Furthermore, in these conditions the adsorbent developed important surface functions.