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Verma G, Venkatesan P, Roy D, Aloni P, Dega NK, Gupta A. Low cost fabrication of continuous flow optofluidic microreactor for efficient dye degradation using graphene QDs@MOF (Ti) photocatalyst. ENVIRONMENTAL RESEARCH 2024; 263:120207. [PMID: 39442662 DOI: 10.1016/j.envres.2024.120207] [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: 07/18/2024] [Revised: 09/20/2024] [Accepted: 10/20/2024] [Indexed: 10/25/2024]
Abstract
The optofluidic microreactor, a convergence of optics and microfluidics, offers advanced functionalities that can be pivotal in the rapid assessment of nanocatalysts for tackling environmental contamination issues. This article presents an efficient approach for degrading Methylene blue (MB) dye, commonly used in the textile industry, within a cost-effective polydimethylsiloxane (PDMS) based continuous flow optofluidic microreactor. This microreactor combines graphene quantum dots (QDs) and NH2-MIL-125 (MOF(Ti)) as a highly effective photocatalyst coating within its microchannels. By directly incorporating graphene QDs@MOF(Ti) into the microchannels, the photocatalytic medium is brought into close proximity with the flowing MB dye solutions, thereby reducing the necessary interaction time and enhancing purification efficiency. Furthermore, the findings demonstrate an impressive degradation efficiency of ∼99% for MB dye at a flow rate of 50 μL min-1 under visible light irradiation, achieved in a single pass. Additionally, the microfluidic reactor exhibits prolonged stability of the photocatalyst, enabling its reuse without significant efficiency loss. In addition, a comparative analysis highlights the advantages of microreactor-based photocatalysis over traditional methods. These advancements in the features of the graphene QDs@MOF(Ti) nanocomposite substantiate their demonstrated superiority in degradation efficiency.
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Liang Y, Yu T, Lang M, Chen F, Cao M, Chen B, Wang P, Liang Y, Wang Y. In situ growth of BiOBr on copper foam conductive substrate with enhanced photocatalytic performance. Heliyon 2024; 10:e25929. [PMID: 38404782 PMCID: PMC10884819 DOI: 10.1016/j.heliyon.2024.e25929] [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: 10/24/2023] [Revised: 01/26/2024] [Accepted: 02/05/2024] [Indexed: 02/27/2024] Open
Abstract
Photocatalysis technology based on solar-powered semiconductors is widely recognized as a promising approach for achieving eco-friendly, secure, and sustainable degradation of organic contaminants. Nevertheless, conventional photocatalysts exhibit drawbacks such as a wide bandgap, and rapid recombination of photoinduced electron/hole pairs, in addition to complicated separation and recovery procedures. In this research, we cultivated BiOBr in situ on the surface of copper foam to fabricate a functional photocatalyst (denoted as BiOBr/Cu foam), which was subsequently employed for the photodegradation of Methylene Blue. Based on photodegradation experiments, the 0.3 BiOBr/Cu foam demonstrates superior photocatalytic efficacy compared to other photocatalysts under solar light irradiation. Furthermore, its ease of separation from the solution enhances its potential for reuse. The analysis of charge transfer revealed that the copper foam functions as an effective electron scavenger within the BiOBr/Cu foam, thereby facilitating charge separation and the generation of photo-induced holes. This phenomenon contributes to a significantly enhanced production of hydroxyl radicals. This study provides a valuable perspective on the design and synthesis of photocatalysts with heightened practicality, employing a conductive substrate.
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Amaro-Gahete J, Romero-Salguero FJ, Garcia MC. Modified surfatron device to improve microwave-plasma-assisted generation of RONS and methylene blue degradation in water. CHEMOSPHERE 2024; 349:140820. [PMID: 38040253 DOI: 10.1016/j.chemosphere.2023.140820] [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: 09/14/2023] [Revised: 11/10/2023] [Accepted: 11/24/2023] [Indexed: 12/03/2023]
Abstract
Microwave-induced plasmas generated at atmospheric pressure are very attractive for a great variety of applications since they have a relatively high electron density and can generate large amounts of reactive species. Argon plasmas can be sustained inside dielectric tubes but are radially contracted and exhibit filamentation effects when the diameter of the tube is not narrow enough (over 1.5 mm). In this work, we describe a new approach for creating microwave (2.45 GHz) plasmas under atmospheric pressure conditions by using a surfatron device and power from 10 W. This modified design of the reactor enables the sustenance of non-filamented argon plasmas. These new plasmas have a higher gas temperature and electron density than the plasma generated in the original surfatron configuration. The new design also allows for the maintenance of plasmas with relatively high proportions of water, resulting in the generation of larger quantities of excited hydroxyl radicals (·OH*). Thus, this novel configuration extends the applicability of microwave-induced plasmas by enabling operation under new conditions. Finally, the degradation of methylene blue (MB) in aqueous solutions has been assessed under different initial dye concentrations and argon flow conditions. The new plasma produces a substantial increase in hydrogen peroxide and nitrate concentrations in water and leads to a noteworthy enhancement in MB degradation efficiency. The introduction of water into the plasma produces a minor additional improvement.
