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•First report on CuCr2O4/anatase-TiO2 nanocomposite as an efficient photocatalyst.•Synthesis at 400 °C causes maximum activity under domestic LED light irradiation.•CuCr2O4/TiO2 is ...active for the degradation of azo dyes like MB, RhB and MO.•Nanocomposite can degrade tetracycline hydrochloride and norfloxacine antibiotics.•It is shown to be a promising candidate for oxygen evolution reaction.
The rutile and anatase polymorphs of TiO2 are the most extensively studied photocatalyst materials with the efficient absorption in the violet to near ultra violet region of the electromagnetic spectrum, which boost tremendous research endeavors in increasing the photocatalytic activity of TiO2 under visible light sources through rational modifications. Here, we report the astonishing performance of CuCr2O4(CCO)/anatase-TiO2 nanocomposite as a Fenton like catalyst with potential impact for sustainable design and environmental protection. All the materials were thoroughly characterized by several physico chemical techniques. CCO/TiO2 nanocomposite obtained by heat-treatment at 400 °C is found to exhibit high performance towards degradation of azo dyes like methylene blue (MB), rhodamine B (RhB) and methyl orange (MO), antibiotics like tetracycline hydrochloride and norfloxacine, and a promising Pt-free candidate for photoelectrocatalytic oxygen evolution reaction under domestic light emitting diode (LED) light irradiation. CCO/TiO2 shows high recycling activity and chemical stability. Under domestic visible LED light irradiation, the electrons are photoexcited from the conduction band of CCO to that of TiO2 resulting in enhanced charge separation eventually facilitating the catalytic performance of the nanocomposite. TiO2 plays two primordial roles, firstly, it acts as an electron receiver to improve the charge separation in the nanocomposite and secondly, it participates in the Fenton like reaction.
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► The instead of Ti substrate with TiO2-NTs greatly improved phenol electrocatalytic degradation. ► Pore diameter and length of TiO2-NTs are crucial to the pollutant degradation ...efficiency. ► TiO2-NTs architecture affects on the electrode morphology and oxygen evolution potential. ► TiO2-NTs/SnO2-Sb with 85nm pore diameter and 5μm length TiO2-NTs performed the best.
There are growing interests in the TiO2 nanotubes (TiO2-NTs) based Sb-doped SnO2 anode (TiO2-NTs/SnO2-Sb) for organic pollutants degradation due to its high oxygen evolution potential and enhanced degradation performance. However, whether and how the TiO2-NTs substrate architecture of the electrodes affects the electrocatalytic capability for organic pollutant degradation has not been reported yet. This work addressed this issue, investigating the effect of the pore diameter and length of TiO2-NTs on the electrocatalytic capability of TiO2-NTs/SnO2-Sb electrode, which was fabricated by Sb-doped SnO2 coating electrodeposition on different TiO2-NTs architecture substrates by successfully adjusting the Ti substrate anodization time and voltage. The characterizations of morphology, crystal structures and composition as well as the electrochemical characteristics were comparably studied. It confirmed the modification of TiO2-NTs substrate greatly improved the electrocatalytic degradation of organic pollutant, using phenol as the target contaminant. The pore diameter and length of TiO2-NTs substrates of the TiO2-NTs/SnO2-Sb electrode were verified to be crucial to the pollutant degradation efficiency, and the one with TiO2-NTs of 85nm pore diameter and 5μm length performed the best.
•The highly effective photocatalysts (BLCF) were fabricated.•PMS/BLCF-NPs was catalyzed by irradiating with LED light.•The pathways of MO decomposition were elucidated.•OH, O2, SO4–, e– and h+ were ...the reactive species.
Element engineering in Mhexaferrite system has been demonstrated as an effective technique to boost catalytic activation of peroxymonosulfate (PMS). This study aimed at catalytic activation of PMS under LED irradiation using a novel LaCr substituted Mhexaferrite photocatalyst (BLCF-NPs) for degradation of organic pollutants in water systems. The chemical and physical characteristics of BLCF catalysts, the effects of BLCF's heterogeneous catalyst, PMS, pH, and pollutant concentration on degradation performance, reusability and stability of BLCF-NPs were systematically investigated. Importantly, under LED illumination, the sample C3 activated PMS to degrade MO more efficiently (99.99% within 80 min) and stably than reported Mhexaferrite NPs, with a first-order-kinetic rate constant (k = 11.41 10−2 min−1). The PMS/LED/BLCF-NPs system was improved effectively in a wide pH range from 3 to 10. Radical quenching experiments demonstrated that SO4− played a dominant role in MO degradation. This research paves the way for developing high-efficiency catalysts, as well as making Mhexaferrites viable options for pollutants removal.
