Improving heterogeneous photo-Fenton catalytic degradation of toluene under visible light irradiation through Ba-doping in BiFeO3 nanoparticles

Strategies for enhancing performance of perovskite bismuth ferrite photocatalysts (BiFeO3): A comprehensive review

Organic pollutants pose a significant threat to water safety, and their degradation is of paramount importance. Photocatalytic technology has emerged as a promising approach for environmental remediation, and Bismuth ferrite (BiFeO3) has been shown to exhibit remarkable potential for photocatalytic degradation of water pollutants, with its excellent crystal structure properties and visible light photocatalytic activity. This review presents an overview of the crystal properties and photocatalytic mechanism of perovskite bismuth ferrite (BiFeO3), as well as a summary of various strategies for enhancing its efficiency in photocatalytic degradation of organic pollutants. These strategies include pure phase preparation, microscopic modulation, composite modification of BiFeO3, and the integration of Fenton-like reactions and external field-assisted methods to improve its photocatalytic performance. The review emphasizes the impact of each strategy on photocatalytic enhancement. By providing comprehensive strategies for improving the efficiency of BiFeO3 photocatalysis, this review inspires new insights for efficient degradation of organic pollutants using BiFeO3 photocatalysis and contributes to the development of photocatalysis in environmental remediation.

An immobilization of aminopropyl trimethoxysilane-phenanthrene carbaldehyde on graphene oxide for toluene extraction and separation in water samples

A new functionalized Nano graphene with aminopropyl trimethoxysilane-phenanthrene-4-carbaldehyde (NGO@APTMS-PNTCA) as a novel adsorbent was used to extract toluene from water samples by the ultrasound-assisted dispersive solid-phase microextraction procedure (USA-D-SPME). So, 50 mg of NGO@APTMS-PNTCA adsorbent was added to water samples and sonicated for 20 min. After toluene extraction, the NGO@APTMS-PNTCA adsorbent separated from the liquid phase with a Whatman membrane filter (200 nm). Then, the toluene was back-extracted from the adsorbent by 2.0 mL of the acetone/ethanol (1:1, eluent) at 25 °C. Due to the physical properties and structure of toluene, fluorobenzene was used as an internal standard. Finally, the toluene values were measured by a gas chromatography-flame ionization detector (GC-FID). In optimized conditions, the limit of detection (LOD), the working range (WR), and the enrichment factor (EF) were obtained at 2.5 μg L^-1, 0.01-1.2 mg L^-1, and 9.63, respectively (MRSD% = 3.38). Also, the limit of quantification (LOQ) 10 μg L^-1 and extraction recovery of more than 95% was efficiently achieved for toluene. Standard additions of toluene to blank solutions had high recoveries between 95.2% and 104.5% with a relative standard deviation (RSD%) of 0.27-5.2. The absorption capacities of NGO and NGO@APTMS-PNTCA adsorbents for toluene extraction were obtained at 32.8 mg g^-1 and 154.9 mg g^-1, respectively. The USA-D-SPME method was validated by spiking the standard concentrations of toluene. The proposed method demonstrated relevant and suitable statistical results with high accuracy and precision for toluene extraction by a novel adsorbent synthesis.

Mechanism and efficiency of photocatalytic triclosan degradation by TiO2/BiFeO3 nanomaterials

Hierarchical porous TiO₂ photocatalytic nanomaterials were fabricated by impregnation and calcination using a peanut shell biotemplate, and TiO₂/BiFeO₃ composite nanomaterials with different doping amounts were fabricated using hydrothermal synthesis. The micromorphology, structure, element composition and valence state of the photocatalyst were analyzed using a series of characterization methods, including X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), BET surface area (BET), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance (UV-vis), fluorescence spectroscopy (PL) and other technological means. Finally, the degradation mechanism and efficiency of BiFeO₃ composite photocatalyst on the target pollutant triclosan were analyzed using a xenon lamp to simulate sunlight. The results showed that TiO₂/BiFeO₃ catalyst fabricated using a peanut shell biotemplate has a specific surface area of 153.64 m²/g, a band gap of 1.92 eV, and forms heterostructures. The optimum doping amount of TiO₂/BiFeO₃ catalyst was 1 mol/mol, and the degradation rate was 81.2%. The main active substances degraded were ·O₂^-and ·OH. The degradation process measured is consistent with the pseudo-first-order kinetic model.

