Degradation Percentage Research Articles

A Comprehensive Comparison of the Structural, Ferroelectric, Energy Storage, and Photocatalytic Properties of Chemical Composition-Tailored Perovskite Ceramics

This article reports on the structural, ferroelectric, energy density, and photocatalytic properties of (Pb0.50Ba0.35Ca0.15)(Fe0.25Nb0.25Ti0.50)O3 [PBCTO] and (Pb0.50Ba0.50)(Fe0.25Nb0.25Zr0.1Ti0.40)O3 [PBZTO] ceramics synthesized by the solid synthesis route. X-ray diffraction and Raman spectra confirmed peaks corresponding to perovskite crystalline structure with tetragonal phase for both PBCTO and PBZTO ceramics. Slim ferroelectric hysteresis was observed in polarization-electric field measurements. Remnant polarization (Pr), and coercive field (Ec) values are ∼3.63 μC cm−2, ∼25.4 kV cm−1, and ∼1.39 μC cm−2 and 17.9 kV cm−1 for PBCTO and PBZTO, respectively. Energy densities were obtained from ferroelectric hysteresis loops. For PBCTO ceramics, the largest unreleased energy density is 0.72 J cm−3 @ 200 kV cm−1; for PBZTO ceramics, the largest unreleased energy density is 0.60 J cm−3 @200 kV cm−1. Photocatalytic performance was studied on methylene blue (MB) and methyl orange (MO) dyes under visible irradiation. The degradation percentage of MB dye in the presence of PBCTO and PBZTO was found to be 56% and 98% in 80 min with irradiation. The degradation percentage of MO dye in the presence of PBCTO and PBZTO at their respective wavelength was 48% and 97% in 120 min with irradiation. These bulk ceramics under study have shown interesting multifunctional properties useful for various potential applications.

Novel Br-doped Bi2WO6 photocatalyst for high-efficiency removal of norfloxacin: mechanism and photocatalytic activity.

In this work, the bismuth tungstate (Bi2WO6) photocatalyst was successfully prepared, and the pure Bi2WO6 was modified with Br (Br-Bi2WO6). The effects of different experimental conditions on the degradation of norfloxacin (NOR) solution under visible light were investigated. The Br-Bi2WO6 photocatalyst was characterized by FTIR, XRD, SEM, BET, XPS, DRS, EIS, and EPR. The results show that the Br-modified Bi2WO6 photocatalyst can effectively improve the photocatalytic performance. The best photocatalytic performance of Br-Bi2WO6 was observed when the doping amount of Br was 3%. The degradation percentage of norfloxacin can reach 94.67%. The presence of anions and cations (Cl-, SO42-, Ag+, and Cu2+) in the solution significantly inhibited the photocatalytic activity of 3%Br-Bi2WO6. The photocatalytic degradation of norfloxacin by 3%Br-Bi2WO6 was not greatly affected in the presence of HCO3- and NO3-. The characterization analysis showed that Br was successfully doped on the Bi2WO6 photocatalyst, and the original structure of Bi2WO6 was not destroyed by the addition of Br. Br doping increased the specific surface area of Bi2WO6 and decreased the band gap of Bi2WO6 resulting in a broader visible light absorption range. In addition, Br doping promoted the migration rate of photogenerated electron-hole pairs. The ·O2- and h+ played a major role in the photodegradation of norfloxacin, and the mechanism of photocatalytic degradation of norfloxacin by Br-Bi2WO6 was proposed.

