[Retracted] Effect of Cu Doping on ZnO Nanoparticles as a Photocatalyst for the Removal of Organic Wastewater

Abstract

Environmental problems with chemical and biological water pollution have become a major concern for society. Providing people with safe and affordable water is a grand challenge of the 21st century. The study investigates the photocatalytic degradation capabilities of hydrothermally prepared pure and Cu-doped ZnO nanoparticles (NPs) for the elimination of dye pollutants. A simple, cost-effective hydrothermal process is employed to synthesize the Cu-doped ZnO NPs. The photocatalytic dye degradation activity of the synthesized Cu-doped ZnO NPs is tested by using methylene blue (MB) dye. In addition, the parameters that affect photodegradation efficiency, such as catalyst concentration, starting potential of hydrogen (pH), and dye concentration, were also assessed. The dye degradation is found to be directly proportional to the irradiation time, as 94% of the MB dye is degraded in 2 hrs. Similarly, the dye degradation shows an inverse relation to the MB dye concentration, as the degradation reduced from 94% to 20% when the MB concentration increases from 5 ppm to 80 ppm. The synthesized cost-effective and environmentally friendly Cu-doped ZnO NPs exhibit improved photocatalytic activity against MB dye and can therefore be employed in wastewater treatment materials.

Recent developments in phycosynthesis of zinc oxide nanoparticles for biomedicine and environmental applications

“…Another approach was made recently in 2022, where ZnO NPs were doped with Cu to increase the photocatalytic efficiency of ZnO NPs. The Cu-doped-ZnO NPs degraded 90% of MB dye in 120 min [118]. In 2020, a very unique approach was made to synthesise Ni-doped-ZnO nanomaterial where the electrocatalytic activity was observed.…”

High performance Co3O4/Sn-ZnO nanocomposite photocatalyst for removal of methylene blue dye

“…Moreover, ZnO synthesized using simple template-free precipitation techniques showed 24.9% photocatalysis efficiency of MB dye under visible light irradiation [16]. This inherent poor photocatalytic properties of ZnO nanoparticles in visible light region can be modified using common strategies such as doping [17,20], making a composite [21,22], and construction of heterojunction [23,24], and combinations of the above strategies at the same time [25,26].…”

“…For instance, the photocatalytic degradation efficiency of methylene blue using ZnO was enhanced by doping such as Sb-ZnO synthesized by sonochemical-assisted precipitation and achieved an efficiency of 91% using 300 mg L −1 catalyst under solar irradiation due to reduction of band gap to visible region [17], Ag-ZnO synthesized by co-precipitation route exhibited an enhanced efficiency of 95% for MB dye removal using 500 W halogen lamp [18], Sn-ZnO synthesized by ultrasonication aided co-precipitation method completely removed MB dye under UV light irradiation [19] and hydrothermally synthesized Cu-ZnO showed 90% efficiency of MB dye degradation under UV light [20].The heterojunction of ZnO/NiO shows enhanced photocatalytic MB dye degradation efficiency of 70% compared to pure ZnO (53%), and NiO (2%) due to enhanced charge separation [23]. Furthermore, hydrothermally synthesized ZnO/NiFe 2 O 4 heterojunction degrades MB (97%) and Rhodamine B (98%) under visible light irradiation for 3 h due to reduction of the band gap and effectively reducing the recombination rate of e-h pairs [24].…”

Фотокаталитические и адсорбционные свойства нанокомпозитов ZnO/ZnAl-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=-/Cu

“…Применение ZnAl 2 O 4 в качестве фотокаталического материала было исследовано в [21][22][23]. Высокие фотокаталитические свойства нанокомпозитов ZnO-Cu были отмечены в целом ряде работ [24][25][26]. В [8]…”