Aminated polyacrylonitrile nanofibers with immobilized gold-silver core-shell nanoparticles for use in a colorimetric test strip for copper(II).

The authors describe colorimetric test strips by using electrospun nanofiber membranes (NFMs) carrying gold/silver core/shell nanoparticles (Au/Ag NPs). The Au/Ag NPs were immobilized on aminated porous polyacrylonitrile NFMs to obtain test strips with a tortuous porous structure and a large surface area (38.6 m2 g-1). The color of the resultant NFMs, measured at a wavelength of 420 nm, is red-shifted when exposed to copper ions (Cu2+) with a color change from yellow to pink to colorless. The effect is due to leaching Au/Ag NPs from the NFMs in the presence of ammonium chloride, thiosulfate and Cu2+ upon which soluble thiosulfate complexes of Ag+, Au3+ and Cu2+ are formed. The effect can be readily seen with bare eyes. Under optimized conditions, this method has a low limit of detection (50 nM at S/N = 3), a fast assay time (3 min), good specificity, and excellent reversibility. The colorimetric test strip was successfully applied to the analysis of Cu2+ in drinking water sample. Graphical abstract Schematic of the preparation of test strips for Cu2+ by immobilizing Au/Ag core-shell nanoparticles on aminated polyacrylonitrile nanofibers.

Synthesis of WS2 Nanowires as Efficient 808 nm-Laser-Driven Photothermal Nanoagents.

A prerequisite for the development of photothermal ablation therapy for cancer is to obtain efficient photothermal nanoagents that can be irradiated by near-infrared (NIR) laser. Herein, we have reported the synthesis of WS2 nanowires as photothermal nanoagents by the reaction of WCl6 with CS2 in oleylamine at 280 degrees C. WS2 nanowires have the thickness of -2 nm and length of -100 nm. Importantly, the chloroform dispersion of WS2 nanowires exhibits strong photoabsorption in NIR region. The temperature of the dispersion (0.10-0.50 mg/mL) can increase by 12.8-23.9 degrees C in 5 min under the irradiation of 808 nm laser with a power density of 0.80 W/cm2. Therefore, WS2 nanowires have a great superiority as a new nanoagent for NIR-induced photothermal ablation of cancer, due to their small size and excellent photothermal performance.

Comparative efficacy of laparoscopic choledocholithotomy with T-tube insertion vs. primary suture in the management of cholecystolithiasis complicated by choledocholithiasis.

OBJECTIVE: To evaluate the efficacy of laparoscopic choledocholithotomy with either an indwelling T-tube or primary suture in treating cholecystolithiasis complicated by choledocholithiasis. METHODS: We conducted a retrospective analysis of 133 patients with cholecystolithiasis complicated by choledocholithiasis treated at Inner Mongolia Aerospace Medical Baogang Hospital from March 2020 to March 2023. Patients were divided into a control group (laparoscopic choledocholithotomy with T-tube placement) and an observation group (laparoscopic choledocholithotomy with primary suture). We compared general and surgery-related data between groups. Factors correlated with favorable postoperative outcomes were identified using univariate and multivariate logistic regression analyses. RESULTS: The observation group exhibited significantly shorter surgical times, faster intestinal function recovery, reduced postoperative hospital stays, and lower total hospitalization costs compared to the control group (all P < 0.05). No significant differences were observed in postoperative total bilirubin (TBIL), aspartate aminotransferase (AST), or alanine aminotransferase (ALT) levels between the groups (all P > 0.05). Both primary suture technique and the absence of postoperative complications were independent predictors of favorable outcomes. CONCLUSION: Laparoscopic choledocholithotomy with primary suture is associated with shorter operation times, reduced medical costs, decreased hospitalization duration, and quicker gastrointestinal recovery compared to the traditional T-tube approach. This method is safe and feasible, provided clinicians are well-versed in its indications.

Waste lignin-based cationic flocculants treating dyeing wastewater: Fabrication, performance, and mechanism.

