Magnetic pomegranate peels activated carbon (MG-PPAC) composite for Acid Orange 7 dye removal from wastewater

A magnetic pomegranate peels activated carbon (MG-PPAC) nanocomposite (23.46–26.75 nm) was prepared as an effective adsorbent for Acid Orange 7 (AO7) dye removal from wastewater. The effects of impregnation ratio and activation temperatures (600–900 °C) on the specific surface area and pore morphology were studied. BET, SEM, EDX, FT-IR, XRD and VSM are considered the synthesized composite MG-PPAC. The prepared magnetic composite at 700 °C activation temperature and impregnation ratio 1/2 (peels/ZnCl₂) exhibited 513.34 m²/g surface area, 0.4025 cm³/g volume of the total pores, and 3.1364 nm mean diameter of the pores. The magnetization saturation, remanence and coercivity of the MG-PPA composite were 14.116 emu/g, 0.50685 emu/g, and 19.705 G, respectively. Also, the composite MG-PPAC was in a super-paramagnetic state at room temperature and could be gathered within 5 S (less than 5 S) with an external magnetic field. The impact of pH, adsorbent dose, initial concentration of adsorbate (AO7 dye), and time of contact have been studied to optimize the removal process. Langmuir, Freundlich and Temkin isotherm models were used to investigate MG-PPAC adsorption behavior for AO7 dye. Applicability of the Langmuir isotherm model demonstrates a monolayer adsorption AO7 dye removal process, and the maximum monolayer capacity (Q_m) attained from linear solvation of LIM is 322.58 mg/g. Furthermore, the highest removal was 99.53% at pH 2.25. Also, the adsorption process was tested using like pseudo-first-order, pseudo-second-order, intraparticle diffusion, film diffusion, and Elovich models. The pseudo-second-order model is well-fitted to the operational data of AO7 dye removal.