Solar Photocatalytic Degradation of Sulfamethoxazole by TiO2 Modified with Noble Metals

Abstract

Application of solar photocatalysis for water treatment is intensively studied. In this work, we investigated TiO2 modified with platinum (Pt/TiO2) and palladium (Pd/TiO2) using sulfamethoxazole (SMX) as the model contaminant. We considered the following parameters: (i) level of TiO2 modification with Pt/Pd, (ii) initial concentration of photocatalysts, (iii) geographic location where processes were conducted, and (iv) natural water matrix. The catalysts characterized by SEM, EDX, DRS, and XRD techniques showed successful deposition of Pd and Pt atoms on TiO2 surface that enabled light absorption in the visible (Vis) range, and therefore caused efficient SMX removal in all tested conditions. A comparison of the rate constants of SMX degradation in various conditions revealed that modification with Pd gave better results than modification with Pt, which was explained by the better optical properties of Pd/TiO2. The removal of SMX was higher with Pd/TiO2 than with Pt/TiO2, independent of the modification level. In the experiments with the same modification level, similar rate constants were achieved when four times the lower concentration of Pd/TiO2 was used as compared with Pt/TiO2. Formation of four SMX transformation products was confirmed, in which both amine groups are involved in photocatalytic oxidation. No toxic effect of post-reaction solutions towards Lepidium sativum was observed.

Mechanistic pathways for the degradation of SMX drug and floatation of degraded products using F–Pt co-doped TiO2 photocatalysts

“…Indeed, the photocatalytic degradation rate of SMX, using pristine P25 TiO 2 , was around 35% within 120 min which remains similar or slightly higher even by increasing the degradation time. 39 The reported results in the literature shows clearly that the unchanged TiO 2 has less effect on 27668 | RSC Adv., 2020, 10, 41 which is matching with degradation rate in the present work. However, in the literature there is no reporting documents that shows the oatation of the degraded product except our earlier published work.…”

Application of TiO2-Based Photocatalysts to Antibiotics Degradation: Cases of Sulfamethoxazole, Trimethoprim and Ciprofloxacin

“…The phytotoxicity of photocatalysis products towards plant Lepidium sativum was studied by Borowska et al [123]. After 60 min of solar irradiation of TiO 2 catalysts doped with noble metals, toxicity was eliminated: germination index increased from 43 ± 4% for initial 1 mgL −1 SMX solution to 93 ± 10% and 110 ± 16% for solutions treated with Pd/TiO 2 and Pt/TiO 2 , respectively.…”

Morphology, Photocatalytic and Antimicrobial Properties of TiO2 Modified with Mono- and Bimetallic Copper, Platinum and Silver Nanoparticles

“…At the metal-semiconductor interface upon UV light irradiation, a Schottky barrier is created, which retards the charge carriers recombination by trapping electrons. Under visible light irradiation, TiO 2 is activated during LSPR decay through electron transfer from metal nanoparticles (Ag, Au, Cu, Pt or Pd) to titanium(IV) oxide conduction band [5,9,22,23,24,25].…”