A novel upregulated hsa_circ_0032746 regulates the oncogenesis of esophageal squamous cell carcinoma by regulating miR-4270/MCM3 axis.

INTRODUCTION: Circular RNAs (CircRNA) have emerged as an interest of research in recent years due to its regulatory role in various kinds of cancers of human body. Esophageal squamous cell carcinoma (ESCC) is one of the major disease subtype in Asian countries, including China. CircRNAs are formed by back-splicing covalently joined 3'- and 5'- ends rather than canonical splicing and are found to have binding affinity with miRNAs that conjointly contribute to oncogenesis. MATERIALS AND METHODS: 4 pairs of normal, cancer adjacent tissues and cancer tissues were analyzed by high-throughput RNA sequencing and 84 differentially upregulated circRNAs were detected in cancer tissues. hsa_circ_0032746 was silenced by siRNA and lentivirus and then further proliferation, migration and invasion were performed by CCK-8 and transwell assays. Bioinformatic analysis  predicted binding affinity of circRNA/miRNA/mRNA axis. RESULTS: After qPCR validation, we selected a novel upregulated hsa_circ_0032746 to explore its biogenetic functions which showed high expression in cancer tissues but not in cancer adjacent tissues. The clinicopathological relation of hsa_circ_0032746 showed positive correlation with the tumor location (P = 0.026) and gender (P = 0.05). We also predicted that hsa_circ_0032746 could sponge with microRNA. Bioinformatic analysis predicted 11 microRNA response element (MRE) sequences of hsa_circ_0032746 and dual luciferase reporter assay confirmed binding affinity with miR4270 evidencing further study of circRNA/miRNA role. The knockdown of hsa_circ_0032746 by siRNA and lentivirus demonstrated that proliferation, invasion and migration of ESCC were inhibited in vitro and vivo experiments. Bioinformatic analysis further predicted MCM3 as a target of miR-4270 and was found upregulated in ESCC upon validation. miR4270 mimic decreased the level of hsa_circ_0032746 and MCM3 while further rescue experiments demonstrated that hsa_circ_0032746 was dependent on miR4270/MCM3 axis on the development process of ESCC. CONCLUSION: We revealed for the first time that circ_0032746/mir4270/MCM3 contributes in proliferation, migration and invasion of ESCC and could have potential prognostic and therapeutic significance.

Energy Recovery from Hexavalent Chromium Reduction for In Situ Electrocatalytic Hydrogen Peroxide Production.

Recovering chemical energy embedded in pollutants is significant in achieving carbon-neutral industrial wastewater treatment. Considering that industrial wastewater is usually treated in a decentralized manner, in situ utilization of chemical energy to achieve waste-to-treasure should be given priority. Herein, the chemical energy released by the electroreduction of Cr(VI) was used to enhance on-site H2O2 generation in a stacked flow-through electrochemical system. The driving force of water flow efficiently coupled O2 evolution with 2-e O2 reduction to facilitate H2O2 generation by transporting anode-produced O2 to the cathode. Meanwhile, the chemical energy released by Cr(VI) promoted O2 evolution and impeded H2 evolution by regulating the electrode potentials, accounting for the enhanced H2O2 generation. The system could completely reduce 10-100 ppm of Cr(VI), reaching the maximum H2O2 concentration of 2.41 mM. In particular, the H2O2 concentrations in the Cr(VI)-containing electrolyte were 10.6-88.1% higher than those in the Cr(VI) free electrolyte at 1.8-2.5 V. A 24-day continuous experiment demonstrated the high efficiency and stability of the system, achieving a 100% reduction efficiency for 100 ppm of Cr(VI) and producing ∼1.5 mM H2O2 at 1.8 V. This study presents a feasible strategy for Cr(VI) detoxification and synchronous on-site H2O2 generation, providing a new perspective for innovative Cr(VI) wastewater treatment toward resource utilization.

GdClean: removal of Gadolinium contamination in mass cytometry data.

