Photocatalytic degradation of antibiotics and dyes by novel Zn/Fe composites under sunlight at ambient conditions

In recent decades, dealing with water pollution caused by industrial dyes and toxic chemicals has become a major problem worldwide. Here a fibrous tubular ZnO-ZnFe2O4 composite with cotton as a biotemplate by a facile calcination method was developed. The fibrous tubular structure provides a larger surface area, effectively inhibits photogenerated electron-hole recombination, and enriches the active site. The photocatalytic degradation performance of cotton-ZnO-ZnFe2O4 (CZFO) for congo red (CR) and ciprofloxacin (CIP) is excellent. The optimal composite 2.3CZFO presents the best degradation performance, 96% removal rate with 20 mg/L CIP, 94% removal rate with 40 mg/L tetracycline (TC), 98% removal rate with 40 mg/L CR, 99% removal rate with 10 mg/L methylene blue (MB). The photocatalytic degradation kinetic rate of 2.3CZFO for CIP, TC, CR, MB is 0.0073/min, 0.0058/min, 0.0527/min, 0.0388/min, respectively. The work offers a new strategy to prepare a fibrous tubular composite material with cotton as a biotemplate by simple calcination and use these photocatalysts to purify wastewater.