The wastewater contaminated with dyes, especially those used in the textile industries, poses a serious environmental problem because of the large amounts of synthetic dyes, such as methylene blue, that are not easily treated using the traditional treatment processes. The existing methods are mainly partial degradation by adsorption or photocatalysis, which demonstrates an important research gap in the complete removal of dyes. The proposed research will establish a sustainable and efficient solution through the synthesis of inorganic metal oxide nanoparticles (ZnO, Fe 2 O 3, and MnO 2 ) with different oxidation states (+ 2, + 3, and + 4). The innovation is that the complete degradation of dye has been done with nanoflower (NF) synthesized through an ultrasonicated-assisted co-precipitation process that improves surface morphology, purity, and yield. Material characterization techniques were used to confirm the nanoflowers with a high surface area. The influence of metal ion concentration, pH, and dye concentration on methylene blue dye removal efficiency was evaluated by optimization studies. The dye removal was the highest in MnO 2 NF (90.42% adsorption, 93.48% photocatalysis), then Fe 2 O 3 and ZnO. MnO 2 NF has the best removal performance for MB, while ZnO NF has the highest retention of activity after the recycling experiments. Thus, MnO 2 NF is the best material under the fresh optimized conditions, while ZnO NF has a relatively better cycling stability. The research findings are that metal oxide flowers are very efficient, sustainable, and scalable to real-life wastewater treatment, which fills the research gap and provides a solution to the environmental problems caused by dye pollutants.
Lee et al. (Mon,) studied this question.