Latest ArticlesFlow-electrode capacitive deionization (FCDI) represents a promising approach for ion separation from aqueous solutions. However, the optimization of spacer, particularly for nitrate-contaminated groundwater systems, has often been overlooked. This research comprehensively investigates the influence of using a conductive (carbon cloth, CC) spacer on nitrate removal performance within FCDI system, comparing it to a non-conductive (nylon net, NN) spacer. In both CC and NN FCDI systems, it is unsurprisingly that nitrate removal efficiency improved notably with the increasing current density and hydraulic retention time (HRT). Interestingly, the specific energy consumption (SEC) for nitrate removal did not show obvious fluctuations when the current density and HRT varied in both systems. Under the auspiciously optimized process parameters, CC-FCDI attained a 20% superior nitrate removal efficiency relative to NN-FCDI, accompanied by a notably diminished SEC for CC-FCDI, registering at a mere 28% of NN-FCDI. This great improvement can be primarily attributed to the decrement in FCDI internal resistance after using conductive spacer, which further confirmed by electrochemical tests such as linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Upon prolonged continuous nitrate removal at the optimized conditions, the CC-FCDI system achieved a consistent 90% nitrate removal efficiency with a low SEC of 2.7–7.8 kWh/kg NO3-N, underscoring its steady performance. Overall, this study highlights the pivotal importance of careful spacer design and optimization in realizing energy-efficient groundwater treatment via FCDI.
A photochromic molecular rotor based on stiff-stilbene (SSB-FMR) was handily prepared through coupled reaction, and further self-assembled with cucurbit[8]uril (CB[8]) to form a 2:2 quaternary supramolecular complex (SSB-FMR/CB[8]). Significantly, the intervention of CB[8] on SSB-FMR achieved dual functions that assembly-induced emission enhancement and assembly-induced improvement of photoisomerized performance (especially reversibility) of stiff-stilbene molecular photoswitch. The supramolecular strategy further facilitated the assembly as a photoresponsive fluorescence switch with outstanding fatigue resistance, which was expediently applied in high-security-level QR code anti-counterfeiting and controllable lysosome targeted imaging. The study unprecedentedly provides a supramolecular method for highly efficiently improving photoisomerized performance especially reversibility of molecular photoswitches based on stiff-stilbene, and is of vital significance for the construction of intelligent materials with excellent capability.
Owing to the serious potential side-effects on the environment and human health, the rapid detection and removal of antibiotics have become an important research focus. In this work, four zinc-based metal-organic frameworks (MOFs) with different functional groups, i.e., Zn-MOF, Zn-MOF-CH3, Zn-MOF-NO2, Zn-MOF-COOH, were utilized for the construction of LDO/MOF composite materials with a nickel-iron-cobalt-based layered double oxide, NiFeCo-LDO. The results showed that the LDO/MOF composites not only had high sensitivity in detecting sulfonamide and quinolone antibiotics, but also had an appreciable ability to adsorb them from wastewater. The maximum adsorption capacities of all the four types of LDO@Zn-MOFs to all antibiotics can at least reach 150 mg/g, and the limits of detection in relation to all four antibiotics were at least as low as 100 µg/L. Our work suggested the dual-function extraction performance can be attributed to the synergistic effects between the LDO and the MOFs. Moreover, the strong ferromagnetism derived from the LDO provided great convenience for the separation and regeneration of the LDO/MOF composites.
Highly branched poly(β-amino ester)s (HPAEs) have emerged as a safe and efficient type of non-viral gene delivery vectors. However, the presence of inactive terminal secondary amine groups compromises their gene transfection capability. In this study, HPAEs with similar topological structures and chemical compositions but varying numbers of terminal secondary 4-amino-1-butanol (S4) and secondary/tertiary 3-morpholinopropylamine (MPA) groups were synthesized. The results demonstrate that an increased number of secondary/tertiary MPA groups in-situ significantly enhances the DNA binding capability of HPAEs, leading to the formation of smaller HPAE/DNA polyplexes with higher zeta potential, ultimately resulting in superior gene transfection efficiency in bladder epithelial cells. This study establishes a simple yet effective strategy to maximize the gene transfection potency of HPAEs by converting the inactive terminal groups in-situ without the need for complex modifications to their topological structure and chemical composition.