Lignin is often considered to be a complex polymeric structural material with excellent scalability. Reduced pressure distillation, a novel effective way, was proposed to recover reusable waste lignin from textile degumming black liquor. The structure of the recovered material was determined by Fourier Transform Infrared Spectroscopy (FT-IR), Gel Permeation Chromatography (GPC) and Klason Component Analysis. Recycled lignin (RL) was used as the basis for the synthesis of a cationic recycled lignin-based polymers (CRLM) through graft polymerizing cationic monomer (DMC). The optimum synthesis conditions were obtained by conducting orthogonal experiments using the cationicity as the studied parameter, while selecting pH, DMC/RL, reaction temperature and time as independent variables. Recovery experiments showed that the maximum recovery concentration of RL in the black liquor was 5 g/L, with a purity of approximately 83 %. Orthogonal experiments showed that a low DMC/RL ratio was crucial for the synthesis of flocculants. When the molar ratio of DMC/RL was 3:1, the cationicity of the prepared CRLM was as high as 11.32 %. Zeta potential and decolorization experiments also confirmed the stable decolorization performance of CRLM in three kinds of anionic dye wastewater. The experimental results showed that charge neutralization, chemical bonding forces and auxiliary effects play great role to remove anionic dyes, resulting in 94 %, 89 % and 94.9 % removal against Reactive Red 195 (RR195), Acid Red 18 (AR18) and Direct 168 (DB168) respectively. Therefore, this study demonstrated the potential of using recycled waste lignin as synthesize lignin-based flocculants in the field of printing and dyeing wastewater by treating waste with waste.

Peroxymonosulfate activation by Fe3O4-MnO2/CNT nanohybrid electroactive filter towards ultrafast micropollutants decontamination: Performance and mechanism.

Electrocatalytic peroxymonosulfate (PMS) activation is a promising advanced oxidation process for the degradation of micropollutants. Herein, we developed an electroactive carbon nanotube (CNT) filter functionalized with Fe3O4-MnO2 hybrid (Fe3O4-MnO2/CNT) to activate PMS towards ultrafast degradation of sulfamethoxazole (SMX). SMX was completely degraded via a single-pass through the nanohybrid filter (τ < 2 s). The ultrafast degradation kinetics were maintained across a wide pH range (from 3.0 to 8.0), in complicated matrices (e.g., tap water, lake water, WWTP effluent and pharmaceutical wastewater), and for the degradation of various persistent micropollutants. Compared with a conventional batch reactor, the flow-through operation provides an 9.2-fold higher SMX degradation kinetics by virtue of the convection-enhanced mass transport (1.47 vs. 0.16 min-1). The efficient redox cycle of Fe2+/Fe3+ and Mn2+/Mn4+ facilitate the PMS activation to generate SO4•- under electric field. Meanwhile, the ketonic groups on the CNT provide active sites for the generation of 1O2. Both experimental and theoretical results revealed the superior activity of nanohybrid filter associated with the synergistic effects among Fe, Mn, CNT and electric field. Therefore, the electrocatalytic filter based PMS activation system provides a green strategy for the remediation of micropollutants in a sustainable manner.

Lithium ion sieve modified three-dimensional graphene electrode for selective extraction of lithium by capacitive deionization.

Faced with the strong demand of clean energy, development of lithium source is becoming exceedingly vital. Spinel-type manganese oxide (λ-MnO2) is a typical lithium ion sieve material. Herein, the conductive three-dimensional (3D) lithium ion sieve electrode material was fabricated by in-situ growth of λ-MnO2 on 3D reduced graphene oxide (3D-rGO) matrix for Li extraction by capacitive deionization (CDI). The λ-MnO2 modified rGO (λ-MnO2/rGO) retained the 3D network structure with uniform distribution of λ-MnO2 nanosheets on rGO. Electrochemical characterization demonstrated its high conductivity and fast lithium ion diffusion rate. By adjusting the rGO concentration, λ-MnO2 activity was improved significantly. With λ-MnO2/rGO as a positive electrode (activated carbon as negative electrode), the corresponding CDI system was successfully applied for the selective extraction of Li+. The final rGO content in the λ-MnO2/rGO was attained by thermogravity analysis. With the appropriate rGO content (15.5%), the obtained λ-MnO2/rGO electrode achieved the optimal Li+ adsorption amount. The corresponding λ-MnO2/rGO-based CDI cell showed good selectivity and high cycle stability. When applied to the extraction of lithium from synthetic salt lake brine, the electrode also obtained high Li+ adsorption amount with good selectivity.

