Synthesis of Activated Carbon Composited With Egyptian Black Sand for Enhanced Adsorption Performance toward Methylene Blue Dye

Abstract The present study reports the feasibility of the synthesis of a novel porous activated carbon (OS400) composite adsorbent prepared from olive stone and impregnated with garnet (GA) types of black sand minerals. The Activated Carbon/ garnet composite (OSMG) was applied for the sorption of macromolecular organic dye. The structural characteristics of the synthesized composite were evaluated by Brunauer–Emmett–Teller (BET), N2 adsorption/desorption measurements, Scanning Electron Microscopy equipped with Energy Dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and a Fourier transform infrared spectrometer (FT-IR). The specific surface area of (GA), (OS400), and (OSMG) were 5.157 m2.g− 1, 1489.598 m2.g− 1, and 546.392 m2.g− 1, respectively. The high specific surface area and effective active centers of the new composite promoted the adsorption of methylene blue (MB). The experiments were carried out under various conditions such as contact time, initial concentration of adsorbate, adsorbent dosage, pH, and temperatures. The equilibrium adsorption data were evaluated using the Langmuir and Freundlich isotherm models. The results display that, the adsorption isotherm had an excellent fitting to the Freundlich model. Furthermore, the data obtained from adsorption kinetic models showed that the pseudo-second-order model more agreeing for describing the (MB) adsorption reaction, suggesting a chemisorption mechanism. The values of thermodynamic parameters indicate that methylene blue dye adsorption onto the (GA) adsorbents through an endothermic reaction, while exothermic sorption of MB onto (OS400) and (OSMG), with a non-spontaneous process.