Rapidly photocatalytic mineralization of typical veterinary drugs with the SnO2/SnIn4S8 composite

Simultaneous Photocatalytic Tetracycline Oxidation and Cr(VI) Reduction by Z-Scheme Multiple Layer TiO2/SnIn4S8

Wastewater pollutants are a major threat to natural resources, with antibiotics and heavy metals being common water contaminants. By harnessing clean, renewable solar energy, photocatalysis facilitates the synergistic removal of heavy metals and antibiotics. In this paper, MXene was both a template and raw material, and MXene-derived oxide (TiO2) and SnIn4S8 Z-scheme composite materials were synthesized and characterized. The synergistic mode of photocatalytic reduction and oxidation leads to the enhanced utilization of e-/h+ pairs. The TiO2/SnIn4S8 exhibited a higher photocatalytic capacity for the simultaneous removal of tetracycline (TC) (20 mg·L-1) and Cr(VI) (15 mg·L-1). The main active substances of TC degradation and Cr(VI) reduction were identified via free radical scavengers and electron paramagnetic resonance (EPR). Additionally, the potential photocatalytic degradation route of TC was thoroughly elucidated through liquid chromatography-mass spectrometry (LC-MS).

One-pot synthesis of interfacially bonded Bi4O5Br2/Bi2S3 Z-scheme heterostructures with boosted photocatalysis towards dodecylbenzenesulfonate and real hotel laundry wastewater

The ubiquitous contamination of surfactants in wastewater has raised global concerns. Photocatalysis is deemed as a promising yet challenging approach for the decomposition of surfactant residues. Herein, a novel Z-scheme heterojunction of Bi4O5Br2/Bi2S3 with covalent S-O bonds was prepared via a facile one-pot hydrothermal and subsequent annealing process. The prepared optimal Bi4O5Br2/Bi2S3 composite exhibited remarkable photo-degradation activity towards the sodium dodecylbenzene sulfonate (SDBS). The Z-scheme reaction mechanism was proposed and validated by meticulous analysis of quenching tests, ESR spectroscopy and DFT calculations. Furthermore, the presence of chemical S-O linkages between Bi4O5Br2 and Bi2S3 was identified via FT-IR and XPS analyses, which served as a distinct bridge to modify the Z-scheme route for carrier transport. The Z-scheme heterostructure, in conjunction with chemical S-O bonds, synergistically enhanced the separation rate of electron-hole pairs and thus greatly boosted the photocatalytic activity. Additionally, the possible degradation pathways of SDBS were proposed by using HR-MS technology. Moreover, real hotel laundry wastewater could be efficiently disposed by the photocatalysis of the Bi4O5Br2/Bi2S3 with a decrease in the COD value from 428 to 74 mg/L, indicating that the fabricated Z-scheme heterojunction hold great promise for effectively removing refractory surfactant contaminants from aquatic environment.

Interfacial S-O bonds specifically boost Z-scheme charge separation in a CuInS2/In2O3 heterojunction for efficient photocatalytic activity

Reducing the recombination rate of photoexcited electron-hole pairs is always a great challenging work for the photocatalytic technique. In response to this issue, herein, a novel Z-scheme CuInS₂/In₂O₃ with interfacial S-O linkages was synthesized by a hydrothermal and subsequently annealing method. The Fourier transform infrared (FT-IR) and X-ray photoelectron spectrometer (XPS) measurements confirmed the formation of covalent S-O bonds between CuInS₂ and In₂O₃. The quenching and electron spin resonance (ESR) tests revealed the Z-scheme transfer route of photogenerated carriers over the CuInS₂/In₂O₃ heterojunctions, which was further verified theoretically via density functional theory (DFT) calculations. As expected, the CuInS₂/In₂O₃ heterojunctions showed significantly boosted photocatalytic activities for lomefloxacin degradation and Cr(vi) reduction under visible light illumination compared with the bare materials. Accordingly, a synergistic photocatalytic mechanism of Z-scheme heterostructures and interfacial S-O bonding was proposed, in which the S-O linkage could act as a specific bridge to modify the Z-scheme manner for accelerating the interfacial charge transmission. Furthermore, the CuInS₂/In₂O₃ heterojunction also exhibited excellent performance perceived in the stability and reusability tests. This work provides a new approach for designing and fabricating novel Z-scheme heterostructures with a high-efficiency charge transfer route.