Enhanced capacitive removal of hardness ions by hierarchical porous carbon cathode with high mesoporosity and negative surface charges.

Capacitive deionization (CDI), as a promising desalination technology, has been widely applied for water purification, heavy metal removal and water softening. In this study, the hierarchical porous carbon (HPC) with extremely large specific surface area (∼1636 m2 g-1), high mesoporosity and negative surface charges, was successfully prepared by one-step carbonization of magnesium citrate and acid etching. HPC carbonized at 800 ℃ exhibited an excellent specific capacitance (207.2 F g-1). The negative surface charge characteristic of HPC was demonstrated by potential of zero charge test. With HPC-800 as a CDI cathode, the super high adsorption capacity of hardness ions (Mg2+: 472 µmol g-1, Ca2+: 425 µmol g-1) with ultrafast adsorption rate was realized, attributed to its abundant mesoporous structure and negative surface charges. The priority order of ion adsorption on HPC in the multi-component salt solution was Mg2+ > Ca2+ > K+ ≈ Na+. The desalination and softening of the actual brackish water have been simultaneously achieved by three-cell CDI stack after four times of adsorption, with 63% decrease of total dissolved solids and 76% reduction of hardness. The current HPC material with outstanding adsorption performance for hardness ions shows great potential in brackish water purification.

CNT-Strung LiMn2 O4 for Lithium Extraction with High Selectivity and Stability.

LiMn2 O4 is of great potential for selectively extracting Li+ from brines and seawater, yet its application is hindered by its poor cycle stability and conductivity. Herein a two-step strategy to fabricate highly conductive and stable CNT-strung LiMn2 O4 (CNT-s-LMO) is reported, by first stringing Mn3 O4 particles with multiwalled carbon nanotube (CNT), then converting the hybrids into CNT-s-LMO through hydrothermal lithiation. The as-synthesized CNT-s-LMO materials have a net-like structure with CNTs threading through LMO particles. This unique structure has endowed the CNT-s-LMO electrode with excellent conductivity, high specific capacitance, and enhanced rate performance. Because of this, the CNT-s-LMO electrode in the hybrid capacitive deionization cell (HCDI) can deliver a high Li+ extraction percentage (≈84%) in brine and an outstanding lithium selectivity with a separation factor of ≈181 at the Mg2+ /Li+ molar ratio of 60. Significantly, the CNT-s-LMO-based HCDI cell has a high stability, evidenced by 90% capacity retention and negligible Mn loss in 100 cycles. This method has paved a new way to fabricate carbon-enabled LMO-based absorbents with tuned structure and superior capacity for electrochemical lithium extraction with high Li+ selectivity and exceptional cycling stability, which may help to tackle the shortage in supply of Li-ion batteries in industry in the future.

Structure-tunable Mn3O4-Fe3O4@C hybrids for high-performance supercapacitor.

Controlling the morphology and structure of nanomaterials is of great importance for enhancing the electrochemical properties. In the paper, Mn3O4-Fe3O4@C hybrids with different architectures were synthesized by incubation of electrospun FeOx-containing carbon fiber (Fe-CNF) in KMnO4 solution followed by annealing. The presence of FeOx on the CNF plays a vital role in determining the morphology and structure of the final hybrids, and the Mn3O4-Fe3O4@C hybrids with half-tube, tube and oolite-filled fibers are formed conveniently by tuning Fe content in the carbon fiber precursor. The good conductivity of fiber and various redox states of Mn and Fe afford the facile charge transfer and excellent reversible redox properties, thus enhancing the capacitor performance. The oolite-filled Mn3O4-Fe3O4@C with tubular structure exhibited a high specific capacitance of 178 F g-1 at a discharge rate of 1 A g-1. This capacitor electrode has an excellent cyclic stability with 95% capacitance retention after 1000 cycles at 3 A g-1. This work provides a very simple strategy to tune the unique nanostructures of metal oxide on Fe-CNF for high-performance supercapacitor application in the future.

Simultaneous decontamination of arsenite and antimonite using an electrochemical CNT filter functionalized with nanoscale goethite.

