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High-performance nitrogen-doped porous carbon adsorbents were prepared from waste cellulose fibers using the spray-drying method and used to remove methyl orange (MO) from water. The carbon adsorbents possessed a honeycomb-like turbostratic microstructure with hierarchical pores. Such waste-cellulose-derived carbon adsorbents were found to exhibit a fast adsorption rate towards MO. A sample thermally treated at 800 °C with the highest specific surface area (about 1259.4 m2/g) and total pore volume (about 2.7 cm3/g) exhibited the best MO adsorption capacity (337.8 mg/g), which is significantly higher than that of ZnCl2-activated carbon. The effect of MO initial concentration, pH and temperature on the carbon adsorption was investigated systematically. It was found that the adsorption system is heterogeneous while the isotherm data on the carbon sample can be well described by both Langmuir and Freundlich isotherm models. The high-performance and cost-effective carbon adsorbent described in this paper holds a great promise for dye removal from aqueous solutions.

High-performance extraction of polar phenols from aqueous samples is challenging because of their hydrophilicity, extremely low concentration, and complicated matrices. Covalent organic frameworks (COFs) are new types of porous organic materials. In this work, spherical TPB-DMTP-COF was fabricated via a simple room-temperature solution-phase approach. The material exhibited high acid/base stability, remarkable thermostability, high crystallinity, and large surface area of 1560 m2 g−1 and thus could be an excellent coating for solid-phase microextraction (SPME) of phenols. This coating provided superior adsorption affinity toward phenols over commercial coatings. TPB-DMTP-coated fiber showed high enhancement factors (EFs, 1741–4265), and EFs increased with the number of chlorine or methyl substituents and high hydrophobicity of phenols. Hence, the strong adsorption affinity could be derived from hydrophobic and steric hindrance effects together with π−π affinity, H-bonding, van der Waals forces, and size-matching effect. The proposed approach based on TPB-DMTP-COF-coated fiber and gas chromatography-tandem mass spectrometry achieved low limits of detection (0.0048–0.015 ng L−1), wide linearity (0.05–1000 ng L−1), good precision (

In this work, we have firstly proposed a mild and facile method to deposit large-area RGO and ZnO QDs/RGO films on diverse substrates through a self-assembly strategy. RGO powders would aggregate to agglomerate in aqueous solution due to its hydrophobicity. Interestingly, it is found that RGO sheets would assemble to film when RGO ethanol solution is dropped into water, and the film layers could be rationally tuned by repeating the deposition procedure. Based on the convenient fabrication method, a co-current Z-scheme system could be constructed by subsequently depositing RGO and ZnO QDs/RGO films on FeVO4 photoelectrodes, in which RGO serves as an electron mediator. Different from the traditional disordered Z-scheme system, the photo-excited electrons in co-current Z-scheme would move toward the same direction due to the absolute separation between FeVO4 and ZnO. As a result, the PEC performances of FeVO4 could be significantly enhanced because the running direction of photo-excited electrons in co-current Z-scheme is consistent with that in external circuit. For comparison, a counter-current Z-scheme has also been built up by replacing FeVO4 with WO3, in which the ruing direction of photo-generated electrons is opposite to the external circuit, and the photo conversion efficiency decreased consequently. Therefore, it can be concluded that the design of pure Z-scheme is not only beneficial for improving the charge separation efficiency and retaining their redox capability, but also favorable for uncovering the charge transfer mechanism.

