Oxygen Vacancy-Laden Confinement Impact on Degradation of Metal Complexes.

Oxygen vacancies (Vo) have been recognized as the superior active site for PS-mediated environmental remediation; however, the formation and activation of Vo associated with the effects of chemical and spatial environments remain ambiguous. Herein, attributing to the low defect-formation energy of Vo in the presence of sulfonate groups, an in situ nucleating Vo-laden CuO nanosheet was deliberately fabricated inside the phase of a sulfonated mesoporous polystyrene substrate (Vo-CuO@SPM). The as-prepared nanocomposite demonstrated an excellent treatment efficiency toward metal complexes [Cu-EDTA as a case] with ignorable Cu(II) leaching, and it can be repeatedly employed for 25 recycles (not limited). Mechanistically, the electron transfer and the mass transport for PDS nonradical activation were proved to be substantially enhanced by the delocalized electrons and with the assistance of the microchannel environment. This work not only establishes insight into the formation of oxygen vacancies but also reveals the PS activation mechanism in the spatially confined sites.

Pioneering Piezoelectric-Driven Atomic Hydrogen for Efficient Dehalogenation of Halogenated Organic Pollutants.

The electrocatalytic hydrodehalogenation (EHDH) process mediated by atomic hydrogen (H*) is recognized as an efficient method for degrading halogenated organic pollutants (HOPs). However, a significant challenge is the excessive energy consumption resulting from the recombination of H* to H2 production in the EHDH process. In this study, a promising strategy was proposed to generate piezo-induced atomic H*, without external energy input or chemical consumption, for the degradation and dehalogenation of HOPs. Specifically, sub-5 nm Ni nanoparticles were subtly dotted on an N-doped carbon layer coating on BaTiO3 cube, and the resulted hybrid nanocomposite (Ni-NC@BTO) can effectively break C-X (X = Cl and F) bonds under ultrasonic vibration or mechanical stirring, demonstrating high piezoelectric driven dehalogenation efficiencies toward various HOPs. Mechanistic studies revealed that the dotted Ni nanoparticles can efficiently capture H* to form Ni-H* (Habs) and drive the dehalogenation process to lower the toxicity of intermediates. COMSOL simulations confirmed a "chimney effect" on the interface of Ni nanoparticle, which facilitated the accumulation of H+ and enhanced electron transfer for H* formation by improving the surface charge of the piezocatalyst and strengthening the interfacial electric field. Our work introduces an environmentally friendly dehalogenation method for HOPs using the piezoelectric process independent of the external energy input and chemical consumption.

Complexation-based selectivity of organic phosphonates adsorption from high-salinity water by neodymium-doped nanocomposite.

Organic phosphonates have been widely used in various industries and are ubiquitous in wastewaters, and efficient removal of phosphonates is still a challenge for the conventional processes because of the severe interferences from the complex water constitutions. Herein, an Nd-based nanocomposite (HNdO@PsAX) was fabricated by immobilizing hydrated neodymium oxide (HNdO) nanoparticles inside a polystyrene anion exchanger (PsAX) to remove phosphonates from high-salinity aqueous media. Batch experiments demonstrated that HNdO@PsAX had an excellent adsorption capacity (∼90.5 mg P/g-Nd) towards a typical phosphonate (1-hydrox-yethylidene-1,1-diphosphonic acid, HEDP) from the background of 8 g/L NaCl, whereas negligible HEDP adsorption was achieved by PsAX. Attractively, various coexisting substances (humic acid, phosphate, citrate, EDTA, metal ligands, and anions) exerted negligible effects on the HEDP adsorption by HNdO@PsAX under high salinity. FT-IR and XPS analyses revealed that the inner-sphere complexation between HEDP and the immobilized HNdO nanoparticles is responsible for HEDP adsorption. Fixed-bed experiments further verified that HNdO@PsAX was capable of successively treating more than 4500 bed volumes (BV) of a synthetic high-salinity wastewater (1.0 mg P/L of HEDP), whereas only ∼2 BV of effective treatment capacity was received by PsAX. The exhausted HNdO@PsAX was amenable to a complete regeneration by a binary NaOHNaCl solution without significant loss in capacity. The capability in removing other organic phosphonates and treating a real electroplating wastewater by HNdO@PsAX was further validated. Generally, HNdO@PsAX exhibited a great potential in efficiently removing phosphonates from high-salinity wastewater.

