Photocatalytic Wastewater Treatment Research Articles

Colloidal down-shifting Gd2O3:Eu3+/SiO2 phosphors nanocomposites using one-pot modified surfactants-based soft templates for catalytic applications

The application of rare earth (RE)-based phosphor materials faces a significant challenge in adopting strategies to bring down the cost without compromising their properties. The most straightforward approach is to minimize the use of RE elements. Herein, we demonstrate the use of SiO2 as an economical solid nano-matrix for lanthanides-based phosphor nanomaterials. Gd2O3:Eu3+(x%) and Gd2O3:Eu3+(x%)/SiO2 nanophosphor composites were prepared through a modified soft templating technique using cetyltrimethylammonium bromide (CTAB) as the surfactant. The photoluminescence properties were studied by excitation, emission, and luminescence decay investigations. Upon excitation in the O2−(2p)→Eu3+(4f6) LMCT state, these nanophosphors exhibited predominantly red emission from the 5D0→7FJ transition (where J = 0–4) of the Eu3+ ion. Moreover, the synthesized low-cost Gd2O3Eu3+(5 %)/SiO2 composites, with a small number of lanthanides, exhibited excellent photocatalytic degradation activity for organic dye (methylene blue) under visible light (λ ≥ 420 nm), showing promising potential for photocatalytic wastewater treatment.

Enhanced Salinity Gradient Energy Conversion by Photodegradable MXene/TiO2 Membrane Utilizing Saline Dye Wastewater

AbstractThe utilization of nanochannel membranes for harvesting salinity gradient energy has shown promising potential in addressing the energy crisis and environmental pollution issues. While previous studies have mainly focused on extracting salinity energy from mixing artificial seawater with river water, the research introduces a creative approach involving dye wastewater treatment using MXene/TiO2 membranes to achieve simultaneous photocatalytic degradation and power generation via salinity gradients. The built‐in electric field generated by MXene/TiO2 heterojunctions enhances ionic transport and electron‐hole separation. After photocatalytic treatment of saline dye wastewater, the membrane is defined as a photodegradable membrane. This membrane exhibits increased surface charge and expanded layer spacing to optimize salinity gradient energy conversion efficiency, yielding an impressive power density of up to 11.78 W m−2, which is 20% higher than that of the original MXene/TiO2 membrane. This work offers valuable insights into the development of multifunctional materials for sustainable power generation that comprehensively utilize industrial wastewater and domestic sewage.

Photocatalytic Fenton-like degradation of Acid Green 25 by novel aluminum nanoferrites with persulfate: Optimization by response surface methodology

Magnetic nanomaterials are gaining increasing attention for their catalytic properties and ease of recovery, making them promising candidates for the degradation of various organic pollutants. In this study, AlFe2O4 nanoparticles were employed for the first time in photocatalytic wastewater treatment. The study focused on removing Acid Green 25 anthraquinone dye through persulfate activation under UV-Visible light. AlFe2O4 nanoparticles were synthesized via sol-gel auto-combustion method and characterized by various techniques (XRD, SEM, EDX, VSM, Raman and FTIR). Moreover, statistical analysis of the experimental data confirmed the strong performance of the RSM model in accurately representing the photocatalytic process. Under optimal conditions including persulfate and catalyst concentrations of 0.3 g/L and 0.83 g/L respectively, a solution pH of 3 and 45 minutes of contact time, a 96 % dye removal rate was achieved. The remaining persulfate concentration was 60 % and fully depleted within 90 minutes, indicating efficient activation by AlFe2O4 photocatalyst. The activation process effectively suppressed electron-hole recombination, enhancing the overall efficiency. Scavenger experiments further identified surface-bound radicals and photogenerated holes as the main reactive species. A degradation mechanism for AG25 dye via a photocatalytic Fenton-like process was proposed, highlighting dual synergistic catalysis in the dye degradation. Ecotoxicity assessments using Vibrio fischeri bioassay revealed a significant reduction in toxicity after treatment with AlFe2O4/PS/UV-Vis system. The stability of AlFe2O4 was demonstrated over five degradation cycles. The findings open new perspectives for the use of AlFe2O4 in advanced wastewater treatment technologies, positioning it as a promising material for the degradation of persistent pollutants.

