Microwave-assisted sol-gel synthesis of an Au-TiO2 photoanode for the advanced oxidation of paracetamol as model pharmaceutical pollutant

Abstract

An Au-TiO 2 photoanode on carbon cloth has been synthesized by microwave-assisted sol-gel method to treat paracetamol solutions at pH 3.0 by photocatalysis (PC), electro-oxidation (EO), photoelectrocatalysis with UVA light (PEC), solar PEC (SPEC) and hybrid methods with photoelectro-Fenton under UVA (PEC + PEF) and sunlight (SPEC + SPEF) irradiation at constant anodic potential (E an). The photoanode has been characterized by XRD, Raman spectroscopy, HRTEM and SEM-EDS. The counter electrode was a 316L stainless steel plate, which was replaced by an air-diffusion electrode for H 2 O 2 generation in hybrid treatments. The most powerful process was SPEC + SPEF, yielding total paracetamol removal in <30 min and 24% mineralization after 180 min, at E an = +0.82 V. The paracetamol decay followed a pseudo-first-order kinetics in PEC. A lower rate constant was obtained upon increase of pharmaceutical concentration, showing good linear fit using a Langmuir-Hinshelwood model.

SiO2@TiO2 Composite Synthesis and Its Hydrophobic Applications: A Review

“…The photocatalytic properties are exhibited under irradiation with UV light, due to the band gap value of 3.2 eV, limiting the application. However, these properties can be increased by diminution of the band gap [39,40]. The photocatalytic process begins with the photogeneration of holes and electrons, which are diffusing to the surface, where reactive species react with the pollutant; as a result, a series of oxidation and reduction phenomena take place as shown in Figure 2 [41].…”

Metal-Loaded Mesoporous MCM-41 for the Catalytic Wet Peroxide Oxidation (CWPO) of Acetaminophen

“…AOPs have proven to be capable and effective to completely degrade pharmaceutical compounds from aqueous solutions. For this purpose, different catalysts have been tested, such as metal oxides [13][14][15][16], oxide metal containing mesoporous silica Santa Barbara Amorphous-15 (SBA-15) [17], metal nanoparticles (NPs) supported on organic-inorganic matrix [18], metal containing zeolite [19], metal-carbon xerogels [20] or clays [21,22], among many others. In all cases, the catalysts used for this type of reactions require the presence of active transition metals in the form of oxides, nanoparticles or zero-charge metallic species.…”

Nanoparticles in Agroindustry: Applications, Toxicity, Challenges, and Trends

“…The degradation processes of the catalysts mentioned above are mainly carried out in wastewater treatments to remove recalcitrant and persistent pollutants such as dyes and pharmaceutical compounds, and the catalysts even work as disinfection agents [ 23 , 24 , 25 , 26 ]. The remaining effluents are used for watering some crop fields without any proper legislation [ 27 , 28 ], and no toxicology studies are well substantiated yet, because the remained NPs in the effluents are considered not dangerous in low concentrations.…”