The co-presence of arsenic (As) and antimony (Sb) in water bodies has been commonly reported. The toxicity of As and Sb varies with different speciation. Herein, we designed a dual-functional electrochemical filter toward "one-step" detoxification and sequestration of highly toxic As(III) and Sb(III). The key to this technology is a functional anodic filter consists of nanoscale goethite and carbon nanotubes (CNT). Results showed that 97.9% As(III) and 91.9% Sb(III) transformation and 86.4% Astotal and 70.1% Sbtotal removal efficiency can be obtained over 2 h continuous filtration under optimized conditions. The Astotal removal kinetics and efficiency enhanced with flow rate and applied voltage (e.g., the Astotal removal efficiency increased from 62.9% at 0 V to 86.4% at 2.5 V). This enhancement in kinetics and efficiency can be explained by the synergistic effects of the flow-through design, plentiful exposed sorption sites, electrochemical reactivity, and nanoscale goethite. Moreover, the proposed technology works effectively across a wide pH range. Only negligible inhibition was observed in the presence of nitrate, chloride, and carbonate. Exhausted hybrid filters can be effectively regenerated by using chemical wash with NaOH solution. This study not only revealed the different adsorption behaviors of As(III) and Sb(III) on the hybrid filters, but also provided new insights into rational design of continuous-flow filters toward simultaneous decontamination of As(III) and Sb(III).

Sea urchin-like FeOOH functionalized electrochemical CNT filter for one-step arsenite decontamination.

Advanced nanotechnologies for efficient arsenic decontamination remain largely underdeveloped. The most abundant inorganic arsenic species are neutrally-charged arsenate, As(III), and negatively-charged arsenite, As(V). Compared with As(V), As(III) is 60 times more toxic and more difficult to remove due to high mobility. Herein, an electrochemical filtration system was rationally designed for one-step As(III) decontamination. The key to this technology is a functional electroactive carbon nanotube (CNT) filter functionalized with sea urchin-like FeOOH. With the assistance of electric field, CNT-FeOOH anodic filter can in situ transform As(III) to less toxic As(V) while passing through. Then, as-produced As(V) could be effectively sequestrated by FeOOH. The sufficient exposed sorption sites, flow-through design, and filter's electrochemical reactivity synergistically guaranteed a rapid arsenic removal kinetic. The underlying working mechanism was unveiled based on systematic experimental investigations and theoretical calculations. The system efficacy can be adapted across a wide pH range and environmental matrixes. Exhausted CNT-FeOOH filters could be effectively regenerated by chemical washing with diluted NaOH solution. Outcomes of the present study are dedicated to provide a straightforward and effective strategy by integrating electrochemistry, nanotechnology, and membrane separation for the removal of arsenic and other similar heavy metals from water bodies.

One-step Sb(III) decontamination using a bifunctional photoelectrochemical filter.

Developing advanced technologies to achieve decontamination of emerging contaminants such as antimony (Sb) is highly demanded. Herein, we successfully designed a dual-functional photoelectrochemical filter system for "one-step" detoxification and sequestration of highly toxic Sb(III). The key to this technology is a photoelectrical-responsive CNT filter functionalized with nanoscale MIL-88B(Fe) photocatalysts. At 2.5 V and under illumination, a 97.7 ±â€¯1.5 % Sb(III) transformation and a 92.9 ±â€¯2.3 % Sbtotal removal efficiency can be obtained using an optimal hybrid filter (e.g. CM(50:3)) over 2 h continuous filtration. This can be explained by the synergistic effects of the filter's flow-through design, photoelectrochemical reactivity, fine pore size, and plentiful exposed sorption sites. Various advanced characterization techniques validated the system efficacy. Improved Sb(III) removal kinetics were observed when compared with conventional batch system (97.5 % vs 75.8 %). A synergistic effect between photocatalytic (PC) and electrochemical (EC) process were identified (kPEC =0.99 h-1 >kPC=0.21 h-1 + kEC =0.30 h-1). EPR and photochemical characterizations suggested that hydroxyl radicals dominated the Sb(III) conversion. The proposed technology works effectively across a wide range of pH values and water matrixes. The outcomes of this study can facilitate mechanistic insights into photoelectrocatalysis and provide a promising nanotechnology for efficient Sb(III) decontamination.

