Green synthesis of TiO2 and ZnO nanoparticles using grape pomace extract: characterization and application in cotton fabric

The textile industry faces significant challenges in water treatment due to chemical dyes used. The agroindustrial waste is an important source of natural dyes and compounds for the green synthesis of nanoparticles (NPs). This study focused on the characterization of TiO₂ and ZnO nanoparticles from pink grape pomace extracts (PGPEs) and their applications in cotton fabrics as colored nanoparticles. Characterization of TiO₂ and ZnO was carried out using an UV–Vis spectrophotometer, and particle sizes were determined using dynamic light scattering. Additionally, the functional groups present in the TiO₂ and ZnO nanoparticles were identified using Fourier-transform infrared spectroscopy (FTIR). Absorption peaks for TiO₂ and ZnO were observed in the range of 270–400 nm. The smallest nanoparticles were obtained for 1 mM pH 6 ZnONPs and 5 mM pH 6 ZnONPs (13.09 ± 6.42 nm and 13.14 ± 7.23 nm, respectively). The values of zeta potential indicated colloidal excellent stability for 5 mM pH 6 TiO₂NPs, and 1 mM pH 6 ZnONPs. The FTIR analysis suggests that phenolic compounds from PGPEs contribute to the synthesis of nanoparticles. Fabrics treated with TiO₂NPs exhibited light brown, and pink tones, while treatments with ZnNPs resulted in grayish-white colors in both cases. Variations in ΔE values indicated clear differences between the untreated cotton fabrics and those treated. In addition, chroma increased as a function of particle size, favoring the UV absorption and color fixation. Therefore, this study reveals the use of TiO₂NPs and ZnONPs from PGPEs as an environmentally friendly alternative to chemical dyes used in the textile industry.