Thesis:

Synthesis and characterization of silver Nanoparticle elecrocatalyst embedded onto indium tin oxide electrodes for degradation of azo dyes

The research was conducted to establish the effectiveness of silver nanoparticles embedded on indium tin oxide (ITO) thin film conducting material in causing the textile azo dyes effluent degradation. The Overall Objective was to synthesize and characterize silver nanoparticles electrocatalyst embedded on indium tin oxide for the degradation of azo dye in the textile effluent. The 40.0 g of powdered crab shells resulted in 23.0g of chitin after demineralization and 7.2 g (31.3 %) of chitosan. Chitosan obtained from crab shells exhibited 89.5% degree of deacetylation showing efficiency in reduction and stabilization of silver nanoparticles from the Ag+ ions. The UV-Vis spectroscopy showed the formation of spectra with λmax at 420 nm. The scanning electron microscope (SEM) depicted nanoparticles showing spherical morphology with size range of 50 nm. FTIR signals were recorded at 1658 cm−1 corresponding to the amide (C=O) bonds, at 1089 cm−1 representing secondary alcohol (C-O-C) bonds at 564 cm−1 plane with bends NH, plane-out and bends C−O. C-H stretching vibrational signal was noted at 2927 cm−1, a broader band at 3426 cm−1 for an overlap between the O−H stretching vibration and the N−H stretching vibration of the oligosaccharide applied in the capping. The intensity of the O−H and N−H stretching bands emanated from the hydroxyl and amino groups thus shifting to 3426 cm−1, implying that chelation of silver with both O−H and N−H groups of chitosan actually took place. The percentages of azo dyes degradation were as follow: 68.4%, 72.5% and 93.1% using electrocoagulation, ITO and ITO-AgNPs coupled electrodes respectively. The results obtained from the two factors ANOVA with replication indicated significant difference (p= 0.0024) when the silver nanoparticles embedded on indium tin oxide electrodes were utilized in the degradation of these azo dyes in the effluent samples. In all the four samples it was noted that, 8 ppm of the silver nanoparticle concentration applied to the ITO thin film electrodes resulted in the least power consumption maximum of 0.4536 watts with average values of 0.0300±0.0023 hours and a current flow of 0.63 A. The average specific consumption of energy at 12 V was 2.110 kWh/m3 compared to 1.318 kWh/m3 at Pd of 24 V respectively. IR drop was minimized by lowering the created gap within the thin film electrodes to 0.2 cm and raising the surface area of the cross section of electrodes and specific solution conductance. The COD listing for the samples after treatment fell below 100 mg/L which is much lower than the acceptable limits of COD ≤250 mg/L. The BOD for dye effluent from the two-way ANOVA with replication portrayed a significant variation (p=0.0000238) when compared to the one of WHO 2002 with the range of 150±5 mg/L. The colour removal was 99.97% showing that, the optimized process was effective and efficient in the degradation of these azo dyes in