Identification of Co-O-Mo Active Centers on Co-Doped MoS2 Electrocatalyst.

Strategies for harmonizing the construction of an active site and the building of electron transport for a hybrid MoS2 catalyst are crucial for its application in electrochemical reactions. In this work, an accurate and facile hydrothermal strategy was proposed to fabricate the active center of Co-O-Mo on a supported MoS2 catalyst by forming a CoMoSO phase on the edge of MoS2, yielding (Co-O)x-MoSy (x = 0, 0.3, 0.6, 1, 1.5, or 2.1). The results show that the electrochemical performances (hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical degradation) of the yielded MoS2-based catalysts were positively correlated with the Co-O bonds, verifying the significant role of Co-O-Mo as the active center. The fabricated (Co-O)-MoS0.9 presented an extremely low overpotential and Tafel slope in both HER and OER, and it also demonstrated excellent BPA removal in the electrochemical degradation reaction. As compared with the Co-Mo-S configuration, the configuration of Co-O-Mo not only serves as the active center but also provides a conducting channel to facilitate electron conductivity with more accessible charge transfer at the electrode/electrolyte interface, which is favorable for electrocatalytic reaction. This work offers a new perspective for the active mechanism of metallic-heteroatom-dopant electrocatalysts and further boosts research on the development of noble/non-noble hybrid electrocatalysts in the future.

Identification and analysis of differentially expressed (DE) circRNA in epididymis of yak and cattleyak.

Circular RNAs (circRNAs), as endogenous non-coding RNA with unique closed ring structure, is closely related to animal reproduction, and understanding the expression of circRNA in yak and cattleyak epididymal tissues is of great significance for understanding cattleyak sterility. Based on this, we screened and identified the differentially expressed circRNA in the epididymis of three yaks and two cattleyak. A total of 1,298 circRNAs were identified in the epididymis of yak and cattleyak, of which 137 differentially expressed (DE) circRNAs and the functions of some of them were elucidated in this research, as well as qPCR verification to 6 circRNAs from the 137 DE circRNAs. Gene Ontology (GO) enrichment analysis suggested that DE circRNAs were mainly related to metabolic process, development process, immune system process, reproductive process, reproduction, biological adhesion and growth. COG classification analysis showed that the DE circRNAs derived genes were mainly related to replication, recombination and repair. KEGG pathway analysis suggested that DE circRNAs were mainly involved in RNA degradation. In addition, we also screened Bta-mir-103, which is a circRNA binding miRNA related to sperm activity.

Comparative transcriptome analysis in the caput segment of yak and cattleyak epididymis.

Cattleyaks are equally adaptable to harsh environment as yaks, but produce far more milk and meat in terms of quality and quantity. However, male cattleyaks with active secondary sexuality are infertile and have restricted productivity and breeding of yaks. Much researches continue to be done in regard to the differences in transcriptome profiling in cattleyak epididymis with respect to yak epididymis. The caput segment of the epididymis is highly specialized for the initiation of spermatozoa maturation, synthesis and secretion. We used RNA-Seq technology to comparatively analyze differentially expressed genes (DEGs) associated with sperm maturation between the caput epididymis of yak and cattleyak. Transcriptomic profiling identified 109 DEGs in which 44 were upregulated and 65 were downregulated. 8 DEGs were validated by quantitative real-time PCR. DEGs were analyzed by GO and KEGG analysis to screen the key genes involved in sperm maturation. The upregulation of PAOX and ATP2C2 may be associated with toxicity and apoptosis resistance in cattleyak with respect to yak. However, downregulated DEFB109, DEFB121, DEFB123, DEFA1, LY6G5C, SLC13A2, CST3, CRYBA4 and ADAM28 were associated with innate immune response, sperm maturation, motility and antimicrobial functions. AMPK and Hedgehog signaling pathways were involved in the top-listed five significantly enriched pathways, and the downregulation of HNF4α and LRP2 may have contributed to infertility in cattleyak. The data provide a powerful resource, contributing to the knowledge on the molecular mechanisms underlying male cattleyak infertility.

Oxygen vacancy-mediated peroxydisulfate activation and singlet oxygen generation toward 2,4-dichlorophenol degradation on specific CuO1-x nanosheets.

