Regulating the valence and size of the active center of Co/Al2O3 catalyst improved the performance and selectivity of NH3-SCO.

To improve the activity of Co/Al2O3 catalysts in selective catalytic oxidation of ammonia (NH3-SCO), valence state and size of active centers of Al2O3-supported Co catalysts were adjusted by conducting H2 reduction pretreatment. The NH3-SCO activity of the adjusted 2Co/Al2O3 catalyst was substantially improved, outperforming other catalysts with higher Co-loading. Fresh Co/Al2O3 catalysts exhibited multitemperature reduction processes, enabling the control of the valence state of the Co-active centers by adjusting the reduction temperature. Changes in the state of the Co-active centers also led to differences in redox capacity of the catalysts, resulting in different reaction mechanisms for NH3-SCO. However, in situ diffuse reflectance infrared Fourier transform spectra revealed that an excessive O2 activation capacity caused overoxidation of NH3 to NO and NO2. The NH3-SCO activity of the 2Co/Al2O3 catalyst with low redox capacity was successfully increased while controlling and optimizing the N2 selectivity by modulating the active centers via H2 pretreatment, which is a universal method used for enhancing the redox properties of catalysts. Thus, this method has great potential for application in the design of inexpensive and highly active catalysts.

Efficiency and mechanism of controlling phosphorus release from sediment using a biological aluminum-based P-inactivation agent.

Eutrophication is a significant challenge for surface water, with sediment phosphorus (P) release being a key contributor. Although biological aluminum-based P-inactivation agent (BA-PIA) has shown effectiveness in controlling P release from sediment, the efficiency and mechanism by BA-PIA capping is still not fully understood. This study explored the efficiency and mechanism of using BA-PIA capping controlling P release from sediment. The main mechanisms controlling P release from sediment via BA-PIA capping involved transforming mobile and less stable fractions into stable ones, passivating DGT-labile P and establishing a 13 mm 'P static layer' within the sediment. Additionally, BA-PIA's impact on Fe redox processes significantly influenced P release from the sediment. After BA-PIA capping, notable reductions were observed in total P, soluble reactive P (SRP), and diffusive gradient in thin-films (DGT)-measured labile P (DGT-labile P) concentration in the overlying water, with reduction rates of 95.6%, 92.7%, and 96.5%, respectively. After BA-PIA capping, the diffusion flux of SRP across the sediment-water interface and the apparent P diffusion flux decreased by 91.3% and 97.8%, respectively. Additionally, BA-PIA capping led to reduced concentrations of SRP, DGT-labile P, and DGT-measured labile Fe(II) in the sediment interstitial water. Notably, BA-PIA capping significantly reduced P content and facilitated transformation in the 0∼30 mm sediment layers but not in the 30∼45 mm and 45∼60 mm sediment layers for NaOH-extractable inorganic P and HCl-extracted P. These findings offer a theoretical basis and technical support for the practical application of BA-PIA capping to control P release from sediment.

A colorimetric sensor based on multiple elements doped carbon dot nanozyme for rapid detection of 1-naphthol in human urine samples.

The residual carbaryl in crops can cause serious damage to the human kidney and nervous system after entering the human body, which may be metabolized to 1-naphthol (1-NAP) and excreted through urine. 1-NAP is often used as the biomarker for carbaryl exposure, so the intake or leakage of carbaryl can be monitored by detecting the concentration of 1-NAP. Herein, Co, N, P ternary co-doped carbon dots (CoNP-CDs) derived from vitamin B12 were synthesized by a facile hydrothermal method. CoNP-CDs exhibited oxidase-like activity and excellent peroxidase-like activity, which was attributed to the Fenton-like reaction of Co2+/Co3+ and the presence of pyrrole N and P elements, which together provided multiple active sites for chromogenic substrates. Due to the dual enzyme-like activity of CoNP-CDs, hydroxyl radicals (OH) and superoxide radicals (O2-) were generated during the catalytic process, which could rapidly oxidize colorless 3,3',5,5'-tetramethyl benzidine (TMB) to blue oxidation products (oxTMB). The α-carbon in 1-NAP can be attacked by OH, and the catalytic oxidation process of TMB can be inhibited by the consumption of OH, so that the blue color of the solution became lighter. Based on this principle, a smartphone-assisted colorimetric sensing platform was constructed for the detection of 1-NAP, and which resulted in a linear range of 1.07-37.3 µM and a visual detection limit of 0.68 µM. Moreover, the colorimetric sensing system showed satisfactory recoveries in the detection of human urine samples. The colorimetric sensing system owned the advantages of fast response, strong selectivity and simple operation, and provided a potential strategy for the on-site detection of 1-NAP.