Recent Advances in Magnetic Feˣ⁺/TiO₂ Microfibers for Wastewater Treatment as Climate Change Mitigation

Chemical dyeing and finishing processes used in the clothing and textile industries are among the main contributors that can increase the impact of climate change. Photocatalysis using nanosized titanium dioxide (TiO2) has been continuously developed as a promising technology for purifying dye wastewater into simpler and environmentally friendly components. In addition, the decoration of iron cations (Fe2+) and (Fe3+) increases the reusability of the photocatalyst due to their magnetic properties, which are easy to collect for the recycling process. Magnetic Fex+/TiO2 microfibers have been successfully prepared using a hydrothermal method using titanium dioxide in an alkaline solution. Cations were added into the solution with the different molar ratios of Ti/Fex+ to produce Fe2+/TNW and Fe3+/TNW, respectively. Photocatalysis activity test using magnetic Fex+/TNW was carried out using methylene blue in a reactor equipped with an incandescent bulb lamp representing solar light. The results showed that adding the cations resulted in a new shape of palm tree leaves, like titanate microfibers. Controlling the cation’s molar ratio produces the magnetic Fex+/TNW with a 50-150 µm length. SEM images of each material presented the uniformly elongated shape and aggregated on one side morphology. In addition, paramagnetic properties indicate that magnetic Fex+/TNW can be easily separated from the dispersion in less than 1 minute using an external magnet. A photocatalysis activity test of magnetic Fex+/TNW was performed by calculating the percent degradation of methylene blue with variations in irradiation time in visible light conditions. The result showed the effectiveness of photodegradation of methylene blue was significantly increased in materials with 3.3 molar ratios of both Ti/Fe2+ and Ti/Fe3+ with a percent degradation reaching 79% and 70%, respectively, in 5 hours. In conclusion, magnetic Fex+/TNW is introduced as an alternative dye wastewater treatment technology that has reusable properties and works well on sustainable energy sources of solar light.

Investigation of structural, optical, and magnetic properties of NiFe2O4 for efficient photocatalytic degradation of organic pollutants through photo fenton reactions

Nowadays, water pollution generated from textile effluents is one of the major problems for the human race and ecology. Hence, development of sustainable strategies to lower the water pollution level has become a burning need. In this regard, the present study focuses on the preparation of nano catalyst NiFe2O4 to catalyze the chemical reactions on industrial organic dyes for their fast cleansing from water. By sol-gel auto-combustion technique, NiFe2O4 nanoparticles were synthesized and exposed to thermal process at temperatures of 400, 600, and 800 °C. Highly crystalline phase with spinel cubic structured NiFe2O4 was formed with a crystal size of 18.71 nm, which was confirmed by XRD analysis. The FTIR spectra showed two fundamental absorption bands in the range 597.80–412.59 cm−1, which are the characteristics of tetrahedral M − O and octahedral M − O bond in NiFe2O4. The surface morphology of calcined NiFe2O4 was investigated by scanning electron microscope (SEM). The nanoparticle size analyzer exhibited that the synthesized NiFe2O4 nanoparticles had an average particle size of ∼ 291.3 nm. Three stage decomposition patterns were observed for NiFe2O4, which was analyzed by a temperature programmed STA. Zeta potential analyzer showed that the synthesized sample S1 and S2 were stable in the dispersion medium. Also, NiFe2O4 exhibited optical band gap energies for direct band transitions within the visible spectrum measured to be 1.43–1.45 eV, rendering them effective as photocatalysts under sunlight. The samples showed magnetic measurements by VSM with saturation magnetization, coercivity, remnant magnetization value of 66.81 emu/g, 4.13 Oe and 12.94 emu/g, respectively. The synthesized photocatalyst, NiFe2O4, at 400 °C, significantly degraded three toxic organic pollutants—Methylene blue, Rhodamine B, and Congo Red—under visible light through ‘Photo-Fenton’ reaction mechanisms. Among the three dyes, Methylene Blue exhibited the highest degradation percentage with a rate constant of 0.0149 min−1 and followed pseudo-first-order kinetic model.

