Solar Light Responsive Poly(vinyl alcohol)-Assisted Hydrothermal Synthesis of Immobilized TiO₂/Ti Film with the Addition of Peroxymonosulfate for Photocatalytic Degradation of Ciprofloxacin in Aqueous Media: A Mechanistic Approach

Abstract

This study is focused on the synthesis of a solar light driven novel poly(vinyl alcohol) (PVA)-assisted TiO 2 /Ti film via a facile one pot hydrothermal technique and then its photocatalytic applications by adding with peroxymonosulfate (PMS) for efficient degradation of ciprofloxacin (CIP). The key hydrothermal synthesis parameters like PVA-content, hydrothermal time (H T ), and pH were optimized. The best photocatalytic performance of the synthesized material was observed when prepared with the conditions of PVA = 8 mg, H T = 3 h, and pH = 2.62. Results showed that 98.3% of CIP was degraded within 60 min by PVA-assisted TiO 2 /Ti film with 0.5 mM PMS added, compared to 89.38% and 88.86% degradation with 0.5 mM persulfate (PS) and 0.5 mM hydrogen peroxide (H 2 O 2 ), respectively. The photocatalytic degradation of CIP by PVA-assisted TiO 2 /Ti film with PMS added was dependent on the [PMS] 0 and increased with increase in [PMS] 0 . The k app values at [PMS] 0 of 0.2, 0.5, 0.8, and 1.0 mM were 0.029, 0.0582, 0.068, and 0.128 min −1 , respectively. The photocatalytic degradation of CIP by PVA-assisted TiO 2 /Ti film with PMS added under solar light irradiation was highly dependent on the [pH] 0 as well as on the presence of coexisting anions like HCO 3 − , CO 3 2− , NO 2 − , Cl − , and SO 4 2− . Natural organic matter (NOM) retarded the photocatalytic degradation of CIP by PVA-assisted TiO 2 /Ti film with PMS added under solar light irradiation due to its strong scavenging ability toward • OH and SO 4 •−. The photocatalytic degradation of CIP by as-prepared photocatalyst under solar light irradiation was higher in Milli-Q water (k app = 0.0582 min −1 ) than tap water (k app = 0.0342 min −1 ) followed by river water (k app = 0.0259 min −1 ) and then synthetic wastewater (k app = 0.0212 min −1 ). The degradation products of CIP were investigated by UPLC-MS/MS, and accordingly degradation pathways were proposed. Moreover, the mineralization, ecotoxicity, and cyclic photocatalytic stability of the as-prepared photocatalyst were also investigated. These findings suggest that as-prepared PVA-assisted TiO 2 /Ti film with PMS added is a promising alternative for the treatment of wastewater containing antibiotics.

Magnetic nano-biocomposite CuFe2 O4 @methylcellulose (MC) prepared as a new nano-photocatalyst for degradation of ciprofloxacin from aqueous solution

“…These by-products compete with the initial concentration of antibiotics in contact with the catalyst, which leads to a decrease in the CIP degradation (35,36). Also, by increasing the initial concentration of antibiotics, more photons are absorbed by CIP and are less involved in photocatalytic process (34), which is consistent with the results of the study of Sayed et al (37). The results showed that by increasing the amount of photocatalyst up to 0.2 g, the removal efficiency was significantly increased (Figure 10).…”

Correlation of Active Sites to Generated Reactive Species and Degradation Routes of Organics in Peroxymonosulfate Activation by Co-Loaded Carbon

“…•− and • OH might transform into less oxidative HSO 5 − and SO 5 2− species, slowing down the kinetics of CIP oxidation. 61,62 Additionally, the generation of SO 4…”

Facile Fabrication of Z-Scheme Bi2WO6/WO3 Composites for Efficient Photodegradation of Bisphenol A with Peroxymonosulfate Activation

“…For pure WO3, the O 1s XPS spectra (Figure 6d) centered at 529.6 eV is deconvoluted to characteristic peaks at 530.22 and 532.05 eV, assigned to oxygen group from lattice oxygen and adsorbed oxygen species, respectively [20,30,34]. Nevertheless, the O 1s spectrum of BW3 could be deconvoluted to three peaks at 529.90, 530.49, and 531.63 eV, which are derived from lattice oxygen of [Bi2O2] 2+ and [WO4] 2− and the adsorbed hydrated species, respectively [15,40]. The results demonstrate that the surfaces of WO3 nanorods are well covered by Bi2WO6.…”

“…PMS could be activated to generate sulfate radicals (•SO 4 − ) and hydroxyl radicals (•OH) [7,8]. The •SO 4 − has been found to be a superior alternative for the environmental remediation of organic contaminants, due to its great advantage, including stronger oxidizing properties, higher oxidation selectivity, and more rapid degradation rate, in contrast to the transfer and separation of photogenerated charges of photocatalysts, leading to an enhanced the catalytic performance [7,13,15]. However, the application of current photocatalytic materials in PMS activation is far from satisfactory due to its insufficient light absorption, low efficiency of photogenerated charge separation, and limited surface active sites [8,16].…”