Adsorption of the Methylene Blue Dye in Environmental Water Samples by Biochar Obtained from the Valorization of Argan Shells

Biochar is an adsorbent material widely used to remove pollutants from industrial discharges. This research focuses on the adsorption capacity of Biochar, obtained by thermal decomposition of Argan shells, to remove methylene blue from aqueous solutions. The influence of some parameters such as carbonization time and temperature on the burn-off and adsorption capacities of this material was studied. A temperature of carbonization of 900 °C and a carbonization time of 2 hours are considered as the optimum conditions for the preparation of this adsorbent. The burn-off, methylene blue adsorption amount, and iodine number of the prepared activated carbon under the optimal conditions were 84.6 %, 19.9 mg g-1 and 431.8 mg g-1, respectively. The powder obtained was characterized by performing the following analyses : pHpzc, SEM, FT-IR, DRX, and TGA-DTG. It was then tested for its ability to remediate methylene blue in water by varying the carbon dosage, contact time, initial concentration and pH. The adsorption kinetics was consistent with the pseudo-second-order model. To analyze the experimental data, Langmuir, Freundlich, and Temkin models were studied. The equilibrium data are in agreement with the Langmuir model with a monolayer maximum adsorption capacity of 31 mg g-1.