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A 3D hierarchical TiO 2/CaIn 2S 4/C 3N 4arrays photoanode with dual-heterojunction for enhanced photoelectrochemical performance. NANOTECHNOLOGY 2024; 35:155402. [PMID: 38198715 DOI: 10.1088/1361-6528/ad1d17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 01/10/2024] [Indexed: 01/12/2024]
Abstract
A novel 3D hierarchical TiO2/CaIn2S4/C3N4arrays with dual heterojunctions photoanode is constructed by stepwise deposition of CaIn2S4nanosheets and ultrathin C3N4onto the well-aligned TiO2nanorods arrays. Integrating the merit of the superior ability of CaIn2S4and C3N4to harvest visible light, dual type-Ⅱ heterojunction band structure and one-dimensional ordered nanostructures, the TiO2/CaIn2S4/C3N4photoanode exhibits simultaneous significant improvements in visible-light harvesting, charge separation and electron transfer capability. At 1.23 V (versus reversible hydrogen electrode) under AM 1.5 G irradiation, the TiO2/CaIn2S475/C3N4photoanode exhibits a photocurrent density of 4.5 mA cm-2, which is 5.2 and 51.1-fold higher than that of TiO2/CaIn2S475 and pristine TiO2photoanode, respectively. Moreover, the applied bias photo-to-current efficiency (ABPE) of the TiO2/CaIn2S475/C3N4photoanode reaches 3.5% at 0.36 V (versus reversible hydrogen electrode). These results are helpful for fabricating more efficient heterostructure photoelectrodes.
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Hybrid TiO 2/Carbon quantum dots heterojunction photoanodes for solar photoelectrocatalytic wastewater treatment. CHEMOSPHERE 2023; 341:140077. [PMID: 37690559 DOI: 10.1016/j.chemosphere.2023.140077] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 08/23/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023]
Abstract
The modification of titanium dioxide (TiO2) is a strategy to maximize the utilization of sunlight. Carbon quantum dots (CQDs) are carbon nanomaterials with outstanding optical and electronic properties that are suitable for that purpose. In this work, three types of hybrid TiO2/CQD photoelectrodes were synthesized following different methods: 1) deposition of a CQD layer on top of TiO2 (labelled as TiO2-CQD); 2) deposition of a TiO2 layer on top of CQDs (labelled as CQD-TiO2) and; 3) deposition of a mixed CQD + TiO2 layer (labelled as CQD + TiO2). The photoelectrodes were investigated for the photoelectrocatalytic degradation of phenol as model pollutant under simulated solar light and TiO2-CQD showed the highest apparent reaction rate constant of kapp = 0.0117 min-1 with 40% of TOC removal in 6 h of treatment. CQDs were found to enhance photon absorption in the visible region of the electromagnetic spectrum and in turn phenol degradation by promoting the separation of photogenerated charge carriers through electron transfer via the Ti-O-C bonds formed at the TiO2-CQD interface. Finally, the performance of the TiO2-CQD photoanode was evaluated for the treatment of real wastewater from the membrane fabrication sector, confirming its photoelectrocatalytic efficiency under solar radiation with 93% of TOC removal in 8 h of treatment and kapp = 0.0058 min-1.
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Design strategies and mechanisms of g-C 3N 4-based photoanodes for photoelectrocatalytic degradation of organic pollutants in water. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118545. [PMID: 37418928 DOI: 10.1016/j.jenvman.2023.118545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/17/2023] [Accepted: 06/27/2023] [Indexed: 07/09/2023]
Abstract
Emerging photoelectrocatalytic (PEC) systems integrate the advantages of photocatalysis and electrocatalysis and are considered as a promising technology for solving the global organic pollution problem in water environments. Among the photoelectrocatalytic materials applied for organic pollutant degradation, graphitic carbon nitride (CN) has the combined advantages of environmental compatibility, stability, low cost, and visible light response. However, pristine CN has disadvantages such as low specific surface area, low electrical conductivity, and high charge complexation rate, and how to improve the degradation efficiency of PEC reaction and the mineralization rate of organic matter is the main problem faced in this field. Therefore, this paper reviews the progress of various functionalized CN used for PEC reaction in recent years, and the degradation efficiency of these CN-based materials is critically evaluated. First, the basic principles of PEC degradation of organic pollutants are outlined. Then, engineering strategies to enhance the PEC activity of CN (including morphology control, elemental doping, and heterojunction construction) are focused on, and the structure-activity relationships between these engineering strategies and PEC activity are discussed. In addition, the important role of influencing factors on the PEC system is summarized in terms of mechanism, to provide guidance for the subsequent research. Finally, suggestions and perspectives are provided for the preparation of efficient and stable CN-based photoelectrocatalysts for practical wastewater treatment applications.