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Luo J, Liu X, Huang W, Cheng X, Wang F, Fang S, Cao J, Liu J, Cheng S. Novel calcium oxide activated peroxymonosulfate system for methylene blue removal: Identification of key influencing factors, transformation pathway and toxicity assessment. CHEMOSPHERE 2024; 349:140955. [PMID: 38104737 DOI: 10.1016/j.chemosphere.2023.140955] [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: 09/16/2023] [Revised: 11/29/2023] [Accepted: 12/12/2023] [Indexed: 12/19/2023]
Abstract
The activation of peroxymonosulfate (PMS) has gained significant interest in the removal of organic pollutants. However, traditional methods usually suffer from drawbacks such as secondary contamination and high energy requirements. In this study, we propose a green and cost-effective approach utilizing calcium oxide (CaO) to activate PMS, aiming to construct a simple and reliable PMS based advanced oxidation processes (AOPs). The proposed CaO/PMS system achieved fast degradation of methylene blue (MB), where the degradation rate of CaO/PMS system (0.24 min-1) was nearly 2.67 times that of PMS alone (0.09 min-1). Under the optimized condition, CaO/PMS system exhibited remarkable durability against pH changes, co-exists ions or organic matters. Furthermore, singlet oxygen (1O2) was identified as the dominant reactive oxygen species by electron paramagnetic resonance (EPR) and quenching tests. Accordingly, the degradation pathways of MB are proposed by combing the results of LC/MS analysis and density functional theory (DFT) calculations, and the predicted ecotoxicity of the generated byproducts evaluated by EOCSAR could provide systematic insights into the fates and environmental risks of MB. Overall, the study provides an eco-friendly and effective strategy for treating dyeing wastewater, which should shed light on the application of PMS based AOPs.
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Fiaz M, Sohail M, Nafady A, Will G, Wahab MA. A facile two-step hydrothermal preparation of 2D/2D heterostructure of Bi 2WO 6/WS 2 for the efficient photodegradation of methylene blue under sunlight. ENVIRONMENTAL RESEARCH 2023; 234:116550. [PMID: 37437862 DOI: 10.1016/j.envres.2023.116550] [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: 04/04/2023] [Revised: 06/26/2023] [Accepted: 07/02/2023] [Indexed: 07/14/2023]
Abstract
A facile two-step hydrothermal method was successfully used to prepare a photocatalyst Bi2WO6/WS2 heterojunction for methyl blue (MB) photodegradation. Fabricated photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). Band gap measurements were carried out by diffuse reflectance spectroscopy (DRS). Results indicated that the prepared heterostructure photocatalyst has increased visible light absorption. Photocatalytic performance was evaluated under sunlight irradiation for methylene blue (MB) degradation as a model dye. Variations in pH (4-10), amount of catalyst (0.025-0.1 g/L), and initial MB concentrations (5-20 ppm) were carried out, whereas all prepared catalysts were used to conduct the tests with a visible spectrophotometer. Degradation activity improved with the pH increase; the optimum pH was approximately 8. Catalyst concentration is directly related to degradation efficiency and reached 93.56% with 0.075 g of the catalyst. Among tested catalysts, 0.01 Bi2WO6/WS2 has exhibited the highest activity and a degradation efficiency of 99.0% in 40 min (min) for MB. MB photodegradation follows pseudo-first-order kinetics, and obtained values of kapp were 0.0482 min-1, 0.0337 min-1, 0.0205 min-1, and 0.0087 min-1 for initial concentrations of 5 ppm, 10 ppm, 15 ppm, and 20 ppm, respectively. The catalyst was reused for six cycles with a negligible decrease in the degradation activity. Heterostructure 0.01 Bi2WO6/WS2 has exhibited a photocurrent density of 16 μA cm-2, significantly higher than 2.0 and 4.5 μA cm-2 for the pristine WS2 and Bi2WO6, respectively. The findings from these investigations may serve as a crucial stepping stone towards the remediation of polluted water facilitated by implementing such highly efficient photocatalysts.