Construction of dual sites on FeS2 surface for enhanced electrocatalytic reduction of nitrite to ammonia.

Cost-effective iron sulfides (FeS2) hold great potential as high-performance catalysts for NO2- electroreduction to NH3 (NO2ER), which is hindered by the weak NO2 activation. Herein, the design of nonmetal-doped FeS2 electrocatalysts was initially conducted by density functional theory (DFT) computations. We found that doping with different nonmetal atoms effectively not only regulates the electronic structures of the d-electrons of Fe atoms but also creates the unique p-d hybridized dual active sites, thereby boosting the efficient NO2 activation. Owing to the optimal NO2 adsorption strength, N-doped FeS2 demonstrates a low limiting potential for the NO2--to-NH3 conversion, thus significantly improving NO2ER activity. Direct experimental evidence was provided afterward: an NH3 yield rate of 424.5 µmol/hcm-2 with a 92.4 % Faradaic efficiency was achieved. Our findings not only suggest a promising NO2ER catalyst through theoretical computations to guide experiments but also provide a comprehensive understanding of the structure-properties relationship.

Enhancing the performance of a lithium-sulfur battery with spatially confined mesoporous nanoreactors in sulfurized polyacrylonitrile cathodes.

Sulfurized polyacrylonitrile (SPAN), which is recognized as a promising cathode material for lithium-sulfur batteries (Li-SBs), effectively mitigates the shuttle effect resulting from polysulfide dissolution. However, conventional SPAN cathodes typically exhibit sulfur loadings below 40 wt%. While encapsulation of sulfur within pores via a solid electrolyte interface addresses the low sulfur loading issue, the suboptimal kinetics of the solid-solid reactions hinder effective utilization of sulfur within the pores. In this work, Me-SeSPAN/SeS fibrous membranes were successfully synthesized through electrospinning and molten salt-assisted pyrolysis of ZIF-8, which resulted in the formation of spatially confined interconnected mesoporous nanoreactors. These nanoreactors function as supplementary storage spaces, loading and constraining the size of internal active material clusters. The fibrous membranes facilitate Li+ movement through pore spaces and promote adsorption of the discharge product Li2S on the pore walls via the spatial confinement effect. Based on density functional theory (DFT) calculations, this process guarantees a supply of electrons and Li+ to the active material, thereby enabling continuous electron transfer during redox reactions. The optimized Me-SeSPAN/SeS electrode, featuring a sulfur and selenium loading of 70 wt%, demonstrates exceptional cycling stability in both coin and pouch cells. This study presents an effective strategy for enhancing the kinetics of active materials encapsulated in SPAN cathodes.

The synergistic effect of NiCo2S4 and carbon nanosheets for supercapacitor: Enhanced adsorption/desorption of OH- on Ni and Co active sites.

To improve the low energy density, low conductivity, and poor cycling stability of NiCo2S4 in supercapacitors, a two-step hydrothermal method was used to prepare a composite material of NiCo2S4 and carbon nanosheets (NiCo2S4/CNs). The electrochemical tests revealed a high specific capacitance of 1576 F g-1 at 1 A/g for the composite, and the NiCo2S4/CNs//AC asymmetric supercapacitor showed a energy density of 49.7 Wh kg-1 at 818 W kg-1. This study confirmed the phase transformation of NiCo2S4 during charge/discharge in alkaline solution through ex-situ X-ray diffraction (ex-situ XRD) for the first time, and proposed a potential reaction pathway. Moreover, Density Functional Theory (DFT) confirmed that the NiCo2S4/CNs heterostructure enhances OH- adsorption/desorption on Ni and Co active sites and improves electronic conductivity. In conclusion, this study advances the application of transition metal sulfide in high-performance energy storage.