MOTIVATION: Mass cytometry (Cytometry by Time-Of-Flight, CyTOF) is a single-cell technology that is able to quantify multiplex biomarker expressions and is commonly used in basic life science and translational research. However, the widely used Gadolinium (Gd)-based contrast agents (GBCAs) in magnetic resonance imaging (MRI) scanning in clinical practice can lead to signal contamination on the Gd channels in the CyTOF analysis. This Gd contamination greatly affects the characterization of the real signal from Gd-isotope-conjugated antibodies, severely impairing the CyTOF data quality and ruining downstream single-cell data interpretation. RESULTS: We first in-depth characterized the signals of Gd isotopes from a control sample that was not stained with Gd-labeled antibodies but was contaminated by Gd isotopes from GBCAs, and revealed the collinear intensity relationship across Gd contamination signals. We also found that the intensity ratios of detected Gd contamination signals to the reference Gd signal were highly correlated with the natural abundance ratios of corresponding Gd isotopes. We then developed a computational method named by GdClean to remove the Gd contamination signal at the single-cell level in the CyTOF data. We further demonstrated that the GdClean effectively cleaned up the Gd contamination signal while preserving the real Gd-labeled antibodies signal in Gd channels. All of these shed lights on the promising applications of the GdClean method in preprocessing CyTOF datasets for revealing the true single-cell information. AVAILABILITY AND IMPLEMENTATION: The R package GdClean is available on GitHub at https://github.com/JunweiLiu0208/GdClean. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Safety and efficacy of grazoprevir/elbasvir in the treatment of acute hepatitis C in hemodialysis patients.

Treatment of hepatitis C virus (HCV) infection with direct-acting antiviral agents (DAAs) in hemodialysis patients requires extensive consideration. At present, studies regarding DAAs for acute HCV infection in such patients are limited. The present study aims to evaluate the efficacy and safety of grazoprevir (GZR) plus elbasvir (EBR) treatment in acute hepatitis C (AHC) patients undergoing hemodialysis. Patients undergoing hemodialysis who had a nosocomial acute HCV infection were enrolled. All patients received GZR 100 mg/EBR 50 mg once daily for 12 weeks and were followed up for 12 weeks. Serum alanine transaminase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and HCV RNA levels were monitored during treatment and follow-up periods. Sustained virologic response at 12 weeks after treatment cessation and treatment-emergent adverse events (AEs) were assessed. A total of 68 AHC patients were enrolled. All patients were infected with HCV genotype 1b and achieved SVR12. Decreasing ALT, AST, and TBIL were observed over time in the first 4 weeks and became steady thereafter. Forty-eight (70.59%) patients reported at least one AEs. The most common AEs were fatigue, headache, and nausea. Two AHC patients discontinued treatment due to serious but drug-unrelated AEs. In conclusion, GZR/EBR has a high efficacy and safety profile in hemodialysis-dependent patients with genotype 1b AHC.

Visualization of Electrochemically Accessible Sites in Flow-through Mode for Maximizing Available Active Area toward Superior Electrocatalytic Ammonia Oxidation.

Active chlorine species-mediated electrocatalytic oxidation is a promising strategy for ammonia removal in decentralized wastewater treatment. Flow-through electrodes (FTEs) provide an ideal platform for this strategy because of enhanced mass transport and sufficient electrochemically accessible sites. However, limited insight into spatial distribution of electrochemically accessible sites within FTEs inhibits the improvement of reactor efficiency and the reduction of FTE costs. Herein, a microfluidic-based electrochemical system is developed for the operando observation of microspatial reactions within pore channels, which reveals that reactions occur only in the surface layer of the electrode thickness. To further quantify the spatial distribution, finite element simulations demonstrate that over 75.0% of the current is accumulated in the 20.0% thickness of the electrode surface. Based on these findings, a gradient-coated method for the active layer was proposed and applied to a Ti/RuO2 porous electrode with an optimized pore diameter of ∼25 µm, whose electrochemically accessible surface area was 381.7 times that of the planar electrode while alleviating bubble entrapment. The optimized reactor enables complete ammonia removal with an energy consumption of 60.4 kWh kg-1 N, which was 24.2% and 39.9% less than those with pore diameters of ∼3 µm and ∼90 µm, respectively.