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Nayak S, Kumar Das K, Parida K. Indulgent of the physiochemical features of MgCr-LDH nanosheets towards photodegradation process of methylene blue. J Colloid Interface Sci 2023; 634:121-137. [PMID: 36535152 DOI: 10.1016/j.jcis.2022.12.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/01/2022] [Accepted: 12/11/2022] [Indexed: 12/15/2022]
Abstract
In the present work, we report the preparatory strategy of MgCr-layered double hydroxide (LDH) nanosheets with 90% degree of delamination by employing a formamide-assisted co-precipitation and mild hydrothermal route for the degradation of methylene blue (MB) under solar light exposure. The as-synthesized MgCr-LDH nanosheets were characterized by assorted characterization techniques such as powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman, thermogravimetric analysis (TGA), N2 adsorption-desorption measurement, X-ray photoelectron spectroscopy (XPS) and UV-Visible diffused reflectance spectroscopy (UV-DRS). The XRD pattern of MgCr-LDH nanosheets quantified the strain (ε) and dislocation density (δ) of 1.371 lines-2 m-4 and 0.5723 lines m-2 related to the (110) plane with d-spacing value of 1.6169 Ȧ. With a minimum band gap of ∼2.63 eV, the as-synthesized MgCr-LDH nanosheets displayed 90.6% MB photodegradation under the experimental protocols such as catalyst dosage of 30 mg/L, initial MB concentrations of 20 ppm, pH of 7 and time duration of 2 h under solar light exposure. Further, the recyclability test of the photocatalyst signifies material stability up to four successive cycles with 90% retention of MB degradation under sunlight exposure. The superior catalytic performances of the MgCr-LDH nanosheets could be ascertained to the suppression of excitonic recombination and effective light harvestation properties, synergistically contributed by the porous structural aspects via association of uni/multi-lamellar nanosheets, surface defect sites and photoactive Cr3+ cations. Additionally, the surface -OH groups of LDH contributed towards the generation of •OH radicals for triggering the catalytic performances. This type of work advances the novel ideas for establishing highly potent photocatalysts via synergizing structural and surface properties, paving towards effective wastewater treatment.
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Wolski L, Sobańska K, Walkowiak A, Akhmetova K, Gryboś J, Frankowski M, Ziolek M, Pietrzyk P. Enhanced adsorption and degradation of methylene blue over mixed niobium-cerium oxide - Unraveling the synergy between Nb and Ce in advanced oxidation processes. JOURNAL OF HAZARDOUS MATERIALS 2021; 415:125665. [PMID: 33773255 DOI: 10.1016/j.jhazmat.2021.125665] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/25/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Formation of reactive oxygen species (ROS) via H2O2 activation is of vital importance in catalytic environmental chemistry, especially in degradation of organic pollutants. A new mixed niobium-cerium oxide (NbCeOx) was tailored for this purpose. A thorough structural and chemical characterization of NbCeOx along with CeO2 and Nb2O5 reference materials was carried out using TEM/STEM/EDS, SEM, XRD, XPS, EPR, UV-vis and N2 physisorption. The ability of the catalysts to activate H2O2 towards ROS formation was assessed on the basis of EPR and Raman measurements. Catalytic activity of the oxides was evaluated in degradation of methylene blue (MB) as a model pollutant. Very high activity of NbCeOx was attributed to the mixed redox-acidic nature of its surface, which originated from the synergy between Nb and Ce species. These two properties (redox activity and acidity) ensured convenient conditions for efficient activation of H2O2 and degradation of MB. The activity of NbCeOx in MB degradation was found 3 times higher than that of the commercial Nb2O5 CBMM catalyst and 240 times higher than that of CeO2. The mechanism of the degradation reaction was found to be an adsorption-triggered process initiated by hydroxyl radicals, generated on the surface via the transformation of O2-•/O22-.