Artificial neural network guided optimization of limiting factors for enhancing photocatalytic treatment of textile wastewater using UV/TiO₂ and kinetic studies

Wastewater effluents discharged from textile industries are characterized by excessive chemical and biochemical oxygen demands with significant amounts of harmful synthetic dyes that spoil the healthy environment. The present investigation focused on process optimization to develop an effective strategy for degrading and decolorizing wastewater from textile industries through an advanced photocatalysis oxidation process. The synergistic effect of Titanium dioxide (TiO2) nanoparticles as a photocatalyst with ultraviolet irradiation was applied as a novel technique to detoxify wastewater effluents from textile industries. In addition, the process was modeled and optimized using response surface methodology (RSM) and artificial neural networks (ANN). The kinetics of the photocatalytic degradation of wastewater effluents from textile industries were analyzed. The optimal condition predicted by the RSM was similar to the experimental outcomes, further, the predicted values from the ANN model had confirmed the prediction. The most significant limiting parameters, such as catalyst dosage, pH, and irradiation time, were optimized systematically as TiO2 dosage of 429.31mg/l, pH of 8.89, and irradiation time of 5h, respectively. Under these optimal conditions, COD reduction and decolorization of 90 and 88%, respectively, were achieved.

High Salinity Tolerance of Zn-Rich g-C3N4 in the Photocatalytic Treatment of Chlorophenol Wastewater

Organic saline wastewater has become a concern in recent decades due to its resistance to biological treatment and potential harm to municipal wastewater treatment plants. While photocatalytic methods have been used for treatment, they often lead to catalyst deterioration. The use of salt-tolerant catalysts presents a viable solution for treating organic saline wastewater. In this study, a Zn-rich g-C3N4 was synthesized, demonstrating excellent performance in removing 2,4-DCP and its derivatives from saline wastewater. More than 75.6% of 2,4-DCP was effectively removed with the addition of Zn-rich g-C3N4, nearly doubling the removal rate compared to pure g-C3N4 and those doped with Co, Ag, Mo, and Bi. Notably, the removal efficiency of 2,4-DCP slightly increased as salinity rose from 0.1 to 2.3 wt.%. Adding 0.1 g L−1 of Zn-rich g-C3N4 resulted in the removal of 2,4-DCP, 2-chlorohydroquinone, chloroacetophenone, and 2-chloropropionic acid by 99.3%, 99.8%, 98.2%, and 99.9%, respectively, from a real saline wastewater sample with 2.2 wt.% salinity, corresponding to a 67.7% removal of TOC. The EPR results indicated that Zn-rich g-C3N4 generated more free radicals compared to pure g-C3N4, such as·OH and Cl, to degrade organic contaminants. The degradation pathway revealed that 2,4-DCP was first dechlorinated into p-phenol and catechol, which were subsequently degraded into maleic acid/fumaric acid, trihydroxyethylene, acetic acid, oxalic acid, and other products. Furthermore, Zn-rich g-C3N4 demonstrated excellent stability and holds promising potential for applications in saline wastewater treatment.

Precise control of photogenerated carrier behavior of zinc oxide through band reconstruction to enhance photocatalytic treatment of dye wastewater

