Background: Most dyes have aromatic rings in their structures, which make them highly toxic for human being and aquatic life. Heterogeneous photodegradation using TiO2 nanoparticles is one of the most applied methods used for dye removal. The wide band gap of TiO2 nanoparticles disables its use of the visible light and thus the vast potential of sunlight. To overcome this deficiency, Ag doped TiO2 nanoparticles were loaded on Fe-ZSM-5.
Methods: Fe-ZSM-5@TiO2-Ag photocatalyst was synthesized through sol-gel and hydrothermal methods to remove hazardous Reactive Red 195 (RR 195) from aqueous solution.
Results: Pure phase of Fe-ZSM-5@TiO2-Ag with specific surface area of 332 m2/g was successfully synthesized. Formation of Ti-O-Ag functional group in the photocatalyst structure confirmed the nanocomposite form of the product. SEM and TEM images portrayed the synthesized zeolite and photocatalyst NPs in a size range of ≤100 nm with homogenous distribution of Ag doped TiO2 on Fe-ZSM-5 surface. The band-gap energy of Fe-ZSM-5@TiO2-Ag was calculated 1.97 eV at λ = 630 nm. Photocatalytic activity of the photocatalyst under natural sunlight was investigated through photodecomposition of RR 195 in an aqueous solution. The dye photodecomposition of about 98% was achieved at photocatalyst concentration of 400 mg/L, pH of 3, and dye concentration of 50 mg/L at ambient temperature after 120 min under sunlight using 0.5 ml of TiO2 and silver ammonium nitrate. The photocatalyst reusability was found significant after 5 frequent cycles.
Conclusion: The novel Ag-doped TiO2-Fe-ZSM-5 nanocomposite with sunlight sensitivity can be a promising candidate to purify wastewater containing organic pollutants.
Keywords: Natural sunlight; Photocatalytic degradation; Reactive red (RR 195) 195; Regeneration; Sunlight-sensitive nanocomposite.