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Photocatalysis-PMS oxidation system based on CQDs-doped carbon nitride nanosheets for degradation of residual drugs in water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:108538-108552. [PMID: 37752394 DOI: 10.1007/s11356-023-30005-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 09/17/2023] [Indexed: 09/28/2023]
Abstract
Graphite-like carbon nitride (g-C3N4) is favored for its excellent physicochemical properties. However, the high complexation rate of photogenerated carriers greatly limits its practical applications. Based on this, a novel CQDs-doped carbon nitride nanosheets composite (CNS/CQDs) was prepared and applied to the visible light-induced activation of peroxymonosulfate (PMS) for meloxicam (Mel) and tetracycline (TC) degradation. The photocatalytic degradation of Mel and TC were remarkably promoted in the CNS/CQDs+PMS+vis system. Mel photodegradation of 99.90% was achieved over 30 min with 20 mg CNS/CQDs and 20 mg PMS at pH11. And TC photodegradation of 95.97% was achieved over 45 min with 20 mg CNS/CQDs and 20 mg PMS at nature pH6.5. The TOC mineralization rates of Mel and TC were 75.49% and 52.00%, respectively. The transient photocurrent response and electrochemical impedance measurements (EIS) results indicated that the doping of CQDs could improve the charge transfer efficiency of pure g-C3N4, and CNS/CQDs had a low charge transfer resistance. Capture experiments and EPR tests explored the effective actives in the CNS/CQDs+PMS+vis system. Possible degradation pathways of Mel were also analyzed. This study provides valid residual drugs degradation under the dual conditions of visible light catalytic oxidation and persulfate oxidation, which will be a novel perspective for advanced oxidation technology to effectively remove organic pollutants from water.
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Photoelectrocatalytic treatment of municipal wastewater with emerging concern pollutants using modified multi-layer catalytic anode. CHEMOSPHERE 2023; 339:139575. [PMID: 37487983 DOI: 10.1016/j.chemosphere.2023.139575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/12/2023] [Accepted: 07/17/2023] [Indexed: 07/26/2023]
Abstract
Municipal wastewater contains emergent chemical and biological pollutants that are resistant to conventional wastewater treatments. Therefore, the focus of the current study was to address the challenge of removing emergent chemical and biological pollutants present in municipal wastewater. To achieve this, a photo electro-catalytic (PEC) treatment approach was employed, focusing on the removal of both micro and biological pollutants that are of emergent concern, as well as the reduction of Chemical Oxidation Demand (COD) and Total Organic Carbon (TOC). The treatment involved the use of a modified multi-layer catalytic anode photo-electroactive anode as an effective anode for PEC treatment of municipal wastewater. In the continuous mode of operation, %COD removal was optimized for the treatment of municipal wastewater under Ultra-Violet C (UVc), 280 nm, and Visible (Vis) radiation, 400 nm. Therefore, a comparative study was performed to investigate the effect of Vis radiation on %COD removal, micropollutants removal, and disinfection of municipal wastewater. Micropollutants present in municipal wastewater were effectively oxidized/degraded with the highest reduction rate between 100% and 80% under the influence of UVc and Vis radiation respectively by the PEC treatment process. Disinfection of various microorganisms present in the wastewater with the effect of UVc and Vis assisted PEC treatment was also monitored. Overall, 75-80% of the disinfection of municipal wastewater was contributed by the modified multi-layer catalytic anode. The UVc in the PEC system, contributes approximately 20-25% to the overall disinfection of municipal wastewater.