Evaluation of individual metal contribution on active sites tailoring in multimetallic oxygen evolution catalytic system.

Synergistic effects among different metals have positioned multimetallic electrocatalysts as promising facilitators for enhancing the oxygen evolution reaction (OER), though understanding their precise mechanisms has remained elusive. Delving into the unique contributions of individual metals is crucial for comprehending the complex synergy within multimetallic systems. In this study, we employed quinary (Co, Ce, Fe, Cu, and Mn) molybdates as a model to systematically investigate the role of each metal species in tailoring active sites. Our systematic analyses unveiled the presence of crucial oxygen vacancies, which can be considered as the active sites in OER. Comparative analyses of the top-performing quinary molybdates and their quaternary counterparts highlighted distinct electronic interactions and varying densities of oxygen vacancies, indicative of the diverse electron and vacancy engineering capabilities inherent to different metals. Mott-schottky plots demonstrated the predominant contribution of Mn to specific catalytic activity, followed by Ce, Fe, Cu, and Co. Leveraging an in-situ methanol probing method, it was found that the introduction of Cu, Ce, Fe, and Mn weakened intermediate adsorption, with Mn and Ce having the most significant effects, whereas Co strengthened adsorption. This work can advance our comprehension of the role played by individual metals within multimetallic catalysts, thereby promoting a more profound understanding of synergistic effects.

Potential-dependent superlubricity of stainless steel and Au(111) using a water-in-surface-active ionic liquid mixture.

HYPOTHESIS: The friction and interfacial nanostructure of a water-in-surface-active ionic liquid mixture, 1.6 M 1-butyl-3-methylimidazolium 1,4-bis-2-ethylhexylsulfosuccinate ([BMIm][AOT]), can be tuned by applying potential on Au(111) and stainless steel. EXPERIMENTAL: Atomic force microscopy (AFM) was used to examine the friction and interfacial nanostructure of 1.6 M [BMIm][AOT] on Au(111) and stainless steel at different potentials. FINDINGS: Superlubricity (vanishing friction) is observed for both surfaces at OCP+1.0 V up to a surface-dependent critical normal force due to [AOT]- bilayers adsorbing strongly to the positively charged surface thus allowing AFM tip to slide over solution-facing hydrated anion charged groups. High-resolution AFM imaging reveals ripple-like features within near-surface layers, with the smallest amplitudes at OCP+1 V, indicating the highest structural stability and resistance to thermal fluctuations due to highly ordered boundary [AOT]- bilayers templating robust near-surface layers. Exceeding the critical normal force at OCP+1.0 V causes the AFM tip to penetrate the hydrated [AOT]- layer and slide over alkyl chains, increasing friction. At OCP and OCP-1.0 V, higher friction correlates with more pronounced ripples, attributed to the rougher templating [BMIm]+ boundary layer. Kinetic experiments show that switching from OCP-1.0 V to OCP+1.0 V achieves superlubricity within 15 s, enabling real-time friction control.

Promoting effect of Cu as electron transfer medium on NH3-SCO reaction in asymmetric Ag-Ov-Ti-Sm-Cu ring active site.

Selective catalytic oxidation of ammonia (NH3-SCO) has become an effective method to reduce ammonia (NH3) emissions, and is a key part to solve the problem of NH3 pollution. Nevertheless, the optimization of this technology's performance relies heavily on innovation and the development of catalyst design. In this study, a SmCuAgTiOx catalyst with an asymmetric Ag-Ov-Ti-Sm-Cu ring active site was prepared and applied to the NH3-SCO reaction. The low conversion of Cu-based catalysts in NH3 at low temperature and the inherent low N2 selectivity of Ag-based catalysts were solved. The successful creation of the asymmetric ring active site improved the catalyst's reduction performance. Additionally, Cu, acting as an electron transfer medium, plays a crucial role in enhancing electron transfer within the asymmetric ring active site, thus increasing the redox cycle of the catalyst during the reaction. In addition, some lattice oxygen is lost in the catalyst, resulting in the formation of a large number of oxygen vacancies. This process stimulates the adsorption and activation of surface-adsorbed oxygen, facilitating the conversion of NH3 to an amide (NH2) intermediate during the reaction and reducing non-selective oxidation. The N2 selectivity was improved without significantly affecting the performance of Ag-based catalyst. In-situ diffuse reflectance fourier transform infrared spectroscopy (In-situ DRIFTS) analysis reveals that the SmCuAgTiOx catalyst primarily follows an "internal" selective catalytic reduction (iSCR) mechanism in the NH3-SCO reaction, complemented by the imide mechanism. The asymmetric Ag-Ov-Ti-Sm-Cu ring active site developed in this study provides a new perspective for efficiently solving NH3 pollution in the future.

