The primary environmental concern associated with antibiotics stems from the emergence of antibiotic-resistant genes and the disruption of beneficial bacteria essential for various organisms. A composite material consisting of graphene oxide (GO) and montmorillonite (Mt) embedded in polyvinyl alcohol (PVA) was studied for its efficacy as an adsorbent for tetracycline (TC) in aqueous solutions. The composite's performance in facilitating the natural degradation of tetracycline under ultraviolet (UV) light exposure was also eva‎luated. The adsorption capacity of the GO-PVA-Mt composite, prepared under standard environmental conditions (pH=7, temperature 25°C), was measured after 48 hours of absorption. The uniform distribution of GO particles on Mt's surface resulted in enhanced adsorption capabilities, making the GO-PVA-Mt composite a proficient adsorbent for tetracycline adsorption, desorption, and photodegradation processes. Notably, the composite exhibited a maximum absorption capacity of 4 8 mg/g at an initial tetracycline concentration of 1000 ppm, surpassing Mt's absorption capacity of 1 8 mg/g under identical conditions. Following 48 hours of absorption and subsequent exposure to distilled water for another 48 hours, the desorption rate of tetracycline from the GO-PVA-Mt adsorbent was merely 4% of the adsorbed quantity, significantly lower than Mt's desorption rate of 26%. Moreover, the intrinsic degradation of tetracycline under UV irradiation was enhanced by the GO-PVA-Mt composite, resulting in a degradation rate exceeding 5 % without the need for a catalyst. This outcome underscores the composite's ability to accelerate the photodegradation of tetracycline. Additionally, the GO-PVA-Mt composite demonstrated efficacy as a potent adsorbent for antibiotic removal. Structural analyses conducted through X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) confirmed the composition's structural integrity and characteristics.

مهدي نصيري سروي

مهدي بازرگاني پور

ابراهيم عظيمي , محمد ديناري