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Nugraha MW, Zainal Abidin NH, Sambudi NS. Synthesis of tungsten oxide/ amino-functionalized sugarcane bagasse derived-carbon quantum dots (WO 3/N-CQDs) composites for methylene blue removal. CHEMOSPHERE 2021; 277:130300. [PMID: 33774232 DOI: 10.1016/j.chemosphere.2021.130300] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/07/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
In this present study, the tungsten oxide/amino-functionalized sugarcane bagasse derived-carbon quantum dots (WO3/N-CQDs) composite has successfully been prepared through a simple mixing process. The WO3 was synthesized through a precipitation method, and CQDs were amino-functionalized using ethylenedinitrilotetraacetic acid (EDTA) and ethylenediamine (EDA) through one-pot hydrothermal method. It is revealed that N-CQDs incorporation into WO3 alters the bandgap energy, crystallinity, surface area, and photoluminescence (PL) properties. The produced composites exhibit higher monoclinic WO3 crystallinity, larger surface area, lower bandgap energy and quenched photoluminescence intensity. The as-prepared WO3/N-CQDs composites exhibit better adsorption and photocatalytic degradation performance of methylene blue (MB) than the pristine WO3. It shows that the combination of N-CQDs and WO3 enhanced visible light absorption, by lowering the bandgap energy of WO3 from 2.175 to 1.495 eV. The best performance composite is WO3/N-CQDs EDA 2.5% with an efficiency of 96.86%, removal rate constant of 0.02017/min, and chemical oxidation demand (COD) removal efficiency achieved 84.61%. Moreover, the WO3/N-CQDs EDA 2.5% shows a significant photocatalytic activity even at higher MB initial concentration with 92.93% removal for 50 ppm MB. Subsequently, the composite also has good stability after a sequential 3-times cycle of degradation with 86.85% removal. The increasing photocatalytic performance is affected by the quenching effect of PL and lower bandgap energy. The lower intensity of the PL indicates the reduced charge carrier recombination resulting in increased photocatalytic activity. The combination of N-CQDs and WO3 resulted in improved photodegradation, which shows its significant potential to be utilized for wastewater treatment.
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Peychev B, Vasileva P. Novel starch-mediated synthesis of Au/ZnO nanocrystals and their photocatalytic properties. Heliyon 2021; 7:e07402. [PMID: 34258459 PMCID: PMC8258847 DOI: 10.1016/j.heliyon.2021.e07402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/22/2021] [Accepted: 06/22/2021] [Indexed: 11/25/2022] Open
Abstract
A novel solution-solid synthesis method for preparation of ZnO and Au/ZnO composite nanocrystals using starch matrix has been developed and optimized. The process is characterized by simplicity, environmental compatibility and good performance. Nanocomposite samples with different gold content have been synthesized and studied with respect to their structure, size and shape of nanocrystals, thermal behavior, surface characteristics and optical properties, as well as their photocatalytic activity. We have found that modification of nanocrystalline ZnO with gold nanocrystals strongly influences the porosity of nanocomposites - less micro- and mesopores are formed, which results in a reduced specific surface area. The synthesized ZnO and Au/ZnO nanocrystals are active photocatalysts for the photocatalytic degradation of methylene blue (MB), as a model pollutant dye, in the UV region. There is a decrease in photocatalytic activity with an increase of the gold content in the nanocomposite photocatalyst. The degree of MB degradation obtained with a pure ZnO sample is comparable to that with the Au/ZnO photocatalyst with the lowest gold content 0.05 at. %. New and interesting result has been obtained relating to maximum specific (intrinsic) photocatalytic activity of 0.05 at. % Au/ZnO nanocrystals.