Identification of true active sites in N-doped carbon-supported Fe2P nanoparticles toward oxygen reduction reaction.

Transition metal-based nanoparticles (NPs) are emerging as potential alternatives to platinum for catalyzing the oxygen reduction reaction (ORR) in zinc-air batteries (ZAB). However, the simultaneous coexistence of single-atom moieties in the preparation of NPs is inevitable, and the structural complexity of catalysts poses a great challenge to identifying the true active site. Herein, by employing in situ and ex situ XAS analysis, we demonstrate the coexistence of single-atom moieties and iron phosphide NPs in the N, P co-doped porous carbon (in short, Fe-N4-Fe2P NPs/NPC), and identify that ORR predominantly proceeds via the atomic-dispersed Fe-N4 sites, while the presence of Fe2P NPs exerts an inhibitory effect by decreasing the site utilization and impeding mass transfer of reactants. The single-atom catalyst Fe-N4/NPC displays a half-wave potential of 0.873 V, surpassing both Fe-N4-Fe2P NPs/NPC (0.858 V) and commercial Pt/C (0.842 V) in alkaline condition. In addition, the ZAB based on Fe-N4/NPC achieves a peak power density of 140.3 mW cm-2, outperforming that of Pt/C-based ZAB (91.8 mW cm-2) and exhibits excellent long-term stability. This study provides insight into the identification of true active sites of supported ORR catalysts and offers an approach for developing highly efficient, nonprecious metal-based catalysts for high-energy-density metal-air batteries.

Menthyl acetate powered self-propelled Janus sponge Marangoni motors with self-maintaining surface tension gradients and active mixing.

HYPOTHESIS: Small scale Marangoni motors, which self-generate motion by inducing surface tension gradients on water interfaces through release of surface-active "fuels", have recently been proposed as self-powered mixing devices for low volume fluids. Such devices however, often show self-limiting lifespans due to the rapid saturation of surface-active agents. A potential solution to this is the use volatile surface-active agents which do not persist in their environment. Here we investigate menthyl acetate (MA) as a safe, inexpensive and non-persistent fuel for Marangoni motors. EXPERIMENTS: MA was loaded asymmetrically into millimeter scale silicone sponges. Menthyl acetate reacts slowly with water to produce the volatile surface-active menthol, which induces surface tension gradients across the sponge to drive motion by the Marangoni effect. Videos were taken and trajectories determined by custom software. Mixing was assessed by the ability of Marangoni motors to homogenize milliliter scale aqueous solutions containing colloidal sediments. FINDINGS: Marangoni motors, loaded with asymmetric "Janus" distributions of menthyl acetate show velocities and rotational speeds up to 30 mm s-1 and 500 RPM respectively, with their functional lifetimes scaling linearly with fuel volume. We show these devices are capable of enhanced mixing of solutions at orders of magnitude greater rates than diffusion alone.

Responsive nanocellulose-PNIPAM millicapsules.