Covalent organic frameworks (COFs) via Schiff base-type linkages (1,3,5-triformylphloroglucinol–paraphenylenediamine, TpPa-1), as an ideal coating, possesses significant potential for solid-phase microextraction (SPME) due to their fascinating properties, such as outstanding thermal and chemical stabilities, inherent porosity, and high crystallinity. A novel SPME device was fabricated based on TpPa-1 as an enrichment coating for capturing trace polybrominated diphenyl ethers (PBDEs). This TpPa-1 coating exhibited a superior enrichment capacity in “catching” PBDEs over commercial SPME fibers. Such performance is attributed to multiple factors, including the coating’s hydrophobic nature, π-π stacked architectures, large specific surface area, high thermal stability, and size-matching effect. High enhancement factors of 2035–6859, low detection limits of 0.0058–0.022 ng L−1, satisfactory linear range of 0.01–100 ng L−1, good repeatability of 4.86%–9.33%, and excellent reproducibility of 5.62%–9.85% were achieved. Finally, as expected, as the most sensitive SMPE technique for detecting PBDEs, to the best of our knowledge, the developed SPME procedure in combination with gas chromatography–negative chemical ion–mass spectrometry analysis was proven to be ultrasensitive, dependable, and practical in analyzing PBDE species in real water. These exceptional results signify that the proposed method offers a fresh prospect to extend the potential applications of COFs to pick up pollutants at ultra-low levels from environmental samples.

Carbonaceous residues and polycyclic aromatic hydrocarbons (PAHs) are discharged simultaneously during the coke production. Chemical-structural properties of coking residues, such as coke powder, tar slag, and fly ash, were characterized by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller (BET) specific surface area, scanning electron microscopy (SEM), and electron paramagnetic resonance (EPR) techniques. Highly disorder amorphous structures with abundant of oxygen functionalities and persistent free radicals were observed for coke powder and tar slag. The potential activation of persistent free radicals (PFRs) on persulfate to generate reactive oxygen species (ROS) and induce the degradation of anthracene (ANT) was studied. The formation of H2O2 and decay rate of ANT highly correlate with the spin densities of bounded PFRs in coking residues. EPR technique combined with different radical scavengers was applied to investigate the generation of ROS. The results suggest that PFRs provide the electron to persulfate or/and O2, inducing the formation of SO4 −, H2O2, and OH. The produced ROS then back-reacts with adsorbed organic compounds, such as ANT, resulting in its oxidation and/or complete mineralization. The obtained results are relevant to the fate of adsorbed pollutants in coke-polluted soil environments and shed light on the development of remediation technologies for solid waste released during the coke production.

Room temperature sodium-sulfur (RT-Na-S) battery represents an advanced energy storage technology because of low cost and large theoretical energy density. However, RT-Na-S battery technology is facing severe challenges such as dissolution of sodium polysulfide, loss of active material on the surface of anode, serious shuttle effect and poor cycle stability. Herein, we synthesis hollow polar iron nitride nanoparticle encased N-doped carbon yolk shell (YS-Fe2N@NC) as sulfur carrier. The synergistic effect of YS-Fe2N@NC as well as wide void can be effectively trap polysulfides and improve the conductivity of sulfur-based cathode. The reversible reaction mechanism of Na-S battery is studied by in/ex-situ characterizations, catalytic behaviour of YS-Fe2N@NC and Density functional theory (DFT) calculations. The as made S/YS-Fe2N@NC composite exhibit promising specific capacity of 1123 mAh g−1 at the rate of 1C for the initial cycle, good rate capability (845 mAh g−1 at 2C) and ultra-stable cycling performance with an ultra-low capacity decay of 0.0724% per cycle. The present work highlights the importance of introducing the Fe2N to catalyse the conversion reactions of polysulfide within NC shell for boosting the RT-Na-S battery in term of high storage capacity, rate capability and stability.

Superstructures have attracted attention because of their potential applications in chemistry and materials science. In this work, we report the preparation of a porous 3D superstructure of nitrogen-doped carbon decorated with ultrafine cobalt nanodots (Co@NCSS) derived from the self-assembly of polyimide nanoparticles. Utilizing modified ultra-small cobalt nanodots as main catalytically active sites, and the excellent quality and electron transport efficiency generated by this 3D porous superstructure, Co@NCSS exhibited excellent catalytic performance as a peroxymonosulfate (PMS) activator towards the degradation of several sulfonamides. Based on radical scavenging tests and electron paramagnetic resonance (EPR), singlet oxygen (1O2) was the dominant oxidative species. Furthermore, through the identification of degradation intermediates by HPLC-MS and DFT calculation, the pathway of sulfamethoxazole (SMX) degradation by Co@NCSS/PMS was analyzed. The possible catalytic mechanism of Co@NCSS/PMS for SMX degradation is also proposed in this paper. Co@NCSS has the potential to be an ideal material for removing antibiotics from wastewater.

