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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•Investigated the photodegradation process of MIT and BIT under simulated sunlight in natural waters.•Alkaline conditions significantly promoted the photodegradation of BIT in its deprotonated form ...(BIT-N−).•Estimated the half-life of photodegradation of MIT and BIT under natural sunlight in actual surface water environments.•Frontier electron density (FED) theory calculations confirmed the degradation pathways of MIT and BIT.•The biological toxicity of photodegradation products was reduced by one level.
Methylisothiazolinone (MIT) and Benzisothiazolinone (BIT) are two widely used non-oxidizing biocides of isothiazolinones. Their production and usage volume have sharply increased since the pandemic of COVID-19, inevitably leading to more release into water environment. However, their photochemical behaviors in water environment are still unclear. Therefore, this study investigated photodegradation properties of MIT and BIT in natural water under simulated sunlight. The results demonstrated that direct photolysis was mainly responsible for their photodegradation which occurred through their excited singlet states rather than triplet states. The quantum yields of MIT and BIT photodegradation were 11 - 13.6 × 10−4 and 2.43 - 5.79 × 10−4, respectively. pH had almost no effect on the photodegradation of MIT, while the photodegradation of BIT was significantly promoted under alkaline condition due to abundance of BIT in its deprotonated form (BIT-N−). Cl−, NO3− and dissolved organic matter (DOM) in natural water inhibited the photodegradation of both MIT and BIT, with the light screening effect of DOM being the most significantly inhibitory factor. The addition of other isothiazolinones, which possibly coexisted with MIT and BIT in actual condition, slightly inhibited the photodegradation of MIT and BIT. The estimated half-life under natural sunlight at a 30°N latitude was estimated to be approximately 1.1 days. The photodegradation pathways of MIT and BIT are similar, primarily initiated from the ring-opening at the N-S bond, with Frontier electron densities (FED) calculations suggesting the likelihood of oxidation and ·OH addition reactions at the O, N, and S sites. While the photodegradation products exhibited significantly reduced acute toxicity compared to their parent compounds, they nonetheless posed substantial chronic toxicity. These insights are vital for assessing the ecological impacts of MIT and BIT in aquatic environments.
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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.
CeO2/TiO2 nanobelt heterostructures are synthesized via a cost‐effective hydrothermal method. The as‐prepared nanocomposites consist of CeO2 nanoparticles assembled on the rough surface of TiO2 ...nanobelts. In comparison with P25 TiO2 colloids, surface‐coarsened TiO2 nanobelts, and CeO2 nanoparticles, the CeO2/TiO2 nanobelt heterostructures exhibit a markedly enhanced photocatalytic activity in the degradation of organic pollutants such as methyl orange (MO) under either UV or visible light irradiation. The enhanced photocatalytic performance is attributed to a novel capture–photodegradation–release mechanism. During the photocatalytic process, MO molecules are captured by CeO2 nanoparticles, degraded by photogenerated free radicals, and then released to the solution. With its high degradation efficiency, broad active light wavelength, and good stability, the CeO2/TiO2 nanobelt heterostructures represent a new effective photocatalyst that is low‐cost, recyclable, and will have wide application in photodegradation of various organic pollutants. The new capture–photodegradation–release mechanism for improved photocatalysis properties is of importance in the rational design and synthesis of new photocatalysts.
The enhanced photocatalytic performance of CeO2/TiO2 heterostructured nanobelts is attributed to a novel capture–photodegradation–release degradation mechanism. During the photocatalytic process, MO molecules are captured by CeO2 nanoparticles on the surface of the heterostructure, then quickly photodegraded under UV or visible light irradiation, and ultimately the degradation products are released to external environment.
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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.
Water pollution caused by organic dyes is one of the greatest threats to the ecosystem. The removal of dyes from water has remained a challenge for scientists. Recently, metal sulphides have emerged ...as a potential candidate for water remediation applications. The efficient charge transportation, greater surface-active sites, and low bandgap of metal sulphides make them an excellent choice of semiconductor photocatalysts for degradation of dyes. This review summarises the potential application of metal sulphides and their heterojunctions for the photocatalytic degradation of organic dyes from wastewater. A detailed study has been presented on the synthesis, basics of photodegradation and heterojunctions and photocatalytic activity. The effect of the use of templates, doping agents, synthesis route, and various other factors affecting the photocatalytic activity of metal sulphides have been summarised in this review. The synthesis techniques, characterisation techniques, mechanism of degradation of organic dyes by Z-scheme heterojunction photocatalyst, reusability and stability of metal sulphides, and the scope of future research are also discussed. This study indicates that Scopus-based core gathered data could be used to give an objective overview of the global dye degradation research from 2008 to 2023 (15 years). All data (articles, authors, keywords, and publications) is compiled in the Scopus database. For the bibliometric study, 1962 papers relevant to dye photodegradation by sulfide-based photocatalysts were found, and this number rises yearly. A bibliometric analysis provides a 15-year evaluation of the state-of-the-art research on the impact of metal sulfide-based photocatalysts on the photodegradation of dyes.
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