LncRNA SNHG16 promotes development of oesophageal squamous cell carcinoma by interacting with EIF4A3 and modulating RhoU mRNA stability.

BACKGROUND: Numerous studies have revealed that long noncoding RNAs (lncRNAs) are closely related to the development of many diseases and carcinogenesis. However, their specific biological function and molecular mechanism in oesophageal squamous cell carcinoma (ESCC) remains unclear. METHODS: RNA-Seq was performed to determine the differential expressions of lncRNAs in ESCC, and the level of SNHG16 expression was detected in ESCC and intraepithelial neoplasia (IEN) samples. In vitro and in vivo experiments were performed to explore the role of SNHG16 and the interaction of EIF4A3 and Ras homologue family member U (RhoU) signalling. RESULTS: One hundred and seventy-five upregulated and 134 downregulated lncRNAs were identified by RNA-Seq. SNHG16 was highly expressed in ESCC and intraepithelial neoplasia (IEN) samples, and its expression level was correlated with tumour differentiation and T stage. Overexpression of SNHG16 can facilitate ESCC cell proliferation and metastasis. Mechanistically, we noticed that SNHG16 could bind RNA binding protein (RBP)-eukaryotic translation initiation factor (EIF4A3) and interact with it to form a complex. Importantly, the coalition of SNHG16 and EIF4A3 ultimately regulated Ras homologue family member U (RhoU). SNHG16 modulated RhoU expression by recruiting EIF4A3 to regulate the stability of RhoU mRNA. Knockdown of RhoU further alleviated the effect of the SNHG16 oncogene in ESCC cells. CONCLUSIONS: The newly identified SNHG16-EIF4A3-RhoU signalling pathway directly coordinates the response in ESCC pathogenesis and suggests that SNHG16 is a promising target for potential ESCC treatment.

In Operando Visualization and Dynamic Manipulation of Electrochemical Processes at the Electrode-Solution Interface.

Revealing the dynamic processes at the electrode-solution interface is imperative for understanding electrochemical phenomena. Most techniques have been developed to sense the electrode surface changes at the nanoscale, but provide limited information on potential-induced interfacial ion redistribution at the mesoscale. Herein, we present an in operando visualization method utilizing a microfabricated electrochemical cell combined with a laser scanning confocal microscope to observe high-resolution and fast-response interfacial processes. We report potential-induced formation and transformation of the Nernst diffusion layer, demonstrating that pulsed voltage dynamically perturbs the interface and promotes ion diffusion. This provides an additional insight into developing a dynamic manipulation method to control the electrochemical process. Our novel visualization method can easily be applied to monitor different ionic behaviors in electrochemical reactions at the mesoscale.

Synergetic Lipid Extraction with Oxidative Damage Amplifies Cell-Membrane-Destructive Stresses and Enables Rapid Sterilization.

Here, we introduce an innovative "poison arrowhead" approach for disinfection based on a nanosheet bacterial inactivation system that acts synergistically to achieve sterilization rates of >99.99 % (Escherichia coli) over an ultrashort time period (≈0.5 min). The two-dimensional MoS2 "arrowhead" configuration has a sharp edge structure that enables the vigorous extraction of lipids from cell membranes and subsequent membrane disruptions. In the presence of permonosulfate, a strong oxidant, sulfur vacancies containing MoS2 activate the stable molecules, which in turn produce reactive oxygen species (ROS) from edge sites to basal areas. This process not only scavenges some portion of the phospholipids to allow for MoS2 surface refreshment but also directly attacks proteins thereby inflicting further damage to injured cells and amplifying the cell-membrane-destructive stresses toward pathogenic microorganisms. With small amounts of the new material, we successfully disinfected natural water (≈99.93 % inactivation in terms of total bacteria) within 30 s.

Hot-Electron-Induced Photothermal Catalysis for Energy-Dependent Molecular Oxygen Activation.

