Synthesis of multiwalled carbon nanotubes supported manganese and cobalt zinc oxides nanoparticles for the photodegradation of malachite green

Multiwalled carbon nanotubes (MWNTs) supported and unsupported bimetallic zinc and manganese oxides nanoparticles (Zn–Mn NPs) were synthesized by wet chemical precipitation method. Zn–Mn and MWNTs/Zn–Mn oxides NPs were used as photocatalysts for the photodegradation of malachite green in aqueous medium under UV irradiation. The photodegradation study of malachite green was carried out by UV/vis spectrophotometer. The Mn–Zn and MWNTs/Mn–Zn oxides NPs degraded about 93% and 96% of dye, respectively, within 2 h of irradiation time. Effect of several parameters like time, pH, catalyst dosage and concentration of dye on the photocatalytic degradation was studied. The optimum conditions were obtained at pH 9 (93% dye degraded in 1.5 h), at 0.0435 g of catalyst (76.04% of dye degraded in 1 h), at 12.5 ppm dye concentration (88.41% dye degraded in 45 min). The activity of recovered catalyst was also examined.