Sustainable wastewater treatment based on the principle of advanced oxidation processes

Abstract

Environmental remediation needs scientific contributions with growing urgency. This research is seeking to provide the foundation of novel products made from renewable by-product waste feedstocks and intended to be reused, recycled, and subsequently the feedstock refreshed through wastewater treatment processes. Utilization of alum sludge waste as a photocatalyst in the catalytic oxidation of wastewater to provide the potential capability of OH radical use as a strong oxidant is explored. Moreover, photo-Fenton oxidation is an advanced oxidation processes used to oxidize wastewater using expensive chemicals. This research work aims to investigate low-cost photo-Fenton catalysts from drinking water treatment residuals and magnetite nanoparticles. The factors that are influencing the oxidation of the model wastewater systems, i.e. dyes and carbamate pesticide were examined and reported. The results of this thesis is divided into several parts, the first part focuses on testing the activity of magnetite nanoparticles as a photo-catalyst to treat different pollutants, MB dye, LB dye and methomyl pesticide solutions. Nanostructured magnetite as the precursor of the oxidation technique has been synthesized via a simple co-precipitation technique. X-Ray Diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied to characterize the prepared samples. Then, the synthesized and examined magnetite nanostructured sample was used as the precursor of the Fenton reaction process. The heterogeneous iron (Fe2+/Fe3+) supported catalyst with hydrogen peroxide (H2O2) were used as a coupled Fenton and Fenton-like oxidation system for methylene blue (MB) dye removal in aqueous media. The obtained results showed that the dye oxidation rate increases with decreasing pH value to 3.0. However, increasing H2O2 and magnetite (Fe3O4) nanoparticles catalyst results in an increase in the dye oxidation rate and the optimum operating values were 80 and 1600 mg/L for Fe3O4 and H2O2, respectively. By optimizing the amount of reagents and process conditions, the results revealed that magnetite was considered an efficient Fenton-based catalyst for dye oxidation that reached to 94% within 3 hr of oxidation time.