ML-BASED PREDICTIONS FOR ENHANCED PHOTOCATALYTIC WASTEWATER TREATMENT USING MN-DOPED BIFEO3 NANOSTRUCTURES

Abstract

ML-BASED PREDICTIONS FOR ENHANCED PHOTOCATALYTIC WASTEWATER TREATMENT USING MN-DOPED BIFEO₃ NANOSTRUCTURES The method for the development of the synergistic effect of enhanced band bending on the surface due to internal screening of charges and the formation of inter-band energy levels while shifting the energy bands close to each other was credited with the higher photocatalytic activity of Mn-doped BiFeO3. Our findings offer a rare chance to develop BiFeO3-based photocatalysts for use in environmental remediation and energy conversion. In order to reveal the relationship between BiFeO3 size, substitution, and doping on the one hand, and the photocatalytic performances on the other, particular attention is given to the degradation of organic pollutants and water splitting, both of which are fueled by photocatalysis. Lastly, we offer helpful suggestions for the advancement of high-performing BiFeO3-based electrodes in the future. There has been a lot of interest in nanostructured semiconductors in advanced oxidation processes using photocatalysis as a promising environmentally friendly and sustainable wastewater treatment technique for a cleaner environment. FIG.1

Specification

Description:ML-BASED PREDICTIONS FOR ENHANCED PHOTOCATALYTIC WASTEWATER TREATMENT USING MN-DOPED BIFEO₃ NANOSTRUCTURES

Technical Field
[0001] The embodiments herein generally relate to a method for ML-based predictions for enhanced photocatalytic wastewater treatment using MN-doped BiFeO₃ nanostructures.
Description of the Related Art
[0002] The world's population is constantly increasing, and industrialization is contributing to the global energy crisis and climate change. These factors are having a significant impact on human safety and well-being in the future. Even though fossil fuels account for over 80% of global energy consumption today, there is growing awareness among the public and policymakers of the need to take immediate action to address CO2 footprints. By reducing the usage of fossil fuels, alternative clean energy sources have a great chance of resolving environmental problems. The energy produced by non-renewable resources like coal, oil, and natural gas can be replaced by hydrogen (H2), a promising energy carrier and green fuel source. It's possible that the estimate was too low. Numerous uncertain geopolitical factors influence the water consumption, availability, and quality projections. However, in order to protect the environment and save human life, it is increasingly necessary to remove environmental pollutants efficiently and treat industrial wastes according to permitted discharge limits. By absorbing high-energy photons and transferring the electrons to the conduction band (CB), the photocatalytic process creates photogenerated electrons and holes. Additionally, for the reduction/oxidation reactions to take place, the excited electrons and holes migrate to the catalyst's surface. Superoxide radicals (O2) are created when excited electrons react with adsorbed oxygen molecules on the surface. The holes then react with water molecules to form hydroxyl radicals (OH), which further reduce the organic compounds.
[0003] Semiconducting photoelectrodes, an electrolyte, a counter electrode, and a light source make up a standard PEC WS system. With an STH efficiency of up to 12.4%, it combines solar energy and water electrolysis in a single reactor. Furthermore, since H2 and O2 are already produced in two spatially separate compartments, a PEC system does not require gas separation. It is important to remember that a successful and long-lasting PEC requires the establishment of three fundamental requirements. In order to achieve good band edge alignment with respect to water redox potentials, the semiconductor electrode material must first have a suitable band gap. Unfortunately, the wide band gap energy of the most well-known good WS photocatalyst limits light absorption, resulting in weak photocatalytic performance. Adsorption, bioremediation, precipitation, electrocoagulation, filtration, membrane separation, flocculation, centrifugation, advanced oxidation processes based on photocatalysis, and chemical coagulation are just a few of the methods used to treat contaminated water and wastewater. These methods have all shown differing degrees of efficacy and limitations that prevent their widespread application. For example, conventional water treatment techniques like sedimentation, filtration, and precipitation are thought to be ineffective because of flaws like the production of hazardous byproducts and the insufficient removal of organic pollutants. However, due to its low band gap and large number of oxygen vacancies, SrTiO3 has demonstrated exceptional photocatalytic activity in the degradation of organic pollutants. LaFeO3, SmFeO3, and GdFeO3 are examples of rare earth-based orthoferrite perovskites that have recently drawn interest as photocatalysts because of their high rate of photodegradation and photo-Fenton-like reaction.