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Photocatalytic degradation of organic pollutants by carbon quantum dots functionalized g-C 3N 4: A review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115133. [PMID: 37327524 DOI: 10.1016/j.ecoenv.2023.115133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/31/2023] [Accepted: 06/10/2023] [Indexed: 06/18/2023]
Abstract
Graphitic carbon nitride (g-C3N4) has received much attention due to its unique characteristics of stable physicochemical features, facile preparation, and inexpensive cost. However, the bulk g-C3N4 has a weak capacity for pollutant degradation and needs to be modified for real application. Therefore, extensive research has been done on g-C3N4, and the discovery of the novel zero-dimensional nanomaterials known as carbon quantum dots (CQDs) provided it with a unique modification option. In this review, the development for the removal of organic pollutants by g-C3N4/CQDs was discussed. Firstly, the preparation of g-C3N4/CQDs were introduced. Then, the application and the degradation mechanism of g-C3N4/CQDs were briefly described. And the discussion of the influencing factors on g-C3N4/CQDs' ability to degrade organic pollutants came in third. Finally, the conclusions of photocatalytic degradation of organic pollutants by g-C3N4/CQDs and future perspectives followed. This review will strengthen the understanding of the photocatalytic degradation of real organic wastewater by g-C3N4/CQDs, including their preparation, application, mechanism, and influencing factors.
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CQDs improved the photoelectrocatalytic performance of plasma assembled WO 3/TiO 2-NRs for bisphenol A degradation. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130250. [PMID: 36327831 DOI: 10.1016/j.jhazmat.2022.130250] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/07/2022] [Accepted: 10/22/2022] [Indexed: 06/16/2023]
Abstract
Carbon quantum dots (CQDs) have been supported on WO3/TiO2-NRs using a hydrothermal method and a novel CQDs/WO3/TiO2-NRs composite formed via dielectric barrier discharge. The composite electrodes were characterized using morphology, structural, optical and electrochemical analysis. The CQDs were successfully prepared on the composite electrode with the highest photocurrent density reaching 2.51 mA·cm-2 under UV-visible light irradiation (100 mW·cm-2) and an applied voltage of 0.6 V vs. Ag/AgCl. The CQDs/WO3/TiO2-NRs electrode exhibited a good degradation effect toward bisphenol A (BPA) (75.66 %) combined with the production of hydrogen (0.89 mmol) in Na2SO4 system after 2 h of the photoelectrocatalytic (PEC) reaction and the BPA degradation rate reached 100 % after 7 min of reaction in both simulated and real seawater. The CQDs/WO3/TiO2-NRs exhibited excellent stability and efficient PEC performance in which the CQDs acted as electron reservoirs to capture and promote charge separation. Our analysis of intermediates of BPA degradation indicated the possible degradation pathways that mainly formed BPA polymers in the Na2SO4 system or chlorinated compounds in the high chloride salt system.
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Synthesis and applications of graphitic carbon nitride (g-C 3N 4) based membranes for wastewater treatment: A critical review. Heliyon 2023; 9:e12685. [PMID: 36660457 PMCID: PMC9842699 DOI: 10.1016/j.heliyon.2022.e12685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/21/2022] [Accepted: 12/21/2022] [Indexed: 01/05/2023] Open
Abstract
Semiconducting membrane combined with nanomaterials is an auspicious combination that may successfully eliminate diverse waste products from water while consuming little energy and reducing pollution. Creating an inexpensive, steady, flexible, and diversified business material for membrane production is a critical challenge in membrane technology development. Because of its unusual structure and high catalytic activity, graphitic carbon nitride (g-C3N4) has come out as a viable material for membranes. Furthermore, their great durability, high permanency under challenging environments, and long-term use without decrease in flux are significant advantages. The advanced material techniques used to manage the molecular assembly of g-C3N4 for separation membrane were detailed in this review work. The progress in using g-C3N4-based membranes for water treatment has been detailed in this presentation. The review delivers an updated description of g-C3N4 based membranes and their separation functions and new ideas for future enhancements/adjustments to address their weaknesses in real-world situations. Finally, the ongoing problems and promising future research directions for g-C3N4-based membranes are discussed.
