Efficient removal of copper ions from wastewater using a novel magnetic ZnO-MnFe2O4 decorated on MWCNTs adsorbent

Copper (Cu), though an essential element, can become environmentally hazardous at elevated concentrations. Industrial releases of Cu(II) into water systems may accumulate in living organisms, posing health risks. Nanocomposite-based adsorption represents one of the most effective methods for Cu removal. In the present study the new magnetic nanocomposite, which includes ZnO and MnFe₂O₄ decorated on MWCNTs (MWCNTs&ZnO&MnFe₂O₄), was synthesized to elucidate its capability to adsorb Cu(II) ions from wastewater. This new adsorbent retained a high specific surface area (58.383 m²/g). This characteristic is crucial as it provides ample adsorption sites. Additionally, the ZnO nanoparticles play a vital role in preventing MWCNT agglomeration, which further improves the accessibility of these sites. These analyses indicated that the new magnetic nanocomposite was synthesized as a mesoporous material with a pore size of 13.5 nm and without impurities. The batch adsorption method and response surface methodology (RSM) were used to study adsorption efficiency. The maximum Cu(II) adsorption efficiency of 99.92 % was achieved at a Cu(II) ion concentration of 24.09 mg/L and an adsorbent dosage of 0.97 g/L. The kinetic study indicated the pseudo-second-order (PSO) exhibit a high level of agreement with the experimental data. The Freundlich isotherm (FI) model exhibited the best fit with the experimental data. Thermodynamic analyses revealed that the adsorption (AD) process is spontaneous and endothermic. As the adsorption/desorption process progressed through five stages, the efficiency showed a slight decline, dropping from 99.92 % to 92.12 %. One advantage is that the lowest concentration of MWCNTs&ZnO&MnFe₂O₄ (CZM) adsorbent can effectively purify water contaminated with Cu(II) ions over multiple cycles.