Synthesis of shape-controlled covalent organic frameworks for light scattering detection of iron and chromium ions.

Fabricating covalent organic frameworks with different morphologies based on the same structural motifs is both interesting and challenging. Here, a TTA-TFP-COF was synthesized by both solvothermal and room temperature methods, with 2,4,6-Tris(4-aminophenyl)-1,3,5-triazine (TTA) and 1,3,5-tris(4-formylphenyl)-benzene (TFP) as raw material. Using different synthesis conditions and adding aniline and benzaldehyde as regulators in the synthesis process, we found that these processes could slow down the reaction speed, increase the exchange and metathesis reactions of dynamic reversible reactions, and improve the reversibility of the reaction system. Thus, controllable synthesis of TTA-TFP-COF with different morphologies, including micro-particles, hollow tubes with controllable diameters, and micro-flowers was achieved. Our further study found that metal ions, Fe3+ and Cr3+ ions, could coordinate with N and O in TTA-TFP-COF and partially destroy the structure of TTA-TFP-COF. The particle size of the TTA-TFP-COF became smaller, thus resulting in the decrease of the light scattering intensity of the COF. An excellent linear relationship exists between the light scattering changes (ΔI) and metal ions concentration (c) from 2.0 to 350.0 µM for Fe3+ and 40.0-800.0 µM for Cr3+, respectively. Thus, rapid and selective analytical methods for detecting metal ions were developed by TTA-TFP-COF here.

Coordination Confined Silver-Organic Framework for High Performance Electrochemical Deionization.

Silver (Ag) is deemed a promising anode material for capacitive deionization (CDI) due to its high theoretical capacity and efficient selectivity to Cl-. However, the strong volume change during the conversion reaction significantly undermines the cycling performance of the Ag electrode. Additionally, achieving well-dispersed Ag in the active matrix is challenging, as Ag electrodes prepared by conventional thermal reduction tend to agglomerate. Herein, the organic linker confinement strategy is proposed, applying metal-organic framework (MOF) chemistry between Ag nodes and organic ligands to construct Ag-based MOF. The uniform dispersion of Ag at the molecular level, confined in the organic matrix, efficiently enhances the utilization of active sites, and strengthens the interfacial stability of Ag. Consequently, the Ag-MOF for the CDI anode exhibits an excellent Cl- removal capacity of 121.52 mg g-1 at 20 mA g-1 in 500 mg L-1 NaCl solution, and a high Ag utilization rate of 60.54%. After 100 cycles, a capacity retention of 96.93% is achieved. Furthermore, the Cl- capture mechanism of Ag-MOF is elucidated through density functional theory (DFT) calculations, ex situ XRD, ex situ Raman and XPS. This ingenious electrode design can offer valuable insights for the development of high-performance conversion electrodes for CDI applications.

In the View of Electrons Transfer and Energy Conversion: The Antimicrobial Activity and Cytotoxicity of Metal-Based Nanomaterials and Their Applications.

The global pandemic and excessive use of antibiotics have raised concerns about environmental health, and efforts are being made to develop alternative bactericidal agents for disinfection. Metal-based nanomaterials and their derivatives have emerged as promising candidates for antibacterial agents due to their broad-spectrum antibacterial activity, environmental friendliness, and excellent biocompatibility. However, the reported antibacterial mechanisms of these materials are complex and lack a comprehensive understanding from a coherent perspective. To address this issue, a new perspective is proposed in this review to demonstrate the toxic mechanisms and antibacterial activities of metal-based nanomaterials in terms of energy conversion and electron transfer. First, the antimicrobial mechanisms of different metal-based nanomaterials are discussed, and advanced research progresses are summarized. Then, the biological intelligence applications of these materials, such as biomedical implants, stimuli-responsive electronic devices, and biological monitoring, are concluded based on trappable electrical signals from electron transfer. Finally, current improvement strategies, future challenges, and possible resolutions are outlined to provide new insights into understanding the antimicrobial behaviors of metal-based materials and offer valuable inspiration and instructional suggestions for building future intelligent environmental health.

Boron-Modulated Electronic-Configuration Tuning of Cobalt for Enhanced Nitric Oxide Fixation to Ammonia.