Synthesis of hollow NiCo2O4 nanospheres with large specific surface area for asymmetric supercapacitors.

Hollow micro-/nanostructured electrode materials with high active surface area are highly desirable for achieving outstanding electrochemical properties. Herein, we report the successful synthesis of hierarchical hollow NiCo2O4 nanospheres with high surface area as electrode materials for supercapacitors. Electrochemical measurements prove that such electrode materials exhibit excellent electrochemical behavior with a specific capacitance reaching 1229 F/g at 1 A/g, remarkable rate performance (∼83.6% retention from 1 to 25 A/g) and good cycling performance (86.3% after 3000 cycles). Furthermore, the asymmetric supercapacitor is fabricated with hollow NiCo2O4 nanospheres electrode and activated carbon (AC) electrode as the positive and negative, respectively. This device exhibits a maximum energy density of 21.5 W h/kg, excellent cycling performance and coulombic efficiency. The results show that hollow NiCo2O4 nanosphere electrode is a promising electrode material for the future application in high performance supercapacitors.

Hierarchical hollow MnO2 nanofibers with enhanced supercapacitor performance.

One dimensional (1D) hollow nanostructures have been considered as one of the most fascinating materials for supercapacitors. Herein, the hollow MnO2 nanofibers are successfully synthesized through a two-step process, in which the electrospun carbon nanofibers acted as sacrificial template. The resulting hollow nanofibers are composed of ultrathin MnO2 nanosheets, which can offer rich electrochemical active sites for electrochemical reactions. Importantly, the open and free interspaces among these ultrathin MnO2 nanosheets can significantly enhance the utilization of the active material even at high current density. Such unique hollow nanostructure endow the hollow MnO2 nanofibers electrode better electrochemical performance with specific capacitance of 291 F/g at 1 A/g, superior rate capability of ∼73% (from 1 to 10 A/g), and excellent cycling stability of 90.9% retention after 5000 cycles, demonstrating the potential for practical application in energy storage devices.

Fabrication of electrospun trace NiO-doped hierarchical porous carbon nanofiber electrode for capacitive deionization.

Trace nickel oxide-embedded hierarchical porous carbon nanofibers (CNF-NiO) were fabricated by electrospinning polyacrylonitrile-Ni(NO3)2 (PAN-Ni) followed by stabilization, carbonization and acid treatment. The resultant CNF-NiO was characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, thermo gravimetric analysis and nitrogen adsorption-desorption isotherm. The NiO amount and porous structure can be tuned by varying the PAN/Ni ratio and acid treatment time. The electrochemical properties of the electrospun CNF-NiO nanofibers were analyzed by cyclic voltammetry and impedance method. The specific capacity of 157.9 F/g was obtained at the PAN/Ni mass ratio of 90:3 with 3 h HCl wash. This porous CNF-NiO composite has been applied as a self-supporting cathode for capacitive deionization. The desalination amount arrived at 6.2 mg/g, which is 3 times as high as that of the electrospun pure carbon fibers. Longer wash time leads to decreased capacitance and desalination performance.

NaYF4:Yb/Er@PPy core-shell nanoplates: an imaging-guided multimodal platform for photothermal therapy of cancers.

Imaging guided photothermal agents have attracted great attention for accurate diagnosis and treatment of tumors. Herein, multifunctional NaYF4:Yb/Er@polypyrrole (PPy) core-shell nanoplates are developed by combining a thermal decomposition reaction and a chemical oxidative polymerization reaction. Within such a composite nanomaterial, the core of the NaYF4:Yb/Er nanoplate can serve as an efficient nanoprobe for upconversion luminescence (UCL)/X-ray computed tomography (CT) dual-modal imaging, the shell of the PPy shows strong near infrared (NIR) region absorption and makes it effective in photothermal ablation of cancer cells and infrared thermal imaging in vivo. Thus, this platform can be simultaneously used for cancer diagnosis and photothermal therapy, and compensates for the deficiencies of individual imaging modalities and satisfies the higher requirements on the efficiency and accuracy for diagnosis and therapy of cancer. The results further provide some insight into the exploration of multifunctional nanocomposites in the photothermal theragnosis therapy of cancers.

