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The novel Co3O4@MXene nanocomposites (CMNs) were fabricated by a facile, green and highly tunable strategy without using any chemical modifiers. Various characterization results proved that nano-size Co3O4 was loaded on MXene nanosheets and CMNs exhibited a large specific surface area, especially for CMNs-3 (76.9 m2·g−1). The catalytic properties of CMNs for ammonium perchlorate (AP) thermal decomposition were investigated by a series of catalytic experiments. The results showed that the high-temperature decomposition (HTD) temperature and decomposition heat of AP mixed with CMNs-3 (2 wt%) could significantly decrease to 316.3 °C and remarkably increase to 1457.9 J·g−1, respectively. Moreover, the CMNs-3 could significantly reduce the apparent activation energy of AP by 49.1% and increase the value of reaction rate constant of AP by 482.0%. As for the effects of mass content of CMNs-3 on AP decomposition, the HTD temperature could decrease by as high as 128.0 °C with ratios of 10.0 wt% CMNs-3. It could be predicted that CMNs-3 with excellent catalytic performance would be a potential catalyst to promote AP decomposition and the synthesis method of CMNs-3 could provide an idea for the preparation of other metal oxide nanomaterials with high catalytic activity.

Electrolysis of seawater makes full use of this natural resource and continuously turns it into a clean fuel, hydrogen. Electrocatalysts for seawater electrolysis must maintain a steady-state operation without suffering from chloride corrosion. In this study, we report a three-dimensional structure metal phosphide electrocatalyst by depositing cobalt-doped Fe2P (Co-Fe2P) on Ni foam. Density functional theory calculations showed that Co-Fe2P was beneficial for the hydrogen evolution reaction (HER) because of its suitable H* adsorption. Thus, the as-prepared Co-Fe2P acted as an efficient bifunctional electrocatalyst, exhibiting enhanced electrocatalytic properties for both the oxygen evolution reaction (OER) and HER. Moreover, the simulated alkaline seawater was used to determine the optimum potential (1.69 V at 100 mA cm−2) required for seawater splitting using the as-synthesized electrocatalyst. This study proposes a novel material for electrocatalytic application.

This paper exhibits a rapid one-step hydrothermal method to prepare three different morphologies (spininess, columnar, lamelliform) of MnO2 covered on the surface of carbon spheres (CS@MnO2) by the control of KMnO4 concentration and hydrothermal temperature. All these CS@MnO2 composites were applied in supercapacitor electrode material, and the superior electrochemical performance of CS@MnO2 indicates that the combination of CS and MnO2 has a synergy effect on the enhancement of electrochemical performance. Among these samples, it is worth noting that the columnar morphology of CS@MnO2 exhibited the best performance achieving the max capacitance 178 F g−1 as the supercapacitor electrode material.

With the widespread use of nuclear energy, uranium containing radioactive waste water has raised global concerns on environmental sustainability, calling for high-performance materials in effective pollution treatments. Here, a novel adsorbent was prepared by immobilizing bayberry tannin onto bovine serum albumin nanospheres (BSA–BT-NSs), which was shaped by antisolvent method. The as-prepared adsorbent was characterized by SEM, TEM, FT-IR, and XPS, and showed excellent adsorption capacity and high selective adsorption for uranyl ions (UO22+) from radioactive wastewater, which included Fe3+, Mn2+, Cs2+, Co2+, and Sr2+. The effects of different adsorption parameters such as pH, temperature, time, and initial UO22+ concentration were investigated. The adsorption isothermal data were well fitted by the Langmuir isotherm model, and a maximum adsorption capacity of 487.805 mg g−1 was estimated. Furthermore, the BSA–BT-NSs possess excellent stability under 60Co γ-ray irradiation at total doses ranging from 10 kGy to 350 kGy. These facts indicated that BSA–BT-NSs could be used as a low-cost and environmentally friendly adsorbent for UO22+ removal with high efficiency and selectivity from various uranium-containing radioactive industrial effluents. More importantly, combined with the characterization analysis, adsorption experimental results, and theory calculations based on density functional theory, the adsorption mechanism of the BSA–BT-NSs is revealed.