Electrocatalytic nitric oxide reduction (eNORR) to ammonia (NH3) provides an environmental route to alleviate NO pollution and yield great-value chemicals. The evolution of eNORR has been primarily hindered, however, by the poor reaction kinetics and low solubility of the NO in aqueous electrolytes. Herein, we have rationally designed a cobalt-based composite with a heterostructure as a highly efficient eNORR catalyst. In addition, by integrating boron to modulate the electronic structure, the catalyst CoB/Co@C delivered a significant NH3 yield of 315.4 µmol h-1 cm-2 for eNORR and an outstanding power density of 3.68 mW cm-2 in a Zn-NO battery. The excellent electrochemical performance of CoB/Co@C is attributed to the enrichment of NO by cobalt and boron dual-site adsorption and fast charge-transfer kinetics. It is demonstrated that the boron is pivotal in the enhancement of NO, the suppression of hydrogen evolution, and Co oxidation to boost eNORR performance.

Enhanced Pseudo-Capacitance Process in Nanoarchitectural Layered Double Hydroxide Nanoarrays Hollow Nanocages for Improved Capacitive Deionization Performance.

Layered double hydroxides (LDHs) are perceived as a hopeful capacitive deionization (CDI) faradic electrode for Cl- insertion due to its tunable composition, excellent anion exchange capacity, and fast redox activity. Nevertheless, the self-stacking and inferior electrical conductivity of the two-dimensional structure of LDH lead to unsatisfactory CDI performance. Herein, the three-dimensional (3D) hollow nanocage structure of CoNi-layered double hydroxide/carbon composites is well designed as a CDI anode by cation etching of the pre-carbonized ZIF-67 template. C/CoNi-LDH has a unique 3D hollow nanocage structure and abundant pore features, which can effectively suppress the self-stacking of LDH sheets and facilitate the transport of ions. Moreover, the introduced amorphous carbon layer can act as a conductive network. When employed as the CDI anode, C/CoNi-LDH exhibited a high Cl- removal capacity of 60.88 mg g-1 and a fast Cl- removal rate of 18.09 mg g-1 min-1 at 1.4 V in 1000 mg L-1 NaCl solution. The mechanism of the Cl- intercalation pseudo-capacitance reaction of C/CoNi-LDH is revealed by electrochemical kinetic analysis and ex situ characterization. This study provides vital guidance for the design of high-performance electrodes for CDI.

Surface redox pseudocapacitance boosting Fe/Fe3C nanoparticles-encapsulated N-doped graphene-like carbon for high-performance capacitive deionization.

The practical application of carbon anode in capacitive deionization (CDI) is greatly hindered by their poor adsorption capacity and co-ion effect. Herein, an N-doped graphene-like carbon (NC) decorated with Fe/Fe3C nanoparticles composite (Fe/Fe3C@NC) with large specific surface area and plentiful porosity is fabricated via a facile and scalable method, namely sol-gel method combined with Fe-catalyzed carbonization. As expected, it exhibits superior CDI performance as a Cl-storage electrode, with Cl- adsorption capacity as high as 102.3 mg g-1 at 1000 mg L-1 Cl- concentration and 1.4 V voltage, and a stable capacity of 68.5 mg g-1 for 60 cycles in 500 mg L-1 Cl- concentration and 100 mA g-1 current density. More importantly, on the basis of electrochemical tests, ex-situ X-ray diffraction, ex-situ X-ray photoelectron spectroscopy (XPS), and XPS analysis with argon ion depth etching, it is revealed that the chlorine storage mechanism of the Fe/Fe3C@NC electrode is dominated by the surface-related redox pseudocapacitance behavior of Fe2+/Fe3+ couple occurring on or near the surface, enabling fast and reversible ion storage. This work proposes an economical and environmentally friendly general method for the design and development of high-performance Cl-storage electrodes for CDI, and offers an in-depth insight into the Cl- storage mechanism of Fe decorated carbon electrodes, further promoting the development of CDI technology.

Carbon Nanoarchitectonics with Bi Nanoparticle Encapsulation for Improved Electrochemical Deionization Performance.

