Gentian violet adsorption on a super magnetic nanocomposite (Fe2O3/Bentonite), non-linear kinetic and isotherm modeling

The health of humans may be at risk from textile wastewater's harmful dye effluents. Searching for effective and inexpensive adsorbents to treat these contaminated waters has attracted a lot of interest over the years. This work aimed to prepare a super nanocomposite based on raw bentonite to remove a cationic dye (gentian violet) from wastewater. Raw and Magnetic bentonite have been characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF). The specific surface area calculated by BET transform for both adsorbents show a high specific area for magnetic bentonite, four times higher than the raw one, it is estimated to 10.3452 and 41.6073 m2. g-1 for raw and magnetic bentonite respectively. A UV-Vis spectrophotometer has also characterized the gentian violet dye (GV). Kinetic non-linear models confirm that the adsorption phenomena are well modeled by the pseudo second order model, and thermodynamic studies show that it is also a spontaneous, endothermic, and inorganized process. The non-linear adsorption isotherm results were best fitted using the Langmuir isotherm, which refers to monolayer adsorption. The effect of some parameters, such as adsorbent mass, temperature, and contact time, has also been optimized. From these results, we concluded that supporting iron oxide on bentonite can increase the adsorption capacity, with a maximum Langmuir monolayer adsorption capacity qm= 137.39 mg. g-1.