Herein, Fe3O4–SnO2 nanoheterojunction has been synthesized and successfully encapsulated in gC3N4 matrix using a novel hydrothermal technique. The synthesized material was characterized using ...sophisticated analytical methods like XRD, TEM, BET, UV–Vis, VSM and XPS to evaluate structural, morphological, optical, magnetic and surface chemical properties. The hybrid nanostructure Fe3O4-SnO2-gC3N4 has been utilized for the LED light-induced photocatalytic degradation of carbofuran. The catalyst exhibited notable photocatalytic performance under visible light with an efficiency of ~89% and pseudo first order rate constant of 0.015 min−1. The result of change in variables like catalyst dose, pollutant concentration, pH and contact time on the photodegradation efficiency and degradation kinetics was studied. The incorporation of Fe3O4 improved the magnetic separation of the catalyst after several cycles of operation, thereby improving the practical utility of the catalyst system to tackle organic pollutants.
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•Fabrication of Fe3O4-SnO2-gC3N4 nanoheretojunction using hydrothermal technique.•Close interfacial contact among Fe3O4, SnO2 and gC3N4 was accomplished.•Synergistic degradation performance against carbofuran under LED irradiation.•Enhanced stability, reproducibility and consistency over multiple cycles of operation.
Nickel ferrites (NF), silver doped nickel ferrites (AgNF), and a composite of silver doped nickel ferrites with reduced graphene oxide (AgNF@rGO) were prepared through the co-precipitation method. ...The X-ray diffraction analysis was carried out to confirm the structure of prepared materials, and the crystallite size of prepared ferrites was less than 10 nm. FT-IR spectroscopy was performed for the confirmation of functional groups present in the synthesized materials. The surface morphology of prepared samples was investigated via scanning electron microscopy. Optical analysis was carried out with the help of UV–Visible spectroscopy. Thermogravimetric analysis was performed to check the thermal stability. The photocatalytic degradation of methylene blue under solar light irradiation was studied. The AgNF@rGO composite showed 76% degradation of coloured compound (methylene blue) and 50% degradation of colourless compound (benzimidazole). The enhanced photocatalytic degradation efficacy of AgNF@rGO was ascribed to the reduced graphene oxide sheets, which provided a large surface area and the ability to trap electrons from the conduction band. As a result, the decreased recombination rate of electrons and holes enhanced the degradation ability of the composite based photocatalyst. A scavenging experiment was also performed to determine the most photoactive species taking part in the degradation process. In comparison among all prepared samples, AgNF@rGO showed the maximum photocatalytic activity. It was because of the large surface area of the AgNF@rGO. It was investigated that AgNF@rGO is the most effective catalyst for the degradation of coloured and colourless organic pollutants.
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Pyraclonil is a new type of pyrazole herbicide, whose photochemical fate in aqueous solution has not been reported yet. In this study, effects on the photolysis rate such as light source, pH, NO3−, ...Fe3+, fulvic acid (FA) and riboflavin (RF) were investigated. Pyraclonil photodegraded in pure water under both UV and simulated sunlight with half-lives of 32.29 min and 42.52 h, respectively. Under UV, the degradation rate of pyraclonil in pH 4 solution (0.0299 ± 0.0033 min−1) was about twice higher than that in pH 9 (0.0160 ± 0.0063 min−1). Under simulated sunlight, low concentration (0.1–1 mg/L) of FA, NO3−, Fe3+ and RF noticeably promoted the photodegradation of pyraclonil. Then, with the combination of experimental UPLC-Q-TOF/MS and computational calculation of density functional theory (DFT), fourteen transformation products (TPs) of pyraclonil were identified with possible mechanism of C–N bond cleavage, photorearrangement, demethylation, hydroxylation and oxidation. Additionally, acute toxicity assessment was conducted through ECOSAR prediction and laboratory bioassays. The prediction results indicated that toxicity of TP157 to daphnid and green algae was 1.3 and 1.4 times higher than that of the parent, respectively. The bioassay results indicated that toxicities of TP157 and TP263 to C. vulgaris were about 1.6 and 5.9 times higher than that of the parent, respectively. The results provided a reference for elucidating the potential hazards of pyraclonil to non-target organisms and promoting its rational use.