Electrochemical deionization (EDI) is hopefully the next generation of water treatment technology. Bismuth (Bi) is a promising anode material for EDI, due to its high capacity and selectivity toward Cl-, but the large volume expansion and severe pulverization aggressively attenuated the EDI cycling performance of Bi electrodes. Herein, carbon-layer-encapsulated nano-Bi composites (Bi@C) were prepared by a simple pyrolysis method using a Bi-based metal-organic framework as a precursor. Bi nanoparticles are uniformly coated within the carbon layer, in which the Bi-O-C bond enhances the interaction between Bi and C. Such a structure effectively relieves the stress caused by volume expansion by the encapsulation effect of the carbon layer. Moreover, the introduction of a carbon skeleton provides a conductive network. As a consequence, the Bi@C composite delivered excellent electrochemical performance with a capacity of 537.6 F g-1 at 1 mV s-1. The Cl- removal capacity was up to 133.5 mg g-1 at 20 mA g-1 in 500 mg L-1 NaCl solution. After 100 cycles, the Bi@C electrode still maintains 71.8% of its initial capacity, which is much higher than the 26.3% of the pure Bi electrode. This study provides a promising strategy for improving EDI electrode materials.

Fluoride remediation from on-site wastewater using optimized bauxite nanocomposite (Bx-Ce-La@500): Synthesis maximization, and mechanism of F─ removal.

Bauxite is a widely available Al-O-rich mineral with great potential for abating fluoride. However, low adsorption capacity, a narrow workable pH range, and a lack of clarity on the best removal mechanism hinder its application. In this work, a highly efficient bauxite nanocomposite (Bx-Ce-La@500) was synthesized via doping and pyrolysis, and its fluoride adsorption in industrial wastewater was examined. Doping Ce/La synergistically improved the fluoride adsorption affinity of the composite (from pHPZC 8.0 ~ 10.0) and enhanced the •OH. The materials were characterized by SEM-EDS, BET, XRD, and TGA while XPS, FTIR, and DFT were used to investigate the mechanism of fluoride sorption. Results show that Bx-Ce-La@ 500 has a positive zeta potential of 26.3-23.1 mV from pH 1~ 10. The Langmuir model was the best fit with a maximum adsorption capacity of 88.13 mg/g and removal efficiency up to 100% in 50 ppm F- solution. The high F- removal was attributed to the enhanced surface affinity and the formation of adequate •OH on the material. Except for carbonate and phosphate ions, other ions exhibited negligible effects and the selective removal of F- in real wastewater was high. The main mechanism of adsorption was the ligand/ion exchange and electrostatic attraction.

Highly selective and rapid detection of silver ions by using a "turn on" non-fluorescent cysteine stabilized gold nanocluster probe.

Cysteine is widely used as a stabilizer for the preparation of fluorescent gold nanoclusters (Au NCs) with different fluorescence properties. Herein, by using cysteine as a stabilizer and controlling the synthesis conditions, a new non-fluorescent cysteine stabilized gold nanocluster (Cys-Au NCs) probe was prepared and a new strategy for "turning on" the fluorescence of the Cys-Au NCs was studied for rapid and selective detection of silver ions. In this strategy, the addition of silver ions to non-fluorescent Cys-Au NCs solution could quickly induce a visible fluorescence "turn on" phenomenon in 30 s. Further studies indicated that this fluorescence "turn on" phenomenon is specific for silver ions and the "turn on" fluorescence intensity has a linear relationship with the amount of silver ions in the range from 3.0 to 30.0 µM. Therefore, the non-fluorescent Cys-Au NCs were applied to the detection of silver ions in environmental water samples and a limit of detection (LOD) of 0.26 µM was obtained. This research sheds light on new applications of Au NCs and proposes a simple, rapid, sensitive, and visual method for the detection of metal ions.

Glutathione stabilized green-emission gold nanoclusters for selective detection of cobalt ion.