The extraction of radioactive minor actinides (An(Ⅲ)) from lanthanides (Ln(Ⅲ)) is an extremely important step in nuclear waste reprocessing. Designing ligands with high-performance actinide-selectivity remains an essential task. Recent works have reported that some polyazole based ligands exhibit good An(Ⅲ)/Ln(Ⅲ) separation performance. Herein, we first evaluated the effects of different polyazole side chains on the Am(Ⅲ)/Eu(Ⅲ) selectivity by exploring three pyridine-derived polyazole ligands L1, L2 and L3 with 1,2,4-triazole, 1,2,3-triazole, and pyrazole side chains, respectively, using scalar relativistic theoretical methods. The coordination structures, bonding properties and thermodynamic behaviors of AmL(NO3)3 and EuL(NO3)3 complexes were investigated, which clarifies that the side chains do affect the electronic structure of ligand and its selectivity for Am(Ⅲ)/Eu(Ⅲ) ions. Moreover, L1 with 1,2,4-triazole side chains exhibited the highest selectivity for Am(Ⅲ) over Eu(Ⅲ) while the lowest complexation ability for metal ions among the three pyridine-derived polyazole ligands. Subsequently, we designed a new ligand L4 containing 1,2,4-triazole side chains and a preorganized phenanthroline backbone. Theoretically, such a new ligand was verified to show stronger complexation ability and higher selectivity for Am(Ⅲ)/Eu(Ⅲ) ions than L1. This work clarifies the complexation nature of polyazole based ligands with Am(Ⅲ)/Eu(Ⅲ) ions and provides design strategies for highly efficient polyazole based ligands for An(Ⅲ)/Ln(Ⅲ) separation.
Electrochemical-nitrate-reduction-reaction (eNitRR) synthesis of ammonia is an effective way to treat nitrate wastewater and alleviate the pressure of the Haber-Bosch ammonia production industry. How to develop effective catalysts to electrochemically reduce nitrate to ammonia and purify sewage under complex environmental conditions is the focus of current research. Herein, the dopamine polymerization process and the [(C12H8N2)2Cu]2+ complex embedding process were run simultaneously in time and space, and ultrafine Cu nanoparticles (Cu/CN) were effectively loaded on nitrogen-doped carbon after heat treatment. Using Cu/CN as the catalyst, the ammonia yield rate and Faradaic efficiency of the electrochemical conversion of to NH3 are highly 8984.0 µg h−1 mgcat.−1 and 95.6%, respectively. Even in the face of complex water environments, such as neutral media, acidic media, coexisting ions, and actual nitrate wastewater, nitrate wastewater can be effectively purified to form high value-added ammonia. The strategy of simultaneous embedding increases the exposure rate of Cu sites, and the support of CN is also beneficial to reduce the energy barrier of *NO3 activation. This study rationally designed catalysts that are beneficial to eNitRR, and considered the situation faced by practical applications during the research stage, reducing the performance gap between laboratory exploration and industrial applications.
Organic lasers with broad emission bands in near-infrared (NIR) region are crucial for their applications in laser communication, night-vision as well as bioimaging owing to the abundance of selectable lasing wavelengths. However, for most organic gain materials, gain regions are limited in a small wavelength range because of the fixed energy level systems. Herein, we design a strategy to realize NIR organic lasers with broad emission bands based on tunable energy level systems induced by cascaded excited-state intramolecular proton transfer (ESIPT). A novel gain material named DHNN was developed, which can undergo a cascaded double-ESIPT process supporting four-level and six-level systems simultaneously. By doping DHNN into polystyrene microspheres, NIR lasers with tunable emission bands can be achieved based on the careful modulation of microcavities. Finally, organic lasers with an ultra-broad emission band ranging from 700 nm to 900 nm was successfully achieved by harnessing four-level and six-level systems simultaneously.
An eco-friendly and practical method for the clean preparation of 5-amino-1,2,4-thiadiazoles was developed. With WS2 as the semiconductor photocatalyst, both TEMPO and O2 (in air) as the redox catalysts, a variety of thiadiazoles were semi-heterogeneously formed in high to quantitative yields and could be easily collected by CPME extraction and rinsing. Furthermore, the catalytic system can be reusable for at least 5 reaction runs.
Heterocycle-braced cyclic peptides have demonstrated enhanced metabolic stability, increased potency and selectivity. Here, we present a rapid synthesis method for constructing Trp(C7)-alkene(E)-crosslinked cyclic peptides with potent anti-proliferative activities against cancer cells, through C-H alkenylation and macrolactamization. This report addresses critical challenges associated with the installation and removal of the directing group N-Piv, configuration selectivity of the olefin, and intramolecular cyclization. Notably, this method exhibits mild reaction conditions, traceless removal of the directing group, and high configuration selectivity.
This study presents an unexpected finding that the cis isomer of β-thio-Asp exhibits higher ligation activity than the trans isomer. This discovery sheds light on the intricate nature of native chemical ligation and highlights the importance of factors beyond the steric effects of the side chain in modulating ligation activity.
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