Browsing by Author "ALAMRI, RAHMAH DHAHAWI"

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HETEROGENEOUS FENTON DEGRADATION OF OFLOXACIN IN AQUEOUS SOLUTION USING Fe3O4-ZEOLITE, Fe3O4-MONTMORILLONITE AND Fe3O4-MONTMORILLONITE ALGINATE COMPOSITES
(2023-04) ALAMRI, RAHMAH DHAHAWI; Adnan, Rohana
The primary aim of this study is to develop an economical, stable and effective heterogeneous catalyst for wastewater remediation via the Fenton oxidation process. Fe3O4 can effectively activate H2O2 to produce hydroxyl radicals, but the particles agglomerate easily. To solve this problem, Fe3O4-zeolite (FeZ) and Fe3O4- montmorillonlite (FeM) composites were synthesized via a facile co-precipitation method and characterized using various techniques. The performance of each of the catalysts was evaluated via the Fenton degradation of ofloxacin (OFL), an antibiotic and a recalcitrant pollutant because of its high activity and poor biodegradability. The effect of parameters such as amount of Fe precursor, catalyst dosage, initial solution pH, initial OFL concentration, different oxidants, H2O2 dosage, reaction temperature and inorganic salts on the OFL removal percentage were investigated.Loading of Fe3O4 onto zeolites resulted in the formation composites with higher surface area and pore volume. Experimental results revealed that as much as 88% OFL from the aqueous OFL solution 20 mg/L and 51.2% total organic carbon (TOC) could be removed in 120 min using FeZ-8 catalyst at the optimum condition. Since montmorillonite is capable to adsorb OFL at higher concentration, the OFL initial concentration was adjusted to 50 mg/L for FeM. The efficiency of the FeM composite in the removal of OFL from the aqueous solution was also investigated using the same experimental parameters. Under the optimum condition and at the pH of the neutral OFL solution via the heterogeneous Fenton in the presence of H2O2 was almost 81%, while the total organic carbon (TOC) reduction was about 56% in 120 minutes. Both FeZ and FeM composites show a decrease in the removal percentage by as much as 8.89 and 21.42% in the fifth cycle, respectively and this was assumed to be due to the high leaching of the Fe ions which are 56.19 and 65.37%, respectively. Since the Fenton degradation efficiency of FeM is higher compared to FeZ, the FeM composite was immobilized into calcium alginate to form FeMA composite beads to overcome this problem. Under otherwise the same condition, the OFL removal percentage using FeMA beads reaches about 80%, while the total organic carbon (TOC) removal reaches about 53% with a minimal decrease (2%) in the removal percentage in the fifth cycle. The composite beads could be easily separated, recycled and the leaching of iron ions is low, 0.142 mg/L (at the fifth cycle). Based on the experimental results, it is thus concluded that the FeMA composite beads synthesized has a great potential as a heterogeneous Fenton catalyst for the degradation of organic pollutants such as antibiotic in real and large scale applications.
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