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Zhang C, Zhang N, Xu Y, Feng J, Yao T, Wang F, Ma Z, Han H. Fenton reaction-mediated dual-attenuation of signal for ultrasensitive amperometric immunoassay. Biosens Bioelectron 2021; 178:113009. [PMID: 33493899 DOI: 10.1016/j.bios.2021.113009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/07/2021] [Accepted: 01/15/2021] [Indexed: 12/20/2022]
Abstract
In order to alter the complexion of immunoprobe with large impedance as negative factor in sensitivity of amperometric immunosensor, a strategy of Fenton reaction-mediated dual-attenuation of signal was proposed. Herein, metal-polydopamine-Fe3+ composite with the ability of Fenton reaction was initially prepared as immunoprobe for an ultrasensitive immunoassay. The polymerization of dopamine occurred on the surface of ZIF-67 to gain the metal-polydopamine shell, which possessed rich functional groups, negative charge and high specific surface. Then the prepared functional shell was further used to absorb Fe3+ and immobilize labeling antibody as immunoprobe, which was used to construct a sandwich type immunosensor. With addition of H2O2 and aniline, Fenton reaction was triggered to produce hydroxyl radicals, which can not only decrease the current value by degrading methylene blue molecules, but also further initiate aniline to polymerize into non-conductive polyaniline for successive abatement of signal intensity. Therefore, the dual-attenuation of signal model rendered the immunoprobe into a favorable factor and synchronously enhance sensitivity. Expectedly, the detection performance with a linear range from 1.0 × 10-4-100 ng mL-1 and ultralow detection limit of 9.07 × 10-5 ng mL-1 toward neuron-specific enolase was obtained under optimal conditions. This work offered a novel tactic for enhancing sensitivity of immunosensor through the preparation of functional immunoprobe and its rational utilization as signal enhancer.
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Matović L, Vujasin R, Kumrić K, Devečerski A, Wu YN, Kabtamu DM, Mirković M, Omerašević M, Petrović D. Waste tire carbon in synergetic interaction with spent gamma radioactive source for efficient radiocatalytic degradation of organic dye. JOURNAL OF HAZARDOUS MATERIALS 2021; 408:124922. [PMID: 33383450 DOI: 10.1016/j.jhazmat.2020.124922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/02/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
Enhanced degradation of organic dye was achieved using two different kinds of waste materials: waste tire granules and spent sealed radioactive sources. Waste tire granules were used as raw material for the production of waste tire char (WTC), which was further utilized as an adsorbent matrix for synergetic adsorption/irradiation degradation of organic dye. The spent radioactive sources were radiographic sealed sources that originate from the industry which generate the high energy radiation. Methylene Blue (MB) was used as an organic model compound. Synthesized WTC has turbostratic structure, irregular shaped particles and developed mesoporous surface. Complete degradation of 0.02 dm3 of 100 mg dm-3 MB solution, having WTC dose of 1.25 g dm-3, was achieved with delivered doze of only 60 Gy. The applied doses were 100 times smaller than those presented in the literature. Degradation pathway was determined: OH radicals that originate from radiolysis of water and from the surface of WTC played the crucial role in the radiocatalytic degradation of MB. Breakage of the aromatic ring of MB appeared by the scission of the double C‒S+˭C bond as a result of the attack of OH species on adsorbed and electronically reorganized MB molecule.
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Venkatesh N, Aravindan S, Ramki K, Murugadoss G, Thangamuthu R, Sakthivel P. Sunlight-driven enhanced photocatalytic activity of bandgap narrowing Sn-doped ZnO nanoparticles. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:16792-16803. [PMID: 33398748 DOI: 10.1007/s11356-020-11763-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
In this paper, we grab to utilize one of the trending techniques with efficient implications in wastewater treatment of organic pollutants, the photocatalytic degradation method shining out in the research field. Herein, tin (Sn)-doped zinc oxide (ZnO) nanoparticles (NPs) (Sn/ZnO) with different doping concentrations (1, 2, 3, 4, and 5 wt%) were synthesized via a simple co-precipitation assisted method and later subjected for their physico-chemical, morphological, and optical characterization. In addition, photocatalytic activity as the concerned study was investigated as to record the different doping levels of Sn/ZnO to examine the effect of doping concentration in relation with the degradation efficiency. We know that the optical bandgap of pure ZnO was 3.26 eV while it tends to increase slightly upon increasing the doping concentration. In the present investigation, methylene blue (MB) dye was used as a model pollutant to evaluate the photocatalytic activity of Sn/ZnO photocatalysts under natural sunlight. Varied doping concentrations of Sn/ZnO were compared with different characterization techniques while XRD analysis shows up 4-Sn/ZnO with sharp peak at (1 0 1) plane with smaller grain size in comparison to other Sn/ZnO samples. The morphological recognition depicts the hexagonal structure with smaller size for 4-Sn/ZnO which offers more active sites with improved photocatalytic activity, higher surface area for the transportation of pollutants. Fluorescence spectra results revealed that Sn dopant suppresses the charge carrier recombination. The lower intensity of PL indicated reduced recombination rate, which resulted in enhancing the photocatalytic activity. To investigate the possible mechanism, kinetics and reusability studies were performed. The 4% Sn-doped ZnO nanoparticle concentration showed highest photocatalytic activity when compared with other doping levels.