Sonochemical Assisted Synthesis of Cr-PTC Metal Organic Framework, ZnO, and Fe3O4 Composite and Their Photocatalytic Activity in Methylene Blue Degradation

Methylene blue pollutants can be treated by photocatalytic methods using metal oxide-based semiconductor materials and metal organic framework (MOF). These two materials are often coupled into a composite to improve their physicochemical properties and catalytic activity. This research focuses on the synthesis of composites based on Cr-PTC MOF, ZnO, and Fe3O4 by the sonochemical method. The obtained composites were characterized and tested for catalytic activity in methylene blue pollutant degradation in an aqueous system under acidic conditions (pH = 5). Our investigation shows that the Cr-PTC@Fe3O4 composite possesses the lowest band gap energy of 1.86 eV and achieves the highest photocatalytic activity in methylene blue degradation at solution pH = 5, with a percent degradation of 84.36%. The sonochemical incorporation of Fe3O4 and Cr-PTC MOF is able to fabricate materials in a short time with better photocatalytic activity in degrading methylene blue than the single materials. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Enhanced Photocatalytic Performance under Ultraviolet and Visible Light Illumination of ZnO Thin Films Prepared by Modified Sol-Gel Method.

Semiconductor oxides are frequently used as active photocatalysts for the degradation of organic agents in water polluted by domestic industry. In this study, sol-gel ZnO thin films with a grain size in the range of 7.5-15.7 nm were prepared by applying a novel two-step drying procedure involving hot air treatment at 90-95 °C followed by conventional furnace drying at 140 °C. For comparison, layers were made by standard furnace drying. The effect of hot air treatment on the film surface morphology, transparency, and photocatalytic behavior during the degradation of Malachite Green azo dye in water under ultraviolet or visible light illumination is explored. The films treated with hot air demonstrate significantly better photocatalytic activity under ultraviolet irradiation than the furnace-dried films, which is comparable with the activity of unmodified ZnO nanocrystal powders. The achieved percentage of degradation is 78-82% under ultraviolet illumination and 85-90% under visible light illumination. Multiple usages of the hot air-treated films (up to six photocatalytic cycles) are demonstrated, indicating improved photo-corrosion resistance. The observed high photocatalytic activity and good photo-corrosion stability are related to the hot air treatment, which causes a reduction of oxygen vacancies and other defects and the formation of interstitial oxygen and/or zinc vacancies in the films.

Dual-pathway charge transfer mechanism of anatase/rutile TiO2-Ag3PO4 hollow photocatalyst promotes efficient degradation of pesticides

Exploring high-performance photocatalysts still remains a big challenge due to poor charge separation efficiency. Herein, we prepare a novel anatase/rutile TiO2-Ag3PO4 hollow photocatalyst (A/R-TiO2-Ag3PO4) for addressing this challenge. Microstructural characterization and photoelectric measurements confirm that the synergy of hollow structure and dual-heterojunction can provide abundant active sites and boost efficient charge separation through dual-pathway charge transfer mechanism. The A/R-TiO2-Ag3PO4 photocatalyst exhibits the highest photocurrent density (15.25 µA cm−2), which is 8.4 and 5.2 times than that of A-TiO2-Ag3PO4 (1.82 µA cm−2) and P25-Ag3PO4 (2.93 µA cm−2), respectively. Photo-degradation experiment shows that A/R-TiO2-Ag3PO4 presents a high degradation percentage (98.7 %) of thiamethoxam (THX) within 30 min, which is 1.45 and 1.23 times than that of A-TiO2-Ag3PO4 (68.1 %) and P25-Ag3PO4 (80.7 %), respectively. Furthermore, the degradation percentage of THX by A/R-TiO2-Ag3PO4 is as high as 96.4 % after seven successive cycles, indicating excellent cycling stability. Therefore, this work provides a new insight into exploring other high-performance photocatalysts by combining hollow structure and dual-heterojunction.

Plant-based synthesis of Selenium-doped Silver/Magnesium Oxide/Zinc Oxide nanocomposite using Mentha pulegium to investigate their photocatalytic and biological properties

In this study, the photocatalytic test and biological effects of Selenium-doped Silver/ Magnesium Oxide/ Zinc Oxide nanocomposite (Se-doped Ag/MgO/ZnO) have been studied. The samples were synthesized by a green method with Mentha pulegium plant extract and investigated by different analyses. The outcomes of X-ray and FESEM display crystal nature and flower-like morphology. According to the ICP results, the removal efficiency of Pb+2 ions was equal to 72 %. The photocatalytic test of the nanocomposite investigated to degradation of organic dyes, and the results show that the degradation percentage of RhB (Rhodamine B), EBT (Eriochrome Black T), MO (Methyl Orange), and MB (Methylene Blue) dyes were about 73 %, 96 %, 99 %, and 97 % respectively. Also, the toxicity of the Se-doped Ag/MgO/ZnO) was studied against the cancer B16F0 cell line and the IC50 value was reported as 269.6 μg/mL.