The trade-off between permeability and rejection limits the widespread application of organic solvent nanofiltration (OSN) membrane. As a promising membrane materials, polyaniline (PANI) has drawn increasing attention owing to its easy synthesis and excellent chemical stability. Nowadays, the reported PANI-based OSN membranes were fabricated by phase inversion process together with chemical crosslinking treatment. In this work, a novel double-layered polyaniline (PANI) composite OSN membrane was firstly developed through in-situ polymerization of aniline onto hydrolyzed polyacrylonitrile (HPAN) porous substrate. The separation performances of PANI/HPAN composite membrane were optimized by varying aniline concentration, polymerization time and oxidant:aniline ratio. The double-layered PANI/HPAN composite membrane prepared with 0.2 M aniline, 1 h polymerization and 1:4 oxidant:aniline ratio displayed ethanol permeance of 14.9 L∙m−2∙h−1∙bar−1 and rose bengal rejection of 98.1%. The membrane performance with the solvents including methanol, isopropanol, 1-butanol, acetone, n-hexane, and toluene were also tested, showing a molecular weight cut-off (MWCO) of 500 ∼ 600 g∙mol−1. In addition, the double-layered PANI/HPAN composite membrane maintained excellent and stable performance under strong acid soaking, ultrasonic vibration and continuous filtration

Due to the high porosity and ordered channels, covalent organic framework (COF) membranes with ultrathin selective layer and high permeance have gained increasing attention in the field of nanofiltration (NF). However, it remains a challenge to fabricate ultrathin and dense COF NF membranes with both high permeance and high rejection. This work presents a facile and efficient method to fabricate COF membrane with limited channel filling through in-situ growth of polyaniline (PANI) layer. Specifically, interfacial polymerized COF-TpPa membrane was fabricated with ~ 1.8 nm pore channel, and then the in-situ grown PANI layer could fill the partial of channels and reduce the effective pore size of COF-TpPa. The obtained PANI-TpPa composite membrane exhibited excellent performance with pure water permeance up to 85.2 L·m−2·h−1·bar−1, congo red rejection above 99.4%, and acid fuchsin rejection above 81.0%. The whole membrane fabrication just cost 3 h and took place at room temperature, which was much more efficient than other membranes with similar performance. Besides, the PANI-TpPa composite membrane showed excellent stability in acidic environment and organic solvent, and maintained great performance in long-term test.

Metal phosphides are promising electrocatalysts for hydrogen evolution reaction (HER). However, their applications are hindered by the low electronic conductivity and sluggish HER kinetics in neutral electrolytes. Here we report an approach to significantly improving the HER performance of hierarchical iron phosphide (pFeP) modified with metallic iron (Fe) in neutral phosphate buffer electrolytes. It was observed that the presence of Fe can accelerate the charge transport kinetics. As a result, a significant improvement on the proton-acceptor (negatively charged P sites) and hydride-acceptor (coordinated Fe sites) were achieved, therefore promoting proton adsorption to the electrocatalyst surface during water electrolysis. Specifically, the Fe modified FeP electrocatalyst (pFe/FeP) displayed high HER catalytic rates (e.g., −100 mA cm−2 at an overpotential of −380 mV), low onset potential (50 mV), and excellent long-term stability for 40 h in neutral electrolyte. This study provides a new approach to the design and synthesis of noble-metal-free electrocatalysts with excellent performance for hydrogen production in neutral electrolytes.