In the field of photocatalytic treatment of dye wastewater, zinc oxide (ZnO) is a typical semiconductor photocatalyst, but it has some disadvantages such as wide band gap, low carrier yield and easy recombination. In this study, Cr-ZnO/N-CQDs catalyst was synthesised using the strategy of p-type doping and construction of Z-scheme heterojunction. The results showed that the removal rate of Cr-ZnO/N-CQDs for MB dye was 97.42 %, which was 70.56 % higher than that of ZnO, and was still 92.16 % after 5 cycles, and the TOC removal rate of methylene blue wastewater was 88.60 %. The reason for the enhanced photocatalytic activity of Cr-ZnO/N-CQDs is that the π* electron (e−) in the N-CQDs interact with the 3d orbitals of Cr-ZnO, so that e− is more easily transferred from the valence band of Cr-ZnO to the conduction band of N-CQDs. The band gap of p-type Cr-ZnO is narrowed, which makes its photogenerated carrier yield increase, hole concentration raise, and the adsorption capacity of H2O molecules reduce by 1.04 eV. The density functional theory calculation shows that the maximum Gibbs free energy of Cr-ZnO for the production of hydroxyl radical is 0.05 eV lower than that of ZnO. This study lays theoretical and practical foundation for the photocatalytic treatment of dye wastewater with ZnO.

A flower-like g-C3N4/CDs/Bi2WO6 hierarchical structure for enhanced photocatalytic degradation of tetracycline

Tetracycline (TC), as one of antibiotic emerging pollutants, has posed potential threats to ecological environment and human health because it is hardly biodegradable and prone to be accumulated in water. In this study, g-C3N4/CDs/Bi2WO6 S-scheme heterojunction with flower-like hierarchical structure was synthesized by hydrothermal method. The optimized composite demonstrates significantly enhanced photocatalytic activity with a TC degradation efficiency of 90.1% after 120 min of visible light irradiation and good reusability up to four consecutive cycles. This can be attributed to the improved light capture capability and efficient separation of photo-generated electron-hole pairs in the constructed S-scheme heterojunction. The introduced carbon dots (CDs) can be served as an efficient carrier transport highway, providing a superior photogenerated carrier separation efficiency and an expanded absorption spectrum. As a result, the strongest redox potentials of the CBCN and VBBWO can be retained for participating the photocatalytic reaction. Free radical capture and electron spin resonance experiments indicate that ·O2- and h+ are the principal active species in the g-C3N4/CDs/Bi2WO6 system. This work provides new strategy for the development of advanced materials in the field of photocatalytic treatment of wastewater.

Development of a sunlight adjustable parabolic trough reactor for 24-hour efficient photocatalytic wastewater treatment

Solar energy is the ideal energy source for activating photocatalysis. However, due to the solar motion, achieving 24-hour solar-powered efficient photocatalytic reactions remains a challenge. In this study, a Sunlight Adjustable Parabolic Trough Reactor (SA-PTR) integrated with flexible parabolic mirror and solar panel was developed. During the daytime, flexible parabolic mirror could be rolled up under sunny condition or expanded under cloudy condition, thus providing optimal light irradiance (1500 W·m−2) and temperature (rises yet below 55 ℃) for photocatalysis. Additionally, the solar panel behind the flexible parabolic mirror could generate solar-electricity. At night, the stored solar-electricity could meet 100 % power demands of UV lamp, enabling a 24-hour solar-powered photocatalytic process. Compared with traditional parabolic trough reactor and inclined plate collector, SA-PTR exhibited higher treatment efficiency against carcinogenic organic dyes (Rhodamine B, Methylene Blue, Methyl Orange), antibiotic (Tetracycline) and pathogenic bacteria (Escherichia coli) during day and night. Moreover, SA-PTR exhibited superior global deployability, economic advantage, safety and lifetime. Therefore, SA-PTR, as a novel solar controllable 24-hour operational photoreactor, is promising to be employed in real wastewater treatment plant.