Design and characterisation of activated magnetic zeolite 4A from naturally occurring kaolin clay of Cameroonian origin for optimised dye removal by Fenton-like degradation

ABSTRACT The transformation of local clay material of Cameroonian origin into magnetic zeolite (Fe@Zeo-4A) for the degradation of acid-blue 90 in solution was investigate herein. The insertion of magnetic iron oxide particles into the zeolitic framework of Zeo-4A was achieved via hydrothermal synthesis. FT-IR spectroscopy, XRD and SEM confirmed the transformation of the clay into zeolite while EDX analysis and elemental mappings confirmed the presence of iron in the magnetic zeolite. Fe@Zeo-4A was strongly attracted to an external magnetic field. N2 adsorption-desorption studies revealed a considerable decrease in specific surface area and pore volume from the zeolite to the magnetic zeolite, suggesting the occupation of the pores of the zeolite by magnetite. The central composite design of the response surface methodology was used as optimisation approach for four parameters affecting the efficiency of degradation: solution pH, H2O2 concentration, initial dye concentration and time of stirring. ANOVA results revealed good correlation between the experimental and predicted results as well as the suitability of the linear regression model for describing the dye degradation process. An adjusted correlation coefficient of 85.17% was obtained for the dye degradation model. An optimal degradation percentage of 95.2% was obtained experimentally under optimal conditions of 7.6 for pH, 20 mg/L for dye concentration, 15.0 mol/L for [H2O2] and 15 min for time, in close agreement with a theoretical response of 96.6% predicted by the model. The magnetic zeolite was found to exhibit good stability over a wide pH range and lost only about 18% of its catalytic efficiency after five cycles of degradation experiments. Therefore, the novel magnetic zeolite-based material is an efficient Fenton catalyst for treating dye-contaminated wastewater.

Biogenic Synthesis Based on Cuprous Oxide Nanoparticles Using Eucalyptus globulus Extracts and Its Effectiveness for Removal of Recalcitrant Compounds

Recalcitrant compounds resulting from anthropogenic activity are a significant environmental challenge, necessitating the development of advanced oxidation processes (AOPs) for effective remediation. This study explores the synthesis of cuprous oxide nanoparticles on cellulose-based paper (Cu2O@CBP) using Eucalyptus globulus leaf extracts, leveraging green synthesis techniques. The scanning electron microscopy (SEM) analysis found the average particle size 64.90 ± 16.76 nm, X-ray diffraction (XRD) and Raman spectroscopy confirm the Cu2O structure in nanoparticles; Fourier-transform infrared spectroscopy (FTIR) suggests the reducing role of phenolic compounds; and ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis DRS) allowed us to determine the band gap (2.73 eV), the energies of the valence band (2.19 eV), and the conduction band (−0.54 eV) of Cu2O@CBP. The synthesized Cu2O catalysts demonstrated efficient degradation of methylene blue (MB) used as a model as recalcitrant compounds under LED-driven visible light photocatalysis and heterogeneous Fenton-like reactions with hydrogen peroxide (H2O2) using the degradation percentage and the first-order apparent degradation rate constant (kapp). The degradation efficiency of MB was pH-dependent, with neutral pH favoring photocatalysis (kapp = 0.00718 min−1) due to enhanced hydroxyl (·OH) and superoxide radical (O2·−) production, while acidic pH conditions improved Fenton-like reaction efficiency (kapp = 0.00812 min−1) via ·OH. The reusability of the photocatalysts was also evaluated, showing a decline in performance for Fenton-like reactions at acidic pH about 22.76% after five cycles, while for photocatalysis at neutral pH decline about 11.44% after five cycles. This research provides valuable insights into the catalytic mechanisms and supports the potential of eco-friendly Cu2O nanoparticles for sustainable wastewater treatment applications.