Efficient and economical catalysts are crucial for activating H2O2 in Fenton-like reactions. Microalgae harvesting by magnetic separation will inevitably result in unrecovered Fe3O4 nanoparticles ...(Fe3O4 NPs) entering the downstream oil production stage. This part of Fe3O4 NPs can play a catalytic role in the co-liquefaction process with microalgae to improve the bio-oil quality, and then be separated from the liquid phase along with microalgae hydrochar (MHC). Herein, this N-rich MHC loaded Fe3O4 NPs composite (Fe3O4@MHC) as a by-product was recycled without reprocessing to remove Rhodamine B (RhB). Detailed characterization data indicates that Fe3O4 NPs can be well anchored and dispersed on MHC surface after liquefaction. The Fe3O4@MHC exhibits an outstanding catalytic performance in the activation of H2O2 for RhB degradation, with a removal rate of >97 % within 60 min at a lower dosage (0.17 g/L). MHC act as electron donors due to the abundant oxygen- and nitrogen-containing functional groups to accelerate Fe2+/Fe3+ cycle. OH and O2− are the dominant active species in catalytic systems. This study not only provides an economical carbon material with high efficiency for environmental remediation, but also proposes a reliable solution for the disposal of solid residues after microalgae bio-oil production.
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•Fe3O4 NPs@MHC was a by-product of microalgal oil production without reprocessing.•Efficient RhB removal was obtained at low catalyst dosage and H2O2 consumption.•The degradation of contaminants benefited from synergistic effect of Fe3O4 and MHC.•The abundant functional groups promoted the RhB adsorption and the Fe3+ reduction.•The MHC surface would also be partially oxidized by active species.
In this paper we prepared via different synthetic processes, two ternary systems based on ZnO, CeO2 and Cu2O for the abatement of organic pollutants. The system ZnO/CeO2 was already known to be ...efficient in the degradation of emergent contaminants, the addition of cuprous oxides allows also to enhance reductive properties to the material thanks to its specific potential. The mixed oxides were characterized via power X Ray Diffraction, UV visible Diffuse Reflectance and Electron Paramagnetic Resonance. The materials obtained through hydrothermal synthesis shown better performances in the abatement of phenol and carbamazepine.
•Precipitation and hydrothermal synthesis of the mixed systems ZnO/CeO2/Cu2O.•Structural and spectroscopic characterization has been performed.•Electron Paramagnetic Resonance and UV vis DR demonstrated the presence of residual Cu2+ ions well dispersed on the surface.•Phenol and carbamazepine were rapidly completed abated by the material prepared via hydrothermal synthesis.
Organic compounds have enhanced different industrial outputs, but many related environmental challenges, such as groundwater and surface water pollution related to these compounds, have piqued ...governments' and citizens' interest worldwide. Photocatalysis has recently been proven to be an effective method of eliminating these pollutants. This study investigated the photocatalytic degradation of 1-naphthyl methylcarbamate (carbaryl pesticide) and methyl orange (dye) using an efficient SnO2 NPs@g-C3N4 nanocomposite photocatalyst. A straightforward solid-state technique created a mesoporous SnO2 NPs@g-C3N4 nanocomposite photocatalyst with various SnO2 NP concentrations. Various analytical approaches were used to characterize the SnO2 NPs@g-C3N4 nanocomposite photocatalyst, including X-ray powder diffraction (XRD) patterns, energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectra (FTIR), transmission electron microscopy (TEM), and ultraviolet–visible spectroscopy (UV–Vis). The degradation of carbaryl, as a model pesticide and methyl orange as a model dye, under visible light was tested to determine the photocatalytic activity of the SnO2 NPs@g-C3N4 nanocomposite with various mass percentages of SnO2 NPs. The results showed that SnO2 NPs successfully improved the photoactivity of g-C3N4. The photocatalytic activity showed that the carbaryl photodegradation rate increased from 32% by g-C3N4 to 85% and 96% for methyl orange by SnO2 NPs@g-C3N4 nanocomposite photocatalyst (20%), indicating that SnO2 NPs@g-C3N4 nanocomposite is a promising photocatalyst for pesticides and dyes. The enhanced photodegradation effectiveness of SnO2 NPs@g-C3N4 nanocomposite photocatalyst was related to increased surface area and improved illumination radiation ability by successfully separating charge carriers.