The influence of silk fibroin (SF) and magnesium ions (Mg2+) on calcium carbonate (CaCO3) bio-mineralization has been investigated. However, the morphology of CaCO3 controlled by the synergistic effect of SF and magnesium ions has not been reported in microbial mineralization systems. Here, we provide novel experimental insights into the role of SF and Mg2+ in the crystallization of CaCO3 in microbial mineralization systems. The morphology and crystallization of CaCO3 aggregates are affected by the self-assembly of SF molecules and the inhibition of Mg2+. This combination promoted the growth of a novel, rod-like superstructure of calcite crystals by aggregating/assembling behavior and crystallization kinetics. In addition, prism-shaped and hemispherical CaCO3 crystal superstructures were obtained in the presence of Mg2+ and SF, respectively. Furthermore, CaCO3 crystals with well-defined morphologies and polymorphs can be obtained by regulating the crystallization conditions (mineralization time and the amount of the additives). The above system has potential applications in the design and preparation of numerous inorganic materials with novel morphologies and specific textures.

Heteroatom doping can change the electrochemical properties of carbon materials, but the simple, cheap and environmentally friendly preparation of these materials still remains a challenge. Herein, we have reported a new general strategy to fabricate heteroatom-doped carbon fiber materials based on the bioconcentration of different toxic organic dyes via fungal hyphae. The doped carbon fibers had a high content of heteroatoms and a three-dimensional network structure, exhibiting great potential as electrode materials for supercapacitors. Among these products, the N–S doped carbon fiber prepared by bioconcentration of methylene blue had the highest specific capacitance of 235 F g−1 at 1 A g−1 and good rate capability (72.8% retention from 1 A g−1 to 20 A g−1). This strategy can turn toxic waste into valuable materials, converting trash to treasure in the most literal sense; this bioconcentration method is green, general, low-cost and suitable for the preparation of fungal hyphae heteroatom-doped carbon fiber materials from different heteroatom precursors.

During large-scale semicoke and bituminous coal co-combustion, the behaviors of turbulence-chemistry interactions were experimentally and numerically used to investigate the effects of char burnout and NOx emissions in a pilot-scale bias combustor at different bluff-body cone angles (α). The results show that with increasing α the main reaction zone moves upstream significantly, and a widened flame and uniform temperature profile are obtained due to enhancing the internal flue gas recirculation. An increase in α can improve the char-oxidation reaction, and further results in increased pore structures and char burnout ratios. For all cases, the Dat (homogeneous Damkohler number) maximum values are below 0.50. The Da,O2, Da,CO2 and Da,H2O (heterogeneous Damkohler numbers) values are within 0.670–1.207, 0.004–0.017 and 0.001–0.004, indicating that the char oxidation reaction is dominated by diffusion/kinetics, while the char gasification reactions are controlled by chemical kinetics. However, both reactions tend to be kinetically-controlled with increasing α. The NOx emissions decrease by 27% at the α = 34° value, because a large cone angle can enlarge the combustion reduction zone and enhance the oxygen diffusion rate. The findings can provide deep insight into the turbulence-chemistry interactions and its effect on NOx emission characteristics of semicoke co-combustion in a bluff-body tangential burner.

Herein, we harmonized the energy band of defective molybdenum disulfide (MoSx) and reduced graphene oxide (RGO) through manipulating the concentration of S vacancies for efficient U(VI) reduction. The analysis of band structure revealed that the EF and conduction band of MoSx downward shifted with the increase of S vacancies, which lowered the schottky barrier but simultaneous decreased the reducibility of photogenerated electrons. Accordingly, the removal rate of U(VI) under the irradiation of simulated sunlight exhibited a volcanic relationship with the concentration of S vacancies in MoSx/RGO. Specifically, the maximum removal rate reached 91.6% with nearly 83.4% of tetrahydrated uranium (U(IV)) species over MoSx/RGO heterojunction. In addition, the extraction efficiency of MoSx/RGO heterojunction kept steady in 5-cycle test and exhibited less than 4.5% decrease in the presence of non-redox-active competing metal cations.

