Photodegradation Of Organic Pollutants Research Articles

Efficient Ternary Organic Photovoltaic Films for Fast Exciton Separation to Generate Free Radicals for Wastewater Treatment

ABSTRACTGiven the effectiveness of organic pollutants photodegradation and the excellent photovoltaic nature of organic solar cells (OSCs), this work first innovatively integrated the cross‐fields of OSCs and environmental photocatalysis. Using knowledge of OSC morphology, an insertion strategy involved adding a suitable quantity of guest acceptor (Y6‐O) to the PM6 donor polymer and BTP‐2F‐ThCl host small molecule acceptor system. Y6‐O leads to tighter π–π packing, reduced domain size, and improved domain purity, resulting in favorable morphology for charge generation and transfer in devices and an improved power conversion efficiency (PCE) from 17.1% to 18.1%. Moreover, terpolymer organic photovoltaic films were applied to wastewater treatment, gaining ions Sb(III) and Sb(V) removals of 100% in 15 min, and guaiacol photodegradations of 90% in 1 h. This work significantly prompts the development of organic photovoltaics and wastewater treatment and opens views for multifunctional organic photovoltaic material applications.

Modified Zeolites for the Removal of Emerging Bio-Resistive Pollutants in Water Resources

The increasing presence of pollutants, including pharmaceuticals and pesticides, in water resources necessitates the development of effective remediation technologies. Zeolites are promising agents for pollutant removal due to their high surface area, ion-exchange capacity, natural abundance, and diverse tailorable porous structures. This review focuses on the efficient application of modified zeolites and mesoporous materials as photocatalysts and adsorbents for removing contaminants from water bodies. The adsorption and photodegradation of pesticides and selected non-steroidal anti-inflammatory drugs and antibiotics on various zeolites reveal optimal adsorption and degradation conditions for each pollutant. In most reported studies, higher SiO2/Al2O3 ratio zeolites exhibited improved adsorption, and thus photodegradation activities, due to increased hydrophobicity and lower negative charge. For example, SBA-15 demonstrated high efficiency in removing diclofenac, ibuprofen, and ketoprofen from water in acidic conditions. Metal doped into the zeolite framework was found to be a very active catalyst for the photodegradation of organic pollutants, including pesticides, pharmaceuticals, and industrial wastes. It is shown that the photocatalytic activity depends on the zeolite-type, metal dopant, metal content, zeolite pore structure, and the energy of the irradiation source. Faujasite-type Y zeolites combined with ozone achieved up to 95% micropollutant degradation. Bentonite modified with cellulosic biopolymers effectively removed pesticides such as atrazine and chlorpyrifos, while titanium and/or silver-doped zeolites showed strong catalytic activity in degrading carbamates, highlighting their environmental application potential.

Correction: Growth of p/n-type BiFeO3 thin films for construction of a bilayer p–n junction for photodegradation of organic pollutants

Correction for ‘Growth of p/n-type BiFeO3 thin films for construction of a bilayer p–n junction for photodegradation of organic pollutants' by Hao-Yun Tu et al., J. Mater. Chem. A, 2024, 12, 12752–12761, https://doi.org/10.1039/D4TA01615G.

Functionalized Fe-BTC films for multi-purpose environmental remediation: Photodegradation of organic pollutants, and oil-water separation

Functionalized Fe-BTC films for multi-purpose environmental remediation: Photodegradation of organic pollutants, and oil-water separation

Cerium-doped Indium Vanadate Microspheres Loaded onto the 2D Conductive Matrix for Boosted Photodegradation of Persistent Organic Pollutants

Cerium-doped Indium Vanadate Microspheres Loaded onto the 2D Conductive Matrix for Boosted Photodegradation of Persistent Organic Pollutants

Graphene quantum dot @ Flower-like Bi2S3 composites for photodegradation of organic pollutants combined photosynthesis of H2 and H2O2 from treated water

Graphene quantum dot @ Flower-like Bi2S3 composites for photodegradation of organic pollutants combined photosynthesis of H2 and H2O2 from treated water

All-in-one photothermal/catalytic flexible membrane for highly efficient desalination and organic pollutant degradation.

