In this work, some adsorbent materials were prepared from residual biomass, which constitutes a real hazard for the environment and human health. So, in order to valorize this vegetal resource, a process of transformation was studied. The residual biomass was turned into adsorbent materials under the effect of chemical activation with phosphoric acid which allows the development of a large pore in the activated materials. The optimization of the conditions for the elaboration of our adsorbents was realized by experimental design by evaluating some parameters (percentage of phosphoric acid, temperature and time of activation) and their effects on the responses (capacity of adsorption of methylene blue, adsorbent yield), these parameters were selected after a screening study. The activation of our residual biomass was effected with 60% of phosphoric acid in 225°C while 115 min. The studied biomass was characterized by different physic-chemical methods (Differential Thermal Analysis /Thermogravimetric Analysis (DTA/TGA), Scanning Electron Microscopy (SEM), Raman and X-Ray Diffraction (XRD)); the results of characterization show the presence of the excellent textural and structural properties. The application of the best adsorbent in the removal of textile dyes (methylene blue) from aqueous solutions was studied. The impact of various parameters such as contact time, pH and concentration on the removal was evaluated by batch method. The adsorption isotherms were studied using Langmuir and Freundlich isotherm models. Langmuir isotherm provided the best fit to the equilibrium data with a correlation coefficient equal to 0.998. This result shows the presence of monolayer adsorption. The experiments demonstrated that the removal of methylene blue followed the pseudo-second-order kinetic model. The correlation coefficient is consistent and equal to unity, and the experimental qe value (44.17) was agreed with the calculated qe value (45.45) of pseudo-second-order then the value of pseudo-first-order which confirm a chemisorption process. The obtained results revealed that the elaborated material is an effective adsorbent for the removal of methylene blue.

The present article aims to optimize the decarbonization of Timahdit oil shale layer Y by removing carbonates from the raw rock using acetic acid. The response surface methodology “central composite design (CCD)” has been used as a method of optimization to study the 3 factors of the process. The factors studied are the concentration of the acid, the processing time, and the ratio (liquid/solid). The optimal conditions with 68.17% of residue rate are obtained with 2 mol/l as concentration, 120 min as a time of treatment and 10.02 for the ratio.The raw (Y) and optimized materials (YO) were characterized by Scanning Electron Microscopy (SEM), X-ray fluorescence (XRF) and X-ray diffraction (XRD). The results showed that the acetic acid used to remove carbonates affects the chemical composition and the texture evolution of the residues.

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