Effect of Nixtamalization on Aflatoxins, Functional and Acceptability of Maize from Mulindi, Rwanda

Rwanda relies highly on maize for human food as well as for animal feed and industrial uses. However, high temperature and wet climate conditions in Rwanda favor the growth of fungi that may lead to mycotoxin contamination in maize and subsequent degradation of its quality. Therefore, this study aimed to assess the effect of nixtamalization on the aflatoxins, the functional and acceptability of maize grains from Mulindi, Rwanda. The maize samples were collected from the Mulindi market in Rwanda; representative samples were collected by the guidelines for sampling food for mycotoxin determination. Subsequently, the treated maize samples were dry-milled to produce fine flour, and the flour obtained was analyzed for swelling capacity, water absorption capacity, water solubility, acceptability, and aflatoxins, which were quantified by the HPLC method. The HPLC results showed that the highest total aflatoxin level in maize grains was 44.99 ppb. Cooking maize in water and calcium hydroxide of 1% resulted in a reduction of aflatoxin with degradation percentages of 25% and 88%, respectively. However, in all treatments, aflatoxins B1 and B2 were less reduced compared to aflatoxins G1 and G2. Cooking maize in pure water showed the lowest reduction of aflatoxin compared to the other treatments. However, cooking maize in water with 1% calcium hydroxide decreased aflatoxin to a higher percentage. Cooking maize in lime enhanced the swelling capacity, water absorption capacity, and water solubility of maize, as well as its acceptability. However, the nixtamalization process was observed to reduce aflatoxins levels in maize and improve the functional properties of maize, and therefore, its application could be encouraged for safe products in the market.

Enhanced removal of hazardous organic contaminants with advanced visible light-active F-doped TiO2/rGO/PVDF photocatalytic membranes

Polyvinylidene fluoride (PVDF) membranes and composite variants with x% FGT/PVDF photocatalytic membranes were prepared at different concentrations (x = 1 %, 5 %, and 10 %) using the phase inversion technique. The synthesized photocatalysts and the membrane materials were thoroughly characterized using different analytical methods. The focus was on determining the photocatalytic efficiency of these materials in degrading two important harmful dyes, namely methylene blue (MB) and crystal violet (CV), under visible light irradiation. High degradation percentages of MB (96 %) and CV (92 %) at 90 minutes were observed with 5 % F-TiO2/rGO (named as 5 %FGT). Similarly, the 5 % F-TiO2/rGO/PVDF (5 %FGT/PVDF) photocatalytic membranes showed 98 % and 93 % degradation of MB and CV, respectively. Kinetic studies revealed that the photocatalytic degradation reaction followed a pseudo-first-order mechanism. The total organic carbon (TOC) analysis of the treated MB and CV dyes showed a degradation of 78 % and 71 %, respectively. Recycling of the most active 5 % FGT/PVDF composite membrane exhibited very high stability of 800 min. The composite material utilizes the photocatalytic properties of TiO2 and the stimulating transport properties of rGO. Additionally, fluorine doping enhances charge carrier separation, tunes the bandgap for visible light response, and increases surface activity, thereby improving the overall degradation of organic pollutants. These properties make the composite material promising for various applications in environmental remediation and wastewater treatment.

Green mediated synthesis of cerium oxide nanoparticles by using Oroxylum indicum for evaluation of catalytic and biomedical activity.

