Application of fly ash-TiO₂ composites for enhanced adsorption and photocatalytic degradation of fuchsin dye

It is important to accomplish both photocatalytic efficiency and adsorption capacity in the catalyst to produce a highly effective photocatalyst for complete dye removal from wastewater. In the current investigation, TiO₂ and fly ash-TiO₂ composites (0.5–5 wt%) were fabricated by sol–gel and wet-impregnation process, and their catalytic performance was evaluated for the effective adsorption and photocatalytic degradation of fuchsin blue dye. The catalysts were characterized by XRD, UV-DRS, SEM, EDS, RAMAN spectroscopy, and N₂ adsorption analysis Adsorption and degradation studies were conducted to investigate factors such as pH (2 − 10), adsorbent dose (1–9 mg), contact time (30–180 min), and initial adsorbate concentration (5–30 mg/L) to eradicate fuchsin dye from water. The 5 wt% fly ash-TiO₂ catalyst showed a maximum capacity for adsorption of 20.32 mg/g and 76% removal of fuchsin dye. The Langmuir isotherm model fitted well to the experimental data, whereas the adsorption process obeyed pseudo-first-order kinetics. When exposed to UV light, a 5 wt% fly ash-TiO₂ composite demonstrated maximum photocatalytic degradation of 88% after 180 min, followed by a pseudo-first-order kinetic model. The catalyst was easily reusable for five cycles without losing dye removal effectiveness.