Visible active narrow/narrow band gap CuO/Cu2SnS3 nanoheterostructures as efficient nanophotocatalysts

Binary metal oxide/ternary metal sulphide based nanoheterostructures, such as CuO/Cu₂SnS₃, were prepared via a modified hydrothermal route. The prepared nanoheterostructures were characterized using scanning electron microscopy, x-ray powder diffractometer, XPS, ultraviolet-visible spectroscopy, isoelectric point, and Brunauer-Emmett-Teller techniques. The XPS results revealed the successful incorporation of Cu⁺/Cu²⁺ with different ratios. The prepared heterostructures were tested as solar active photocatalysts for Methylene Blue (MB) photodegradation. The CuO/Cu₂SnS₃ (20% Cu₂SnS₃/80% CuO) photocatalytic results exhibited a high photodegradation efficiency (90%) after 60 min. In addition, the photonic efficiency values (ζ) were calculated to be 15.9%, 44%, and 61.4% for CuO, Cu₂SnS₃, and CuO/Cu₂SnS₃ nanoheterostructures, respectively. In addition, the reactive oxidative species were detected by the trapping experiments to get a clear insight about the photocatalytic reactivity factors. Total organic carbon (TOC) was conducted to confirm the safe photodegradation of MB dye without the formation of colorless hazardous (95.5% TOC removal). Based on the electronic band structure, the mechanism of photodegradation was investigated. The currently investigated heterostructure system is narrow/narrow bandgap, which fulfills the two contradictory conditions in terms of high solar photocatalytic activity and overcomes the rapid recombination process.

Facile access to high-efficiency degradation of tetracycline hydrochloride with structural optimization of TiN

As a broad-spectrum antibiotic, tetracycline has become a potential ecological hazard. Herein, titanium nitride (TiN), with an advantageous structure, was synthesized by simple heating rate regulation and constructed for tetracycline hydrochloride (TC-HCl) degradation under light irradiation. All the samples were characterized by X-ray diffraction (XRD), N2-adsorption/desorption isotherm, ultraviolet-visible diffuse reflectometry (DRS), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The results showed that the as-prepared TiN-x catalysts exhibited obviously enhanced photocatalytic property toward TC-HCl degradation compared with the commercial pure phase TiN (p-TiN). According to the results of photocatalytic degradation, TiN synthesized at 6 °C/min heating rate had the best removal rate of TC-HCl (90%) after dark reaction for 10 min and photo-degradation for 90 min. In addition, the trapping experiments have demonstrated that the photogenerated holes (h+) and superoxide radical ([Formula: see text]) are the main oxidation products of the present system. Strikingly, the reuse experiments showed high stability of TiN.

Efficient mineralization of TBBPA via an integrated photocatalytic reduction/oxidation process mediated by MoS2/SnIn4S8 photocatalyst