Due to the scarcity of water resources and the harmful effects of sewage on water bodies, water purification becomes an important issue. The application of ultrasonic waves is a novel technique ...developed for water purification. This technology works as an advanced method of oxidation, contributing to the elimination of various types of contaminants. The basic principle of ultrasound is based on the destruction of both bacterial cells and difficult to- degrade organics. A brief overview of water purification methods, application of ultrasound, ultrasound waves theory and the benefits and drawbacks of using ultrasound waves in water purification will be discussed in this article. In addition, the role of ultrasound waves in the degradation of various organic contaminants, microbial pollutant disinfection, and other pollutants removal.
The continuous rise in atmospheric CO2 concentration, overconsumption of energy resources, and release of extraordinary organic pollutants are challenging issues of the modern era. Catalytic ...technology offers a promising solution to tackle these energy and environmental challenges in parallel by facilitating highly effective and sustainable processes. Herein, we report the fabrication of a series of different nature polyarylimide (PAI)-based covalent–organic frameworks (COFs) via the polycondensation reaction by altering linkers, organic solvents, and other experimental conditions. To optimize their catalytic performance, the resultant PAI-COFs were further decorated with metal–organic frameworks (ZIF-67). The decoration of COF4 with ZIF-67 led to adjusted bandgaps, created an active site, enhanced charge separation and migration of photoexcited electron–hole (e–h) pairs, extended the light absorption to the visible region, and also facilitated the transferring of electrons between the COFs and MOFs via the photoelectron modulation approach. Based on our findings, it is confirmed that COF4 and ZIF-67 (MOFs) are the optimal catalysts compared to the other COFs (COF1, COF2, and COF3) and MOFs (ZIF-8). Interestingly, compared to the pristine COF4, the 5ZIF-67/COF4 nanohybrid revealed ∼8-fold and ∼5.3-fold for CO2 conversion, direct CO2 capturing, and photoelectrochemical CO2 conversion with a faradaic efficiency of 50%. Likewise, the as-fabricated catalyst also exhibits exceptional activities for photocatalytic hydrogen production and pollutant oxidation. Ultimately, this work will provide a roadmap for the design and fabrication of COF-based nanohybrids for energy and environmental applications.
In this work atomically dispersed antimony P-doped carbon nitride was prepared with the aim of producing hydrogen peroxide under visible light irradiation and of obtaining organic contaminants ...degradation. The conjugation of the P-doping can induce significant increase in visible light harvesting, narrowing of band gap energy and shift of the upper edge of the VB to less positive value and the introduction of Sb can efficiently trap oxygen molecules in the Sb-OO end-on structure and at the same time accumulate electrons which act as the photoreduction sites for O2 via a 2e− ORR pathway. Pristine C3N4 and P-doped C3N4 were prepared as references using melamine and ammonium dihydrogen phosphate as precursors and different amount of Sb were added (x = 0.5, 1, 3, 5 mmol) to synthetize Sbx P-doped C3N4. All materials were characterized with multiple techniques, tested for the hydrogen peroxide production and for the degradation of carbamazepine. The pristine C3N4 led to a H2O2 poor production but with the introduced modifications the yield increased and an upward trend during the time was observed. The optimum amount of Sb was found to be 1 mmol and it led to the production of more than 7 times the amount produced by pristine carbon nitride. The degradation of carbamazepine using only visible radiation required prolonged timescales but when we expand the light spectrum to include near-UV, the abatement of the pollutant is achieved in a few hours. The efficiency of the synthesized materials in hydrogen peroxide production suggests possible future developments that take advantage of the excellent peroxide production of atomically dispersed antimony P-doped carbon nitride photocatalysts in Fenton-like processes or involve the use of peroxidase enzymes to achieve enhanced degradative performances.
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