Theses and Dissertation

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Browsing Theses and Dissertation by Author "Oyetade,Joshua"

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    Development of nano-size doped polyaniline composites for enhanced photocatalytic degradation of selected industrial azo dyes
    (NM-AIST, 2025-06) Oyetade,Joshua
    The toxic impacts of dye-polluted industrial effluent and the limitations of conventional treatments drive the need for innovative photocatalytic techniques. The study carried out a preliminary evaluation of the current efficiency of treatment plants from selected textile industries. It also fabricated, characterized and tested the performance of the photocatalysts for the remediation of dye-polluted effluent while mediating the process with a Fenton-like reagent (FeCl3 and H2O2). The preliminary treatment plant performance reported that the corresponding effluent consists of a high amount of NH3, phosphorus and NH3-N, Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) above the set limits. The first industry (Morogoro) examined, revealed a colour value of 4042.67 ± 1.76 which was reduced to 1800 ± 0.00 after the filtration treatment technique. Likewise, an initial colour value of 2051.00 ± 0.58 was reported in another industry (Arusha) which later was quantified as 237.33 ± 0.67 after treatment with the activated carbon system. The instrumental characterization of the acid and alkali-treated TiO2 and the fabricatednanocomposite photocatalysts indicated that their respective adsorption-desorption isotherms are of type IV. This illustrates mesoporous materials similar to all the nanocomposites having an amorphous diffraction pattern while the metal oxide (TiO2) exhibited a crystalline diffraction pattern. The surface functionality revealed the functional group features of Ti-O-Ti bonding for the metal oxides. Thereafter, the nanocomposites exhibited the features of polyaniline blended with TiO2 (P-AKT) and polyaniline blended with graphene oxide, magnetite and silver nanoparticle from the in situ reduction of silver nitrate (PANI-GFA), respectively. The study revealed that TiO2 treated with 3 M NaOH showed the highest degradation efficiency of 89.15% after 90 minutes using 18 W UV light-emitting diode photon irradiation. The first fabricated nanocomposite (PAKT) had 94% efficiency and significant reusability up to the 4th cycle while the second fabricated nanocomposite (PANI-GFA) had 95% and high reusability potential up to the 6th run. This value was established optimal conditions of 20 mg dosage, pH of 5 and at 90 mins irradiation time using 100 mL dye polluted effluent. The optimization studies suggested a quadratic model with good correlation and reliability and the variables were statistically significant (p-values < 0.0001). Also, the PANI-GFA test demonstrated high efficiency in treating four real industrial effluents with azo dyes.