Currently, Tetrabromobisphenol A (TBBPA) has been regarded as an emerging organic pollutant and efficient TBBPA elimination technology has been attracting increasing attention. In this work, a novel photocatalyst, MoS₂/SnIn₄S₈, was synthesized through hydrothermal method by introducing few-layer MoS₂ nanosheets and then employed to establish an integrated photocatalytic reduction/oxidation system for the remediation of TBBPA under visible light. The characterization results demonstrated that the few-layer MoS₂ nanosheets were well combined with SnIn₄S₈ and significantly lowered the recombination rate of the photo-induced electron and holes, leading to outstanding photocatalytic performance of MoS₂/SnIn₄S₈ composite. Besides, the MoS₂/SnIn₄S₈ composite also exhibited excellent reusability (over 10 runs) and stability. The TBBPA degradation experiments showed that the integrated photocatalytic reduction/oxidation system was able to completely degrade TBBPA and mineralize its byproducts (60.2 ± 2.9%). In the photocatalytic reduction, due to the cleavage of C-Br bonds by photo-induced electrons, TBBPA underwent stepwise debromination and finally transferred into BPA in 6 h. In the following photocatalytic oxidation, under the attack of reactive oxygen species (¹O₂, h⁺,OH and O₂^-), BPA was first decomposed into aromatic products (such as phenol, benzoic acid, p-hydroxybenzyl alcohol and so on) via C-C bond cracking and hydroxylation, and then further oxidized into organic acids like maleic acid and muconic acid through ring-opening, and finally mineralized into CO₂ and H₂O. What was noteworthy was that the final effluent from the photocatalytic reduction/oxidation system showed no toxicity to the luminescent bacteria.

Efficient Cr(vi) photoreduction under natural solar irradiation using a novel step-scheme ZnS/SnIn4S8 nanoheterostructured photocatalysts

Removal of heavy metal pollutants from water is a challenge to water security and the environment. Therefore, in this work, multinary chalcogenide based nanoheterostructures such as ZnS/SnIn₄S₈ nanoheterostructure with different loading amounts were prepared. The prepared nanoheterostructures were utilized as photocatalysts for chromium (Cr(vi)) photoreduction. The prepared nanoheterostructures were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy, dynamic light scattering (DLS), and X-ray photoelectron spectroscopy (XPS) and BET measurements. The absorption spectra of the prepared nanoheterostructures revealed that they are widely absorbed in the visible range with bandgap values 2.4–3.5 eV. The photocatalytic activities of prepared nanoheterostructures were studied toward the photoreduction of heavy metal, chromium (Cr(vi)), under irradiation of natural solar light. The ZnS/SnIn₄S₈ (with ZnS molar ratio 20%) nanoheterostructures results showed a high photocatalytic activity (92.3%) after 120 min which could be attributed to its enhanced charge carrier separation with respect to the bare ZnS and SnIn₄S₈ NPs. Also, the optoelectronic, valence-band XPS and electrochemical properties of the investigated photocatalysts were studied and the results revealed that the photocatalysts behave the step-scheme mechanism. The recyclability tests revealed a beneficial role of the surface charge in efficient regeneration of the photocatalysts for repeated use.

The Cr(vi) photoreduction tests demonstrated an improved photocatalytic activity of SIS and 2Z-SIS to be 61.0% and 92.3% respectively after 120 min. The results indicated the photocatalyst's capability under sun light, allowing for its industrial use.

Elevated metallothionein expression in long-lived species mediates the influence of cadmium accumulation on aging

Cadmium (Cd) accumulates with aging and is elevated in long-lived species. Metallothioneins (MTs), small cysteine-rich proteins involved in metal homeostasis and Cd detoxification, are known to be related to longevity. However, the relationship between Cd accumulation, the role of MTs, and aging is currently unclear. Specifically, we do not know if long-lived species evolved an efficient metal stress response by upregulating their MT levels to reduce the toxic effects of environmental pollutants, such as Cd, that accumulate over their longer life span. It is also unknown if the number of MT genes, their expression, or both protect the organisms from potentially damaging effects during aging. To address these questions, we reanalyzed several cross-species studies and obtained data on MT expression and Cd accumulation in long-lived mouse models. We confirmed a relationship between species maximum life span in captive mammals and their Cd content in liver and kidney. We found that although the number of MT genes does not affect longevity, gene expression and protein amount of specific MT paralogs are strongly related to life span in mammals. MT expression rather than gene number may influence the high Cd levels and longevity of some species. In support of this, we found that overexpression of MT-1 accelerated Cd accumulation in mice and that tissue Cd was higher in long-lived mouse strains with high MT expression. We conclude that long-lived species have evolved a more efficient stress response by upregulating the expression of MT genes in presence of Cd, which contributes to elevated tissue Cd levels.