Continuous removal of tetracycline in a photocatalytic membrane reactor (PMR) with ZnIn₂S₄ as adsorption and photocatalytic coating layer on PVDF membrane

Based on the concept of dynamic membrane and photocatalytic membrane reactor (PMR), the dynamic photocatalytic membrane reactor is developed via deposition of ZnIn₂S₄ suspension on polyvinylidene fluoride (PVDF) membrane. Operating with effluent circulating to the photocatalytic membrane reactor, the highest total organic carbon (TOC) removal efficiency of 57% is obtained after 3 h reaction with 1.88 mg cm⁻² photocatalyst under the flux of 84.06 L m⁻² h⁻¹ and light intensity of 50 mW cm⁻². Operating with continuous influent and effluent mode under the flux of 26.09 L m⁻² h⁻¹ and light intensity of 50 mW cm⁻², an average of 50% removal efficiency can be maintained during the 24 h photocatalytic reaction with photocatalyst loading of 1.88 mg cm⁻² when the initial concentration of tetracycline is 10 mg L⁻¹. Under the same operating conditions, more than 92% removal efficiency can be maintained during 36 h photocatalytic reaction when lower initial concentration of 100 μg L⁻¹ is applied. After this reaction, the characterizations show that the surface and structure of PVDF basement membrane are not affected.