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Zhu J, Luo G, Xi X, Wang Y, Selvaraj JN, Wen W, Zhang X, Wang S. Cu 2+-modified hollow carbon nanospheres: an unusual nanozyme with enhanced peroxidase-like activity. Mikrochim Acta 2021; 188:8. [PMID: 33389187 DOI: 10.1007/s00604-020-04690-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/15/2020] [Indexed: 01/30/2023]
Abstract
A Cu2+-modified carboxylated hollow carbon nanospheres (Cu2+-HCNSs-COOH) was designed with enhanced peroxidase-like activity for the detection of hydrogen peroxide (H2O2) and degradation of methylene blue (MB). Hollow polymer nanospheres were fabricated from aniline, pyrrole, Triton-100, and ammonium persulfate via confined interfacial copolymerization reaction, which can be pyrolyzed to create HCNSs with the hollow gap diameter of about 20 nm under high temperature. Combining the synergistic effect of coordination and electrostatic interaction, Cu2+-HCNSs-COOH was constructed by anchoring Cu2+ on the surface of HCNSs-COOH. Furthermore, Cu2+-HCNSs-COOH has higher affinity for 3,3',5,5'-tetramethylbenzidine and H2O2 of 0.20 mM and 0.88 mM, respectively. Based on the rapid response of Cu2+-HCNSs-COOH to H2O2, we constructed a colorimetric sensing platform by detecting the absorbance of the 3,3',5,5'-tetramethylbenzidine-H2O2 system at 652 nm for quantifying H2O2, which holds good linear relationship between 1 and 150 μM and has a detection limit of 0.61 μM. We also investigated the degradation of MB in the presence of Cu2+-HCNSs-COOH and H2O2, which can degrade 80.7% pollutants within 30 min. This research developed an unusual nanozyme for bioassays and water pollution treatment, which broadened the way for the rapid development of clinical diagnostics and water pollution treatment.
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Gao W, Tian J, Fang Y, Liu T, Zhang X, Xu X, Zhang X. Visible-light-driven photo-Fenton degradation of organic pollutants by a novel porphyrin-based porous organic polymer at neutral pH. CHEMOSPHERE 2020; 243:125334. [PMID: 31995864 DOI: 10.1016/j.chemosphere.2019.125334] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 10/27/2019] [Accepted: 11/06/2019] [Indexed: 06/10/2023]
Abstract
Developing novel heterogeneous photo-Fenton catalysts with high efficiency and stability, driven by visible-light rather ultraviolet light at neutral pH has been a major challenge for degradation of organic pollutants. In this work, we successfully synthesized a metalloporphyrin-based porous organic polymer (FePPOP-1) by the Sonogashira cross-coupling reaction. UV-vis absorption spectra showed FePPOP-1 exhibits a significant coverage of the natural solar irradiance spectrum. As a result, the prepared FePPOP-1 has a significantly enhanced photocatalytic activity for the visible-light-driven degradation of methylene blue. By using only 4 mg of FePPOP-1 as a catalyst, it was found that 50 mL of organic wastewater containing 70 ppm MB could be totally degraded in 80 min even at neutral pH. The effects of the initial MB, H2O2 concentrations, pH value and common ions on MB degradation were studied in detail. Both the catalytic mechanism of FePPOP-1 and the degradation route of MB were also proposed.