Interfacial solar vapor generation (ISVG) accompanied by photocatalytic degradation holds immense potential to mitigate water scarcity and pollution. Distinct from the two detached functional components (photothermal agent and photocatalyst) in a conventional evaporator, in this study, an all-in-one photothermal/catalytic agent, nitrogen-containing honeycomb carbon nanosheets (NHC), was engineered for synergistic high-efficiency steam generation and photocatalysis functions. It was demonstrated that the superoxide radical generated on the surface of NHC conferred its catalytic activity to the photodegradation of organic pollutants under full solar spectrum irradiation. A proof-of-concept multifunctional evaporator (called NHC@PEI/MCE), consisting of NHC grafted with polyethyleneimine (PEI) and a hydrophilic mixed cellulose ester membrane (MCE), was fabricated to achieve both solar-driven desalination and organic pollutant degradation. Owing to its excellent light absorption capability (∼96%), reduced evaporation enthalpy (1358 J g-1) and minimized heat loss (8.8%), the bi-layered evaporator performed a rapid water evaporation rate of 1.66 kg m-2 h-1 under one standard sun illumination. Notably, the edge-preferential crystallization strategy enabled the bi-layered evaporator to maintain long-term stability for continuous water evaporation and salt harvesting over 80 h in a concentrated 3.5 wt% NaCl solution. The design of the all-in-one photothermal/catalytic agent NHC ensured the synchronous removal of organic pollutants. The removal rates of methylene blue and phenol were 99.82% and 79.6%, respectively. Additionally, the reduction rate of total organic carbon (TOC) in the actual coking wastewater was found to be 96.6%. The exceptional purification capabilities across diverse water systems surpassed those of membrane materials lacking NHC. The exploration of the multifunctional evaporator offers a novel approach to achieving high-efficiency utilization of solar energy for the conversion of both seawater and industrial wastewater into freshwater.

Fabrication of biocarbon modified BiOI heterostructures for enhanced organic pollutants photodegradation activity

Fabrication of biocarbon modified BiOI heterostructures for enhanced organic pollutants photodegradation activity

Bimetallic Mesoporous MCM-41 Nanoparticles with Ta/(Ti, V, Co, Nb) with Catalytic and Photocatalytic Properties.

Bimetallic (Ta/Ti, V, Co, Nb) mesoporous MCM-41 nanoparticles were obtained by direct synthesis and hydrothermal treatment. The obtained mesoporous materials were characterized by XRD, XRF, N2 adsorption/desorption, SEM, TEM, XPS, Raman, UV-Vis, and PL spectroscopy. A more significant effect was observed on the mesoporous structure, typically for MCM-41, and on optic properties if the second metal (Ti, Co) did not belong to the same Vb group with Ta as V and Nb. The XPS showed for the TaTi-MCM-41 sample that framework titanium is the major component. The new nanoparticles obtained were used as catalysts for oxidation with hydrogen peroxide of olefinic compounds (1,4 cyclohexadiene, cyclohexene, styrene) and photodegradation of organic pollutants (phenol, methyl orange) from water. The results showed improvementsin activity and selectivity in oxidation reactions by the addition of the second metal to the Ta-MCM-41 catalyst. The slow addition of H2O2 was also beneficial for the selectivity of epoxide products and the stability of the catalysts. The band gap energy values decreased in the presence of the second metal, and the band edge diagram evidenced positive potential for all the conduction bands of the bimetallic samples. The highestlevels of photocatalytic degradation were obtained for the samples with TaTi and TaV.