Hot electrons activate reactants and reduce the activation energy barrier (Ea ) of a reaction through electron donation. However, a comprehensive understanding of the intrinsic driving force of this electron-donating effect is lacking, let alone the precise manipulation of electron donation processes. Herein, the essential and promotional role of hot electron energy on the electron-donating effect was elucidated using molecular oxygen activation (MOA) as a model reaction. Through providing an available electron source to the conventional photo-thermal conversion system, the high energy carried by hot electrons was liberated and greatly enhanced the electron donation towards the LUMO (π*) orbit of O2 . The energy was also transferred to O2 and elevated the potential energy surface (PES) of MOA, which was reflected by the enhanced formation of superoxide oxygen anions. As predicted, the Ea of MOA decreased by 45.1 % and exhibited a substantial light dependence, demonstrating that MOA became energy-efficient due to improved exploitation and conversion of photon energies.

In Situ Creation of Oxygen Vacancies in Porous Bimetallic La/Zr Sorbent for Aqueous Phosphate: Hierarchical Pores Control Mass Transport and Vacancy Sites Determine Interaction.

Porous materials constructed from hierarchical pores are beneficial for the mass transport during the aqueous adsorption process. To achieve high performance, it is important to create adequate numbers of active centers to anchor the target ions in the solution. Synchronous construction of powerful bonding sites in the surface area amplification process should be a promising path for developing outstanding sorbents. By in situ evaporation of reductive soft organic templates, we successfully confined oxygen vacancies (VO) in porous La/Zr bimetallic oxides. For aqueous phosphate contaminants, the as-produced porous sorbent exhibited superior removal performance, with equilibrium adsorption capacities almost ∼2 times higher those that of the VO-free counterpart. Based on mass transfer model analysis, pore structure has the potential to buffer external influence on mass transfer. Under an adverse condition (pH 9.0), the mass transfer was ∼2.5 times higher than that in the pore-free one (0.10 min-1 vs 0.04 min-1), ensuring the possibility of diffusing phosphate in further contact with these active sites. According to results of orbital interaction analysis and X-ray spectroscopy measurements, VO-dominated active sites not only enhanced attractive orbital bonding interaction toward phosphate but also converted repulsive interaction into attractive reaction, thereby eliminating this kinetics barrier and promoting the rate of phosphate chemisorption reaction.

pH-Independent Production of Hydroxyl Radical from Atomic H*-Mediated Electrocatalytic H2O2 Reduction: A Green Fenton Process without Byproducts.

Hydroxyl radical (•OH) can hydroxylate or dehydrogenate organics without forming extra products and is thereby expediently applied in extensive domains. Although it can be efficiently produced through single-electron transfer from transition-metal-containing activators to hydrogen peroxide (H2O2), narrow applicable pH range, strict activator/H2O2 ratio requirement, and byproducts that are formed in the mixture with the background matrix necessitate the need for additional energy-intensive up/downstream treatments. Here, we show a green Fenton process in an electrochemical cell, where the electro-generated atomic H* on a Pd/graphite cathode enables the efficient conversion of H2O2 into •OH and subsequent degradation of organic pollutants (80% efficiency). Operando liquid time-of-fight secondary ion mass spectrometry verified that H2O2 activation takes place through a transition state of the Pd-H*-H2O2 adduct with a low reaction energy barrier of 0.92 eV, whereby the lone electron in atomic H* can readily cleave the peroxide bridge, with •OH and H2O as products (ΔGr = -1.344 eV). Using H+ or H2O as the resource, we demonstrate that the well-directed output of H* determines the pH-independent production of •OH for stable conversion of organic contaminants in wider pH ranges (3-12). The research pioneers a novel path for eliminating the restrictions that are historically challenging in the traditional Fenton process.

Enhanced phosphate removal using zirconium hydroxide encapsulated in quaternized cellulose.