Tailoring the geometry of visible and near-infrared light active CuSe nanostructure for enhanced photocatalytic activity

Semiconductor photocatalysts play a pivotal role in fostering a sustainable environment by harnessing solar energy directly into chemical energy to achieve various photocatalytic processes. Therefore, a visible-infrared active photocatalyst is the next level of demand for solving the alarming environmental issues. In this regard, the present article reports the investigations of crucial mechanisms and conditions leading to pure and defect-free hexagonal 2D CuSe nanosheets (NSs) and the influence of their structural architecture on visible-infrared active photocatalytic performance. Here, it was achieved by the conventional hydrothermal method by varying the pH of the reaction mixture. XRD analysis was used to examine the crystal structure and lattice parameters of CuSe NSs. The presence of H+ ions was suggested to significantly influence the observed anisotropic crystallite growth across different pH conditions. EDS and XPS analysis exhibited the purity and stoichiometry of 2D CuSe NSs, revealing that the obtained stoichiometry was consistent with CuSe composition. The morphological characteristics were investigated using FE-SEM as well as HR-TEM analyses, and the specific surface area was determined using Brunauer-Emmett-Teller analysis in which a significant change occurred in response to the variation in reaction conditions. The optical properties of optimized 2D CuSe NSs show excellent absorption in the visible and near-infrared region utilizing full solar with a notable decrease in emission intensity, suggesting a reduction in recombination rates due to pH-induced changes in the nanoarchitecture. Herein, methylene blue, a well-established model dye, was used as a probe to assess the photocatalytic activity of the synthesized CuSe NSs. Notably, the CuSe NSs synthesized under neutral conditions demonstrate a remarkable methylene blue degradation efficiency, reaching approximately 98 % within approximately 45 minutes, indicating a high degradation rate. Finally, an in-depth exploration into the intricacies of photocatalytic performance, degradation mechanisms, and the recyclability test was conducted, accompanied by a thorough investigation into the feasibility of CuSe NSs for their practical application in photocatalytic wastewater treatment.

Enhanced photocatalytic reduction of Cr (VI) using porous hierarchical Bi2O3/Bi2S3 high-low heterojunctions: Novel strategies and charge transfer mechanisms

High-low heterojunctions derived from metal-organic frameworks (MOFs) have promising applications in photocatalytic wastewater treatment because of their high photo-redox ability and boosted charge separation efficiency. Herein, Bi-MOF derived porous hierarchical Bi2O3/Bi2S3 nanoflower-like heterojunctions were prepared by the calcination-hydrothermal method. The optimized Bi2O3/Bi2S3-2 composite showed a higher degradation rate of Cr (VI) (99.79 % in 30 min) than the pure substance. Moreover, comprehensive studies were conducted on the kinetics, stability and recycling of Bi2O3/Bi2S3, as well as optical characteristics. The active species trapping experiments confirmed that e- plays a dominant role in the elimination of Cr (VI). These findings provided novel strategies for construction of porous hierarchical heterojunctions with advanced visible-light-induced degradation performance. The enhanced photo-degradation efficiency of the optimal nanocomposite was assigned to the higher visible-light absorbance, separation of photogenerated carriers, reduced recombination of photo-induced carriers, and enhanced redox capability owing to the construction of porous hierarchical heterojunctions amongst the components.

Effect of Operating Parameters on Photocatalytic Treatment of Synthetic Wastewater Using CaTiO3

Photocatalysis is thought to be a long-term, environmentally friendly, economically feasible, and promising technique for treating wastewater. The development of semiconductor nanoparticles has generated a great deal of interest in the treatment of wastewater. To break down complex contaminants found in wastewater into simpler compounds, including H2O and CO2, several UV/visible light excitable nanomaterials have been explored as photocatalysts. Their effectiveness can be managed by adjusting several reaction-related parameters like the intensity of light, irradiance time, pH, catalyst dose, temperature, doping, etc. The performance of the photocatalyst in the photodegradation of contaminants is greatly affected by these parameters. The main goal of this study is to find the best operational parameters and their impact on the photocatalytic treatment of synthetic waste-water using calcium titanate (CaTiO3) nanoparticles. For this purpose, sol-gel synthesized CaTiO3 with a band gap of 3.57 eV was used. The size of the synthesized nanoparticles is smaller than 47.62 nm. The results of photocatalytic treatment of synthetic wastewater demonstrate that CaTiO3 exhibits its best photocatalytic performance at 33 W UV light, pH 6.0, and 3.33 g L-1 CaTiO3 dose with 8 hours of irradiation time. With chemical oxygen demand (COD) concentrations varying from 700 to 40000 mg L-1 at the initial stages, the percentage of COD removal under these conditions was 100% to 77%.

