Promotion of brass nanowires with lanthanum oxide and its application for photodegradation of tetracycline wastewater.

Today, pharmaceuticals are considered as one of the sources of water pollution, among which antibiotics have complicated structure and antibacterial property, so they cannot be removed from water by common treatment methods. Tetracycline is an antibiotic which is used to treat humans and infected animals. Photocatalytic degradation is an effective method which is used for the removal of antibiotics from water. In this work, brass foils were coated by lanthanum oxide using dipping method. The coated foils were calcined; nanowires grew, so lanthanum oxide was sintered to the brass nanowires. The prepared photocatalyst was characterized by inductively coupled plasma spectroscopy, X-ray diffraction, scanning electron microscopy, and porosimetry techniques. The photocatalytic degradation operating conditions including pH, initial concentration of tetracycline wastewater, and time were modeled and optimized by Design Expert software (version 10). The La ₂ O ₃ /brass photocatalyst was active under irradiation of ultraviolet, LED, and sunlight. The maximum tetracycline photodegradation yield was 89.97% obtained by La ₂ O ₃ /brass foil with the dimensions of 1 cm × 3 cm, 100 mL of tetracycline solution with the concentration of 5 mg/L and pH of 10 under ultraviolet irradiation for 120 min.