Removal of tetracycline from aqueous solution by beach sand-based silica

Abstract

As a class of broad-spectrum antibiotics, tetracyclines find extensive use in human, veterinary, and aquacultural applications. Releasing tetracycline in the form of parent or derivative compounds into the aquatic environment is extremely dangerous to human health. This study investigates the ability of silica (SiO2) extracted from Beureunut beach sand to remove tetracycline in an aqueous solution by combining adsorption and Fenton-like oxidation. The beach sand was used as a precursor, and it was reacted with a sodium hydroxide solution at 80 °C before being precipitated with sulfuric acid and dried. The extraction yielded 9.22 g of silica, which was then further characterized using Fourier transform infrared (FT-IR) spectroscopy. Prior to the adsorption test, the stability of tetracycline solution was evaluated at two different temperatures (11 °C and 30 °C). The findings of a 6-day stability test performed in water showed that tetracycline was more stable at 11 °C than at 30 °C. The adsorption capacity of silica was found to be 1.68 mg/g (17.00%) at 50 mg/L tetracycline concentration after 3 hours of contact time. Meanwhile, the adsorption method combined with the Fenton-like process increased the percentage of tetracycline removal from 17.00% to 56.32%. In conclusion, combining adsorption and Fenton-like processes provides an option for greatly increasing the ability of beach sand-based silica as a potential adsorbent to remove tetracyclines from water.