CeO2 microspheres/Ni0.5Zn0.5Fe2O4/MWCNT ternary hybrid composites for ultrasonic-enhanced photocatalytic wastewater treatment

The global water resource shortage has evolved into a pressing concern, necessitating the advancement of effective and environmentally sustainable water treatment techniques. Photocatalysis has surfaced as a hopeful technology for eliminating organic contaminants from wastewater because of its efficiency, cost-effectiveness, and eco-friendliness. Here, CeO2 microspheres and Ni0.5Zn0.5Fe2O4 (NiZn-ferrite) nanoparticles were synthesized using the hydrothermal method, followed by the fabrication of ternary hybrid composites CeO2/NiZn ferrite/multiwalled carbon nanotubes (MWCNT) via ultrasonic treatment. Various analytical techniques including XRD, FESEM, VSM, PL, BET and UV–Visible spectroscopy were employed to characterize the resulting synthesized samples. The hybrid ternary composites demonstrate remarkable efficiency in degradation of reactive red-35 dye through photocatalysis attributed to enhanced surface area. This efficiency is further enhanced when coupled with ultrasonic treatment, leading to a synergistic effect. The catalysts can be easily separated from the suspension due to their magnetic behaviour and thus hold great potential for utilizations in the field of wastewater treatment and environmental remediation.

Performance and mechanic insights into potassium-oxygen co-doping graphic carbon nitride for UV photocatalytic oxidation of carbamazepine

Graphitic carbon nitride (g-C3N4) has good prospect in the field of photocatalysis, but its small specific surface area and low photogenerated carrier separation efficiency limit the large-scale application in photocatalytic wastewater treatment. In this study, the one-step thermal polymerization method was employed to synthesize potassium and oxygen co-doped g-C3N4 (OCN-3), which was used in photocatalytic degradation of carbamazepine (CBZ). Compared with the original g-C3N4, the pseudo first-order kinetic constant of CBZ degradation by OCN-3 was increased from 0.00820 min−1 to 0.17529 min−1 under UV irradiation. The results of competitive oxidation kinetics experiment demonstrated that ·OH played a main role in CBZ degradation. The photoelectric experiments and calculation based on density functional theory revealed that potassium and oxygen atoms can not only regulate the local electron density, but also reduce the band gap width and promote electron transfer as well as photogenerated carrier separation. Furthermore, OCN-3 was loaded on carbon cloth to prepare supported photocatalyst, which can be conveniently applied in continuous wastewater treatment reactor, and the results shows that the degradation efficiency of CBZ remains over 90% within 600 min continuous operation when the hydraulic retention time was 1.25 h.

Mechanistic study of novel ordered BiVO4/C/TiO2 S-heterojunctions with C layers as the electron transport pathways

Assembling the composition synergism and structure adjustment to efficiently accelerate the electron transfer and separation, is emerging as a promising strategy for advanced photocatalytic wastewater treatment. Henein, a novel ordered BiVO4/C/TiO2(BVCT) S-scheme heterojunction were successfully synthesized. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) show the composite of BiVO4 and C/TiO2, with the C layer as the contact surface. UV–vis diffuse reflectance spectra (UV–vis DRS) and X-ray photoelectron spectra (XPS) indicate that BVNT could follow S-scheme electron transfer. Electron paramagnetic resonance (EPR) shows that ·OH, ·OH, and h+ can all participate in photocatalytic reactions. Moreover, BVNT can degrade 91.2 % methylene blue (MB) within 40 min. This study provides new insights for the design of high-performance photocatalysts.