A glutathione stabilized Au nanoclusters (GSH-Au NCs) was synthesized here and used to selective detection of cobalt ion. The as-prepared GSH-Au NCs had strong green light emission around 500 nm, and the features of the NCs have been systematically characterized by UV-vis absorption, X-ray photoelectronic spectroscopic, Fourier transform infrared spectroscopy and transmission electron microscope characterization. The interactions between the GSH-Au NCs and metal ions was studied, and the results indicated that the fluorescence of the GSH-Au NCs could be quenched in the presence of Co2+ ion at pH of 6.0. The quenching ratio was linear with the concentration of Co2+ ions, and the calibration curve was I0/I = 0.1187cco + 0.6085 in the Co2+ concentration ranges from 2.0 to 50.0 µM with correlation coefficient (R2) of 0.9950 and the limit of detection (LOD, 3σ) of 0.124 µM. In addition, we collected environmental water samples to test the reliability of the method and demonstrated this method is simple, rapid, and selective.

Defluorination by ion exchange of SO42- on alumina surface: Adsorption mechanism and kinetics.

Electrostatic and complexation effects have been considered as the primary adsorption mechanisms for defluorination using aluminum based materials, while the effect of ion exchange between anions and fluorine ion has been mostly ignored, although synthesized alumina materials usually contain a large amount of anions, such as SO42-, NO3-, and Cl-. In this study, the effect of anions exchanges and its key role on defluorination were systematically investigated for adsorption by aluminas loaded with various typical anions (SO42-, NO3- and Cl-). Experimental results showed that SO42-- loading alumina had the best defluorination performance (94.5 mg/g), much higher than NO3- (45.0 mg/g) and Cl- (19.1 mg/g). The contribution ratio of ion exchange between SO42- and F- was as high as 20-60% in all potential defluorination mechanisms. By using Density Functional Theory calculation, the detailed mechanism revealed that the ion exchange process was mainly driven by the tridentate chelation of SO42- which reduced the exchange energy ( [Formula: see text] 4.8 eV). Our study clearly demonstrated that ion exchange between SO42- and F- is a critical mechanism in defluorination using aluminum-based materials and provides a potential alternative method to enhance the adsorption performance of modified alumina.

Enhanced chloride removal of phosphorus doping in carbon material for capacitive deionization: Experimental measurement and theoretical calculation.

Heteroatoms doping is an important modification method in carbon electrode for CDI technology. In this study, a new facile approach of homogeneous phosphorus doping in carbon matrix was proposed via crosslinking polymerization of m-phenylenediamine and phytic acid. The carbonized composites (NPC) showed the characteristics of phosphorus/nitrogen co-doping with excellent hydrophilicity, high electrochemical performance, lower inner resistance and good cycling stability, far beyond that of carbon without phosphorus doping. Compared with reported similar materials and commercial carbon, the chloride adsorption capacity of NPC used as electrode for deionization capacitors was significantly improved (21.4 mg g-1 in a 500 mg L-1 Cl- solution at 1.2 V). Particularly, based on the charge distribution analysis of phosphorus doping in carbon matrix by using Material Studio calculation, the possible enhanced dichlorination mechanism of the carbon composites as electrode for deionization capacitors was carefully explored. The phosphorus/nitrogen co-doped carbon displayed a promising prospect for chloride removal in the application of CDI technology.

Porous and flexible membrane derived from ZIF-8-decorated hyphae for outstanding adsorption of Pb2+ ion.

Metal-organic frameworks (MOFs) based membranes with superior mechanical properties are of particular interest in purification, separation, and catalysis. Nevertheless, their fabrication still remains a grand challenge. Here, fungus hyphae (Mucor) were used as a robust scaffold to load the MOFs and induced the formation of porous and flexible membranes. ZIF-8 was used as a representative of MOFs. The ZIF-8@Mucor membrane was formed by the in-situ growth of ZIF-8 on hyphae and then a vacuum filtration of the ZIF-8/hyphae composite. ZIF-8 was effectively dispersed on the ZIF-8@Mucor membrane, and the shear modulus of ZIF-8@Mucor-3 was 864 MPa by calculation. The ZIF-8@Mucor membrane exhibited promising properties for adsorption application to remove the highly toxic Pb2+. The adsorption capacity of this membrane was as high as 1443.29 mg/g. Results from dynamic adsorption indicated that the penetration concentration of Pb2+ ions was less than 5% of the original level before 80 min whereas after 160 min, penetration concentration of Pb2+ ions was more than 90%. This study would open a new way of how to synthesize composite MOFs/bacterial membranes for energy and environment purposes.

