Photocatalytic Degradation Research Articles

Nanostructured bismuth ferrite nanoparticles: synthesis, characterization, electrical/magnetic properties and photocatalytic performance.

Nanostructured bismuth ferrite (BiFeO3) single-phase nanoparticles with 76.2% crystallinity and 100% perovskite structure were synthesized using a co-precipitation method. The X-ray diffraction pattern confirmed the perovskite structure of BFO, and Rietveld refinement demonstrated the presence of a triclinic structure with the P1 space group. The Scherrer and Williamson-Hall equations were used to calculate the crystallite size (63 and 83 nm, respectively) with a grain size of almost 246 nm and an activation energy of 0.53 eV. The accumulation of free charges at interfaces, which correlate with the sample bulk and the interface between the compound and electrode space-charge polarization, was the reason behind the high values of ε'. As the frequency increased up to 1000 Hz, both dielectric constant ε' and dielectric loss ε' fell quickly. In contrast, at high frequencies, the ε' became more frequency-independent, notably when ε' increased with a temperature of up to 423 K. The sample exhibited considerable soft ferromagnetic-like activity due to the acquired nanoscale structure that promotes spin coating in the BiFeO3 antiferromagnetic phase. The significant coercivity 2624.5 Oe provides each materials in permanent magnetic and transformers. Photocatalytic activity of the BiFeO3 nanocomposite under UVA-light irradiation was performed using Congo red dye. The maximum photocatalytic degradation efficiency after 200 min for CR was 66%. The exceptional electrical and magnetic characteristics of nanostructured BiFeO3 provide new possibilities for its use in potential technological applications, i.e., spintronics, data storage microelectronics, and water treatment.

Preparation of Red TiO2 with Excellent Visible Light Absorption from Industrial TiOSO4 Solution for Photocatalytic Degradation of Dyes

Preparation of Red TiO₂ with Excellent Visible Light Absorption from Industrial TiOSO₄ Solution for Photocatalytic Degradation of Dyes

Molecular insights on benzoic acid, 3-hydrazino-4-methyl-, ethyl ester-modified gold nanoparticles for improved SERS sensing and photocatalytic degradation of dye contaminants

Molecular insights on benzoic acid, 3-hydrazino-4-methyl-, ethyl ester-modified gold nanoparticles for improved SERS sensing and photocatalytic degradation of dye contaminants

Synthesis of Gamma Irradiated Cobalt Oxide Nanoparticles for Visible Light- Induced Photocatalytic Degradation of Methylene Blue Dye

This research focuses on synthesizing and characterizing cobalt oxide (Co3O4) nanoparticles using an ionizing radiation technique. The precursor cobalt (III) hydroxide, Co(OH)3 was chemically synthesized from cobalt (II) nitrate hexahydrate, [Co(NO3)2·6H2O] as a solution precipitation technique in an alkali medium. The Co(OH)3 precursor was then exposed to a 60Co gamma radiation source at a dose of 30 kGy with a dose rate of 10 kGy/hr to obtain Co3O4 nanoparticles. The synthesized Co3O4 nanoparticles were subjected to various characterization techniques. Fourier-Transform Infrared (FT-IR) spectroscopic analysis of raw Co(NO3)2·6H2O, Co(OH)3 precursor, and Co3O4 nanoparticles revealed distinctive absorption peaks for the Co3O4 nanoparticles. X-ray diffraction analysis exhibited different characteristic diffraction angles (2θ) values, lattice spacing, and crystal size for the Co3O4 nanoparticles. SEM images of raw Co(NO3)2·6H2O, Co(OH)3 precursor, and Co3O4 nanoparticles displayed distinguishable surface morphologies. Additionally, the thermogravimetric analysis provided insight into the decomposition behaviour of the Co(OH)3 precursor. The characterization data indicated that the ionizing radiation-synthesized Co3O4 nanoparticles possessed similar properties to those synthesized using conventional methods. Furthermore, the ionizing radiationsynthesized Co3O4 nanoparticles demonstrated an efficient photo-catalytic effect in the degradation of methylene blue (MB) dye. Therefore, this study shows the successful synthesis and characterization of Co3O4 nanoparticles using an ionizing radiation technique, highlighting their potential application in photo-catalysis for the degradation of MB dye. J. of Sci. and Tech. Res. 6(1): 175-185, 2024

Engineered oxygen vacancies in NiCo2O4/BiOI heterostructures for enhanced photocatalytic pollutant degradation.

