Synergistic Effects of Doping Aluminum and Poly (Vinyl Alcohol) on ZnO Photocatalyst for Catalytic Degradation of Methyl Orange under Sunlight

Abstract

^{Photocatalytic wastewater treatment using suitable semiconductor nanomaterials as photocatalysts is currently a promising alternative for addressing urgent environmental issues related to various persistent pollutants, such as dyes and pesticides. To this end, ZnO, Al-modified ZnO and ZnO/PVA nanoscale photocatalysts were synthesized using co-precipitation methods. UV-Vis, XRD, SEM and FTIR methods were then used to characterize these nanomaterials. Additionally, the photocatalysts' catalytic activity was determined by evaluating their ability to remove methyl orange (MO) dye from an aqueous medium using sunlight. To enhance the efficiency of the photocatalytic process, ZnO was doped with aluminum, after which a composite was formed with polyvinyl alcohol (PVA). This process is responsible for both narrowing the band gap and hindering the recombination of charge carriers, thereby improving the activity of the ZnO nanocomposite when exposed to sunlight. The extent of MO removal was as follows: (Al- modified ZnO /PVA) > (Al-modified ZnO) > (ZnO/PVA) > (pure ZnO). The results showed that doping ZnO with aluminum and combining it with PVA enhanced the catalytic activity. Using Al- modified ZnO /PVA as a catalyst achieved 83.7% MO removal in 90 minutes. The Al- modified ZnO composite with PVA exhibited a synergistic effect. This could inform strategies for the removal of organic dyes. Furthermore, these results suggest that doping is an alternative mechanism for enhancing the removal of organic dyes, such as MO, under sunlight, thereby helping to green the environment.}