Ag/MgO-functionalized zeolite via hydrothermal-calcination method for efficient Cu(II) removal and antibacterial activity

The raw zeolite was functionalized with magnesium oxide (MgO) and silver (Ag) by the hydrothermal-calcination method for dual functions: antibacterial activity and copper ions (Cu⁺²) removal from water. A main gap in current work is that unfunctionalized natural zeolites exhibit limited adsorption capacity for cationic pollutants and lack antibacterial activity without surface modification. The raw zeolite and functionalized zeolite samples were characterized by different techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). This work aims to study the efficiency of the functionalized zeolite with MgO and Ag nanoparticles (ZMA) in removing Cu⁺² ions and bacteria, specifically Escherichia coli and S. aureus, compared to raw zeolite. The results of the adsorption study showed that ZMA exhibited 31.3% higher removal efficiency and 14.6 mg/g adsorption capacity for Cu⁺² ions than raw zeolite. A feed pH level between 4 and 10 was optimal for Cu⁺² ions removal (99.95%) using 2 g/L of ZMA. The adsorption capacity decreased from 209.7 mg/g to 51.6 mg/g as the adsorbent dose increased from 0.125 g/L to 3 g/L, respectively. Several adsorption isotherm and kinetic models were investigated in this study, and adsorption thermodynamics was also examined. The minimum inhibitory concentration (MIC) results confirmed a clear dose-dependent inhibition of bacterial growth. Regeneration study results showed that Cu²⁺ ions removal by regenerated ZMA did not change significantly after four regeneration cycles.