Solar-powered photocatalysis in water purification: applications and commercialization challenges

Although heterogeneous photocatalysis has been recognized as a promising technology for decontaminating and disinfecting municipal and industrial wastewater over the last few decades, it has not yet successfully transitioned from laboratory-scale research to real-world applications. This limited progress is attributed to inherent physicochemical properties of most photocatalytic materials available, which exhibit reduced photoefficiency under visible light irradiation, along with multiple engineering considerations. This comprehensive review delves into the intricate dynamics of photocatalytic reactions kinetics, exploring several types of photocatalytic reactors and elucidating the significance of materials employed in photocatalytic wastewater treatment. This critical survey systematically examines the effectiveness of different materials such as titania, zinc oxide and graphitic carbon nitride which are commercially applied for different reactor systems. Understanding the role of these materials for photocatalytic reactions is essential to address the challenges associated with wastewater treatment. Furthermore, the discussion extends beyond the technical aspects to encompass the broader landscape of challenges hindering the commercialization and widespread adoption of photocatalytic technologies. By critically evaluating these challenges, the minireview aims to provide valuable insights for researchers, engineers, and policymakers seeking to advance and implement photocatalytic wastewater treatment on a broader scale. This synthesis of knowledge consolidates the current state of the field and outlines future prospects for overcoming barriers and optimizing the potential of photocatalytic processes in environmental remediation.

Enhancing photocatalytic wastewater treatment: investigating the promising applications of nickel ferrite and its novel nanocomposites.

Water contamination ranks highest among the challenges posed by the rapidly increasing environmental contamination, which is thought to be the most pressing issue globally. The development of innovative techniques for the successful removal of diverse types of undesirable pollutants from wastewater would therefore yield a huge return on investment. Nowadays, the removal of many organic and synthetic pollutants from the environmental matrix is anticipated to be possible by photocatalytic degradation, owing to its low energy consumption, high catalytic activity, and low overall cost. In this context, magnetic nanoparticles received greater attention as photocatalytic materials from the scientific community in wastewater treatment for the removal of different kinds of pollutants due to their specific properties. The present study provides an overview of the recent advances in water treatment using nickel ferrite nanoparticles and their nanocomposites as photocatalysts. Furthermore, a proposed mechanism for these photocatalysts to generate active free radicals under visible and ultraviolet light has been described. The review concludes that photocatalysts based on NiFe2O4 have potential applications in water purification technologies. However, more research is still needed to determine their practical application in water treatment facilities.

A readily synthesized ZnIn2S4/attapulgite as a high-performance photocatalyst for Cr(VI) reduction

Herein, a ZnIn2S4-decorated attapulgite photocatalyst (ZnIn2S4/ATP) was successfully synthesized by a facile oil bath heating method. It shows superior reduction efficiency for the removal of Cr(Ⅵ). The improved photocatalytic performance is primarily attributed to the intercalation effect of ZnIn2S4 and attapulgite (ATP), enhanced separation efficiency of photogenerated electron-hole pairs, and improved transport efficiency of photogenerated carriers. Moreover, insight into the photocatalytic mechanism demonstrates that •O2− and e− are the major active species in the photocatalytic reduction of Cr(VI) over ZnIn2S4/ATP. This work serves as a reference for integrating natural clay with semiconductors for photocatalytic wastewater treatment.

Construction of BiOCl/bismuth-based halide perovskite heterojunctions derived from the metal-organic framework CAU-17 for effective photocatalytic degradation

