Concurrent use of NaHCO3 and NH4Cl for synthesis of ZnO-Al2O3 nanocomposite and investigation of its adsorption property

The utilization of the adsorption capability of semiconducting materials plays a pivotal role in the treatment of industrial effluents. In the present study, ZnO–Al₂O₃ binary nanocomposites with varying weight ratios were synthesized via the co-precipitation method. The synthesized nanocomposites were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), simultaneous thermal analysis (STA), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDX) to elucidate their functional groups, crystal structure, and morphological features. The experimental results demonstrated that the concurrent use of bicarbonate and ammonium significantly influenced the morphology of the nanocomposites and, consequently, their adsorption performance. Furthermore, with increasing ZnO content, the morphology of the nanocomposites evolved from platelet-like to aggregated structures. Under the optimized conditions of pH = 5, initial dye concentration of 10 mg L⁻¹, and a nanocomposite dosage of 0.02 g (40 wt% Al₂O₃–60 wt% ZnO), a maximum methyl orange removal efficiency of 98% was achieved.