Hierarchically structured polysulfone/titania fibrous membranes with enhanced air filtration performance.

Hierarchically structured, superhydrophobic filter medium exhibiting robust filtration performance to airborne particulate were prepared by a facile deposition of electrospun polysulfone/titania nanoparticles (PSU/TiO2 NPs) on a conventional nonwoven substrate. The air permeability, tensile strength and abrasion resistance of pristine PSU fibrous membranes could be finely controlled by regulating the solvent composition and number ratios of jets. By employing the TiO2 NPs incorporation, the pristine PSU fibers were endowed with promising superhydrophobicity with a water contact angle of up to 152°. The quantitative hierarchical roughness analysis using N2 adsorption method has confirmed the major contribution of TiO2 NPs on enhancing the porous structure and surface fractal features with irregular rough structure. Filtration performance studies have revealed that the filtration efficiency and pressure drop of resultant hybrid membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. Furthermore, the as-prepared PSU/TiO2-5 membrane exhibited improved filtration efficiency (99.997%) and pressure drop (45.3 Pa) compared with pristine PSU membrane, which would make them a promising media for fine particle filtration, and a new insight was also provided into the design and development of high performance filter medium based on hierarchical structured fibers.

Folic acid-conjugated hollow mesoporous silica/CuS nanocomposites as a difunctional nanoplatform for targeted chemo-photothermal therapy of cancer cells.

In this work, we have developed a novel difunctional nanoplatform for targeted chemo-photothermal therapy. It is based on hollow mesoporous silica nanospheres as a carrier for anticancer drug-loading CuS nanoparticles attached on a silica nanosphere surface as a photothermal agent, and folic acid (FA) conjugated with a silica nanosphere as a cancer cell target. The nanoplatform has demonstrated a good photothermal effect and excellent doxorubicin (DOX) loading capacity (as high as 49.3 wt%). The photothermal agent and DOX can be targeted to deliver into cancer cells via a receptor mediated endocytosis pathway. Moreover, the release of DOX from the hollow mesoporous silica nanospheres can be triggered by pH and NIR light. Both chemotherapy and photothermal therapy can be simultaneously driven by irradiation with a 980 nm laser. More importantly, the combination of chemotherapy and photothermal therapy shows a better therapy effect than the individual therapies, thus demonstrating a synergistic action.

Coaxial electrospinning with acetic acid for preparing ferulic acid/zein composite fibers with improved drug release profiles.

This study investigated drug/zein composite fibers prepared using a modified coaxial electrospinning process. With unspinnable acetic acid as sheath liquid and an electrospinnable co-dissolving solution of zein and ferulic acid (FA) as core fluid, the modified coaxial process could run smoothly and continuously without any clogging. Compared with those from the single-fluid electrospinning process, the FA-loaded zein fibers from the modified process were rounder and possessed higher quality in terms of diameter and distribution, as verified by scanning electron microscopic observations of their surface and cross-section. Differential scanning calorimetry and X-ray diffraction showed that fibers from both processes similarly formed a composite with the FA present in the zein matrix in an amorphous state. The driving force of encapsulation of FA into zein fibers was hydrogen bonding, as evidenced by the attenuated total reflectance Fourier transform infrared spectra. However, in vitro dissolution tests demonstrated that the fibers from the coaxial process exhibited better sustained-release profiles with a smaller initial burst effect and less tailing-off release compared with those from the single process. The modified coaxial electrospinning process is a useful tool for generating nanofibers with higher quality and improved functional performance.

Dendrimer-mediated hydrothermal synthesis of ultrathin gold nanowires.

We report the use of poly(amidoamine) dendrimers as stabilizers to synthesize ultrathin Au nanowires (NWs) with a diameter of 1.3 nm via a hydrothermal approach. The formation of uniform Au NWs was optimized by varying the Au/Ag salt molar ratio, dendrimer stabilizers, and reaction solvent, temperature, and time. A novel growth mechanism involving a synergic facet-dependent deposition/reduction of Ag(I) and oriented migration of Au atoms is proposed based on density functional theory calculations and the experimental results. This work can significantly expand the scope of dendrimers as stabilizers to generate metal NWs in aqueous solution that may be further functionalized for different applications.