SUMMARY
[0001] In view of the foregoing, an embodiment herein provides a method for ML-based predictions for enhanced photocatalytic wastewater treatment using Mn-doped BiFeO₃ nanostructures. In some embodiments, wherein in order to attain more sustainable water resources, pragmatic approaches and solutions have been implemented. It makes sense to use solar energy to combat waste degradation by synthesizing materials that can be used directly, as it is one of the most accessible renewable energy sources. To combat the problem of dangerous pollutants, a novel technology called waste degradation through photocatalysis is presently being developed. In order to transform these pollutants into less toxic or non-toxic compounds, a chemical reaction in a photocatalyst material is started by using light's power. The photocatalyst produces electron-hole pairs when exposed to light, which can act as strong reducing or oxidizing agents. These electron-hole pairs can then react with oxygen or water molecules to produce highly reactive oxygen species (ROS), including hydrogen peroxide (H2O2), superoxide radicals (•O2−), and hydroxyl radicals (•OH). High sunlight absorption, a suitable gap (1.5-2.8 eV), long-term charge carrier separation, high photo-transporter mobility, suitable physical and chemical properties, adequate band alignment to fulfill the target reaction's kinetic requirements, and anti-corrosion stability in reactive environments are some of the prerequisites that an efficient photocatalyst system must meet.
[0002] In some embodiments, wherein the lead-free BiFeO3 (BFO) has a high spontaneous polarization value of P~90 μC·cm−2, making it a promising multiferroic material. Air purification, H2 production, and the breakdown of organic materials are just a few of the many uses for BFO. Furthermore, BFO shows relative stability under photocatalytic conditions and a high absorption coefficient in the visible region. To raise the STH, however, the BFO's band alignment must be adjusted to the water redox potentials. Numerous techniques, including doping/co-doping, size control, surface modification, co-catalysts, and heterostructures, were used to increase the photocatalytic activity of BFO. The produced interfacial charge carriers concurrently oxidize and reduce impurities, the generated charge carriers recombine and produce heat, or the generated charge carrier may continue to interact with an electron donor or acceptor on the photocatalyst surface. In the first case, nothing occurs. To create a stable and transparent solution, the solutions were combined and vigorously stirred for 30 minutes using a magnetic stirrer. The metal nitrates and citric acid were taken in a 1:1 ratio and dissolved in deionized water. The metal nitrate solution was mixed first, and then the citric acid solution was added. The above mixture was then mixed with metal nitrates in a 1:4 ratio before ethylene glycol was added drop by drop.
[0003] In some embodiments, wherein the proper band alignment with the redox potentials of water is a crucial characteristic needed in a photocatalyst material for effective water splitting. BFO has been shown to exhibit a good alignment with water's oxidation potential, indicating an efficient O2 evolution reaction (OER). However, in order to facilitate an effective H2 evolution reaction (HER), its conduction band minimum (ECB) must be lowered below the EH+/H2 energy. The well-dispersed Bi 6s orbital increases the mobility of the photogenerated charge carriers. Bi-based photocatalysts have a steeper absorption edge in the visible light spectrum because of their unique structure. Furthermore, photocatalytic activity is facilitated by the reverse bond between the cation and anion, which is more advantageous for the creation and movement of holes.
[0004] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS
[0001] The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:
[0002] FIG. 1 illustrates a method for ML-based predictions for enhanced photocatalytic wastewater treatment using Mn-doped BiFeO₃ nanostructures according to an embodiment herein; and
[0003] FIG. 2 illustrates a method for common bismuth-based nanostructured photocatalysts according to an embodiment herein.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0001] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0002] FIG. 1 illustrates a method for ML-based predictions for enhanced photocatalytic wastewater treatment using Mn-doped BiFeO₃ nanostructures according to an embodiment herein. In some embodiments, the numerous parameters, including dopants, substitutions, and grain and particle sizes, have a significant impact on the physical characteristics of materials based on multiferroic BFO. For specific applications, these parameters-which are typically influenced by the fabrication process-could be adjusted to achieve the desired qualities. The impact of particle size on BFO's physical characteristics, including its remanent polarization (Pr) and dielectric constant (̑r), has been extensively studied. Ferroelectric materials' dielectric permittivity (ʛr) and remanent polarization (Pr) are crucial characteristics that aid in efficient charge separation and mobility, which is why they are important in photocatalytic applications. Nowadays, almost everyone in the world recognizes the presence of pharmaceuticals in both artificial and natural systems due to their extensive use, particularly antibiotics. Specifically, it has been asserted that antibiotic metabolites or residues have tainted surface water, wastewater, sludge, groundwater, soil, and sediment. The organic pollutant Rh-B was degraded as part of the photocatalytic experiment while being exposed to visible light from a 250-watt MPMVL UV-vis lamp. To achieve the adsorption-desorption equilibrium, the Rh-B solution (5 mg L1) and photocatalyst suspension was agitated for an hour using a magnetic stirrer. One milliliter of 4% H2O2 was added to start the reaction in order to improve the materials' photocatalytic performance.