Durable and stable removal of 2,4-dichlorophenpl (2,4-DCP) by CuO1-x nanosheets is reported. CuO1-x nanosheets were fabricated by a simple defect engineering strategy and greatly increased the efficiency of peroxydisulfate (PDS) activation to improve 2,4-DCP removal by introducing abundant oxygen vacancy (Vo) to produce an electron-rich surface. Results showed that CuO1-x nanosheets exposed more Vo as active sites for PDS activation as compared with that of CuO nanoparticles, giving rise to dramatic enhancement of catalytic performance with ultrahigh reaction rate that is qualified for serving in flow filtration system, completely degrading 100 mg L-1 of 2,4-DCP within 3 s of residence time. Besides, experimental studies confirmed that 1O2 generated by Vo - mediated PDS activation plays the dominate role in the degradation of contaminants. Relative to the previously reported CuO/PDS systems, the obtained CuO1-x nanosheets demonstrated 2.7 times higher specific PDS activity and 67 times higher specific CuO activity for 2,4-DCP removal. Our study not only improves the fundamental understanding of active sites in morphologically tunable metal oxides but also proposes a guideline for future research and engineering application of persulfate.

Identifying the Active Sites of Heteroatom Graphene as a Conductive Membrane for the Electrochemical Filtration of Organic Contaminants.

The dopants of sulfur, nitrogen, or both, serving as the active sites, into the graphitic framework of graphene is an efficient strategy to improve the electrochemical performance of electrochemical membrane filtration. However, the covalent bonds between the doped atoms and the substrate that form different functional groups have a significant role in the specific activity for pollutant degradation. Herein, we found that the singly doped heteroatom graphene (NG and SG) achieved superior removal efficiency of pollutants as compared with that of the double doped heteroatom graphene (SNG). Mechanism studies showed that the doped N of NG presented as graphitic N and substantially increased electron transfer, whereas the doped S of SG posed as -C-SOx-C- provided more adsorption sites to improve electrochemical performance. However, in the case of SNG, the co-doped S and N cannot form the efficient graphitic N and -C-SOx-C- for electrochemical degradation, resulting in a low degradation efficiency. Through the fundamental insights into the bonding of the doped heteroatom on graphene, this work furnishes further directives for the design of desirable heteroatom graphene for membrane filtration.

RNA-Seq reveals the functional specificity of epididymal caput, corpus, and cauda genes of cattleyak.

The first filial generation of the cattleyaks demonstrates hybrid vigor; however, the male cattleyaks are infertile and restrict productivity and breeding. The discovery of genes in a segment-specific approach offers valuable information and understanding concerning fertility status, yet the biology of cattleyak epididymis is still progressing. Comparative transcriptome analysis was performed on segment pairs of cattleyak epididymis. The caput versus corpus epididymis provided the highest (57.8%) differentially expressed genes (DEGs), corpus versus cauda (25.1%) followed, whereas caput versus cauda pair (17.1%) had the least DEGs. The expression levels of genes coding EPHB6, TLR1, MUC20, MT3, INHBB, TRPV5, EI24, PAOX, KIF12, DEPDC5, and KRT25, which might have the potentials to regulate the homeostasis, innate immunity, differentiation, motility, transport, and sperm maturation-related function in epididymal cells, were downregulated in the distal segment of epididymis. Top enriched KEGG pathways included mTOR, axon guidance, and taste transduction signaling pathways. EIF4B, EPHB6, and TAS2R42 were enriched in the pathways, respectively. Identifying key, new, and unexplored DEGs among the epididymal segments and further analyzing them could boost cattleyak fertility by maximizing sperm quality from genetically better sires and also facilitate better understanding of the epididymal biology.

Multifunctional Piezoelectric Heterostructure of BaTiO3@Graphene: Decomplexation of Cu-EDTA and Recovery of Cu.

About 3.93 billion tons of wastewater containing heavy metal complexes are discharged (e.g., from the electroplating industry) every year in China alone. It is challenging to appropriately treat such wastewaters. Here, a multifunctional composite nanowires BaTiO3@graphene was designed based on Comsol simulations and made into 3D millimeter-sphere in order to facilitate practical application. Results indicate 100% of Cu-EDTA was decomplexed in situ via piezoelectric potential by BaTiO3@graphene. Notably, the addition of graphene sharply increased the surface potential (from 19.8 ± 0.97 to 96.8 ± 1.48 mV) of BaTiO3@graphene by its flexoelectric effect then effectively promoted piezoelectric electrons to be separated and transferred, which favors the piezoelectric catalysis. Moreover, the released Cu(II) from Cu-EDTA decomplexation were recovered simultaneously via the interaction on graphene groups. This method efficiently recovered Cu(II) to avoid the consumption of massive chemical reagents and the generation of secondary hazardous solid waste containing heavy metal ions, compared with the conventional oxidative decomplexation/precipitation strategy for heavy metal complexes removal. Piezoelectric catalysis paves a new possibility for advanced oxidation in wastewater treatment.