Photocatalytic degradation evaluation using ternary structures of titanium dioxide, silver and carbon quantum dots

The catalytic photodegradation of organic pollutants offers an eco-friendly alternative to improving water quality by reducing the use of strong oxidants. This method is particularly promising in dealing with emerging pollutants that are not completely removed using only the traditional methodologies. However, limitations of the main photocatalysts used such as high bandgap value and electronic recombination are a challenge to face when trying to upscale applications. In this study, photocatalytic heterostructures were synthesized using TiO2 P25, carbon quantum dots (CQDs), and silver (Ag) to enhance photocatalytic performance and overcome these challenges. The results demonstrated significant improvements in photodegradation efficiency, with an 827% increase for the catalyst containing only CQDs and a 400% increase for the heterostructures containing both CQDs and Ag. These enhancements are attributed to the synergy of the ballistic electronic transferer properties and the diminished availability of recombination sites of the semiconductor which enables the generation of oxidative radicals.

Structural Characteristics and Photocatalytic activity of TiO2/Si3N4 nanocomposite synthesized via plasma sputtering technique

This work evaluates a new TiO2/Si3N4 catalyst that was prepared by deposition of thin films of Si3N4 and TiO2 nanostructures on glass using lab made closed field unbalanced dc reactive magnetron sputtering technique. A highly-pure silicon sheet and titanium sheet were used as a sputtering target and gas mixture of (Ar: N2), (Ar∶O2) with mixing ratios of (50:50) for each were used to prepare TiO2/Si3N4 sample, respectively. This sample has been heat treatment. The structure and morphology of the catalyst were determined by X-ray diffraction, Field-Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray (EDX) Spectroscopy, and Fourier transform infrared (FTIR) spectroscopy tests. The resultant nanocomposite sample was polycrystalline and there were no impurities in the investigated nanocomposite as revealed by XRD analysis. The absorption edge was found to be at 420 nm, as revealed by d UV-visible spectroscopy. The results obtained from the photodegradation of organic pollutants under a Xenon lamp indicate that TiO2/Si3N4 nanocomposite's photocatalytic activity is significantly more effective than TiO2 nanophotocatalyst.

Photodegradation of organic water pollutants using magnetically separable and reusable novel Ag-doped Fe3O4/TiO2 nanocomposites synthesized by green route

Photodegradation of organic water pollutants using magnetically separable and reusable novel Ag-doped Fe3O4/TiO2 nanocomposites synthesized by green route

Facile Preparation of Composite Coatings with Incorporated 13X Zeolite and CeO2

One-step methods for the formation of efficient thin-film catalysts for wastewater treatment under the sunlight spectrum is a topic of interest for many research groups. This article reports on the facile preparation of photocatalytic coatings by plasma electrolytic oxidation processing from 0.01 M sodium tungstate electrolyte solution containing both 13 X zeolite and CeO2. Obtained coatings are characterized with respect to their surface morphology, chemical and phase composition, and possible application as photocatalysts in photodegradation of organic pollutants. All prepared coatings contain elements originating from both substrate and electrolyte solution. Addition of 1 g/L of 13X zeolite and CeO2 in various concentrations to electrolyte solution results in increased photodecomposition of model organic pollutant. The highest photodegradation under simulated sunlight is observed for coatings formed in 0.01 M sodium tungstate with addition of 1 g/L of 13 X zeolite and 1 g/L of CeO2, reaching 50% after 6 h of irradiation.

Studies of ZnO/NiO/MoO3 Ternary Nanocomposite as an Effective Visible Light Photocatalyst

In this work, following a facile coprecipitation technique, a novel ternary ZnO/NiO/MoO3 heterojunction photocatalysts was synthesized and characterized using SEM, TEM, UV-Vis DRS, XRD and FTIR analysis. Under visible light irradiation, the photodegradation of organic pollutants, such as methylene blue, was studied. Comparing the ternary nanocomposite to ZnO, NiO, MoO3 and binary ZnO/NiO, NiO/MoO3 nanocomposite, the former showed better photocatalytic performance. The energy band gap of ZnO/NiO/MoO3 nanocomposite was evaluated using Tauc plot from absorption spectra and resulted as 2.67 eV. The best photocatalytic activity for methylene blue (100%) was shown by ternary ZnO/NiO/MoO3 photocatalyst within 55 min. The development of the ZnO/NiO/MoO3 heterojunction photocatalyst, which is advantageous for effective fast transfer and separation of the photoexcited charge carriers, could be attributed to the better photocatalytic presentation.