The present perspective emphasizes the green synthesis of CeO2-NPs using Oroxylum indicum fruit extract. The synthesized NPs were characterized utilizing analytical techniques, including FT-IR, UV-vis, XRD, SEM-EDX, and VSM. Of them, XRD analysis ratifies the cubic fluorite crystal structure along with a particle size of 23.58 nm. EDX results support the presence of cerium and oxygen in a proper ratio. The surface morphology of NPs, however, was scrutinized using SEM. The lower IC50 value (20.8 μg mL-1) of NPs compared to the reference substance, ascorbic acid (33.2 μg mL-1), demonstrates CeO2-NPs to be a compatible antioxidant. Moreover, the drug-releasing capability of CeO2-NPs was a buffer pH-dependent parameter. The acidic pH solution was 20.5%, while the basic pH solution was 16.9%. The drug-releasing capability was analyzed using the Higuchi model and Korsmeyer-Peppas kinetics. The values of the determination coefficient (R 2) were found to be 0.9944 and 0.9834, respectively. The photocatalytic activity of CeO2-NPs was evaluated, considering methylene blue as a model dye. The degradation percentage was attained up to 56.77% after it had been exposed for 150 min. Apart from this, the synthesized NPs were screened against two fungus species, Bipolaris sorokiniana and Fusarium. The percentage of growth was measured at 56% and 49%, respectively.

Removal of acid red dye 1 from textile wastewater by heterogenous photocatalytic ozonation employing titanium dioxide and iron zeolite

Clean water is a necessity for all life to survive and flourish. However, natural waters are being continuously contaminated due to the release of waste streams in water. Hence, it is important to remove pollutants from wastewater to fulfill human needs. Conventional treatment methods are neither efficient nor economical for wastewaters that especially contain refractory toxic pollutants. This requires novel techniques like Advanced oxidation processes (AOPs), that may successfully degrade persistent micropollutants more efficiently. In this study, an azo dye Acid Red 1 was removed by three AOPs, namely Photocatalytic oxidation, Ozonation and Photocatalytic Ozonation, by employing heterogenous catalysts. TiO2 was used as photocatalyst, whereas Fe-Zeolite has been further added as Ozonation catalyst. The study revealed that photocatalysis degraded only 28% Acid red dye after 15 min, whereas for ozonation, the degradation percentage was 95% in same time. In combined photocatalytic ozonation process using TiO2, 95% degradation was achieved in just 9 min and treatment time further reduced to 5 min when Fe-zeolite was added. Optimization studies for initial concentration, UV intensity and catalyst loading were performed. Finally, rate constants and Electrical Energy per Order (EEO) values were determined for all AOPs, and mechanism was proposed.

Enhancement of ozone dissolution and oxidation treatment of phenolic wastewater by a static spiral shear rig with a variable screw pitch

A novel static spiral shear rig (SSSR) with variable screw pitch was developed to enhance the ozone–water mass transfer and the oxidative degradation of phenolic wastewater. The effects of critical operational parameters on the dissolution and mass transfer of ozone in water and the oxidative degradation rate of phenol were investigated with the proposed SSSR. Moreover, the mass transfer and oxidative degradation of phenols with the SSSR were compared to conventional static mixer (CSM) methods. The results showed that the mass transfer coefficient obtained with the SSSR is 5.33 times greater than that obtained with CSM. With the SSSR, the degradation percentage of phenolic wastewater with an initial concentration of 100 mg/L reached 97.09% within 12 min, and the reaction kinetic constant for phenol degradation obtained with the SSSR is 3.68 times higher than that obtained with the CSM. The SSSR dramatically enhances ozone dissolution and mass transfer, resulting in a higher phenol oxidative degradation percentage and a constant kinetic reaction.

Photocatalytic degradation of 2,4-dichlorophenoxyacetic acid by electrospun TiO2 nanofibres synthesised from two different titanium molecular precursors.

