Zinc-chromium layered double hydroxides anchored on carbon nanotube and biochar for ultrasound-assisted photocatalysis of rifampicin

In this study, ZnCr layered double hydroxide (LDH), ZnCr LDH/carbon nanotube (CNT), and ZnCr LDH/Biochar (BC) were synthesized and characterized by various analyses. The successful synthesis and the great crystallinity of the samples were consented by XRD analysis. SEM and TEM were applied to study the morphology of the synthesized samples. The simultaneous presence of C, Zn, and Cr elements was well confirmed by EDX and dot mapping analyses demonstrating the successful preparation of nanocomposites. According to the BET analysis, ZnCr LDH nanocomposites with BC and CNT had more specific surface area compared to ZnCr LDH alone. The catalytic performances of the samples were determined for the degradation of rifampicin (RF). The degradation efficiency of the sonophotocatalytic process in the presence of 0.6 g L-1 of ZnCr LDH/BC toward 15 mg L-1 of RF under 150 W ultrasound and visible light irradiation was found to be about 100% within 40 min. The influence of the reactive species on the sonophotocatalytic process was assessed via the addition of different scavengers (para- benzoquinone (p-BQ), formic acid (FA), isopropyl alcohol (IPA)), and enhancers (hydrogen peroxide and potassium persulfate). The GC-MS analysis was carried out and eleven by-products during the RF decomposition were detected.