[0003] In some embodiments, the hydrothermal synthesis of multiferroic micro-particles Bi1−xLaxFeO3 was reported by Y. Du et al. Following La doping, the Bi1−xLaxFeO3 sample showed an increase in its dielectric constant, with the sample with x = 0.2 and a particle size of 10 µm showing the highest value 225 (at RT/102 Hz) in both the low and high frequency ranges at room temperature. Furthermore, a comparative analysis of La3+-doped multiferroic BFO (LBFO) revealed that the solid-state (SS) method produces powder with a trace amount of the secondary Bi25FeO40 phase, while the sol-gel (SG) synthesis process can produce BFO with a high purity at comparatively lower temperatures. Because of their smaller bandgaps, bi-based semiconductors in particular are believed to be able to overcome the limitation of TiO2-based photocatalytic materials' ability to harvest solar light. Bismuth can change from a semimetal to a semiconductor by reducing the size of its crystallites due to its highly anisotropic Fermi surface charge, low carrier density, small electron effective mass, long electron means free path, and extremely low band overlap energy. A galvanostat-potentiostat equipped with a conventional three-electrode cell was used to examine the photo-electrochemical (PEC) characteristics of the produced materials. Pt wire served as the counter electrode in this three-electrode system, saturated Ag/AgCl served as the reference electrode, and the thin layer of the material as prepared on the FTO served as the working electrode. In a centrifuge tube, 1 mg of the synthesized powder was combined with 2.5 mL of ethylene glycol (EG) under sonication to create the thin film, which was then applied to the FTO glass as a paste.
[0004] In some embodiments, the Bi0.9Eu0.1FeO3 had the highest dielectric constant value, 150 (at RT/102 Hz). Similarly, Rani et al. looked into how doping Er3+ into BFO affected its dielectric characteristics. The dielectric constant values of the Er-doped BFO samples showed a significant improvement (500 at RT/102 Hz for x = 0.15), which can be attributed to a reduction in leakage current and O2 vacancies. On the other hand, the impact of doping and BFO B-site substitution on its dielectric characteristics has been the subject of various investigations. It has been documented how Ti doping affects the dielectric characteristics of BFO nanoparticles made by the solvothermal technique. The dielectric constant increased significantly with a 5% Ti doping rate, reaching 1000 at RT/102 Hz with a particle size of 695 nm. Furthermore, Zr-doped BFO nanostructures made by the hydrothermal method were reported by Kathirvel et al. Aurivillius-type bismuth oxide-based semiconductors' distinct layered crystal structure makes it possible to induce an internal static electric field, which efficiently facilitates the separation and transfer of photogenerated carriers. Because of their distinct electrical and optical characteristics, which are closely linked to the plasmonic and photocatalytic properties, bulk Bi and Bi-based nanostructure morphologies can also be readily modified using a range of synthesis techniques. A C 1s binding energy (BE) of 285 eV was used to compensate for the measured binding energies in a traditional way. The XPSPEAK 4.165 software was used to de-convolute the ions' core level XPS spectra. The spectra were fitted using the sum of the Lorentzian-Gaussian peaks after the unwanted spectrum was eliminated using Shirley-type background subtraction. Peak position can be determined with an accuracy of 0.03 eV.