Zirconium-based materials are efficient adsorbent for aqueous phosphate removal. However, current zirconium-based materials still show unsatisfied performance on adsorption capacity and selectivity. Here, we demonstrate a zirconium hydroxide encapsulated in quaternized cellulose (QC-Zr) for the selective phosphate removal. Zirconium hydroxide nanoparticles were simultaneously generated in situ with the QC framework and firmly anchored in the three-dimensional (3D) cross-linked cellulose chains. The maximum P adsorption capacity of QC-Zr was 83.6 mg P/g. Furthermore, the QC-Zr shows high P adsorption performance in a wide pH range, generally due to the electrostatic effects of quaternized cellulose. The enhanced adsorption of P was also achieved in the presence of competing anions (including Cl-, NO3-, SO42-, SO44-) and humic acid (HA) even at a molar ratio up to 20 levels. The column adsorption capacity of QC-Zr reached 4000 bed volumes (BV) at EBCT = 0.5 min as the P concentration decreased from 2.5 to 0.5 mg/L. Mechanism study revealed that both -N+(CH3)3 groups and zirconium hydroxide were involved in phosphate adsorption via electrostatic interactions between -N+(CH3)3 and phosphate, and the formation of zirconium hydrogen phosphate (Zr(HPO4)x). The 31P nuclear magnetic resonance (NMR) study implied that P surface-precipitated and inner-sphere complexed with zirconium hydroxide at a ratio of 3:1.

Field-Enhanced Nanoconvection Accelerated Electrocatalytic Conversion of Water Contaminants and Electricity Generation.

The development of high-performance electrocatalytic systems for the extraction of energy from contaminants in wastewater are urgently needed in emerging renewable energy technologies. However, given that most of the contaminants are present in low concentrations, the heterogeneous catalytic reactions often suffer from slow kinetics due to mass transfer limitations. Here, we report that localized free convection induced by enthalpy change of the reaction can enhance interfacial mass transport. This phenomenon can be found around high-curvature nanosized tips. The finite-element numerical simulation shows that the heat of reactions can produce temperature gradients and subsequently lead to fluid motion at the interfaces, which facilitates the rate-limiting step (mass transfer). To demonstrate the effects of localized field-enhanced mass transport in electrocatalytic conversion of aqueous dilute species, a galvanic cell is constructed with a vertically aligned polyaniline array with sharp tips (as cathode) for the detoxification of a low concentration of carcinogenic chromate and synchronous electricity generation, which show lower overpotential (0.17 V decreased), higher reaction rate (increased by 28%), and power density (22.3 W m-2 in 2 mM chromate). The power output can be scaled up (open voltage of ∼3.7 V and volumetric power density of 840.1 W m-3) by using a continuous flow-through cell with stacked electrodes for further improve the mass transport.

Activation of Lattice Oxygen in LaFe (Oxy)hydroxides for Efficient Phosphorus Removal.

Lanthanum (La)-based materials have been recognized as promising adsorbents for aqueous phosphate removal. The incorporation of base metals into La (oxy)hydroxides represents an effective strategy to improve adsorption performance. Understanding how base metals affect phosphate adsorption is challenging but essential for the development of effective materials for phosphorus control. Herein, we demonstrated a high-performance LaFe (oxy)hydroxide and studied its mechanisms on phosphate adsorption. The P K edge X-ray absorption near edge structure (XANES) analysis showed that PO43- was preferentially bonded with La, and the lattice oxygen in LaFe (oxy)hydroxide was demonstrated to be the active site. The O K edge XANES suggested that Fe optimized the electron structure of La, and Fe/La metal orbital hybridization resulted in the shift of oxygen p character to unoccupied states, facilitating phosphate adsorption. Furthermore, surface analysis showed that the pore size and volume were increased due to the introduction of Fe, which enabled efficient utilization of the active sites and fast adsorption kinetics. The dual effects of Fe in LaFe (oxy)hydroxide greatly enhance the effectiveness of La and represent a new strategy for the development of future phosphorus-control materials.

Enhanced Stabilization and Effective Utilization of Atomic Hydrogen on Pd-In Nanoparticles in a Flow-through Electrode.