The tendon enthesis is a very complex tissue interface that connects a flexible tissue (tendon) to a stiff tissue (bone). Few available forms of gradient scaffolds with multiple components have been fabricated for applications in vivo because of the complexities of enthesis. In the present work, gradient-poly(e-caprolactone)/calcium phosphate silicate (G-P/C) composite films were fabricated with tape casting technique. Films with different P/C ratio were used to evaluate the material’s properties and effects of composition on cellular behaviors. The results showed that the G-P/C composite film offered a gradually changing composition transition. The higher levels of calcium phosphate silicate of each film stimulated stronger osteogenic differentiation and mineralized matrix deposition. When the films were interposed between the supraspinatus tendon and humerus bone, the G-P/C composite film group exhibited more tissue cellularity, better collagen alignment, better gradient mineralized cartilage formation and gradient Ca distribution than other groups. All these histological improvements were well consistent with the biomechanical results of the G-P/C composite film group. Thus, the G-P/C composite film may be a promising scaffold for tendon-to-bone interface engineering.

The repair of chronic rotator cuff injury primarily depends on surgery to biomechanically strengthen the connection between the tendon and bone. There are numerous studies on tendon-to-bone healing to promote bone regeneration or collagen reconstruction in tendons. However, chronic rotator cuff injuries are often associated with fat infiltration, and few studies have taken this aspect into account, let alone overcome the two challenges of bone healing and fat infiltration at the same time. Here, inspired by the structure of cowpea (Vigna unguiculata), we have developed lithium-containing mesoporous silica combined with electrospun PEUU nanofibers (Li+@MSNs/PEUU), which can slowly release lithium ions, inhibiting rotator cuff fat infiltration, and promoting bone regeneration to enhance tendon-to-bone healing on the basis of surgical repair. Using in vitro experiments we studied the mechanism of lithium ions playing a two-way role, which was found to be closely related to the Wnt pathway. In vivo, the system showed significant success in the treatment of chronic rotator cuff injury model in rats. Both histological and micro-CT results confirmed that the healing condition of the Li+@MSNs/PEUU nanofibrous mat group was better than that of the other control groups after 8 weeks. Overall, this work shows that lithium-containing mesoporous silica-bound electrospun nanofibrous mat have a long-term effect on promoting postoperative healing of rotator cuff injury with fat infiltration, and the regulation of the two lineages is achieved using only a single medium, leading to good potential for application.

Spherical vanadium phosphate (VPO4) particles grown on flexible electron-conductive carbon fiber cloth (CFC) is developed as a binder-free anode for lithium-ion batteries (LIBs). The flexible composite electrode (VP@CFC) exhibits an excellent performance, including high reversible lithium-ion storage capacity (541.2 mAh g−1 at 0.1C), high rate capability (350.2 mAh g−1 at 10C), and good cycling stability (a capacity retention ratio of 91.8% after 250 cycles at 1C). Moreover, a flexible full cell fabricated with the VP@CFC as anode and a commercial LiCoO2 (LCO) coated on CFC (LCO@CFC) as cathode displays good flexibility against mechanical bending at a wide range of angle while maintaining its good electrochemical performance. The flexible VP@CFC electrode holds a great promise in applications for flexible energy storage devices.

Covalent organic frameworks (COFs) with crystalline imide structure achieved remarkable application in the field of water treatment membrane. In this work, 1,3,5-triformylphloroglucinol (Tp) and benzidine (Bd) or melamine (Me) monomers as the assemble units were firstly in-situ interfacial polymerized upon polysulfone (PSf) porous substrate to form COFs composite membrane with a thin and stable COFs selective layer. Furthermore, adding melamine monomer during interfacial polymerization between Tp and Bd monomers could further introduce a triazine ring type-keto-enol tautomeric type into COFs selective layer, and adjust the molecular network structure and crystallinity of the COFs layer with variable pore aperture. The results indicated that the as-prepared TpBd/PSf and TpBdMe/PSf membranes could be efficiently applied for dye separation process with congo red rejection above 99.0%. Compared with TpBd/PSf membrane, water permeability of TpBdMe/PSf membrane increased from 33.6 L·m−2·h−1·bar−1 to 62.2 L·m−2·h−1·bar−1. Moreover, both TpBd/PSf and TpBdMe/PSf membranes exhibited excellent anti-fouling property, chemical and thermal stability. This work develops a facile method to prepare the imine-linked COFs membrane with variable pore aperture by changing reaction parameters and selecting appropriate amine monomers.

