Optimization of the photocatalytic degradation process of amoxicillin antibiotic using SiO2@TiO2 nanocomposite

Today, one of the most important challenges in wastewater treatment is the destruction of organic pollutants, especially antibiotics. This research investigated the efficiency of the photocatalytic process in removing the antibiotic amoxicillin from the water environment using SiO2@TiO2 nanocomposite. The desired nanocomposite has been synthesized using sol-gel method and characterized by XRD, FTIR and TEM techniques. To improve the performance of the fabricated nanocomposite, parameters such as pH, contact time, nanocomposite concentration, and drug concentration were studied and optimized using the response surface method and the Central Composite Design model. Characterization of nanocomposite with XRD showed the formation of crystalline phases and anatase structure. The formation of SiO2@TiO2 nanocomposite with Ti-O-Si bond was confirmed in FT-IR spectrum. Also, the TEM image showed that the particles have a spherical and uniform structure. The results of photocatalytic optimization experiments showed that the highest degradation efficiency (98.7%) of amoxicillin under pH:3, amoxicillin initial concentration: 10 mg/L, nanocomposite concentration: 2 g/L, contact time: 10 minutes, which is very close to the efficiency of predicted removal under optimal conditions in the BBD model (100%). Due to the high degradation efficiency and high production of free radicals, the synthetic photocatalyst has a high ability to degrade pharmaceutical pollutants, especially antibiotics, which develops its future applications for the degradation of organic pollutants with a similar chemical structure.