| Summary: | In fulfilling the needs of the society, the introduction of new synthetic chemicals into the industry have created a new threat to the environment. Advanced Oxidation Processes (AOPs) are one of the treatment technologies currently being developed to deal with this problem. Fenton's Reagent (FR) can be considered as the oldest AOPs available today. In this thesis, study has been conducted to explore the effect of several reaction variables on FR and ultra-violet (UV) photo-Fenton processes. The aim of this study was to improve the process through manipulation of these variables which include mixing intensity, reagent dosing strategy (i.e. addition timing and position), initial dissolved oxygen content (IOOe) and UV light intensity. With consideration to the wastewater generated by textile dyeing industry, a reactive dyestuff, Reactive Black S (RBS) was used as the model pollutant. Within the range of the experimental conditions used in this study, the RBS was found to be easily decolourised by FR. RBS was observed to further increase the degradation of HZ02, which is expected to generate more hydroxyl radicals (HO·) for better RBS degradation. Mineralisation of the dyestuff, however, required higher reagents dosage and longer reaction time. Mixing intensity was found to have a significant effect on the process. The behaviour of the mixing effect appears to be a function of reagents dosing strategy applied. In general, increasing mixing intensity was found to improve the RBS mineralisation in the early stages. For a given dosing strategy, this effect was still observed later. A very high mixing rate, however, caused reduction in TOe removal. The requirement for mixing intensity could be reduced by adopting an appropriate dosing strategy, hence reducing the potential process operational cost. Initial dissolved oxygen content was also observed to have a significant influence on the FR process. Reducing the looe was found to enhance the process performance. However, the influence was trivial for the photo-Fenton process. The presence of UV light greatly enhances the FR process and the light intensity also has significant effect on the process. The significance of some of the factors was observed to change as the reaction progress. Several factors were also found to affect the process interactively and some of the effects as a function of the factors were non-linear.
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