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•Photolytic behavior of pyraclonil in water was studied for the first time.•Light source, pH, NO3−, Fe3+, FA, RF affect the photodegradation of pyraclonil.•Fourteen TPs were identified and two TPs were confirmed using LC-HRMS.•Photodegradation pathways were proposed based on the identified TPs and DFT.•Toxicities of 2 TPs to C. vulgaris were both higher than that of parent compound.
Tetracycline (TC) antibiotics are widely used in animal husbandry and can cause environmental risk due to its high ecological toxicity and persistence. In this study, cobalt doped/ZnTiO3 ...(ZTO)/Ti3C2Tx MXene (ZCxTM, x indicates wt% of Co loading) was synthesized and explored to remove TC by adsorption and photocatalysis under visible light irradiation. The as-prepared ZC5TM was characterized using various analytical techniques, and key operating parameters such as solution pH, background ions, and temperature were systematically investigated. Interestingly, ZC5TM (14.9 mg/g) showed excellent adsorption capacity for TC, which was higher than activated carbon (7.7 mg/g), ZTO (4.9 mg/g), ZC3T (5.2 mg/g), ZC5T (5.3 mg/g), MXene (12.1 mg/g), ZTOM (12.5 mg/g), and ZC3TM (12.9 mg/g). The pseudo-second-order kinetics and Langmuir isotherm models well explained the effect of contact time and initial concentrations on the adsorption of TC. The adsorption process was primarily through the electrostatic attraction, surface complexation, and hydrogen bonding. In addition, MXene and Co doped on ZTO served as co-catalyst and reduced recombination rate of photo-generated e–-h+ pairs by the intimate interface of its heterojunction. Thus, ZC5TM was highly effective for the photocatalytic degradation of residual TC after adsorption by showing 18% TC degradation rate, compared to 8% and 9% degradation rate for ZTO and MXene, respectively. There results finally support the feasible use of ZC5TM as efficient adsorbent and photocatalyst in removal of TC in wastewater.
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•ZC5TM was synthesized for enhanced adsorption and photocatalytic degradation of TC.•ZC5TM exhibited outstanding adsorption capacity for TC compared to activated carbon.•The adsorption of TC onto ZC5TM is endothermic, spontaneous, and highly favorable.•ZC5TM demonstrated the remarkable stability and reusability as adsorbent and photocatalyst.
A novel 3D PANI/MgIn2S4 nanoflower with high photocatalytic activity for the removal of pollutants, heavy metals and photocatalytic hydrogen production.
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•3D PANI/MgIn2S4 nanoflower ...exhibited excellent photoreduction of Cr (VI).•The photodegradation of organic and photocatalytic H2 evolution was enhanced.•The introduction of PANI enhances light absorption and promote charge separation.•3D PANI/MgIn2S4 nanoflower displayed high stability as photocatalyst.
A novel 3D PANI/MgIn2S4 nanoflower photocatalyst was synthesized for the wastewater treatment and energy conversion. In all composites, 1% 3D PANI/MgIn2S4 nanoflower composite exhibits the top-flight photocatalytic activity, which can be nearly 100% reduction of Cr (VI) after 30 min and nearly 97.0% of methyl orange (MO) is degraded in 50 min. At the same time, it was proved that the Cr (VI) was completely reduced by liquid ultraviolet and XPS. The as-prepared 3D PANI/MgIn2S4 nanoflower composites showed a significantly increased photocatalytic performance for hydrogen production under visible light irradiation. The photocatalytic mechanism illustrates that the introduction of polyaniline can prominently enhance the light absorption and promote effective separation of electron-hole pairs of the composites. PL spectrum and Transient photocurrent response show excellent photoinduced charge separation efficiency possess in 3D PANI/MgIn2S4 nanoflower. Electron spin response (ESR) technique and active species trapping experiments confirmed that e−, O2 and O2− played a very important role in the process of photoreduction of Cr (VI) and h+ and O2− were the principal active groups participated in photo-degradation of methyl orange (MO). In addition, the degradation process is accompanied by the generation of singlet oxygen (1O2) and hydrogen peroxide (H2O2), suggesting that these reactive oxygen species play a cardinal part in the photodegradation mechanism. The cycling and stable performance of 3D PANI/MgIn2S4 nanoflower also shows excellent photocatalytic effect. Such 3D PANI/MgIn2S4 nanoflower composite present a cracking strategy to enhance the photoactivity of the catalysts for wastewater treatment.