To address the bottleneck issue of poor carrier separation and transfer efficiency in NiCo2O4 photocatalyst, a novel 1D/2D-rod-on-rose-like NiCO2O4/BiOI nanohybrid with abundant OV's was successfully synthesized using a single-step hydrothermal method and employed to the photocatalytic degradation of Rhodamine B (RhB). The study revealed that the optimized NiCo2O4-OV/BiOI hybrid could possess superior photocatalytic degradation efficiency towards RhB degradation under visible light with a rate constant that was 3.8 and 3.03 times greater than that of BiOI and NiCo2O4-OV. Experimental findings indicated that the formation of NiCo2CO4-OV/BiOI heterojunction significantly improved the charge separation efficiency and facilitated the formation of surface OV's. These OVs enhanced photogenerated e--h+ separation and increased catalytic efficiency. Quenching experiments results confirmed that both holes and superoxide radicals are playing crucial roles in the degradation process. Thus, an oxygen vacancy and engineering NiCo2CO4-OV/BiOI heterojunction-enhanced degradation mechanism was proposed, offering insights for the integration of advanced oxidation technologies and the development of catalytic materials to enhance pollutant degradation efficiency.

Utilization of egg white for the eco-friendly synthesis of cobalt oxide nanoparticles aimed at the photocatalytic degradation of methylene blue and ciprofloxacin

Utilization of egg white for the eco-friendly synthesis of cobalt oxide nanoparticles aimed at the photocatalytic degradation of methylene blue and ciprofloxacin

Utilization of Novel (KNbO3)1−x(Ba2FeNbO6)x (x = 0.1, 0.2, 0.3) Solid Solutions for Efficient Photo‐Assisted Fenton Degradation of Methylene Blue Dye

Novel (KNbO3)1−x(Ba2FeNbO6)x (x = 0.1, 0.2, 0.3) solid solutions corresponding to K0.82Ba0.18Fe0.09Nb0.91O3, K0.64Ba0.36Fe0.18Nb0.82O3, and K0.46Ba0.54Fe0.27Nb0.73O3 compounds have been synthesized via molten salt method. X‐ray diffraction confirms the formation of solid solutions, while transmission electron microscopy combined with energy‐dispersive spectroscopy results demonstrates a homogeneous distribution of elements. The obtained solid solutions crystallized in a cubic crystal structure, whereas the parent KNbO3 possesses an orthorhombic structure. The wide bandgap semiconductor KNbO3 transformed into a visible‐light‐active material, with its bandgap energy reduced from 3.56 eV to ≈2.4 eV. The substitution of K in KNbO3 with Ba is responsible for structural modification from orthorhombic to cubic symmetry, whereas both structural modification and the substitution of Nb with Fe correlated with optical properties. The photocatalytic activities of all obtained solid solutions are improved compared with the parent KNbO3 and Ba2FeNbO6 compounds for photocatalytic degradation of methylene blue (MB) dye. Among the series of solid solutions, K0.82Ba0.18Fe0.09Nb0.91O3 photocatalysts show the highest MB removal efficiency owing to its relatively higher surface area, suppressed charge carrier recombination, and more negative conduction band edge. Moreover, K0.82Ba0.18Fe0.09Nb0.91O3 photocatalyst (0.1 g) combined with hydrogen peroxide (H2O2) to form a novel photo‐Fenton system, achieving almost complete degradation of 100 mL of 10 mg L−1 MB dye in 30 min.