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In-situ one-step synthesis of porous monolayer carbon nitride nanosheets doped with carbon quantum dots for photocatalytic degradation of Meloxicam. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Carbon nano-structures and functionalized associates: Adsorptive detoxification of organic and inorganic water pollutants. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109579] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Chlortetracycline degradation performance and mechanism in the self-biased bio-photoelectrochemical system constructed with an oxygen-defect-rich BiVO 4/Ni 9S 8 photoanode. CHEMOSPHERE 2022; 295:133787. [PMID: 35104538 DOI: 10.1016/j.chemosphere.2022.133787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/15/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Efficient photoelectrodes are highly desired in bio-photoelectrochemical systems (BPES). Herein, in this paper, the oxygen defect-rich BiVO4/Ni9S8 photoanode was developed and coupled with a biocathode for enhanced chlortertracycline (CTC) degradation and current generation in the self-biased BPES. Characterization results showed that the optimized BiVO4/Ni9S8-7 mg-150 °C NF exhibited the best photocatalytic activity, due to that the rich oxygen vacancies and Ni9S8 could significantly improve light absorption, enhance photo-generated carriers separation, and accelerate charges transfer. CTC (20 mg L-1) removal efficiency from the BPES was about 1.3 times (82.3% vs 64.7%) of that from the unilluminated reactor, and current output (0.68 A m-3) was about 7.6 times (0.09 A m-3). The dominant species in genus level was Geobacter, which is capable of reducing nitroaromatics and in favor of reductive dehalogenation of CTC. Besides, Comamonas and Rhodopseudomonas that are capable of degrading antibiotics were also detected. Possible degradation pathways and mechanism of CTC degradation in the BPES were proposed. This research advances the development of photoelectrode materials for light-driven BPESs and enriches antibiotics degradation mechanism.
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Insight into the activity of TiO 2@nitrogen-doped hollow carbon spheres supported on g-C 3N 4 for robust photocatalytic performance. CHEMOSPHERE 2022; 288:132392. [PMID: 34624354 DOI: 10.1016/j.chemosphere.2021.132392] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 09/12/2021] [Accepted: 09/26/2021] [Indexed: 06/13/2023]
Abstract
Designing an advance nanostructure semiconductor is an efficient strategy to promote the charge separation and thus improve the photocatalytic activity. Herein, a relatively high recombination rate of electron-hole pairs and low specific surface area of g-C3N4 (GCN) were subjected to the surface deposition of the core shell nanoparticles composed of nitrogen doped hollow carbon spheres (N-HCSs) as the supporting scaffold and TiO2 nanoparticles as the photoactive layer. The ternary composites with different TiO2@N-HCS content were prepared through a simplified nanocasting method followed by the two consecutive hydrothermal process. The effects of nitrogen doping in carbon framework, and nanoparticles amount were evaluated on the photocatalytic ability through the photodegradation of tetracycline (TC) molecules under the visible light irradiation. At the optimum content of core shell nanoparticles (7 wt%), the solar-driven TC photocatalytic degradation for ternary composite was approximately 85%, which was much better (about three times) than that of the pure GCN. More interestingly, the experimental results revealed that doping of nitrogen atoms has a positive role on the charge separation and the resulting photocatalytic efficiency. The employed hollow carbon spheres here play three important roles: (1) providing a substrate to uniformly dispersion of TiO2 nanoparticles without any aggregation; (2) reducing the combination of charge carriers and improving the separation of photoinduced carriers; (3) formation of larger surface area and more active sites on the photocatalyst surface. Furthermore, the underlying photocatalytic degradation mechanism was introduced by the controlled experiments using photoluminescent and radical scavenger tests.
