Complete decomposition of sulfamethoxazole during an advanced oxidation process in a simple water treatment system

A simple water treatment system consisting of a deep UV light (λ = 222 nm) source, a mesoporous TiO₂/boron-doped diamond (BDD) photocatalyst, and a BDD electrode was prepared and used to decompose sulfamethoxazole (SMX) in an advanced oxidation process. The mesoporous TiO₂/BDD photocatalyst used with the electrochemical treatment promoted SMX decomposition, but the mesoporous TiO₂/BDD photocatalyst alone had a similar ability to decompose SMX as photolysis. Fragments produced through photocatalytic treatment were decomposed during the electrochemical treatment and fragments produced during the electrochemical treatment were decomposed during the photocatalytic treatment, so performing the electrochemical and photocatalytic treatments together effectively decomposed SMX and decrease the total organic carbon concentration to a trace.

Carbamazepine degradation by visible-light-driven photocatalyst Ag3PO4/GO: Mechanism and pathway

Carbamazepine (CBZ), as one of the most frequently detected pharmaceuticals, is of great concern due to its potential impact on the ecosystem and human health. This study provides an effective approach to remove CBZ by using photocatalyst silver phosphate combined with graphene oxide (Ag₃PO₄/GO) under visible irradiation. The morphology, composition, and optical properties of Ag₃PO₄/GO were characterized employing SEM, XRD, and DRS. Graphene oxide could improve the visible-light utilization and promote electron's charge to enhance the photocatalytic performance of Ag₃PO₄/GO. With the optimal reaction condition of 5.86 mW/cm² light intensity, 15-25 °C temperature, 5-7 pH, and 0.5 mg/L catalytic dosages, 5 mg/L CBZ could be completely degraded in 30 min, and the apparent rate constant could reach 0.12 min^-1. Additionally, the radical trapping experiments indicated •OH and O₂-• were the main reactive oxygen species employed to eliminate CBZ. The decay pathways of CBZ had been proposed accordingly, and the main product was the low-molecular products.

Immobilized Ag3PO4/GO on 3D nickel foam and its photocatalytic degradation of norfloxacin antibiotic under visible light

In this study, a series of Ag₃PO₄/graphene oxide (GO) films were dip-coated on a metal nickel foam. The immobilized catalysts were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy and photoluminescence spectroscopy. The results show that Ag₃PO₄/GO was successfully supported on a nickel foam. The photocatalytic activity of the film catalyst under visible light was investigated by the degradation of norfloxacin, an antibiotic. Photocatalytic stability of this catalyst was also investigated. An optimized film exhibited superior activity and stability, the degradation rate of norfloxacin was about 83.68% in 100 min and the reaction rate constant k was 1.9 times that of pristine Ag₃PO₄. Further investigation found that photo-generated holes (h⁺) and superoxide anion radicals (·O₂⁻) are the main active species in the photodegradation process. The result indicates that the addition of GO inhibits the recombination of photogenerated electron–hole pairs, and thus has improved the photocatalytic activity and cyclic stability under visible light. The photocatalytic mechanism of the film catalyst was proposed. The prepared Ag₃PO₄/GO film catalyst is a promising candidate for treatment of wastewater containing antibiotics.

A series of Ag₃PO₄/graphene oxide catalysts were dip-coated onto 3D nickel foam for photocatalytic degradation of norfloxacin antibiotics.

An advanced composite with ultrafast photocatalytic performance for the degradation of antibiotics by natural sunlight without oxidizing the source over TMU-5@Ni–Ti LDH: mechanistic insight and toxicity assessment

Pharmaceuticals are considered as emerging organic contaminants that have become a serious environmental problem, which endanger human health and environmental bio-diversity.

