Synthesis and Characterization of Cobalt–Gallium Layered Double Hydroxide for Sonocatalytic Degradation of 2-Mercaptobenzoxazole from Water

Abstract

In this study, cobalt–gallium layered double hydroxide (CoGa LDH) was synthesized using the coprecipitation technique. The characteristics of the prepared LDH were assessed in detail using various analytical techniques, including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N₂ adsorption/desorption, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, energy-dispersive X-ray spectroscopy, elemental dot mapping, and X-ray photoelectron spectroscopy. 2-Mercaptobenzoxazole (MBO), an organosulfur model pollutant, was utilized to investigate the sonocatalytic capability of CoGa LDH. The effect of the operational parameters, including catalyst dosage, pollutant concentration, and pH, on the performance of the sonocatalytic system was investigated. The results showed that CoGa LDH with a catalyst dosage of 0.5 g/L exhibited considerable sonocatalytic activity (80.9%) for the removal of MBO, compared to adsorption (17.9%) and sonolysis (30.4%) within 120 min. A plausible sonocatalytic degradation mechanism was proposed using the gas chromatography–mass spectrometry method. The developed sonocatalytic system showed high performance in the degradation of diverse mercaptan derivatives, including 2-mercaptobenzimidazole (71.2%) and 2-mercaptobenzothiazole (100%), and also pharmaceutical pollutants, including oxytetracycline (100%), tilmicosin (100%), and levofloxacin (86.1%). The findings revealed that CoGa LDH is a durable and efficient sonocatalyst for environmental remediation and wastewater treatment.