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Advances in application of g-C 3N 4-based materials for treatment of polluted water and wastewater via activation of oxidants and photoelectrocatalysis: A comprehensive review. CHEMOSPHERE 2022; 286:131737. [PMID: 34352551 DOI: 10.1016/j.chemosphere.2021.131737] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/29/2021] [Accepted: 07/28/2021] [Indexed: 05/15/2023]
Abstract
Recently, graphitic carbon nitride (g-C3N4) has received significant attention as a non-metallic, visible-light-activated photocatalyst for treating water and wastewater by degrading contaminants. Accordingly, previous review articles have focused on the photocatalytic properties of g-C3N4-based materials. However, g-C3N4 has several other notable features, such as high adsorption affinity towards aromatic substances and heavy metals, high thermal and chemical resistances, good compatibility with various materials, and easily scalable synthesis; therefore, in addition to simple photocatalysis, it can be widely used in other decontamination systems based on activation of oxidants and electrocatalysis. This critical review provides a comprehensive summary of recent advancements in g-C3N4-based materials and their use in treating polluted water and wastewater via the following routes (1) activation of oxidizing agents (e.g., hydrogen peroxide, ozone, peroxymonosulfate, and persulfate): and (2) photoelectrocatalysis using fabricated g-C3N4-based photocathodes and photoanodes. For each route, we briefly summarize the primary mechanisms, distinctive features, and performances of various water treatment systems using g-C3N4-based catalysts. We also highlight the specific roles of g-C3N4 in improving the efficiencies of these treatment processes. The advantages and limitations of previously reported water treatment systems using g-C3N4-based materials are also described and compared in this review. Finally, we discuss the challenges and prospects of improving g-C3N4-based water purification applications.
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A critical review on graphitic carbon nitride (g-C3N4)-based composites for environmental remediation. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119769] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Deposition of CeO2 on TiO2 nanorods electrode by dielectric barrier discharge plasma to enhance the photoelectrochemical performance in high chloride salt system. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119252] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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A review on graphitic carbon nitride (g-C 3N 4) based hybrid membranes for water and wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 792:148462. [PMID: 34465053 DOI: 10.1016/j.scitotenv.2021.148462] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/27/2021] [Accepted: 06/10/2021] [Indexed: 05/15/2023]
Abstract
Graphitic carbon nitride (g-C3N4) has gained enormous attention for water and wastewater treatment. Compared with g-C3N4 nanopowders, g-C3N4 based hybrid membranes have demonstrated great potential for its superior practicability. This review outlines the preparation and characterization of g-C3N4 based hybrid membranes and presents their representative applications in water and wastewater treatment (e.g., removal of organic dyes, phenolic compounds, pharmaceuticals, salt ions, heavy metals, and oils). Meanwhile, g-C3N4 based films for the removal of contaminants through photocatalytic degradation is also summarized. In addition, the corresponding mechanisms and relevant findings are discussed. Finally, the challenges and research needs in the future and application of g-C3N4 based hybrid membranes are highlighted.
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Treatment of real wastewater by photoelectrochemical methods: An overview. CHEMOSPHERE 2021; 276:130188. [PMID: 33743419 DOI: 10.1016/j.chemosphere.2021.130188] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/24/2021] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
An inadequate and inefficient performance ability of conventional methods to remove persistent organic pollutants urges the need of alternative or complementary advanced wastewater treatments methods to ensure the safer reuse of reclaimed water. Photoelectrochemical methods are emerging as promising options among other advanced oxidation processes because of the higher treatment efficiency achieved due to the synergistic effects of combined photochemical and electrolysis reactions. Synergistic effects of integrated photochemical, electrochemical and photoelectrochemical processes not only increase the hydroxyl radical production; an enhancement on the mineralization ability through various side reactions is also achieved. In this review, fundamental reaction mechanisms of different photoelectrochemical methods including photoelectrocatalysis, photo/solar electro-Fenton, photo anodic oxidation, photoelectroperoxone and photocatalytic fuel cell are discussed. Various integrated photochemical, electrochemical and photoelectrochemical processes and their synergistic effects are elaborated. Different reactor configurations along with the positioning of electrodes, photocatalysts and light source of the individual/combined photoelectrochemical treatment systems are discussed. Modified photoanode and cathode materials used in the photoelectrochemical reactors and their performance ability is presented. Photoelectrochemical treatment of real wastewater such as landfill leachate, oil mill, pharmaceutical, textile, and tannery wastewater are reviewed. Hydrogen production efficiency in the photoelectrochemical process is further elaborated. Cost and energy involved in these processes are briefed, but the applicability of photocatalytic fuel cells to reduce the electrical dependence is also summarised. Finally, the use of photoelectrochemical approaches as an alternative for treating soil washing effluents is currently discussed.
