Degradation of Sulfamethoxazole Using Iron-Doped Titania and Simulated Solar Radiation

Abstract

This work examined the photocatalytic destruction of sulfamethoxazole (SMX), a widely used antibiotic, under simulated solar radiation using iron-doped titanium dioxide as the photocatalyst. Amongst the various iron/titania ratios examined (in the range 0%–2%), the catalyst at 0.04% Fe/TiO2 molar ratio exhibited the highest photocatalytic efficiency. The reaction rate followed pseudo-first-order kinetics, where the apparent kinetic constant was reduced as the initial concentration of SMX or humic acid increased. The photodecomposition of SMX was favored in natural pH but retarded at alkaline conditions. Unexpectedly, the presence of bicarbonates (in the range of 0.125–2 g/L) improved the removal of SMX, however, experiments conducted in real environmental matrices showed that process efficiency decreased as the complexity of the water matrix increased. The presence of sodium persulfate as an electron acceptor enhanced the reaction rate. However, only a small synergy was observed between the two individual processes. On the contrary, the addition of tert-butanol, a well-known hydroxyl radical scavenger, hindered the reaction, indicating the significant contribution of these radicals to the photocatalytic degradation of SMX. The photocatalyst retained half of its initial activity after five successive experiments.

New Evidence of the Enhanced Elimination of a Persistent Drug Used as a Lipid Absorption Inhibitor by Advanced Oxidation with UV-A and Nanosized Catalysts

“…A strong influence of the water matrix on the photooxidation of methylparaben was previously reported by Velegraki et al [56]. Similarly, Tsiampalis et al [2], who studied the degradation of sulfamethoxazole with iron-doped titania, found a decrease in the degradation rate of this molecule Figure 7. Effect of the water matrix on the photocatalytic degradation of clofibric acid (30 mg/L of clofibric acid, 1 g/L of catalyst, 9.52 mW/cm 2 , room temperature).…”

“…A strong influence of the water matrix on the photooxidation of methylparaben was previously reported by Velegraki et al [56]. Similarly, Tsiampalis et al [2], who studied the degradation of sulfamethoxazole with iron-doped titania, found a decrease in the degradation rate of this molecule when the reaction is conducted in secondary treated wastewater and diluted wastewater.…”

“…In a global environmental context, the formulation of novel synthetic pharmaceuticals is sadly associated with their misuse. These molecules are detected in water bodies, effluents of wastewater treatment plants (WWTPs), and even in drinking water in very low concentrations (low ppb levels); as a consequence, they are considered an important class of emergent water pollutants [1][2][3][4]. For example, numerous scientific reports indicate the presence of acidic drugs in wastewater treatment plants, as well as in surface water and groundwater [1].…”

UV-Catalyzed Persulfate Oxidation of an Anthraquinone Based Dye

“…A source of clean water is important for various industrial, social and economic development sectors; therefore, it has to be constantly monitored for impurities. Increased human activity has introduced a wide range of toxic chemicals including inorganic (e.g., chromium, mercury, lead) and organic (e.g., pesticides, surfactants, pharmaceuticals) pollutants into the aqueous environment [1,2]. A significant source of such polluting compounds is wastewater from the textile industry, which is classified as the most polluting of all industrial sectors in terms of effluent volume and its chemical content [3].…”

Nanocomposites containing titanium dioxide for environmental remediation

“…At 30% loading of calcite in titania exhibited the best degradation of tetracycline under neutral conditions. Iron doped titania was studied by Tsiampalis for sulfamethaxoazole degradation under solar radiation [ 141 ]. Moosavi et al reported the degradation of Amoxicillin using supported titania nano photocatalysts [ 142 ].…”