Fabrication of Ternary Nanoparticles for Catalytic Ozonation to Treat Parabens: Mechanisms, Efficiency, and Effects on Ceratophyllum demersum L. and Eker Leiomyoma Tumor-3 Cells

The use of parabens in personal care products can result in their leakage into water bodies, especially in public swimming pools with insufficient water treatment. We found that ferrite-based nanomaterials could catalytically enhance ozone efficiency through the production of reactive oxygen species. Our objective was to develop a catalytic ozonation system using ternary nanocomposites that could minimize the ozone supply while ensuring the treated water was acceptable for disposal into the environment. A ternary CuFe2O4/CuO/Fe2O3 nanocomposite (CF) delivered excellent degradation performance in catalytic ozonation systems for butylparaben (BP). By calcining with melamine, we obtained the CF/g-C3N4 (CFM) nanocomposite, which had excellent magnetic separation properties with slightly lower degradation efficiency than CF, due to possible self-agglomeration that reduced its electron capture ability. The presence of other constituent ions in synthetic wastewater and actual discharge water resulted in varying degradation rates due to the formation of secondary active radicals. 1O2 and •O2− were the main dominant reactive species for BP degradation, which originated from the O3 adsorption that occurs on the CF≡Cu(I)−OH and CF≡Fe(III)−OH surface, and from the reaction with •OH from indirect ozonation. Up to 50% of O3-treated water resulted in >80% ELT3 cell viability, the presence of well-adhered cells, and no effect on the young tip of Ceratophyllum demersum L. Overall, our results demonstrated that both materials could be potential catalysts for ozonation because of their excellent degrading performance and, consequently, their non-toxic by-products.

Photocatalyst production from wasted sediment and quality improvement with titanium dioxide to remove cephalexin in the presence of hydrogen peroxide and ultrasonic waves: A cost-effective technique

In this study, wasted sediment (sludge waste from shipping docks) was coupled with titanium isopropoxide by the thermal and sol-gel method as a new photocatalyst. The sediment-titanate catalyst alongside ultrasonic and UV was activated hydrogen peroxide to produce OH radicals and decompose cephalexin (CEP). The photocatalyst was crystalline with 52.29 m²/g BET area. The best destruction rate of 87.01% based on COD test was achieved at optimal conditions (pH: 8, cephalexin concentration: 100 mg/L, H₂O₂: 1.63 mg/L, UV: 15 W/m², ultrasonication time: 100 min at 40 kHz, photocatalyst quantity: 1.5 g/L). The trend of anions effect was NO₃^- ≤ SO₄^2- ≤ Cl^-. Decomposition of cephalexin in water solution followed the first-order kinetics (k > 0.01 min^-1, R² > 0.9). The percentage of cephalexin removal from urban water (76%) and hospital wastewater (63%) has decreased compared to the distilled water solution (87%), which is probably due to the presence of radical inhibitors. The consumed electrical energy of the studied system was calculated by 0.031 kW/h. The developed system is a promising and economical method to remove cephalexin.

Highly efficient microwave-assisted Fenton degradation bisphenol A using iron oxide modified double perovskite intercalated montmorillonite composite nanomaterial as catalyst

In this work, perovskite intercalated montmorillonite (MMT) composite catalyst loaded by different mass fraction iron oxide, xFe₂O₃/LaCu_0.5Co_0.5O₃-MMT_0.2 (x was the mass fraction of Fe₂O₃ and x = 0.02, 0.04, 0.06), were prepared by impregnation method, and their catalytic activity were evaluated by microwave induced catalytic degradation of bisphenol A (BPA). Fe₂O₃ had a certain absorption effect on microwave, which could enhance the absorption property of composite material, improve the catalytic activity of catalyst. XRD, SEM, XPS and vector network analysis were used to analysis the structure, morphology, surface element composition and microwave absorption performance of the composite catalyst. The results indicated that the sample had uniform structure, a larger specific surface, a higher ratio of O_ads/O_lat and excellent microwave absorption performance. The effects of microwave power, pH value and H₂O₂ dosage on the catalytic degradation performance were studied, and 0.04Fe₂O₃/LCCOM_0.2 had the most obvious effect on the removal of BPA. The possible reaction mechanisms were discussed by characterization and experimental results of free radical capture. The surface active sites of the catalyst could be excited by microwave to generate oxidative free radicals, which could degrade BPA through electron hole transport. Response surface methodology (RSM) was used to optimize the operation parameters for the 0.04Fe₂O₃/LCCOM_0.2-BPA microwave degradation system.

