Multifunctional metal oxides synthesized via a solvo-hydrothermal process for photocatalytic degradation of organic dye and bacteria in wastewater

The persistent occurrence of textile industrial dyestuff in water bodies has continuously threatened aquatic life and public health, requiring effective remediation. This study explores the solvo-hydrothermal synthesis of Ag2O, Fe2O3, AgFe2O3, TiO2, Ag-TiO2, Fe-TiO2, and AgFe-TiO2 catalysts. Various techniques, including SEM-EDS, FTIR, XRD, BET, TGA, and XPS characterized the as-prepared metal oxide (MO) catalysts. The multi-functionality of the catalysts was assessed on the degradation of Congo red dye and the inhibition of gram-positive B. subtilis in simulated wastewater. SEM analysis shows that MOs mostly appeared in granular morphologies except for Fe2O3, which comprised elongated grains, and showed that both Ag and Fe were successfully doped into the TiO2 framework. The XRD survey revealed that Fe2O3 and TiO2 were abundant in hematite and anatase phases. The BET findings indicated that the MOs are fine mesoporous particles, with TiO2 showing the highest surface area of 83 m2/g, followed by 63, 28.27, and 24.03 m2/g for AgFe-TiO2, AgFe2O3, and Ag-TiO2, respectively. The antibacterial assays showed that Ag-TiO2 and AgFe2O3 inhibited 58 % and 64 % of B. subtilis, correspondingly. The highest removals 98 and 99.99 % of Congo red (CR) dye were achieved with AgFe2O3 and TiO2 after 5 h of irradiation time. At optimum conditions, AgFe2O3 and TiO2 performed well and reached complete degradation up to 3 cycles. The outcomes of this study show that the multifunctional metal oxides produced via the solvohydrothermal method are thermally stable and can effectively be used for the simultaneous degradation of organic dye and disinfection of bacterial-polluted water.