Green Synthesis of Silver-Incorporated Rutile TiO2 for Enhanced Photocatalytic Degradation of Ciprofloxacin and Carmine G Dye Pollutants

Developing sustainable TiO2-based photocatalysts for environmental remediation is an increasingly significant area of research. However, a limited understanding of the long-term ecological impact of these photocatalysts poses a barrier to their practical and industrial-scale applications. To address this challenge, this work employed a green synthesis approach to prepare an Ag/TiO2 photocatalyst designed to improve environmental compatibility and enhance efficiency in pollutant degradation. Ag/TiO2 was synthesized using mushroom biomass as a natural capping to evaluate its effectiveness in the degradation of ciprofloxacin (CIP) and azo Carmine G dye (ACGD). The mushroom biomass served as a renewable cost-effective support for Ag incorporation, while the Ag modification of TiO2 could enhance the photocatalyst’s performance. Structural, chemical, and morphological characterization techniques were applied and showed that the Ag/TiO2 particles consisted of irregularly shaped nanoparticles. The CIP removal reached 82.46% after 300 min and ACGD removal efficiency went up to 83.64%. The enhanced performance is attributed to the unique electronic and structural properties of Ag-modified TiO2. This study highlights the potential of Ag/TiO2 synthesized via green methods as a high-performance photocatalyst for the effective remediation of pharmaceutical and dye pollutants in wastewater treatment applications.

Synthesis of Tin Oxide Nanoparticles from E-Waste for Photocatalytic Mixed-Dye Degradation under Sunlight

Synthesis of Tin Oxide Nanoparticles from E-Waste for Photocatalytic Mixed-Dye Degradation under Sunlight

Optimized Photocatalytic Degradation of Methylene Blue Using Titaniferous Sand/ZnO Composite: A Sustainable Approach to Wastewater Treatment

This study explores a novel approach to enhancing photocatalytic efficiency by utilizing an industrial residue, titaniferous sand, in combination with ZnO. The purifying efficiency of this semiconductor mixture was studied for the removal of methylene blue in a fixed-bed reactor. The main objective was to find out with what percentage the titaniferous sand could be incorporated into the ZnO for maximum photocatalytic performance. Box-Behnken Design (BBD) in the Response Surface Methodology (RSM) was used to optimize the operative parameters. The influence of titaniferous sand/ZnO ratio (A:1-2.8), pH (B:4-10) and irradiation time (C:120-480 minutes) on the degradation efficiency of the dye was studied. Initial concentrations of methyl blue and total semiconductor mixture were set at 25 mg/L and 10 g/L, respectively. The ANOVA analysis showed that the photocatalytic process was significantly affected by a positive individual effect of the titaniferous sand/ZnO ratio and the irradiation time. A quadratic polynomial of the second order accurately represented the experimental values with a correlation coefficient R2 of 0.9921. In addition, this model had a p-value of less than 0.0001 and an F-value of 84.09. Thus, the model used was quite appropriate. Optimal conditions were obtained for a ratio (titaniferous sand/ZnO) of 1.51057, i.e. a titaniferous sand percentage of 66%, a pH of 9.97487 and an irradiation time of 479.765 minutes. Under these conditions, a degradation of 99.4915% was obtained. In addition, the photocatalytic degradation kinetics of methylene blue on the titaniferous sand and ZnO mixture followed the Langmuir-Hinshelwood model and was of the first order with an apparent kinetic constant of 0.402 h-1.

Assessing the Photocatalytic Degradation of Penconazole on TiO2 in Aqueous Suspensions: Mechanistic and Ecotoxicity Studies in Aerated and Degassed Systems

Penconazole (C12H15Cl2N3) is widely used to prevent fungal infection of fruits. Since this toxic fungicide is recalcitrant to biological degradation, it has harmful impacts on aquatic ecosystems. TiO2-based heterogeneous photocatalysis proved to be an efficient method for its mineralization. To monitor the processes occurring under the influence of illumination, the light absorbance, the pH, and the TOC of the samples were measured. The concentration of the model compound and the degradation products were determined by HPLC and IC. Penconazole did not decompose under UV light (λmax = 371 nm) without a catalyst. In the presence of TiO2, mineralization took place. The initial degradation rate in air (7.7 × 10−4 mM s−1) was 5 times higher than under argon. The formation rate of hydrochloric acid (1.04 × 10−3 mM s−1) in the former case significantly contributed to the acidification of the liquid phase. NH4+ also formed, at the rate of 5.9 × 10−4 mM s−1, and very slightly transformed to NO3−. Due to the intermediates identified by HPLC-MS, hydroxylation, H abstraction, and Cl elimination are involved in the degradation mechanism, in which photogenerated HO● radicals, conduction-band electrons, and (under air) superoxide radical anions (O2●−) play considerable roles. The intermediates proved to be much less toxic than penconazole.

