Photocatalytic treatment of AO7 and real textile wastewater using green-synthesized ZnO nanoparticles: RSM and Taguchi approach

L. peel extract, and their photocatalytic performances for the removal of Acid Orange 7 (AO7) dye and real textile wastewater were investigated. The effects of pH, initial dye concentration, and catalyst dosage on AO7 removal were optimized using a Box-Behnken experimental design and Response Surface Methodology (RSM). Under the optimum conditions (pH 10, initial dye concentration of 10 ppm, and catalyst dosage of 0.13 g), 100% dye removal was achieved within 270 min. The photocatalytic treatment of real textile wastewater was optimized using a Taguchi experimental design, and a color removal efficiency of 98.1% was achieved under the optimum conditions (pH 7, constant wastewater volume of 50 mL, and catalyst dosage of 0.13 g). Additionally, radical scavenging experiments performed to elucidate the photocatalytic mechanism indicated that hydroxyl radicals (•OH) play a significant role in the photocatalytic degradation of AO7. The synthesized ZnO nanoparticles exhibited high photocatalytic stability, good reusability and acted as efficient photocatalysts even under low-energy UV light conditions. Overall, the green-synthesized ZnO nanoparticles demonstrated promising potential as an effective photocatalyst for the removal of dyes and color from real textile wastewater.