HYPOTHESIS: Milli- and micro-capsules are developed to facilitate the controlled release of diverse active ingredients by passive diffusion or a triggered burst. As applications expand, capsules are required to be increasingly multi-functional, combining benefits like encapsulation, response, release, and even movement. Balancing the increasingly complex demands of capsules is a desire to minimize material usage, requiring efficient structural and chemical design. Designing multifunctional capsules with complex deformation should be possible even after minimizing the material usage through use of sparse fiber networks if the fibers are coated with responsive polymers. EXPERIMENTS: Here capsules are created with a shell made from a mesh of nanoscale bacterial cellulose fibers that provide mechanical strength at very low mass levels, while a coating of thermoresponsive Poly(N-isopropylacrylamide), PNIPAM, on the fibers provides control of permeability, elastic response, and temperature response. These properties are varied by grafting different amounts of polymer using particular reaction conditions. FINDINGS: The addition of PNIPAM to the cellulose mesh capsule enhances its mechanical properties, enabling it to undergo large deformations and recover once stress is removed. The increased elastic response of the capsule also provides reinforcement against drying-induced capillary stresses, limiting the degree of shrinkage during dehydration. Time-lapse microscopy demonstrates thermoreversible swelling of the capsules in response to temperature change. Cycles of swelling and shrinkage drive solvent convection to and from the capsule interior, allowing exchange of contents and mixing with the bulk fluid on a time scale of seconds. Because the cellulose capsules are produced via emulsion-templated fermentation, the polymer-modified biocapsule concept introduced here presents a pathway toward the sustainable and scalable manufacture of multifunctional responsive capsules.

Efficiency of electrochemical immuno- vs. apta(geno)sensors for multiple cancer biomarkers detection.

The interest in biosensors technology has been constantly growing over the last few years. It is still the biggest challenge to design biosensors able to detect two or more analytes in a single measurement. Electrochemical methods are frequently used for this purpose, mainly due to the possibility of applying two or more different redox labels characterized by independent and distinguished electrochemical signals. In addition to antibodies, nucleic acids (aptamers) have been increasingly used as bioreceptors in the construction of such sensors. Within this review paper, we have collected the examples of electrochemical immuno- and geno(apta)sensors for simultaneous detection of multiple analytes. Based on many published literature examples, we have emphasized the recent application of multiplexed platforms for detection of cancer biomarkers. It has allowed us to compare the progress in design strategies, including novel nanomaterials and amplification of signals, to get as low as possible limits of detection. We have focused on multi-electrode and multi-label strategies based on redox-active labels, such as ferrocene, anthraquinone, methylene blue, thionine, hemin and quantum dots, or metal ions such as Ag+, Pb2+, Cd2+, Zn2+, Cu2+ and others. We have finally discussed the possible way of development, challenges and prospects in the area of multianalyte electrochemical immuno- and geno(apta)sensors.

Tumor-targeted delivery of hyaluronic acid/polydopamine-coated Fe2+-doped nano-scaled metal-organic frameworks with doxorubicin payload for glutathione depletion-amplified chemodynamic-chemo cancer therapy.

Chemodynamic therapy (CDT), an emerging cancer treatment modality, uses multivalent metal elements to convert endogenous hydrogen peroxide (H2O2) to toxic hydroxyl radicals (•OH) via a Fenton or Fenton-like reaction, thus eliciting oxidative damage of cancer cells. However, the antitumor potency of CDT is largely limited by the high glutathione (GSH) concentration and low catalytic efficiency in the tumor sites. The combination of CDT with chemotherapy provides a promising strategy to overcome these limitations. In this work, to enhance antitumor potency by tumor-targeted and GSH depletion-amplified chemodynamic-chemo therapy, the hyaluronic acid (HA)/polydopamine (PDA)-decorated Fe2+-doped ZIF-8 nano-scaled metal-organic frameworks (FZ NMs) were fabricated and utilized to load doxorubicin (DOX), a chemotherapy drug, via hydrophobic, π-π stacking and charge interactions. The attained HA/PDA-covered DOX-carrying FZ NMs (HPDFZ NMs) promoted DOX and Fe2+ release in weakly acidic and GSH-rich milieu and exhibited acidity-activated •OH generation. Through efficient CD44-mediated endocytosis, the HPDFZ NMs internalized by CT26 cells not only prominently enhanced •OH accumulation by consuming GSH via PDA-mediated Michael addition combined with Fe2+/Fe3+ redox couple to cause mitochondria damage and lipid peroxidation, but also achieved intracellular DOX release, thus eliciting apoptosis and ferroptosis. Importantly, the HPDFZ NMs potently inhibited CT26 tumor growth in vivo at a low DOX dose and had good biosafety, thereby showing promising potential in tumor-specific treatment.