Phytoextract-assisted synthesis of Fe2O3/MgO nanocomposites for efficient photocatalytic degradation of gentian violet

Organic-based pollutants are extensively released from various industries and they potentially harm the environment and human health. Photocatalysis is regarded as one of the most promising techniques for removal of organic contaminants from wastewater. Therefore, in this study, iron oxide-based nanocomposites were synthesized by an emerging green and sustainable method using Ethiopian endemic plant extract, Echinops kebericho M. as a capping and stabilizing agent. The phytoextract-assisted synthesized nanoparticles (NPs) α-Fe2O3 and nanocomposites (NCs) α-Fe2O3/MgO calcinated at a temperature of 400°C were characterized and used for their photocatalytic activities toward gentian violet (GV) dye degradation using ultraviolet–visible spectroscopy (UV-vis) at optimized catalyst dose, initial GV concentration, pH, and time conditions. The X-ray diffraction (XRD) analysis result revealed that the mean crystal size of α-Fe2O3 and α-Fe2O3/MgO is 11.2 and 15.4 nm, respectively. Characterization results of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) clearly showed the successful deposition of MgO on α-Fe2O3. The maximum degradation of GV, 96.2%, was observed by using α-Fe2O3/MgO after 60 min under visible light irradiation. Thus, synthesized NCs were shown to have better GV degradation efficiency in a shorter time as compared to the previously reported nanomaterials. The results revealed photocatalytic degradation using endemic plant extract-assisted synthesized NCs, α-Fe2O3/MgO, is considered a greener, simple, and more efficient method for the removal of organic dyes.

Surfactants Modulating of BiVO4 on Photocatalytic Property as a Regulation of Surface Free Energy.

BiVO4 is a stable photocatalytic material but has poor photocatalytic activity in visible light. Herein, the surfactants were investigated to enhance the photocatalytic degradation of tetracycline (TC) of BiVO4 through a hydrothermal method. The different molecular structures and properties of surfactant-modified BiVO4 show clustered small spheres and stacked plate-like microcrystals. The N-hexadecyltrimethylammonium chloride (CTAC)-modified BiVO4 (BiVO4-CTAC) with stacked plate-like morphology increases the light absorption range and decreases the energy band gap. Surfactants with different hydrophilic groups and molecular structures affect the formation process of BiVO4, regulating the morphology, crystal structure, and crystalline surface exposure of BiVO4. BiVO4-CTAC has demonstrated superior TC degradation efficiency compared with the original BiVO4 (BiVO4-Blank). This enhancement is attributed to the observation in the Nyquist plot, where BiVO4-CTAC exhibits the smallest arc radius, indicative of reduced charge transfer resistance and improved charge separation. Furthermore, holes (h+) and superoxide radicals (•O2-) reactive species are the main active radicals for TC photocatalytic degradation. This study develops a novel method to synthesize monoclinic phase lamellar BiVO4 materials by simply changing the surfactant type. This study holds potential implications for advancing surfactant-assisted synthesis of high-efficiency photocatalysts.

Photocatalytic Estrogen Degradation by the Composite of Tin Oxide Fine Particles and Graphene-like Carbon Nitride

Photocatalytic Estrogen Degradation by the Composite of Tin Oxide Fine Particles and Graphene-like Carbon Nitride

Highly Efficient Biomass Derived Carbon Quantum Dots as Metal Free Green Photocatalyst for Degradation of Dyes

AbstractThe demand for wastewater treatment for a sustainable future has provoked the development of an ecologically acceptable photocatalytic approach. However, exploration of highly efficient green metal free catalyst for photocatalytic dye degradation under normal light is yet challenging. In this work, the prepared sericin derived carbon quantum dots (CQDs) are presented as green photocatalyst for the degradation of well‐known hazardous dyes namely crystal violet and Rhodamine‐B under normal light. Using several radical scavenging agents, the mechanism involved in photocatalytic activity of CQDs is demonstrated. This novel photocatalyst offers a well alternative for the degradation and mineralization of organic dyes with a good efficiency.