A novel and facile method for the synthesis of rGO/ZnO nanocomposite and its versatile use in water treatment

We introduce a novel, rapid, and environmentally friendly method for synthesising reduced graphene oxide (rGO)/ZnO nanocomposite. This single-step synthesis involves the pyrolytic decomposition of sucrose to produce rGO, simultaneously with zinc acetate to produce the rGO/ZnO nanocomposite. Unlike conventional methods, this approach is distinguished by its environmental sustainability, avoiding the use of toxic chemicals and generating no harmful byproducts. This method advances the development of sustainable technologies by providing a green alternative for the cost-effective production of rGO/ZnO composites from inexpensive precursors. The process enables bulk production within minutes, making it suitable for industrial-scale applications. Various characterisation techniques confirmed the successful formation of rGO and rGO/ZnO nanocomposites. The materials were then evaluated for their efficacy as a comprehensive water purification solution, demonstrating effectiveness in heavy metal removal, photodegradation of organic pollutants, and bacterial disinfection.

Hydrothermally synthesized hierarchical Pom-Pom-like gadolinium modified tungsten oxide reinforced with rGO for annihilation of acetylsalicylic acid and crystal violet

Herein, novel hierarchical Gd@WO3 pom-pom-like microstructures have been prepared through the hydrothermal method and combined with RGO sheets (denoted as RGO/Gd@WO3). The synthesized materials, along with their analogs, were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), Mott-Schottky, current-voltage (I-V), electrochemical impedance spectroscopy (EIS), and optical analyses. The unique morphology of pom-pom-like microstructures allowed better interaction with pollutant molecules. Rare earth element (Gd3+) ions act as trapping species for photo-generated electrons and prolong the life span of reactive oxygen species (ROS). The high conductivity and flexible nature of RGO sheets provided fast transport of active species and provided stability to the photocatalytic material. To test the photocatalytic efficiency of RGO/Gd@WO3, crystal violet (CV) and acetylsalicylic acid (ASA) were used as model pollutants. Under a mimetic light source, RGO/Gd@WO3 exhibited maximum photodegradation of 98.8 % and 84 % for CV and ASA within 120 min of irradiation, respectively. Photocurrent, Mott-Schottky, and EIS experiments proved the production, effective separation, and transmission of photo-active species in the presence of RGO/Gd@WO3 as compared to Gd@WO3 and WO3. Given the electrochemical testing and optical analysis, the photocatalytic mechanism is anticipated for the high photocatalytic activity of RGO/Gd@WO3. The novel RGO/Gd@WO3 photocatalyst proved to be a superior photocatalytic material for the photodegradation of organic pollutants.

Accelerated Indirect Photodegradation of Organic Pollutants at the Soil-Water Interface.

Indirect photolysis driven by photochemically produced reactive intermediates (PPRIs) is pivotal for the transformations and fates of pollutants in nature. While well-studied in bulk water, indirect photolysis processes at environmental interfaces remain largely unexplored. This study reveals a significant acceleration of indirect photodegradation of organic pollutants at the soil-water interface of wetlands. Organic pollutants experienced ubiquitously enhanced indirect photodegradation at the soil-water interfaces, with rates 1.41 ± 0.01 to 4.27 ± 0.03-fold higher than those in bulk water. This enhancement was observed across various natural and artificial wetlands, including coastal wetlands and rice paddies. In situ mapping indicated that soil-water interfaces act as hotspots, concentrating both organic pollutants and PPRIs by 9.30- and 4.27-folds, respectively. This synchronized colocation is the primary cause of the accelerated pollutant photolysis. Additionally, the contribution of each PPRI species to pollutant photolysis and a coupled transformation pathway at the soil-water interface significantly differed from those in bulk water. For instance, the contribution of singlet oxygen to metoxuron photolysis increased from 10.1% in bulk water to 44.4% at the soil-water interface. Our study highlights the rapid indirect photolysis of organic pollutants at the soil-water interfaces, offering new insights into the natural purification processes in wetlands as "Earth's kidneys."