Photochemical activation of seemingly inert SO42- in specific water environments.

Sulfate ions (SO42-) are ubiquitous in aqueous environments and are generally considered to be inert due to their chemical stability. For the first time, we found that SO42- can be activated into SO42--type radicals (e.g., SO3-, SO5-, SO4-) in the presence of phenolic compounds under simulated or natural solar irradiation. In turn, the radicals promoted the transformation and mineralization of phenolic compounds compared to that in the absence of SO42- with reaction rate constants ranging from 0.008 h-1 to 0.021 h-1. In addition, the activation mechanisms of inert SO42- in the photochemical transformation of phenolic compounds were elucidated. A hydrated electron (eaq-) is first generated during the photolysis of phenolic compounds and is the most important step in the activation of SO42-. Then, the eaq- reduces SO42- to SO32-, and SO32- is further photochemical activated to become a reactive species (e.g., eaq- and SO3-), which can evolve into strong oxidants (e.g., SO5- and SO4-), via a series of radical chain reactions. These oxidants are responsible for the enhanced phenolic compound degradation. The photochemical activation of seemingly inert SO42- sheds new light on studies on the transport, transformation and environmental impact of matter (e.g., phenolic compounds) in specific water environments and provides a novel strategy for the generation of SO4- and photochemical removal of phenolic pollutants.

Environmentally Friendly in Situ Regeneration of Graphene Aerogel as a Model Conductive Adsorbent.

Adsorption is a classical process widely used in industry and environmental protection, and the regeneration of exhausted adsorbents, as the reverse process of adsorption, is vital to achieving a sustainable adsorption process. Chemical and thermal regeneration, which feature high costs and environmental side effects, are classical but not environmentally friendly methods. Herein, a new regeneration method based on an electrochemical process using graphene aerogel (GA) as a model conductive adsorbent was proposed. First, 3D GA was prepared to adsorb organic and inorganic pollutants, avoiding the inconvenience of using powdered graphene. Then, the exhausted GA was cleaned by the electrochemical desorption and degradation of adsorbed organic pollutants if undesired and the electrorepulsion of adsorbed metal ions in the absence of any additional chemicals, showing a high processing capability of 1.21 L g-1 GA h-1 and low energy consumption (∼0.2 kWh m-3 solution). The mechanisms involved in the electrochemistry-induced desorption process cover a decline in the GA adsorption performance depended on the electrochemically adjustable surface charge conditions, and the further repulsion and migration of adsorbates is subject to the strong in situ electric field. This work has important implications for the development of environmentally friendly regeneration processes and qualified adsorbents as well as the application of a green and efficient regeneration concept for traditional adsorption processes.

Flat Graphene-Enhanced Electron Transfer Involved in Redox Reactions.

Graphene is easily warped in the out-of-plane direction because of its high in-plane Young's modulus, and exploring the influence of wrinkled graphene on its properties is essential for the design of graphene-based materials for environmental applications. Herein, we prepared wrinkled graphene (WGN-1 and WGN-2) by thermal treatment and compared their electrochemical properties with those of flat graphene nanosheets (FGN). FGN exhibit activities that are much better than those of wrinkled graphene nanosheets (WGN), not only in the electrochemical oxidation of methylene blue (MB) but also in the electrochemical reduction of nitrobenzene (NB). Transformation ratios of MB and NB in FGN, WGN-1, and WGN-2 were 97.5, 80.1, and 57.9% and 94.6, 92.1, and 81.2%, respectively. Electrochemical impedance spectroscopy and the surface resistance of the graphene samples increased in the following order: FGN < WGN-1 < WGN-2. This suggests that the reaction charges transfer faster across the reaction interfaces and along the surface of FGN than that of WGN, and wrinkles restrict reaction charge transfer and reduce the reaction rates. This study reveals that the morphology of the graphene (flat or wrinkle) greatly affects redox reaction activities and may have important implications for the design of novel graphene-based nanostructures and for our understanding of graphene wrinkle-dependent redox reactions in environmental processes.