Surface-adsorbed active species are intermediates with strong activities in heterogeneous catalytic reactions. Effective stabilization of these intermediates is crucial to improve the catalytic performance. Here, we demonstrated highly active bimetallic palladium-indium (Pd-In) nanoparticles (NPs) that can stabilize atomic H* on the surface and show efficient electrocatalytic reduction performance toward bromate. The optimal atomic ratio of Pd to In was investigated with the aim of efficient formation and strong stabilization of H*, thus facilitating the reduction and decontamination of carcinogenic bromate. Pd2In3 was the most active catalyst, with a high rate constant of 0.029 min-1, whereas the rate constant for monometallic Pd NPs was only 0.009 min-1. Density functional theory calculations suggest that Pd2In3 NPs decrease the work function and provide strong H* stabilization ability. By employing a flow-through electrode coated with Pd2In3 NPs to enhance the mass transport, the utilization of H* could be boosted and the reduction kinetics increased up to 7.5 times.

Synchronous Reduction-Oxidation Process for Efficient Removal of Trichloroacetic Acid: H* Initiates Dechlorination and ·OH Is Responsible for Removal Efficiency.

Degradation of chlorinated disinfection by-products using the electroreduction process has been considered as a promising approach for advanced water treatment, while the removal efficiency is restricted by a high barrier for dechlorination of intermediates only by reductive atomic hydrogen (H*) and excessive cost required for reducing atmosphere. In this paper, we predict that the dechlorination efficiency for trichloroacetic acid (TCA), a typical chlorinated disinfection by-product, can be accelerated via a synchronous reduction-oxidation process, where the dechlorination barrier can be lowered by the oxidation reactions toward the critical intermediates using hydroxyl radicals (·OH). Based on scientific findings, we constructed a synchronous reduction-oxidation platform using a Pd-loaded Cu/Cu2O/CuO array as the core component. According to the combined results of theoretical and experimental analyses, we found that the high dispersion of nano-sized Pd on a photocathode was beneficial for the production of a high concentration of H* at low overpotential, a perquisite for initiating the dechlorination reaction. Simultaneously, excess H* has the potential to convert O2 to H2O2 in ambient conditions (air condition), and H2O2 can be further activated by a Cu-containing substrate to ·OH for attacking the critical intermediates. In this system, ∼89.1% of TCA was completely dechlorinated and ∼26.8% mineralization was achieved in 60 min, which was in contrast to the value of ∼65.7% and mineralization efficiency of only ∼1.7% achieved through the reduction process (Ar condition).

Higher variety and quantity of microRNA-139-5p isoforms confer suppressive role in hepatocellular carcinoma.

MiRNA isoforms (isomiRs) were defined as an addition or deletion of one or more nucleotides at the 5' or 3' ends or both. Different isomiRs of the same miRNA can target different genes, which have extended the regulatory scale medicated by miRNA. In this study, we systematically analyzed miRNA isoforms in hepatocellular carcinoma (HCC) based on The Cancer Genome Atlas (TCGA) data and further explore their role by in silico and in vitro studies. We found that higher variety and quantity of miR-139-5p isoforms negatively correlated with the malignancy of HCC. And patients with higher variety and quantity of iso-miR-139-5p exhibited favorable survival, independent of tumor stage. Interestingly, miR-139-5p -1|-1 showed increased complementary effect of its target IGF1R than the archetype of miR-139-5p, and could further inhibit cellular movement more vigorously than its archetype. In conclusion, not only miR-139-5p itself, but its isoforms' variety and quantity confer suppressive role in HCC.

Pore Structure-Dependent Mass Transport in Flow-through Electrodes for Water Remediation.