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Seng RX, Tan LL, Lee WPC, Ong WJ, Chai SP. Nitrogen-doped carbon quantum dots-decorated 2D graphitic carbon nitride as a promising photocatalyst for environmental remediation: A study on the importance of hybridization approach. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 255:109936. [PMID: 32063312 DOI: 10.1016/j.jenvman.2019.109936] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/15/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
Growing concerns of water pollution by dye pollutants from the textile industry has led to vast research interest to find green solutions to address this issue. In recent years, heterogeneous photocatalysis has harvested tremendous attention from researchers due to its powerful potential applications in tackling many important energy and environmental challenges at a global level. To fully utilise the broad spectrum of solar energy has been a common aim in the photocatalyst industry. This study focuses on the development of an efficient, highly thermal and chemical stable, environmentally friendly and metal-free graphitic carbon nitride (g-C3N4) to overcome the problem of fast charge recombination which hinders photocatalytic performances. Nitrogen-doped carbon quantum dots (NCQDs) known for its high electronic and optical functionality properties is believed to achieve photocatalytic enhancement by efficient charge separation through forming heterogeneous interfaces. Hence, the current work focuses on the hybridisation of NCQDs and g-C3N4 to produce a composite photocatalyst for methylene blue (MB) degradation under LED light irradiation. The optimal hybridisation method and the mass loading required for maximum attainable MB degradation were systematically investigated. The optimum photocatalyst, 1 wt% NCQD/g-C3N4 composite was shown to exhibit a 2.6-fold increase in photocatalytic activity over bare g-C3N4. Moreover, the optimum sample displayed excellent stability and durability after three consecutive degradation cycles, retaining 91.2% of its original efficiency. Scavenging tests were also performed where reactive species, photon-hole (h+) was identified as the primary active species initiating the pollutant degradation mechanism. The findings of this study successfully shed light on the hybridisation methods of NCQDs which improve existing g-C3N4 photocatalyst systems for environmental remediation by utilising solar energy.
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Wang F, Yu X, Ge M, Wu S, Guan J, Tang J, Wu X, Ritchie RO. Facile self-assembly synthesis of γ-Fe 2O 3 /graphene oxide for enhanced photo-Fenton reaction. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 248:229-237. [PMID: 30798024 DOI: 10.1016/j.envpol.2019.01.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/28/2018] [Accepted: 01/07/2019] [Indexed: 05/14/2023]
Abstract
A novel self-assembly method was developed to prepare a γ-Fe2O3/graphene oxide (GO) heterogeneous catalyst that showed excellent synergy between photocatalysis and Fenton-like reactions. The γ-Fe2O3/GO catalyst prepared on the iron plates demonstrated efficient and reproducible catalytic activities for water treatment. It takes only 80 min to degrade 50 mg L-1 methylene (MB) completely, which is the main non-biodegradable dye in wastewater from the textile industry. The heterogeneous catalyst is stable over a wide range of pH (from 2.0 to 10.2) for MB degradation, and can be easily extracted from solution and repeatedly used with little loss of catalytic activity. The high activity and stability of the catalyst system can be attributed to charge separation between γ-Fe2O3 and GO, which could accelerate Fenton-like process and photocatalysis. In addition, the dominant reactive oxidant species responsible for the MB degradation, including the hydroxyl radicals (•OH) and holes (h+), were trapped on the surface of the γ-Fe2O3/GO composite, as proved by a free-radical quenching experiment. The γ-Fe2O3/GO heterogeneous catalyst could potentially provide a solution for removal of non-biodegradable dyes from wastewater in the textile industry.
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Zarrabi M, Haghighi M, Alizadeh R. Sonoprecipitation dispersion of ZnO nanoparticles over graphene oxide used in photocatalytic degradation of methylene blue in aqueous solution: Influence of irradiation time and power. ULTRASONICS SONOCHEMISTRY 2018; 48:370-382. [PMID: 30080562 DOI: 10.1016/j.ultsonch.2018.05.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/20/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
In this paper, ZnO/Graphene Oxide (ZnO/GO) is synthesized via ultrasound assisted precipitation method and the effect of power and ultrasound time irradiation is studied on photocatalyst properties. The synthesized samples are used for methylene blue (MB) degradation as an organic water pollutant. Physicochemical properties of the samples are investigated by XRD, FESEM, EDX, BET-BJH, FTIR and DRS techniques. Moreover, pHpzc of the sample with the best performance is calculated to study the effect of acidity on the photocatalyst efficiency in photocatalytic process. Ultrasound has a positive effect on photocatalyst performance that is because of its effect on distribution of particles and semiconductor band gap, but it has no effect on photostability of the nanocomposite. Sonication has modified distribution of particles by enhancing the active sites for oxidation process. Making structural gaps by ultrasound irradiation increases available surface area which has a similar effect on photocatalyst performance. Graphene oxide as electron collector and transporter prevents electron-hole recombination and it can be an acceptable reason for enhancement at photocatalyst performance. Finally, some of operational parameters such as pH, photocatalyst loading and dye concentration are investigated.
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