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Catalytic conversion of seawater to fuels: Eliminating N vacancies in g-C 3N 4 to promote photocatalytic hydrogen production. ENVIRONMENTAL RESEARCH 2021; 197:111167. [PMID: 33861976 DOI: 10.1016/j.envres.2021.111167] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/17/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
The use of solar energy to decompose seawater and produce hydrogen is of great significance in solving the energy crisis. Numerous studies have shown that vacancies can significantly improve photocatalytic activity due to their electron-rich nature. However, our recent research has shown that materials with vacancies are not suitable for photocatalytic reactions in seawater. In this study, g-C3N4 with rich N vacancies was selected as the research object, and urea was used as the precursor; in this system, the N vacancies in g-C3N4 could be effectively reduced by the addition of ZIF-8 (ZCNQx). The activity of ZCNQ40 was 5.6 times higher than that of g-C3N4 in fresh seawater, but only 3.1 times higher in freshwater. Based on the analysis of the experimental results, we believe that g-C3N4 has a limiting relationship between H+ adsorption catalysis and H2 product desorption. In addition, seawater contains many heteroatoms that will also compete with proton (H+) reduction. The results of our study show that catalysts with vacancies are not necessarily suitable for catalytic reactions in seawater media. This research will stimulate new ideas for research into the conversion of solar energy to chemical energy in seawater media.
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Synergistic effect of g-C3N4 nanosheets/Ag3PO4 microcubes as efficient n-p-type heterostructure based photoanode for photoelectrocatalytic dye degradation. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.113127] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ni 2P QDs decorated in the multi-shelled CaTiO 3 cube for creating inter-shelled channel active sites to boost photocatalytic performance. J Colloid Interface Sci 2021; 584:332-343. [PMID: 33070073 DOI: 10.1016/j.jcis.2020.09.090] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 09/22/2020] [Indexed: 11/25/2022]
Abstract
Control and insight into the abundance of inter-shelled channel active sites and charge transport mechanism are the long-term challenges for enhancing photocatalytic activity. Herein, the Ni2P quantum dots (QDs) are decorated in the multi-shelled CaTiO3 cube for creating the abundance of inter-shelled channel active sites, which greatly improve the photocatalytic performances for generating H2 and degrading tetracycline (TC) relative to pure CaTiO3 and Ni2P. Moreover, the Z-scheme mechanism and the quantum effect of the Ni2P in multi-shelled CaTiO3 cube play a crucial role for enhancing photocatalytic performance. Furthermore, the photoelectric researches demonstrate that the Ni2P/CaTiO3 heterostructure possesses more abundant active sites, smaller interface transmission resistance and faster photo-generated charge transfer efficiency. This work provides a meaningful model to research other materials with creating the abundance of inter-shelled channel active sites for the photo-electrocatalytic field.
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Graphitic Carbon Nitride-Based Composite in Advanced Oxidation Processes for Aqueous Organic Pollutants Removal: A Review. Processes (Basel) 2020. [DOI: 10.3390/pr9010066] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In recent decades, a growing number of organic pollutants released have raised worldwide concern. Graphitic carbon nitride (g-C3N4) has drawn increasing attention in environmental pollutants removal thanks to its unique electronic band structure and excellent physicochemical stability. This paper reviews the recent progress of g-C3N4-based composites as catalysts in various advanced oxidation processes (AOPs), including chemical, photochemical, and electrochemical AOPs. Strategies for enhancing catalytic performance such as element-doping, nanostructure design, and heterojunction construction are summarized in detail. The catalytic degradation mechanisms are also discussed briefly.
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