Transition-metal oxides based materials have recently been shown to be promising anode material for lithium ion batteries (LIBs) application to replace graphite material. In the present work, highly dispersed ultra-small MoOx nanoparticles anchored on N-doped three-dimensional (3D) hierarchically porous carbon (3D-MoOx@CN) are prepared on the basis of an efficient in-situ chelating and hard-templating strategy. The MoOx nanoparticles with particle sizes between 1.5 and 3.5 nm are observed to be anchored on the surface of the 3D N-doped carbon. The 3D-MoOx@CN composite anode electrode exhibits several appealing characteristics for lithium ion storage, including high specific capacity, good stability against cycling and fast charge transport kinetics. An optimized 3D-MoOx@CN sample (3D-MoOx@CN-700) delivers specific capacities of 742 mAh g−1 at current density of 100 mA g−1 and 431 mAh g−1 at 1000 mA g−1 after 1000 cycles, respectively. The observed excellent performance is due to the unique hierarchical pore structure with strong binding of the ultra-small MoOx nanoparticles onto N-doped carbon surface, which can avoid the agglomeration and alleviate the volume expansion of MoOx nanoparticles in the charge-discharge process. The composite electrode material described in this work holds a great potential for the development of high-performance lithium-ion batteries. Meanwhile, the synthesis method presents a common strategy to prepare other composite materials with highly dispersed metal oxide on the hierarchically porous carbon materials.

Magnetic and recyclable calcined CoFe-LDH/g-C3N4 catalyst was prepared by co-precipitation and calcination method, and used as a multifunctional material to remove hexavalent chromium (VI) via the synergistic effect of adsorption and photocatalysis. The calcined CoFe-LDH provide surface adsorption in the composite, which could lead to the adsorption of Cr (VI) with high adsorption capacity and fast speed. The g-C3N4 nanosheets have high photocatalytic activity in situ for the composite to reduce Cr (VI) into Cr (III). The results demonstrated that 60% Cr (VI) (50 mg L−1) can be adsorbed by the nanocomposite in 10 min and the removal efficiency of Cr (VI) reached 100% in 90 min under visible light irradiation by adsorption and photocatalysis. In addition, the calcined CoFe-LDH/g-C3N4 exhibits a mostly pore size about 2.58 nm, large specific surface area (101.61 m2 g−1) with the high structural stability and saturation magnetization (23.06 emu g−1), hence, could be easily recycled for ten subsequent runs with little activity loss.

Porous polymeric materials (PPMs) with phosphine oxide/chalcogenide (P = X) ligands were exploited, for the first time, for efficient capture of iodine from the vapor phase. Using triphenylphosphine oxide/sulfide/selenide (TPPO/S/Se), P = X ligands were introduced onto polyhedral oligomeric silsesquioxane (POSS) skeleton via a facile Friedel-Crafts reaction. They show iodine loading capacities, 1.22 g/g to 1.37 g/g at 90 °C, and 0.76 g/g to 0.85 g/g at 160 °C. Once heated at 160 °C under vacuum, they can still keep a considerable iodine loading capacity, 0.41 g/g and 0.51 g/g for POSS-TPPS and POSS-TPPSe, respectively. After soaking in ethanol, the POSS-TPPS/Se retained iodine more than 50%, the highest ratio reported so far for iodine release from PPMs. Besides, the dynamic column experiments were carried out to test their competitive adsorption performance of iodine from a mixed stream with water vapor (40% Relative humidity), and the results suggest that the elevated temperature (160 °C) can reduce the adverse effect of water adsorption remarkably. Moreover, the spectral evidence and DFT calculations reveal that a strong charge transfer through P = X to iodine originates from the three aromatic rings and the chalcogens. The adsorption energy for POSS-TPPSe complexing iodine can reach up to 66 kJ/mol I2, higher than other PPMs. As the first study of adsorbents with P = X ligands for iodine capture, this work opens a new avenue for the adsorptive capture of radioiodine in vapor at elevated temperatures and provides new insights for the interaction mechanism between P = X ligands and iodine molecules.