The designed synthesis of an S-scheme heterojunction has possessed a great potential for improving photocatalytic wastewater treatment by demonstrating increased the photoredox capacity and improved the charge separation efficiency. Here, we introduce the fabrication of a heterojunction-based photocatalyst comprising bismuth oxychloride (BiOCl) and bismuth-based halide perovskite (BHP) nanosheets, derived from metal-organic frameworks (MOFs). Our composite photocatalyst is synthesized through a one-pot solvothermal strategy, where a halogenation process is applied to a bismuth-based metal-organic framework (CAU-17) as the precursor for bismuth sourcing. As a result, the rod-like structure of CAU-17 transforms into well-defined plate and nanosheet architectures after 4 and 8 h of solvothermal treatment, respectively. The modulation of the solvothermal reaction time facilitates the establishment of an S-scheme heterojunction, resulting in an increase in the photocatalytic degradation efficiency of rhodamine B (RhB) and sulfamethoxazole (SMX). The optimized BiOCl/BHP composite exhibits superior RhB and SMX degradation rates, achieving 99.8% degradation of RhB in 60 min and 75.1% degradation of SMX in 300 min. Also, the optimized BiOCl/BHP composite (CAU-17-st-8h sample) exhibited the highest rate constant (k = 3.48 × 10−3 min−1), nearly 6 times higher than that of the bare BHP in the photocatalytic degradation process of SMX. The enhanced photocatalytic efficiency can be endorsed to various factors: (i) the in-situ formation of two-components BiOCl/BHP photocatalyst, derived from CAU-17, effectively suppresses the aggregation of pristine BHP and BiOCl particles; (ii) the S-scheme heterostructure establishes a closely-knit interfacial connection, thereby facilitating efficient pathways for charge separation/transfer; and (iii) the BiOCl/BHP heterostructure enhances its capacity to absorb visible light. Our investigation establishes an effective strategy for constructing heterostructured photocatalysts, offering significant potential for application in photocatalytic wastewater treatment.

Effect of calcination temperature on structural, optical and photocatalytic properties of calcium titanate (CaTiO3) nanoparticle

In this study, the sol–gel method was used to synthesize calcium titanate (CaTiO3) at different calcination temperatures (400–800 °C). The main objective of this work is to find, using various characterization techniques, how the calcination temperature influences the optical, structural, and photocatalytic properties of CaTiO3. According to the DTA/TGA analysis, 600 °C was the ideal calcination temperature for the synthesis of CaTiO3 nanoparticles. The photocatalytic treatment of simulated wastewater demonstrates its potential application in wastewater treatment. For all calcination temperatures, the percentage of Chemical Oxygen Demand (COD) removed after treatment was 100 % for the initial COD of 700 mg/L, more than 83 % for the initial COD of 5000 mg/L, and more than 71 % for the initial COD of 16000 mg/l.

Unveiling the cobalt vanadate supported hexagonal boron nitride nanocomposite for photocatalytic wastewater treatment: Enhanced degradation of dyes, antibiotics, and real industrial wastewater

In recent years, the expansion of industrial sectors has imposed a burden on water resources globally owing to unsustainable consumption and discharges into the environment. Here, a Co3V2O8 (CV)/hexagonal boron nitride (HBN) heterojunction has been constructed using an applicable solid-state technique that produces efficient photocatalytic action during water cleanup activities. The nanocomposite was studied utilizing different approaches such as XRD, SEM, TEM, FT-IR, EDX, XPS, UV–Vis spectroscopy, EIS, PL, BET, and M − S plots. The pristine HBN has a band gap of 5 eV, while the CV/HBN nanocomposite has a band gap of 1.8 eV. According to our findings, the photocatalyst has a high degradation ratio of up to 98.1%, 89.8%, 87.5%, 96.5%, and 90.2% in brilliant cresyl blue (CB), rhodamine-B (Rh–B), amoxicillin (AMX), metronidazole (MNZ), and industrial wastewater (IW) under visible light irradiation, correspondingly. It emphasizes that the remarkable photocatalytic activity is mostly due to the photocatalyst's superior performance and dominant absorption of visible light, as well as the efficient photogenerated carrier separation brought about by the interaction of cobalt vanadate and HBN. The catalyst demonstrated stable behavior, adhering to five reuse cycles. The present research reveals that the CV/HBN nanocomposite is a very stable and active photocatalyst that may be used as an alternative to costlier noble metal-based photocatalysts in photocatalysis applications. When compared to untreated IW, the degraded IW sample exhibits superior plant growth, which is visible from the phytotoxicity tests.