Tetracycline removal from aqueous solution by visible-light-driven photocatalytic degradation with low cost red mud wastes

Antibiotics wastewater poses a major threat to the global environment and human health. In this work, red mud (RM) and modified RM (after calcination treatment), as industrial solid wastes discharged from the aluminum industry, were used as effective photocatalysts for removal of tetracycline (TC) from water under visible light irradiation. The results showed that the photocatalytic degradation activity of modified RM on TC was obviously better than that of original RM (RM-raw). Furthermore, RM-350 (calcination temperature is 350 degrees C) exhibits the best photocatalytic performance (100 mL, 10 mg/L; 88.4% degradation of TC within 80 min) under visible light as well as outstanding stability after three reaction cycles. The improvement in photocatalytic performance by modified RM is mainly due to an increase in specific surface area and crystallinity, which is benefit for promoting adsorption of organic pollutants and accelerating photo-induced charges. The effects of catalyst dosage and initial concentration on the catalytic degradation of TC were studied. Our work has proved that RM is a novel low-cost photocatalyst, which not only provides a useful solution for the reuse of RM, but also plays an important role in environmental protection.