Multi-characteristic optimization and modeling analysis of Cu2+ removal from wastewater using activated coke/MnFe2O4 magnetic composite

Abstract

This study used pyrolytic coke (PC) as a viable source for producing an adsorbent. The surface magnetization of activated coke (AC) with MnFe2O4 nanoparticles was carried out to remove Cu2+ from aqueous media after PC activation via a chemical activation method. The structural and surface properties of the adsorbents were examined using a variety of analyses, including thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), Burner-Emmett-Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) mapping, Raman, vibrating-sample magnetometry (VSM), atomic force microscopy (AFM), and dynamic light scattering-zeta potential (DLS-ZP). Several parameters were investigated to determine the efficacy of the adsorption process: initial Cu2+ concentration (10–50 mg/L), pH (2−10), adsorbent dosage (0.75–3.75 g/L), temperature (25–65 °C), and contact time (30–150 min). Response surface methodology-central composite design (RSM-CCD) and artificial neural network-genetic algorithm (ANN-GA) methods were used to optimize the process and have correlation coefficients of 0.9890 and 0.9943, respectively. Optimum conditions were determined at an initial Cu2+ concentration of 40 mg/L, a pH of 7.61, an adsorbent dosage of 0.75 g/L, a temperature of 55 °C, and a contact time of 150 min using the RSM-CCD approach. The adsorption process efficiency for AC and AC/MnFe2O4 magnetic composite was determined to be 90.24 and 99.06 %, respectively. According to the results, the adsorption capacity of AC/MnFe2O4 was 72.71 mg/g. The Cu2+ adsorption using magnetic composites followed the Elovich kinetic model. Thermodynamic studies revealed that the process is endothermic and spontaneous. Adsorption efficiency decreased for all adsorbents when Ca2+ and Na+ ion concentrations in aqueous solutions rose. As the number of steps in the adsorption/desorption process increases, the adsorption marginally reduces. Adsorbents' ability to adsorb Cu2+ ions in multi-metallic solutions compared to single-metallic solutions has diminished. The results showed that the AC/MnFe2O4 adsorbent has a high capacity to adsorb-desorb Cu2+ and remove polluted effluent. Additionally, actual wastewater treatment outcomes demonstrated the AC/MnFe2O4 magnetic composite's high efficacy in removing Cu2+ ions.