MIL-88-A(Fe)/PVDF coated stainless steel mesh using the drop casting method: A Superior photocatalyst for Cr(VI) reduction in aqueous solutions

Abstract

Chromium (VI) contamination in water sources poses severe environmental and health risks due to its high toxicity and carcinogenic properties, necessitating the development of efficient treatment methods. This study presents a novel technique for the photocatalytic reduction of Cr(VI) using iron-based MOF combined with a polymer coated on a stainless steel mesh using the drop-casting method. The photocatalyst was created by coating MIL-88-A(Fe) and PVDF as polymeric binders on the mesh surface, displaying strong adhesion and suitable exposure to the target pollutant, maintaining 85 % efficiency after 5 recovery cycles, indicating good stability and reusability. The photocatalytic performance of the modified stainless steel mesh was evaluated under photocatalytic and sonophotocatalytic conditions. The results show that a significant increase in Cr(VI) reduction is achieved when ultrasonic irradiation is applied simultaneously with light irradiation, attributed to the synergistic effects of ultrasound and the photocatalyst. Additionally, under optimal conditions, including pH 2, 60 min, 25 mg hole scavenger, 30 ppm initial Cr(VI) concentration, and 75 mg MOF loading, the photocatalytic system achieved 96 % Cr(VI) reduction. The prepared photocatalysts were characterized using X-ray diffraction, fourier transform infrared, UV–Visible, scanning electron microscopy, and energy-dispersive X-ray analysis. This study confirmed the superior efficiency of the sonophotocatalytic method compared to the photocatalytic method for MIL-88-A(Fe). It also shows the potential of integrating MOFs with polymer binders on stainless steel mesh for efficient and sustainable water treatment solutions.