Effectiveness and Mechanisms of CdS/Porous g-C3N4 Heterostructures for Adsorption and Photocatalytic Degradation of Tetracycline Hydrochloride Wastewater in Visible Light

In this study, CdS/porous g-C3N4 heterostructures were successfully synthesized via in situ co-precipitation to efficiently degrade tetracycline hydrochloride (TCH) under visible light. The heterostructures, particularly at a 2:1 mass ratio of CdS to porous g-C3N4, demonstrated significant improvements in both adsorption and photocatalytic performance. The adsorption and degradation rates increased 4-fold and 9.64-fold, respectively, compared to pure porous g-C3N4, with optimal removal rates achieved at a catalyst dosage of 0.2 g/L. Detailed mechanistic studies revealed that photogenerated holes (h+) and superoxide radicals (·O2−) were the primary active species driving the degradation process, while hydroxyl radicals (·OH) played a minimal role. The composite material also maintained over 70% degradation efficiency after five cycles, indicating excellent stability. This research presents a promising route for the photocatalytic treatment of wastewater containing persistent organic pollutants, offering practical insights into dosage optimization, reaction kinetics, and mechanistic pathways that enhance performance.

Synthesis of magnetic NiFe2O4/g-C3N4 heterojunction photocatalysts for boosting dye degradation performance under visible-light irradiation.

Water pollution from dyes in wastewater is a critical global issue, as these stable organic dyes resist biodegradation, posing serious threats to aquatic ecosystems. To address this situation, advanced photocatalysts have been developed. Here, NiFe2O4/g-C3N4 was synthesized for the photocatalytic degradation of Rhodamine B (RhB) dye in the presence of H2O2 and visible light. Physicochemical analysis results showed NiFe2O4 nanoparticles dispersed in the g-C3N4 matrix, with an upward trend in the saturation magnetization of CNFx as NiFe2O4 content rose. The surface area of CNF30 was 62.3 m2 g-1, outperforming both NiFe2O4 (23.2 m2 g-1) and g-C3N4 (48.5 m2 g-1). NiFe2O4/g-C3N4 could be reused up to four cycles, and efficiently catalyzed the degradation of nearly 98% RhB dye, showing a decreased rate of up to 95% COD. Through scavenger studies, the main role of ˙OH was demonstrated. Therefore, highly efficient and recyclable NiFe2O4/g-C3N4 can be a potential photocatalyst for degradation of dyes.

Aqueous Atrazine Photocatalytic Degradation over g-C3N4/graphene/NiFe2O4 Nanocomposite in the Presence of Potassium Peroxymonosulfate

Aqueous Atrazine Photocatalytic Degradation over g-C3N4/graphene/NiFe2O4 Nanocomposite in the Presence of Potassium Peroxymonosulfate

Significance of ZnO nano photocatalysts in the clean hospital environment: Effective bacterial disinfection and antibiotic waste (ciprofloxacin) disposal

Hospital waste containing antibiotics is toxic to the ecosystem. Ciprofloxacin is one of the essential, widely used antibiotics and is often detected in water bodies and soil. It is vital to treat these medical wastes, which urge new research towards waste management practices in hospital environments themselves. Ultimately minimizes its impact in the ecosystem and prevents the spread of antibiotic resistance. The present study highlights the decomposition of ciprofloxacin using nano-catalytic ZnO materials by reactive oxygen species (ROS) process. The most effective process to treat the residual antibiotics by the photocatalytic degradation mechanism is explored in this paper. The traditional co-precipitation method was used to prepare zinc oxide nanomaterials. The characterization methods, X-Ray diffraction analysis (XRD), Fourier Transform infrared spectroscopy (FTIR), Ulraviolet-Visible spectroscopy (UV-Vis), Scanning Electron microscopy (SEM) and X-Ray photoelectron spectroscopy (XPS) have done to improve the photocatalytic activity of ZnO materials. The mitigation of ciprofloxacin catalyzed by ZnO nano-photocatalyst was described by pseudo-first-order kinetics and chemical oxygen demand (COD) analysis. In addition, ZnO materials help to prevent bacterial species, S. aureus and E. coli, growth in the environment. This work provides some new insights towards ciprofloxacin degradation in efficient ways.

Magnesium-doped hydroxyapatite for application in the photocatalytic degradation of different dye mixtures simultaneously under sunlight irradiation

Magnesium-doped hydroxyapatite for application in the photocatalytic degradation of different dye mixtures simultaneously under sunlight irradiation