Removal of textile dye from synthetic wastewater using microporous polymer nanocomposite

This study investigates the combined adsorption and photocatalysis on degradation of textile dye using microporous polymer nanocomposite. First, nanocomposites were synthesized by loading TiO2 nanoparticles of different weights (0.1–0.5 g) in polyurethane (PU) foam. The synthesized nanocomposites were characterized for bulk density, sol fraction and morphology. Degradation of methylene blue (MB) dye from an aqueous model pollutant was performed using pure TiO2 nanoparticles, unloaded PU foam and TiO2-loaded PU foam by exposing under UV and solar irradiations. It has been observed that degradation (due to TiO2 nanoparticles) and adsorption (due to PU foam) were happening simultaneously upon irradiation under solar and UV source. This mechanism was confirmed by analysing and comparing the MB dye degradation results for pure TiO2 nanoparticles (85% of dye degraded in 40 min), unloaded PU foam (40% degradation in 40 min) and TiO2-loaded PU foam (95% degradation in 20 min). Experimental data show pseudo-zero-order kinetics for UV irradiation (rate constant = 0.016 h–1), whereas solar irradiation follows first-order kinetics with rate constant 0.265 h–1.