Nanoparticles of undoped ZnS, Mn-doped-ZnS,N-doped-ZnS and Mn-N co-doped ZnS were prepared by using chemical co-precipitation method. The precursors used to synthesize the photocatalyst nanoparticles were:Zn(CH3COO)2.2H2O, Mn(CH3COO)2.4H2O and Na2S.9H2O. The characterization of nanoparticles was done using X-ray powder diffraction (XRD) and UV–VIS Spectrophotometric technique.The average crystalline size of as-sythesized photocatalysts calculated using the Debye- Scherrer formula was 7.80, 7.48, 6.61 and 6.59 nmfor Zc, NZ, MZ, and MNZ respectively. The percentage degradation of methylene blue under UV irradiation at 180 minutes were: 10.12, 24.85, 45.19, 38.09, and 55.60 for uncalcined zinc sulfide (Znc), calcined zinc sulfide (Zc), Mn-doped zinc sulfide (MZ),N-doped zinc sulfide( NZ) and Mn-N co-doped zinc sulfide (MNZ) respectively. Under solar irradiation the Percentage photodegradation of MB were: 13.53, 30.17, 49.00, 57.30 and 70.75 for Znc, Zc, MZ, NZ, and MNZ respectively.The pseudo first order rate constant (k) of MB photodegradation for Znc, Zc, NZ, MZ, and MNZ were 5.72 × 10-4, 1.64× 10-3, 2.54× 10-3, 3.23× 10-3 and 4.48 × 10-3 min-1 and 0.8×10-3, 2.15×10-3, 4.16×10-3, 5.3×10-3 and 8.66×10-3 min-1 under UV irradiation and under solar irradiation, respectively.
Keywords: Chemical co-precipitation, Degradation, Photocatalysis, Rate constant, Xrd