Ultraviolet (UV) disinfection is an environmental-friendly technology for water treatment. However, design and operation of UV disinfection reactors is very difficult without a good model. In this work, motion trajectories of micro-organism particles in various UV water disinfection reactors with different shapes, sizes and lamp arrangements were simulated in the computational fluid dynamics (CFD) software: FLUENT, using the Monte-Carlo method and adopting a new methodology. The reactor performance based on micro-organism log reduction was analyzed under constant UV dosage. Effects of design and operating parameters on reactor performance were analyzed and discussed.

Over the last decade, mesoporous TiO2 nanocrystalline films have been intensively investigated not only for fundamental research interest but also for technological applications. This critical review summarizes recent progress of the block copolymer-templated highly organized mesoporous TiO2-based films prepared via an evaporation-induced self-assembly (EISA) process and their photoelectrochemical applications. With a brief introduction to the principle of block copolymer self-assembly and EISA process, control of the cooperative self-assembly between Ti species and block copolymer in the sol solution as well as in the deposited films, aging under a controlled humid environment, and subsequent thermal treatment is described. Key experimental parameters for the preparation of highly organized mesoporous TiO2 films are analyzed. Applications of mesoporous TiO2-based films in photocatalytic reactions, catalytic chemical synthesis, dye-sensitized solar cells, and electrochromic and photochromic devices are discussed. The synthesis-component-structure-property relationship in mesoporous TiO2-based films is highlighted, and the perspectives in this rapidly developing field are suggested.

The Mn doping nanocrystalline Co–Ce–Zr–O x catalysts were prepared by the co-precipitation method and characterized by various physico-chemical characterization techniques such as X-ray diffraction (XRD), temperature- programmed reduction (TPR), O 2 temperature-programmed desorption (O 2 -TPD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed hydrogenation (TPH). Their catalytic performances for methane reforming with CO 2 to hydrogen and carbon monoxide were investigated. Adding Mn remarkably enhanced the catalytic activity and stability of the Co–Ce–Zr–O x catalyst. The highest catalytic activity and long-term stability was obtained when the molar ratio of Mn/(Ce + Zr + Mn) was 10%. The improved catalytic behavior was closely related to the surface oxygen species and oxygen mobility. In comparison with that of Co–Ce–Zr–O x catalyst, the migration of bulk lattice oxygen species became easier, and the content of surface oxygen species was higher for the Mn-doped nanocrystalline Co–Ce–Zr–O x samples. TPH characterization showed that the surface coke species could be easily oxidized into CO x for the Mn-doped nano cobalt-composite catalyst due to the higher amount of mobile oxygen. The Mn incorporation promoted the dispersion of the nano-sized CoO x crystallites. In comparison with the impregnated samples, CoO x species dispersed better in the co-precipitated catalysts.

Micro combustor is one of the critical components of micro-thermophotovoltaic (TPV) system. To maximize the output power of the system, a high and uniform temperature distribution along the combustor wall is required. For the first time, SiC porous media foam is employed in a micro modular combustor to augment combustion, enhancing heat transfer between the hot gas and the wall, thereby increasing the wall temperature. The results indicate that with SiC porous media, the peak wall temperature increases by 90–120 K. This increase in wall temperature significantly enhances radiation energy which is useful for electricity generation.