Boosted electrocatalytic activity and durability of CuFe/NC by modulating the interfacial composition and electronic structure for efficient oxygen reduction reaction.

Oxygen reduction reaction (ORR) serves as the foundation for various electrochemical energy storage devices. Fe/NC catalysts are expected to replace commercial Pt/C as oxygen electrode catalysts based on the structural tunability at the atomic level, abundant iron ore reserves and excellent activity. Nevertheless, the lack of durability and low active site density impede its advancement. In this work, a durable catalyst, CuFe/NC, for ORR was prepared by modulating the interfacial composition and electronic structure. The introduction of Cu nanoclusters partially eliminates the Fenton effect from Fe and optimizes the electron structure of FeNx, thereby effectively enhancing the long-term durability and activity. The prepared CuFe/NC exhibits a half-wave potential (E1/2) of 0.90 V and superior stability with a decrease in E1/2 of only 20 mV after 10,000 cycles. The assembled alkaline Zinc-Air batteries (ZABs) with CuFe/NC exhibit an open-circuit potential of 1.458 V. At a current density of 5 mA cm-2, the batteries are capable of operation for 600 h with a stable polarization. This CuFe/NC may promote the practical application of novel and renewable electrochemical energy storage devices.

Boosting supercapacitive performance of pristine covalent organic frameworks via phenolic hydroxyl groups: A two-in-one strategy.

Two-dimensional covalent organic frameworks (COFs) are ideal electrode materials for electrochemical energy storage devices due to their unique structures and properties, and the accessibility and utilization efficiency of the redox-active sites within COFs are critical determinants of their pseudocapacitive performance. Via introducing meticulously designed phenolic hydroxyl (Ar-OH) groups with hydrogen-bond forming ability onto the imine COF skeletons, DHBD-Sb-COF exhibited improved hydrophilicity and crystallinity than the parent BD-Sb-COF, the redox-active sites (SbPh3 moieties) in COF electrodes could thus be highly accessed by aqueous electrolyte with a high active-site utilization of 93%. DHBD-Sb-COF//AC provided an excellent supercapacitive performance with an energy density of 78 Wh Kg-1 at the power density of 2553 W Kg-1 and super cycling stability, exceeding most of the previously reported pristine COF electrode-based supercapacitors. The "two-in-one" strategy of introducing hydroxyl groups onto imine COF skeletons to enhance both hydrophilicity and crystallinity provides a new avenue to improve the electrochemical performance of COF-based electrodes for high-performance supercapacitors.

Incorporation of Polygonatum cyrtonema extracts of NADES into chitosan/soybean isolate protein films: Impact on sweet cherry storage quality.

This study developed a biodegradable food film, incorporating bioactive components of Polygonatum cyrtonema extracted using natural deep eutectic solvents (NADES) into a matrix of chitosan and soy protein isolate. The films containing varying concentrations (0 %-5 %) of P. cyrtonema extract (PCE) were characterized. The addition of PCE improved the mechanical (+25.9 MPa for tensile strength), optical (+11.29 mm-1 for opacity), and thermal stability (-14.39 % for weight loss) of the films. The DPPH and ABTS radical scavenging rates increased by approximately 1.1 times and 0.5 times, respectively, and malondialdehyde formation reduced by 8 %. The films also effectively inhibited the growth of Staphylococcus aureus or Escherichia coli. The films showed complete biodegradability after 7 days. Using the NADES-PCE coated film reduced the weight loss of sweet cherries by 41.04 % while significantly decreasing the loss of hardness, total phenols, vitamin C, total soluble solids, and titratable acidity, thereby considerably extending the storage life of the sweet cherries. Overall, this study developed a new environmentally friendly packaging material and improved the functionality of the packaging film by leveraging natural plant extracts, demonstrating tremendous potential in the field of food preservation and packaging.