Graphene and graphene-based nanocomposites used for antibiotics removal in water treatment: A review

Due to their extensive application in human and veterinary medicine, antibiotics have been found worldwide and studied as new pollutants in the aquatic environment. In order to remove such pollutants, adsorption and photocatalysis have attracted tremendous attention because of their great potential in antibiotics removal from aqueous solutions. Graphene, as a novel two-dimensional nanomaterial, possesses unique structure and physicochemical properties, which can be used to efficiently adsorb and photodegrade antibiotics. This review provides an overview of the adsorptive and catalytic properties of graphene, and recent advances in adsorption and photodegradation of antibiotics by graphene and its derivatives. The factors that affect the adsorption and photodegradation of antibiotics are reviewed and discussed. Furthermore, the underlying mechanisms of adsorption and photodegradation are summarized and analyzed. Meanwhile, statistical analysis is conducted based on the number of papers and the maximum adsorption and photodegradation ability on various antibiotics removal. Finally, some unsolved problems together with major challenges that exist in the fabrication and application of graphene-based nanocomposites and the development for antibiotics removal is also proposed. This work provides theoretical guidance for subsequent research in the field of adsorption and photocatalytic removal of antibiotics from aqueous solution, especially on influence factors and mechanisms aspects.

Key role of hydrochar in heterogeneous photocatalytic degradation of sulfamethoxazole using Ag3PO4-based photocatalysts

To overcome the practical application limitations of Ag₃PO₄ such as photocorrosion and relatively low efficiency of photogenerated carrier seperation, Ag₃PO₄ particles were loaded onto hydrochar. The particles in the composite had a smaller crystallite size and different phase structure with more edges than pure Ag₃PO₄ particles. The as-prepared composite catalyst exhibited a different photocatalytic performance for sulfamethoxazole (SMX) degradation when varying the mass ratio of hydrochar and Ag₃PO₄. In addition to higher SMX degradation efficiency, the composite exhibited much higher TOC degradation efficiency, recycling stability, and less-toxic intermediate production. The composites enhanced visible light response, and accelerated electron transfer and photogenerated carrier separation as well. The addition of H₂O₂ to the photocatalytic system enhanced the photocatalytic activity of the composite catalyst. According to a mechanistic examination, the hole (h⁺) is the dominant reactive species for SMX degradation. This study provides new insight into high-efficiency, low cost, and easily prepared photocatalysts for pollution removal from water.

To overcome the practical application limitations of Ag₃PO₄ such as photocorrosion and relatively low efficiency of photogenerated carrier seperation, Ag₃PO₄ particles were loaded onto hydrochar.

Enhanced visible-light photocatalytic activity and photostability of Ag3PO4/Bi2WO6 heterostructures toward organic pollutant degradation and plasmonic Z-scheme mechanism

Novel Ag3PO4/Bi2WO6 heterostructured materials with enhanced visible-light catalytic performance were successfully synthesized by assembly combined with a hydrothermal treatment. The microstructures, morphologies, and optical properties of the prepared samples were characterized by multiple techniques. The irregular Ag3PO4 nanospheres dispersed on the surface of Bi2WO6 nanoflakes, and their catalytic performances were evaluated via the degradation of organic pollutants including rhodamine B (RB), methylene blue (MB), crystal violet (CV), methyl orange (MO), and phenol (Phen) under visible-light irradiation. The resulting Ag3PO4/Bi2WO6 heterostructured materials displayed higher photocatalytic activity than that of either pure Bi2WO6 or Ag3PO4. The enhanced photocatalytic activity was due to the good formation of heterostructures, which could not only broaden the spectral response range to visible light but also effectively promoted the charge separation. Meanwhile, the reasonable photoreactive plasmonic Z-scheme mechanism was carefully investigated on the basic of the reactive species scavenging tests, photoelectrochemical experiments, and photoluminescence (PL) spectrum. In addition, the excellent photostability of Ag3PO4/Bi2WO6 was obtained, which Ag formed at the early photocatalytic reaction acted as the charge transmission-bridge to restrain the further photoreduction of Ag3PO4.

Preparation of Y2SiO5:Pr3+,Li and Na2NbxTa2−xO6/(Au/RGO) composites and investigation into visible-light driven photocatalytic hydrogen production

A three-component photocatalytic system is constructed by using Na₂Nb_xTa_2−xO₆ as the main catalyst, Y₂SiO₅:Pr³⁺,Li as the up-conversion luminescence agent and Au/RGO as the co-catalyst.

Z-scheme Ag3PO4/POM/GO heterojunction with enhanced photocatalytic performance for degradation and water splitting

To develop solar light-driven photocatalysts with high activity and structural stability, Ag₃PO₄/POM/GO heterojunction has been successfully prepared by a facile method at room temperature.