Ti-Modified LaFeO3/β-SiC Alveolar Foams as Immobilized Dual Catalysts with Combined Photo-Fenton and Photocatalytic Activity

Ti-modified LaFeO₃/β-SiC alveolar foams were used as immobilized, highly robust dual catalysts with combined photocatalytic wet peroxide oxidation and photocatalytic activity under UV-A light. They were prepared by incipient wetness impregnation of a β-SiC foam support, by implementing a sol-gel Pechini synthesis at the foam surface in the presence of dried amorphous sol-gel titania as a titanium source. The physicochemical and catalytic features suggest the stabilization at the foam surface of a substituted La_1-xTi_xFeO₃ catalyst analogous to its powdery counterpart. Taking 4-chlorophenol removal in water as a model reaction, its dual nature enables both high reaction rates and full total organic carbon (TOC) conversion because of a synergy effect, while its macroscopic structure overcomes the drawback of working with powdery catalysts. Further, it yields photonic efficiencies for degradation and mineralization of ca. 9.4 and 38%, respectively, that strongly outperform those obtained with a reference TiO₂ P25/β-SiC foam photocatalyst. The enhancement of the catalyst robustness upon Ti modification prevents any Fe leaching to the solution, and therefore, the optimized macroscopic foam catalyst with 10 wt % catalyst loading operates through pure heterogeneous surface reactions, without any activity loss during reusability test cycles.

Activity enhancement pathways in LaFeO3@TiO2 heterojunction photocatalysts for visible and solar light driven degradation of myclobutanil pesticide in water

LaFeO₃@TiO₂ heterojunction composites with a core-shell porous structure and LaFeO₃ contents in the 2.5-25 wt.% range have been synthesized via consecutive sol-gel syntheses and tested for the photocatalytic oxidation of the myclobutanil pesticide in water under solar light and pure visible light. Whatever the light spectrum, the kinetic rate constants for both myclobutanil degradation and TOC conversion exhibited a volcano-like profile with increasing the narrow band-gap (2.1 eV) LaFeO₃ content, the optimum composite strongly overperforming both single phases, with full myclobutanil mineralization achieved in 240 min in the best case. The light spectrum influenced the optimum LaFeO₃ content in the composite, being observed at 5 wt.% and 12.5 wt.% under solar and visible light, respectively. This has been attributed to the existence of different light-mediated reaction mechanisms. The optimum LaFeO₃/TiO₂ composite photocatalyst was active and stable after several runs under solar light with leached iron concentration below 0.1 mg/L in solution.

Photocatalytic Advanced Oxidation Processes for Water Treatment: Recent Advances and Perspective

Nowadays, an ever-increasing variety of organic contaminants in water has caused hazards to the ecological environment and human health. Many of them are persistent and non-biodegradable. Various techniques have been studied for sewage treatment, including biological, physical and chemical methods. Photocatalytic advanced oxidation processes (AOPs) have received increasing attention due to their fast reaction rates and strong oxidation capability, low cost compared with the non-photolytic AOPs. This review is dedicated to summarizing up-to-date research progress in photocatalytic AOPs, such as Fenton or Fenton-like reaction, ozonation and sulfate radical-based advanced oxidation processes. Mechanisms and activation processes are discussed. Then, the paper summarizes photocatalytic materials and modification strategies, including defect chemistry, morphology control, heterostructure design, noble metal deposition. The future perspectives and challenges are also discussed.

Bi2O3-BiFeO3 Glass-Ceramic: Controllable β-/γ-Bi2O3 Transformation and Application as Magnetic Solar-Driven Photocatalyst for Water Decontamination

Glass and glass-ceramic materials containing photoactive and magnetic crystalline phases were prepared from Fe₂O₃ and Bi₂O₃ using the conventional melt method. All samples were characterized in terms of formed phases, morphological analyses, optical properties, and magnetic properties. Formation of the photoactive tetragonal β- and body-centered cubic γ-Bi₂O₃ phases along with the magnetic BiFeO₃ and Fe₃O₄ phases was revealed. However, the crystalline structure relied on the composition and the applied heat-treatment time. β-/γ-Bi₂O₃ transformation could be controlled by the heat-treatment time. The samples exhibited variable magnetic properties depending on their composition. All of the samples showed excellent absorbance in visible light with an optical band gap of 1.90-2.22 eV, making them ideal for solar-light-driven photocatalysis. The best performance was recorded for the sample containing equal amounts of Fe₂O₃ and Bi₂O₃ due to the formation of γ-Bi₂O₃/BiFeO₃ heterojunction in this sample.

Synergy effect between photocatalysis and heterogeneous photo-Fenton catalysis on Ti-doped LaFeO3 perovskite for high efficiency light-assisted water treatment

Synergy effect between photocatalysis and H₂O₂-mediated heterogeneous photo-Fenton catalysis on highly robust Ti-substituted La_1−xTi_xFeO₃ perovskites led to high performances under UV-A light in water treatment.

Influence of precursor pH on the structure and photo-Fenton performance of Fe/hydrochar

Fe/hydrochar exhibited high visible light photo-Fenton activity because hydrochar accelerated the Fe³⁺/Fe²⁺ cycle at the catalyst/water interface.