The evaluation of the photocatalytic properties of electrospun TiO2 nanofibres (TiO2-NFs) synthesised in the same experimental conditions using two distinct precursors, tetraisopropyl orthotitanate (TTIP) and tetrabutyl orthotitanate (TNBT), with morphology and crystalline structure controlled by annealing at 460°C for 3h is presented. The presence of circular-shaped TiO2-NFs was corroborated by scanning electron microscopy (SEM). By using X-ray photoelectron spectroscopy (XPS), the chemical binding energies and their interactions of the TiO2 with the different incorporated impurities were determined; the most intense photoelectronic transitions of Ti 2p3/2 (458.39eV), O 1s (529.65eV) and C 1s (284.51eV) were detected for TTIP and slightly blue-shifted for TNBT. By using energy-dispersive X-ray spectroscopy (EDS), the chemical element percentages in TiO2 were determined. Using X-ray diffraction, it was found that the annealed electrospun TiO2-NFs presented the anatase crystalline phase and confirmed by Raman scattering. Bandgap energies were determined by diffuse reflectance spectroscopy at room temperature. The photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide under exposure to ultraviolet light was studied using the TiO2-NFs obtained with the two molecular precursors. The results showed that the catalyst, prepared with the TTIP precursor, turned out to be the one that presented the highest photocatalytic activity with a half-life time (t1/2) of 28min and a degradation percentage of 93%. The total organic carbon (TOC) in the solutions resulting from the 2,4-D degradation by the TiO2-NFs was measured, which showed a TOC removal of 50.67% for the TTIP sample and 36.14% for the TNBT sample. Finally, by using FTIR spectroscopy, the final chemical compounds of the degradation were identified as H2O and CO2.

Preparation of Manganese-Doped Bismuth Oxide for the Photocatalytic Degradation of Methylene Blue

The current study describes a unique method for degrading methylene blue dye utilizing Mn-doped Bi2O3 nanoparticles (NPs) exposed to UV light. Bi2O3 nanoparticles (NPs) doped with Mn were produced using a hydrothermal process. Scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and were use to characterize the prepared nanoparticles. It was discovered that the band gaps of Mn/ Bi2O3 NPs are 2%, 3%, and 4%, respectively, and are 4.13 eV, 3.92 eV, and 3.77 eV. Functional group identification using Fourier transforms infrared spectroscopy (FT-IR). Mn-doped Bi2O3 nanoparticles were captured in SEM pictures at various magnifications, and the photos clearly display the particles' dual morphologies, cubic and cylindrical. The Mn-doped Bi2O3 particles were found to be crystalline, with mean diameters of 20 nm, according to the XRD data. The photodegradation efficiency of Mn/Bi2O3 at experimental dye concentrations of 2%, 3%, and 4% was determined to be 90.29, 91.6, and 93.16 percent, respectively, over a 150 minute time interval. At the ideal catalyst dosage of 0.2 g and concentration of 40 ppm, a high percentage of dye degradation was observed. Numerous metals have been doped into zinc oxides, although no work has documented doping of Bi2O3 with Mn. Additionally, it was utilized for the first time to look at the deterioration of methylene blue dye. Received: 11 May 2024 | Revised: 9 July 2024 | Accepted: 18 July 2024 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data available on request from the corresponding author upon reasonable request. Author Contribution Statement Mansoor Jamal: Conceptualization; Gul Asimullah Khan Nabi: Methodology; Hao Sun: Software; Khair Ullah: Validation; Osama Ali Khattak: Formal analysis; Muhammad Kashif: Investigation; Salman Khan: Resources; Mohsin Alam: Data curation; Shah Hussain: Writing - original draft; Mati Ullah: Writing - review & editing; Seeqal Aleena: Visualization; Hameedul Haq: Supervision; Saira Umar: Project administration; Muhammad Atif: Project administration; Ijaz Hussain: Project administration; Aalia Masood: Project administration.

Enhanced photocatalytic degradation of methylene blue dye using CuO nanoparticles from the fruit extracts of Diplocyclos palmatus (L) C. Jeffrey for wastewater remediation