Sunlight-driven photo-transformation of bisphenol A by Fe(III) in aqueous solution: Photochemical activity and mechanistic aspects.

Iron is one of the most abundant elements in aquatic environments, and plays important roles in the fate and transport of environmental contaminants. Previous studies on the photochemical properties of Fe(III) species have largely focused on complexes formed between Fe(III) and environmental ligands such as natural organic matter (NOM) under UV irradiation, whereas the potentially important roles of hydrolysis species of Fe(III) in Fe(III)-mediated photo-transformation of environmental contaminants under solar light are not fully understood. In this study, the solar light-driven photochemical activities of hydrolysis species of Fe(III) were further explored, using a system containing only 0.5 mM Fe2(SO4)3 and bisphenol A. The important role of colloidal [Fe(OH)3]m, formed from the hydrolysis of Fe3+, as a core photochemical species of Fe(III) was proposed and verified. Interestingly, O2-, rather than OH, was identified (via electron spin resonance) as the key active radical responsible for the degradation of bisphenol A. We propose that unlike Fe(OH)2+, which under UV irradiation can yield OH (Fe(OH)2+ + hv â†’ Fe2+ + OH), colloidal [Fe(OH)3]m produces O2- even in sunlight ([Fe(OH)3]m + 2O2 + hv â†’ Fe(II) + 2O2- + H2O). The fact that Fe(III) can produce strong radicals in sunlight may have important environmental implications.

To Set Up a Logistic Regression Prediction Model for Hepatotoxicity of Chinese Herbal Medicines Based on Traditional Chinese Medicine Theory.

Aims. To establish a logistic regression (LR) prediction model for hepatotoxicity of Chinese herbal medicines (HMs) based on traditional Chinese medicine (TCM) theory and to provide a statistical basis for predicting hepatotoxicity of HMs. Methods. The correlations of hepatotoxic and nonhepatotoxic Chinese HMs with four properties, five flavors, and channel tropism were analyzed with chi-square test for two-way unordered categorical data. LR prediction model was established and the accuracy of the prediction by this model was evaluated. Results. The hepatotoxic and nonhepatotoxic Chinese HMs were related with four properties (p < 0.05), and the coefficient was 0.178 (p < 0.05); also they were related with five flavors (p < 0.05), and the coefficient was 0.145 (p < 0.05); they were not related with channel tropism (p > 0.05). There were totally 12 variables from four properties and five flavors for the LR. Four variables, warm and neutral of the four properties and pungent and salty of five flavors, were selected to establish the LR prediction model, with the cutoff value being 0.204. Conclusions. Warm and neutral of the four properties and pungent and salty of five flavors were the variables to affect the hepatotoxicity. Based on such results, the established LR prediction model had some predictive power for hepatotoxicity of Chinese HMs.

Facet-dependent catalytic activity of nanosheet-assembled bismuth oxyiodide microspheres in degradation of bisphenol A.

Photocatalysts with different exposed facets often exhibit different photochemical performances, but the underlying mechanisms are not fully understood. In this study, we synthesized two nanosheet-assembled bismuth oxyiodide (BiOI) microspheres with exposed (110) and (001) facets, respectively, to further investigate facet-dependent photocatalytic activity. Our experimental results showed that the BiOI microspheres with exposed (110) facets exhibited much greater catalytic activity than the BiOI microspheres with exposed (001) facets in the degradation of bisphenol A under visible light irradiation. Density functional theory calculation revealed that the (110) facets can adsorb a greater amount of O2 and, thus, form more O2(•-) and (•)OH radicals than the (001) facets. The electron spin resonance spectroscopy and radical scavenging experiments verified that the BiOI microspheres with exposed (110) facets could produce a greater amount of O2(•-) radicals than the BiOI microspheres with exposed (001) facets, and more importantly, between the two BiOI products, only the BiOI microspheres with exposed (110) facets could generate (•)OH radicals directly. The facet-dependent radical formation mechanisms were previously unidentified. The findings of this study may have important implications for the understanding of the facet-dependent photochemical performance of photocatalysts and the design of novel catalytic materials with inorganic nanostructures.