Efficient natural pyrrhotite activating persulfate for the degradation of O-isopropyl-N-ethyl thionocarbamate: Iron recycle mechanism and degradation pathway.

Natural pyrrhotite (NP) shows promising future in activating persulfate (PS) due to its easy availability at a low cost and easy separation. This study discussed the degradation of O-isopropyl-N-ethyl thionocarbamate (IPETC) in NP/PS system. NP-PS system showed the best IPETC mineralization at the initial pH of 6.0 (62.84%). The kinetics study suggested that the IPETC degradation followed the pseudo-first-order equation in the NP-PS system. NP-PS system worked better in bottled water (96.46%) and tap water (85.14%) than river water (31.28%). Combined with Fourier transform-infrared spectroscopy, gas chromatography-mass spectrometry and computational calculation, the degradation products, including acetone, formic acid isopropyl ester and ethylamine, were identified and the degradation pathway of IPETC in NP-PS system was proposed. The S, O and N atoms in IPETC are easier to be attacked by. SO4-Ethylamine and reduced S ions coordinately worked to recycle Fe2+ in NP/PS/IPETC system.

Surface characterization of arsenopyrite during chemical and biological oxidation.

The surface properties of arsenopyrite during chemical and biological oxidation were investigated by synchrotron X-ray diffraction (S-XRD), X-ray absorption near-edge structure (XANES) and scanning electron microscope (SEM), accompanying with leaching behaviors elucidation. The moderate thermophile S. thermosulfidooxdians was used as the bioleaching microorganism. Leaching experiments showed that only 16.26% and 44.37% of total arsenic extractions were obtained for sterile acid and culture medium controls, whereas 79.20% of total arsenic was recovered at the end of bioleaching. SEM indicated that new products were layered on the surface of arsenopyrite after chemical and biological oxidation. As displayed in S-XRD patterns, scorodite and elemental sulfur were formed after acid leaching, while only elemental sulfur was detected in the residue leached by acid culture medium. During bioleaching, elemental sulfur was produced from day 4 and jarosite was produced from day 9. The results of iron and arsenic L-edge XANES were in good consistence with S-XRD. The accumulation of scorodite and jarosite on arsenopyrite surface should be the main reason for the hindered dissolution of arsenopyrite during acid leaching and bioleaching. These studies are pretty meaningful for better understanding the oxidation mechanism of arsenopyrite and evaluating arsenic risk to the environment.

[A prospective comparison between surgery alone and postoperative chemoradiotherapy for locally advanced esophageal squamous cell carcinoma].

OBJECTIVE: To investigate the role of postoperative chemoradiotherapy (CRT) as a multimodality treatment option for locally advanced thoracic esophageal squamous cell carcinoma (ESCC) by a prospective comparison between surgery alone and postoperative CRT. METHODS: Using preoperative computed tomography (CT)-based staging criteria, 158 patients with ESCC (stage II-III) were enrolled in this prospective study. With informed consent, the patients were randomized into two groups: postoperative CRT (78 cases) and surgery alone (S, 80 cases). After a few minor adjustments to the enrolled patients, the actual patients of postoperative CRT group and S group were 74 cases and 77 cases, respectively. Comparison of the complications, local recurrence rate, distant metastasis rate, survival rate and progression-free survival in the two groups was carried out. RESULTS: With a median follow-up of 37.5 months, the 1-, 3-, 5-, 10-year overall survival (OS) rates were 91.0%, 62.8%, 42.3%, 24.4% and 87.5%, 51.3%, 33.8%, 12.5% for the postoperative CRT and S arm, respectively. A significant difference in OS was detected between the two arms (P = 0.0276). There was a significant difference of progression-free survival (PFS) between the two arms (P = 0.0136). The local recurrence rates in the postoperative CRT group and S group were 14.9% and 36.4%, respectively (P < 0.05). No significant difference was detected between the complications of the two groups (P > 0.05). Toxicities of chemoradiotherapy in the postoperative CRT arm were moderate, which can be relieved rapidly by adequate therapy. CONCLUSION: Rational application of postoperative chemoradiotherapy can provide a benefit in progression-free survival and overall survival in patients with locally advanced esophageal squamous cell carcinoma.