Decoding of the enhancement of saltiness perception by aroma-active compounds during Hunan Larou (smoke-cured bacon) oral processing.

The enhancement of saltiness induced by odrants perceived from the retronasal cavity during Larou oral processing was analyzed. During the oral processing of Xiangtan Larou, the smoky attribute was the dominant when chewing 0-15 times, followed by the savory (15-24 times) and meaty (24-42 times). Partial least squares analysis predicted 33 aroma compounds from the retronasal cavity significantly (p < 0.05) contributing to the aroma perception. A total of 12 aroma compounds with saltiness-enhancement ability were confirmed by odorant-NaCl mixture model experiments. Results revealed that 2-methoxy-4-vinylphenol (1.00-1000.00 µg/L) had the strongest enhancing effect on saltiness at NaCl (2969.85 mg/L), followed by diallyl sulfide (0.156-2.50 µg/L), 2,5-dimethylthiophene (0.156-50.00 µg/L), 2,6-dimethylphenol (1.00-100.00 µg/L), 2,5-dimethylpyrazine (0.391-50.00 µg/L), and 2,3-butanedione (0.50-100.0 µg/L). The sulfur-containing, nitrogen-containing, and phenolic odorants with savory, roasty, sulfide, meaty or smoky, attributes showed the better ability in saltiness enhancement.

Development of multifunctional chitosan packaging film by plasticizing novel essential oil-based hydrophobic deep eutectic solvent: Structure, properties, and application.

To improve the limited mechanical and water barrier properties of chitosan film while granting extra functionalities simultaneously, present study pioneered the incorporation of chitosan film with newly developed essential oil (EO)-based hydrophobic deep eutectic solvents (HDES, EO:octanoic acid (OA), EO:menthol (ME) and OA:ME:EO). The highest tensile strength (66.22 MPa) and elongation at break (45.99 %) were obtained in OA:ME:EO-40 and OA:ME:EO-80 films, respectively. The OA:EO-based films showed excellent and stable hydrophobicity. HDESs also endowed film with additional functionalities including thermal stability, bio-compatibility, controlled release, antioxidant, and antibacterial capacity. The extension of the storage period of strawberry treated with OA:EO-containing films confirmed their preservation ability. Compared with ME:EO and OA:ME:EO, OA:EO had better compatibility with chitosan matrix and could serve as a promising plasticizer for strengthening functionalities of chitosan film. These results also promote application of HDESs as emerging plasticizers in manufacture of other polymer-based packaging film.

Mechanism of extracellular electron transport and reactive oxygen mediated Sb(III) oxidation by Klebsiella aerogenes HC10.

Microbial oxidation and the mechanism of Sb(III) are key governing elements in biogeochemical cycling. A novel Sb oxidizing bacterium, Klebsiella aerogenes HC10, was attracted early and revealed that extracellular metabolites were the main fractions driving Sb oxidation. However, linkages between the extracellular metabolite driven Sb oxidation process and mechanism remain elusive. Here, model phenolic and quinone compounds, i.e., anthraquinone-2,6-disulfonate (AQDS) and hydroquinone (HYD), representing extracellular oxidants secreted by K. aerogenes HC10, were chosen to further study the Sb(III) oxidation mechanism. N2 purging and free radical quenching showed that oxygen-induced oxidation accounted for 36.78% of Sb(III) in the metabolite reaction system, while hydroxyl free radicals (·OH) accounted for 15.52%. ·OH and H2O2 are the main driving factors for Sb oxidation. Radical quenching, methanol purification and electron paramagnetic resonance (EPR) analysis revealed that ·OH, superoxide radical (O2•-) and semiquinone (SQ-•) were reactive intermediates of the phenolic induced oxidation process. Phenolic-induced ROS are one of the main oxidants in metabolites. Cyclic voltammetry (CV) showed that electron transfer of quinone also mediated Sb(III) oxidation. Part of Sb(V) was scavenged by the formation of the secondary Sb(V)-bearing mineral mopungite [NaSb(OH)6] in the incubation system. Our study demonstrates the microbial role of oxidation detoxification and mineralization of Sb and provides scientific references for the biochemical remediation of Sb-contaminated soil.