[0005] FIG. 2 illustrates a method for common bismuth-based nanostructured photocatalysts according to an embodiment herein. In some embodiments, it is difficult to design effective BFO-based photocatalytic materials for photocatalysis applications. Large band gaps, high recombination rates of photogenerated electrons and holes, and a low separation rate of the photogenerated carriers are some of the unresolved problems that limit the practical application of BFO-based photocatalysts, despite the fact that they have shown great promise in the degradation of organic contaminants. Therefore, it is essential to create photocatalysts with a high selective adsorption capacity and a suitable semiconducting band gap, which can be attained through doping, in order to optimize solar energy harvesting and enhance the adsorption of photodegraded organic compounds. Bi is less hazardous than its neighbors in the periodic table, antimony, lead, and polonium, due to its low melting point of slightly above 544 K. The rhombohedral symmetry of the bismuth crystal structure is characteristic of group-V semimetals. Perpendicular to the rhombohedral plane, biatoms form puckered bilayers of atoms with three equidistant nearest neighbors and three equidistant, slightly farther-off next-nearest neighbors. The initial structure was derived from the orthorhombic GFMO's experimental structure. Using the DFT formalism and the modified Beckee Johnson (mBJ)67 potential as the exchange correlation term, all of the geometries were fully optimized by relaxing the ionic positions and the cell parameters.
[0006] In some embodiments, the addition of Mn and the substitution of the Fe site can effectively address the reduction of Fe and O2 vacancies. Furthermore, more O2 vacancies may be created if the Ti site is replaced with Mn. Samples with 1% (mole) Mn-doped BFO-STO were found to have a dielectric constant of 720 at 102 Hz and a remnant polarization of 6 μC·cm−2 at room temperature. For a solid-state reaction, BiFeO3-BaTiO3 solid solution ceramics made by microwave sintering (MWS) and traditional sintering (CS) techniques yielded a high dielectric constant value (4300 at RT/102 Hz). Several studies have demonstrated that the optical properties of Bi are impacted by the quantum confinement effect. The reduction of Fe and O2 vacancies can be successfully addressed by both the addition of Mn and the substitution of the Fe site. Moreover, substituting Mn for the Ti site could result in the creation of additional O2 vacancies. At room temperature, samples containing 1% (mole) Mn-doped BFO-STO had a remnant polarization of 6 μC·cm−2 and a dielectric constant of 720 at 102 Hz. Using both traditional sintering (CS) and microwave sintering (MWS) techniques, BiFeO3-BaTiO3 solid solution ceramics produced a high dielectric constant value (4300 at RT/102 Hz) for a solid-state reaction. Numerous investigations have shown that the quantum confinement effect affects the optical characteristics of Bi.
[0007] In some embodiments, it has been demonstrated that doping certain bismuth photocatalysts with rare earth elements reduces their band gap, potentially increasing their photocatalytic activities. It should be mentioned that in order to significantly alter the structure of the BFO lattice and improve the photocatalytic properties, Bi3+ cations must be replaced with rare earth ions with ionic radii smaller than Bi3+ (1.03 Å), such as Dy3+ (0.912 Å), Gd3+ (0.938 Å), or Sm3+ (0.958 Å). It was discovered that under simulated solar irradiation, the photocatalytic activities of Gd-doped (10%) BFO significantly improved its photocatalytic performance. The results indicate that the degradation rates of 10% Gd BFO photocatalyst for ciprofloxacin and levofloxacin are 80% and 79%, respectively. These 3-D photocatalysts have demonstrated a high specific surface area, a large number of channels, and sufficient photocatalytic activity-all of which are beneficial for photocatalysis. Dang et al., for example, synthesized 3-D nanostructured Bi2WO6 nanoparticles using a microwave-assisted method and reported 92% degradation of methylene blue dye after 180 minutes of exposure to visible light. It is believed that 2-D nanostructured materials outperform 3-D nanostructured photocatalysts in photocatalytic processes. The high crystallinity of the as-prepared materials is evident from the HRTEM images that are displayed. With interplanar spacings of 0.33, 0.2, and 0.347 nm, which correspond to the planes of the orthorhombic structure of GFO, GFMO1, and GFMO3, respectively, the nanoparticles show well-resolved lattice fringes in the HRTEM images. Notably, better crystallinity has been observed for the doping materials compared to the pure material which may enhance the photocatalytic efficiency under light illumination.
, Claims:1. A method for ML- predictions for enhanced photocatalytic wastewater treatment using based Mn-doped BiFeO₃ nanostructures, wherein the method comprises;
predicting the efficiency of photocatalytic wastewater treatment, providing insights into optimal reaction conditions;
offering a high surface area and enhanced charge separation, which significantly improves the photocatalytic degradation of pollutants in wastewater;
enabling a targeted approach where conditions such as pH, catalyst loading, and light intensity are fine-tuned for maximum degradation efficiency;
predicting the most effective parameters for the photocatalytic process, such as optimal doping concentration and nanostructure morphology; and
allowing the method to be adapted to larger, industrial-scale wastewater treatment systems.

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