Cr3+doped α-Fe2O3 nanoparticles for photodegradation of organic pollutants with their disinfection efficacy

Pristine and Cr-doped α-Fe2O3 nanoparticles were synthesized using a low-cost and simple one-step hydrothermal method without any precipitating agent. Cr-doped α-Fe2O3 was found to be a promising candidate for recyclable photocatalytic application for Tetracycline (TC) and Congo-red (CR) degradation under normal sunlight irradiation along with excellent antibacterial properties. Addition of Cr shows a significantly improved degradation efficiency from 20% to 91% in just 25 min for CR, while the degradation rate reached to 81% for TC, which was also monitored in real-time using internet of things (IoT). Also, a high degree of mineralization was achieved (∼87.9%), which was confirmed using total organic carbon (TOC) content. In parallel, the biochemical oxygen demand/chemical oxygen demand (BOD5/COD) ratio confirmed the fast degradation efficiency using a small amount of catalytic dosage (∼ 0.40 g/L). Also, degradation of multiple dyes provides a promising avenue for addressing complex waste water treatment challenges. Moreover, Cr-doped α-Fe2O3 displays excellent antibacterial activity towards E.coli and E.Faecium. Major factors involved in sunlight driven photocatalytic activity for example absorbance range, porosity, separation between e--h+, and charge transfer property were surprisingly improved by Cr doping and henceforth increased photocatalytic activity and antibacterial properties. This work highlights the potential utilization of Cr-doped α-Fe2O3 for the purification and disinfection of industrial waste water.

Modified Titanium Dioxide Nanoparticles for Photocatalytic Splitting of Water and Its Application in Environmental Remediation as a Potential Alternative

Herein we reviewed Titanium dioxide (TiO2) nanoparticles and how they are applied in the photocatalytic splitting of water to generate hydrogen but also to remove both organic and inorganic pollutants. Hydrogen generation through the splitting of water by TiO2 which is a cheap, efficient, and non-toxic photocatalyst has found wide application in clean energy production. The efficiency of the photocatalyst can be improved by using water or sacrificial agents as electron donors, thereby enhancing hydrogen production. In addition, this review explores the fundamental principles, mechanisms, and applications of TiO2-based photocatalysis. It further, highlights the structural properties, bandgap engineering, and surface modifications that influence the catalytic activity of TiO2. Additionally, we discuss the doping of TiO2 with both metals and non-metals to narrow the energy band gap which lowers the recombination effects. Finally, it introduces the potential applications of TiO2-based photocatalysis in the photodegradation of organic and inorganic pollutants.

Iron mediated n → π* electron transitions and mid-gap states formation in CN under low-temperature secondary calcination enhances photodegradation of organic pollutants

Iron modified carbon nitride (CN) materials have attracted widespread attention from researchers in different application fields. In this paper, single atom iron anchored CN (FeCN) with mid-gap states and n → π* electron transition was synthesized through low temperature secondary calcination. The mid-gap states introduce surface states capable of trapping photogenerated electrons, enabling FeCN to absorb photons with energies lower than its intrinsic optical bandgap. 10%FeCN also exhibits distinct optical absorption above 490 nm derived from the n → π* electron transition, which expand the visible light response range of photocatalysts and enhance electron transport ability. Additionally, the Fe-Nx site enhances the separation and transmission efficiency of photoexcited charges. The prepared 10%FeCN exhibits extremely high photocatalysis and photo-Fenton activity. Mercaptobenzothiazole (MBT) degradation rate of 10%FeCN is 3.47 times higher than CN, achieving a mineralization rate of 86.7% in 100 min. Additionally, the oxytetracycline hydrochloride (OTC) degradation rate of 10%FeCN in photo-Fenton reaction is 11.9 times higher than CN. After five cycles, this catalyst still has good reactivity, indicating its good stability.