Synthesis and characterization of undoped and Ag doped TiO2, ZnO and ZnS nanoparticles for the photocatalytic degradation of 2-chlorophenol under UV irradiation.

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dc.contributor.authorOnkani, Shirley Priscilla
dc.contributor.co-supervisorDiagboya, N. Paul, Dr.
dc.contributor.co-supervisorKlink, Michael, Dr.
dc.contributor.supervisorMtunzi, Fanyana M., Prof.
dc.date.accessioned2022-04-22T04:02:35Z
dc.date.available2022-04-22T04:02:35Z
dc.date.issued2019-07-08
dc.descriptionM. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology.en_US
dc.description.abstractPhenol, 2-chlorophenol (2-CP) is used in the manufacture of several chemical compounds including other chlorophenols, dyes, dentifrice and pesticides. The usage of these chemicals results in the discharge of 2-CP that is harmful to most biota in the environment. Therefore there is need to remove or degrade 2-CP from the environment, especially in water. This research focused on the synthesis, characterization and application of Ag doped semiconductor (TiO2, ZnO, and ZnS) nanoparticles for the removal of 2-CP from water. Sol-gel and co-precipitation methods were used to synthesize the nanoparticles with different Ag contents (1%, 3% and 5%). Silver metal was used as a doping agent due to its antibacterial activity and ability to improve the photocatalytic activity of the semiconductors for 2-CPdegradation under UV irradiation. Characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), Ultra-violet visible spectroscopy (UV-Vis) and photoluminescence spectra (PL) were used to characterize the structural, optical and physical properties of the nanoparticles, while Transmission electron microscopy (TEM) was used to characterize the surface of the nanoparticles. The XRD results confirmed the formation of anatase, wurtzite and blend phases of TiO2, ZnO and ZnS nanoparticles, respectively. The band gaps of the synthesized nanoparticles were 3.42 eV, 3.23 eV and 3.12 eV for TiO2, ZnO and ZnS nanoparticles respectively. The TEM images showed that all synthesized nanoparticles were uniform in shape. Photocatalytic degradation of 2-CP under UV irradiation confirmed that the semiconductor’s photocatalytic activities improved with the addition of Ag ions. The best removal percentage was obtained at doped Ag percentages of 5, 1 and 5 % using TiO2, ZnO and ZnS, respectively. In addition, the effects of various parameters affecting the photocatalytic degradation such as pH, initial concentrations of 2-CP and amount of catalyst (Ag doped TiO2, ZnO and ZnS, respectively) loading were examined and optimized. At the different initial concentrations of 2-CP, namely, 8, 20 and 50 ppm, the highest degradation efficiency was obtained at pH of 10.5 and 5 mg of catalyst dosage. However a decrease in initial concentration of 2-CP showed an increase in the photocatalytic efficiency. The degradation percentage of 2-CP obtained with Ag doped TiO2; ZnO and ZnS nanoparticles were 74.74, 57.8 and 45.49 %, respectively. Doping of these materials with Ag enhanced their photocatalytic activity; thus, they have the potential of degrading phenolic compounds, especially 2-chlorophenol, in water.en_US
dc.identifier.urihttp://hdl.handle.net/10352/506
dc.language.isoenen_US
dc.publisherVaal University of Technologyen_US
dc.subjectChemical compoundsen_US
dc.subjectPhotocatalytic degradationen_US
dc.subjectAg doped semiconductoren_US
dc.subjectTiO2en_US
dc.subjectZnOen_US
dc.subjectZnSen_US
dc.subjectSynthesized nanoparticlesen_US
dc.subjectUndopeden_US
dc.subjectSilver dopeden_US
dc.subject.lcshDissertations, Academic -- South Africaen_US
dc.subject.lcshNanostructured materialsen_US
dc.subject.lcshChemical kineticsen_US
dc.subject.lcshNanoparticlesen_US
dc.subject.lcshPhotodegradationen_US
dc.subject.lcshPhotocatalysisen_US
dc.titleSynthesis and characterization of undoped and Ag doped TiO2, ZnO and ZnS nanoparticles for the photocatalytic degradation of 2-chlorophenol under UV irradiation.en_US
dc.typeThesisen_US
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