Sonocatalytic degradation of Congo Red using biomass-based cellulose/TiO2 composite

Abstract The current work reports the preparation of cellulose, titanium dioxide (TiO2), and cellulose/TiO2 composite for the sonocatalytic degradation of Congo Red. Cellulose was extracted from the oil palm empty fruit bunch (OPEFB) was conducted with alkali treatment, acid hydrolysis, and bleaching. TiO2 and cellulose/TiO2 composite were prepared through hydrothermal route. Characterization studies of the prepared sonocatalysts were performed with Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM), and surface area analysis. FTIR analysis revealed the functional groups of C–O, C–H, O–H, Ti–O, Ti–O–Ti, Ti–OH in the cellulose/TiO2 composite. The crystal structure of cellulose I was observed in cellulose, while the cellulose, mixture of anatase and rutile phases were being detected in both TiO2 and cellulose/TiO2 composite. SEM analysis demonstrated smooth surface of cellulose and spherical TiO2 particles in the cellulose and TiO2, respectively. The immobilization of TiO2 on the surface of cellulose did not affect the surface morphologies in the cellulose/TiO2 composite sample at mass ratio of 0.1:1. The Brunauer-Emmett-Teller (BET) measured specific surface areas for cellulose, TiO2, and cellulose/TiO2 were 0.5829 m2/g, 149.65 m2/g, and 141.9259 m2/g, respectively. The sonocatalytic degradation efficiencies of Congo Red by cellulose, TiO2, and cellulose/TiO2 composite were 1%, 34%, and 48%, respectively at an initial dye concentration of 10 mg/L, catalyst loading of 0.5 g/L, treatment time of 30 min, ultrasonic frequency of 24 kHz and ultrasound power of 280 W.