Fe₃ O₄-SiO₂-Alginate Photocatalyst for Textile Dyes Waste Degradation

Fe₃ O₄ is a photocatalyst that is used to degrade textile dye waste which can be collected and reused. Fe₃ O₄ was prepared by coprecipitation method, then impregnated with SiO₂ and sodium alginate. The purposes of this study were to investigate the degradation of textile dye waste using a Fe₃ O₄-SiO₂-alginate photocatalyst, to examine the light and dark test of photocatalyst under the influence of concentration and irradiation time. The type of light used was a 14.5-watt Philips LED lamp with a wavelength of 400-640 nm. Photocatalyst characterizations were conducted using FTIR, UV-Vis DRS, and XRD. The light and dark test of photocatalyst was carried out by photodegradation of textile dye waste with 0.5 g of photocatalyst with concentrations of 5%, 10%, and 15% and irradiation times were varied for 60, 90, 120 min. The degradation results were measured by calculating the COD value. The results of characterization by FTIR showed that the photocatalyst Fe₃ O₄-SiO₂-Alginate had absorption at wavelengths of 637.56 cm⁻¹ and 3365.86 cm⁻¹ which indicated the Fe-O-Si functional group and O-H stretching vibration. Results of UV-Vis DRS were analyzed using Origin Pro 2022 and revealed that the band energy gap for Fe₃ O₄ and Fe₃ O₄-SiO₂ were 2.20 eV and 1.77 eV, respectively. The XRD results analysis with Match!3 software showed that for Fe₃ O₄ had magnetite phases, while SiO₂ had amorphous cristobalite phases. The 15% (w/v) Fe3O4 concentration in the form of powder and granules degraded batik liquid waste by 79.6% and 84.48%, respectively.