ABSTRACT The degradation of synthetic organic dyes through photocatalysis requires structured nanoparticles (NPs). Copper oxide (CuO) NPs were used as the newest developed catalyst for the organic dye degradation under the irradiation of sunlight: The metal oxide NPs were synthesized using the fruit extract of Diplocyclos palmatus (L) C. Jeffrey. UV–visible light spectra showed an absorption band for CuO NPs at 277 nm. X-ray diffraction confirmed the monoclinic phase of CuO NPs. Scanning electron microscopy confirmed rod-shaped stacked particles. Energy-dispersive X-ray spectra indicating the presence of Cu in oxide form. For the degradation of methylene blue dye (MB), CuO NPs were used as photocatalyst for dye degradation under sunlight irradiation. This study confirmed the effects, such as irradiation time, concentration, pH, and catalyst dosage. The CuO NPs showed high photocatalytic degradation, degrading 90% of the dye in 120 min. The increased degradation of dye was observed on exposure to longer irradiation time. The increased concentration of dye resulted in a decreased rate of photodegradation. 95% degradation achieved at pH 9 showing that the pH medium also enhances the degradation. A higher dye degradation percentage was achieved by increasing the higher catalyst dosage of 0.013 g degraded 93% of dye. Thus in the treatment of wastewater containing pollutants, the synthesized CuO NPs acted as an efficient photocatalyst.

Generation of biosurfactants by P. aeruginosa gi |KP163922| on waste engine oil in a free and immobilized cells system

AbstractThis study investigated biosurfactant production by the bacterial strain of P. aeruginosa gi |KP 163922| for a free and immobilized cells system using waste engine oil (WEO) as a substrate. The polyurethane foam (PUF) cubes (1 cm × 1 cm × 1 cm) were used as carriers for the immobilization. The batch experiments were performed in Erlenmeyer flasks and monitored at every 24‐h interval for both cell systems. The microbial population was counted using the plate count method, and the hydrocarbon degradation percentage was calculated to evaluate the bacterial activity. Surface tension was measured at regular intervals to ensure the presence of biosurfactants. The maximum reduction was 37 and 35 mN/m in a free and immobilized cells system. Immobilization of cells using PUF was found to be efficient in supporting bacterial growth, and after 48 h of incubation, the growth was 2.5 (±0.58) × 1011 CFU/mL. The chemical characterization using Fourier transform infrared (FTIR) spectroscopy confirmed the obtained product as rhamnolipid. Crude biosurfactant yield was found to be maximum in the case of the immobilized system, which was approximately 18 g/L. Scanning electron micrographs (SEM) of the used PUF cubes showed the strong adherence of biofilm to the cube surface and the potential of its reuse in multiple cycles. Gas chromatography–mass spectrometry (GC–MS) analysis confirms that the immobilized strain of P. aeruginosa exhibited superior biodegradation capabilities compared to free cells. Specifically, it was capable of reducing the concentration of polyaromatic hydrocarbons and converting more significant aliphatic compounds into metabolic byproducts such as alkanes, alkenes, cycloalkanes, and carbonyl groups.

An Experimental and Theoretical Investigation on Highly Reusable Visible Light Active CoTe Nanosheets for Improved Photocatalytic Degradation of Toxic Aniline Blue Dye

AbstractSemiconductor‐assisted photocatalytic treatment is among the most effective methods for eliminating persistent contaminants from industrial wastewater. This study presents a hydrothermal approach for the preparation of Cobalt Telluride (CoTe) nanosheets for the degradation of aniline blue dye under visible light irradiation. The synthesized catalyst was characterized using various techniques, including X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, RAMAN spectroscopy, high‐Resolution transmission electron microscopy (HRTEM), and X‐ray photoelectron spectroscopy (XPS). Tauc's model was used to determine the optical band gap. The key operating parameters, such as the amount of CoTe, initial aniline blue (AB) concentration, and contact time, have been optimized to achieve the highest AB degradation percentage. Under visible light, 98 % of dye degradation occurred within 60 minutes. The degradation process was further assessed using total organic carbon (TOC) measurements. Free‐radical capture experiments were conducted to identify the role of radical species in the photocatalytic process. The photocatalytic process revealed that the equilibrium data aligns well with the Langmuir‐Hinshelwood kinetic model. A rate constant of 0.03486 min−1 was obtained. The photocatalyst demonstrated excellent recyclability, maintaining efficiency and structural integrity over five cycles. The photocatalytic experiment results also have been confirmed by a density functional theory (DFT) calculation.