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The present task explains how the photocatalytic properties of the PbFe12O19 enhanced after the doping of rare earth metal praseodymium (Pr3+). The PbFe12-xPrxO19 with different ...dopant concentrations x = 0.00, 0.25, 0.50 were prepared by sol gel auto-combustion method and annealed at 900°C. The XRD analysis confirmed that average crystal size decreases (23–30 nm) with the increase in Pr3+ concentration. Scanning electron microscopy was employed to determine the shape and particle size which was estimated to be 68 nm. The band gap of the samples was tuned from 3.25 to 2.49 eV after intervention of praseodymium ions in the PbFe12O19 crystal system. Our doped samples exhibited exceptional photodegradation efficiency during the degradation of nicotine. The results revealed that Pr3+doped PbFe12O19 (x = 0.50) sample degraded almost 91 % of the nicotine with a first order kinetics rate constant (k = 0.0099 min−1), while undoped PbFe12O19 sample degraded just 45 % within 90 min. Quenching experiments demonstrated that superoxide and hydroxide radicals play important role in the degradation of nicotine. We deduce that praseodymium doped M type lead hexaferrite is efficient photocatalyst for nicotine removal.
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•Synchronous N/Zn was in-situ doped into MIL-125(Ti) via one-pot strategy.•N/Zn doping narrowed band gap and enhanced electron transfer on MOF(Ti).•Dopant of N/Zn enhanced surface ...alkalinity and humidity resistance on MOF(Ti).•MIL-125(N-Ti9Zn1) showed high moisture-resistance and catalytic activity for CH3CHO.•CH3CHO degradation mechanism and deactivation of MOF(Ti) were deeply investigated.
High photo-catalytic activity and stable recycling performance under high humidity are main hindering factors in practical applications of metal organic frameworks (MOFs) for volatile organic compounds (VOCs) degradation. In-situ co-doping strategy of pyrrolic N/Zn was proposed to enhance surface charge separation and cycling stability of MIL-125(Ti) for degradation of vaporous acetaldehyde under highly humid conditions. Characterizations results show that pyrrolic N/Zn co-doped MIL-125(Ti) exhibited an integrated crystal structure and high surface area (1415 m2/g). The constructed Ti/Zn-N/O clusters narrowed band gap (from 3.40 to 1.85 eV) of MIL-125(Ti) and boosted electron conductivity. Also, it was proved to enhance surface alkalinity and hydrophobicity of MIL-125(Ti), which would strengthen MOFs selective adsorption towards CH3CHO and accelerated the transfer of degradation product CO2 from catalytic active sites in MIL-125(Ti) under high humidity. As a result, synergistic effect of N/Zn co-doping exhibited an enhanced the ability of activating oxygen and H2O molecules into superoxide radical (O2−) and hydroxy radical (OH), showing 10 times faster reaction kinetics for CH3CHO degradation under humid air compared to MIL-125(Ti). Moreover, co-dopant of N/Zn into MIL-125(Ti) has significantly promoted the recycling stability of MIL-125(Ti) under high humidity. According to the work, co-dopant elemental strategy to modify MOF surface can provide the synergistic effect for efficient degradation of aldehyde VOCs under humid conditions.
The simple solution combustion method has been used for the synthesis of NiO nanoparticles using nickel nitrate as an oxidizer, Samanea saman pod extract as a fuel at 500°C. The crystalline nature of ...the nanoparticles was confirmed by X-ray diffraction studies and SEM images the information about surface morphology of the nickel oxide. The EDS spectrum confirms the composition and purity of the nanoparticles. Further, the nanoparticles are subjected for antimicrobial activity. The results revealed that NiO nanoparticles exhibit good antimicrobial properties.
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