The degradation of Sulfamethoxazole using a heterojunction photocatalytic membrane composed of Z-scheme LaFeO3/Ag3PO4@GO: Assessment of activity and degradation mechanisms

Abstract

We synthesized La-deficient LaFeO₃ through a simple hydrothermal method, enhancing the physicochemical properties and catalytic performance of the initial LaFeO₃. Subsequently, Ag₃PO₄ was grown on 0.7 LaFeO₃ using electrostatic deposition to obtain composite materials LA-1, LA-2, and LA-3 with different composite ratios, improving the transfer rate of photogenerated charge carriers and reducing impedance. By physically combining LA with GO, a photocatalytic membrane LAG was produced, effectively enhancing the stability and recyclability of the photocatalytic membrane. The photocatalytic membrane LAG-2 achieved an 80.4 % SMX degradation efficiency under neutral conditions, with a degradation rate of 76.5 % at pH=3. The retention rate for SMX was 82 %, with a flux of 106.2 L·m⁻² h⁻¹ bar⁻¹. Additionally, the flux for CIP reached 530.8 L·m⁻² h⁻¹ bar⁻¹, with a retention rate of 65.5 %. After six cycling experiments, the degradation rate of LAG-2 was 67.4 %, and the leaching concentration of iron ions exhibited good performance. SEM analysis reveals that the morphology of the membrane remains intact before and after the cycle, with LAG retaining its integrity and exhibiting excellent mechanical properties. This indicates that the photocatalytic membrane demonstrates good stability and reusability. The excellent integration of the photocatalyst and membrane overcomes the challenge of difficult recovery of the photocatalyst, promising extensive applications and providing new insights for the practical application of photocatalytic degradation of antibiotics.