Hierarchical three-dimensional architectures of granphene-based materials with tailored microstructure and functionality exhibit unique mass transport behaviors and tunable active sites for various applications. The micro- /nanochannels in the porous structure can act as micro- /nano- reactors, which optimize the transport and conversion of contaminants. However, the size-effects of the micro- /nanochannels, which are directly related to its performance in electrochemical processes, have not been explored. Here, using lamellar-structured graphene films as electrodes, we demonstrate that the interlayer spacing (range from ∼84 nm to ∼2.44 µm) between graphene nanosheets governs the mass transport and electron transfer in electrochemical processes; subsequently influence the water decontamination performances. The microchannel (interlayer spacing = ∼2.44 µm) can provide higher active surface areas, but slow reaction kinetics. Densely packed graphene nanosheets (interlayer spacing = ∼280 nm), which possessed better electron conductivity and could provide higher surface-area-to-volume ratio in narrow nanochannels (7.14 µm-1), achieved the highest reaction kinetics. However, the ion-accessible surface area was decreased in highly dense films (interlayer spacing = ∼84 nm) due to serious interlayer stacking of graphene nanosheets, thereby leading poor reaction kinetics. These results demonstrate the size-effect of nanochannels in porous materials and highlight the importance of controlling mass transport and electron transfer for optimal electrochemical performance, enabling a deep understanding of the benefits and utilization of these hierarchical three-dimensional architectures in water purification.

Photoactuation Healing of α-FeOOH@g-C3 N4 Catalyst for Efficient and Stable Activation of Persulfate.

Inspired by living systems, the construction of smart devices that can self-heal in response to structural damage is a promising technology for maintaining the high activity and stability of catalysts during heterocatalytic reactions. Here this study demonstrates an ingenious platform that enabled efficient persulfate (PS) activation for contaminant degradation via integrating a catalyst with photoactuation regeneration. Under irradiation, it is unambiguously confirmed that the collective properties of a tailored FeOOH@C3 N4 catalyst permit interfacial photoexcited electron transport from the photocatalyst substrate to needle-shaped FeOOH. This results in the simultaneous recovery of Fe(III) and optimization of the Fe(II)/Fe(III) ratio on FeOOH surface during PS activation process, so that the healed chemical structure ensures that subsequent PS activation remains unimpaired. Aqueous organic contaminant (bisphenol A) oxidation efficacy in this system is almost 20 times higher than for photo- or Fenton-oxidation alone. This work highlights the concept of catalyst regeneration for stable reactive species generation in solution, which represents alternative application of photocatalysis for practical environmental remediation. Further, the photoactuation healing approach can be expanded into various domains, such as material fabrication or chemical synthesis.

Microfluidic Flow through Polyaniline Supported by Lamellar-Structured Graphene for Mass-Transfer-Enhanced Electrocatalytic Reduction of Hexavalent Chromium.

Owing to its high efficiency and environmental compatibility, electroreduction holds great promise for the detoxification of aqueous Cr(VI). However, the typical electroreduction system often shows poor mass transfer, which results in slow reduction kinetics and hence higher energy consumption. Here, we demonstrate a flow-through electrode of polyaniline supported on lamellar-structured graphene (LGS-PANI) for electrocatalytic reduction of Cr(VI). The reaction kinetics of the LGS-PANI flow-through electrodes are 6.4 times (at acidic condition) and 17.3 times (at neutral condition) faster than traditional immersed parallel-plate electrodes. Computational fluid dynamics simulation suggests that the flow-through mode greatly enhances the mass transfer and that the nanoscale convection induced by the PANI nanodots increases the nanoscale mass transport in the interfacial region of the electrode/solution. In situ Raman spectroscopy shows that the PANI-Cr(VI) redox reactions are dominated by the leucoemeraldine/emeraldine transition at 1.5 V cell voltage, which also remarkably contributes to the fast reaction kinetics. Using single-pass flow-through mode, the LGS-PANI electrode reaches an average reduction efficiency of 99.8% with residual Cr(VI) concentration of 22.3 ppb (initial [Cr(VI)] = 10 ppm, flux = 20 L h(-1) m(-2)). A long-term stability test shows that the LGS-PANI maintains stable performance over 40 days of operation and achieves >98% reduction efficiency, with average current efficiency of as high as 99.1% (initial [Cr(VI)] = 10 ppm, flux = 50 L h(-1) m(-2)).