Antibiotics fermentation residue (AFR) is an environmental threat, as well as a valuable mycelial biomass resource. However, there is still a lack of safe and high-value conversion routes for AFR. Herein, torrefaction was applied to safely dispose of oxytetracycline fermentation residue (OFR) and simultaneously convert it into a high-performance adsorbent, and the adsorption performances of the resultant torrefaction char (TC) and pyrochar from pyrolysis were compared to show the advantage of torrefaction in converting the biomass waste into a functional adsorbent. Results showed that no oxytetracycline in OFR was detected after drying, and antibiotic resistant genes in OFR were reduced by > 6 logs after torrefaction, suggesting that torrefaction was efficient in eliminating environmental threats from OFR. Attributed to the richer oxygen- and nitrogen-containing functional groups, the TC far outperformed the pyrochar in adsorption performances at various conditions, suggesting that torrefaction was more efficient than pyrolysis for converting the biomass waste into a functional adsorbent. Specifically, the maximum adsorption amounts for uranium (U(VI)) and methylene blue (MB) by the TC reached 141 and 582 mg/g, respectively. Spectroscopic analyses evidenced that the oxygen-/nitrogen-containing groups on the TC dominated the adsorption of these pollutants. Moreover, no decreases of U(VI) and MB adsorption amounts and intensity of surface organic functional groups were observed for the TC after several cycles, suggesting the high reusability of the TC. Therefore, this study suggested that the AFR could be safely valorized via torrefaction into a powerful adsorbent for the removal of various pollutants from the solution.

Two-dimensional graphene has become one of the most intensively explored carbon allotropes in materials science owing to its attractive features, such as its outstanding physicochemical properties. To advance its practical application, the fabrication of self-assembled 2D graphene sheets into 3D nitrogen-doped graphene aerogels (NGA) with novel functions is becoming essential. Herein, the first attempts to modify graphene with Plectranthus amboinicus (PA), to introduce double nitrogen doping, and to prepare NGA by a natural drying (ND) method are reported. Natural drying was achieved by increasing the pore structure of NDPA-NGA using PA to simultaneously cross-link the graphene sheets and increase the stiffness of the sample. Meanwhile, we used ammonia and urea as double nitrogen sources to achieve an N-doping amount as high as 12.06 atom %. In addition, NDPA-NGA exhibited superelastic properties (with 95% maximal strain and almost no loss after 60 replicates), a high oil absorption capacity, and an excel...

The urease of carbonate-mineralization bacteria (bacillus) secretion is conducive to the formation of carbonate. At the presence of urea and Sr2+, carbonate-mineralization bacteria could lead to the rapid formation of strontium carbonate precipitation. The mineralization process and efficiency were observed by adding nano-montmorillonite (nano-MMT). The effect of bacillus and bacillus/nano-MMT on the mineralization efficiency of Sr2+ was investigated by atomic spectrophotometer. The results showed that both the bacillus and nano-MMT played an important role in the nucleation, growth, and accumulation of strontium carbonate crystals. And this method can efficiently separate simulated radionuclide strontium from high-level radioactive waste.

As an effective way to obtain solar energy and separate the soluble contaminants from water, solar-driven interfacial evaporation is used in desalination, wastewater treatment, electricity generation, and domestic water heating system. Herein, we demonstrate a monolithic sponge with three-dimensional porous structure as the solar-energy evaporator, which is composed of hydrophilic polymer (Konjac Glucomannan, KGM) and solar absorbent (reduced graphene oxide, rGO). Under one sun irradiation, the sponge achieves a rapid evaporation rate (1.60 kg m−2 h−1) and high interfacial water evaporation efficiency (92 %) due to its good absorption, photothermal, thermal insulation, and fast water transport properties. Meanwhile, the concentrations of radioactive elements (strontium, cesium, and uranium) in wastewater dropped from grams to micrograms after purification, even under radiation and acidic conditions. Additionally, the durability and repeatability of the sponge also have been verified. The results showed that solar-driven interfacial evaporation can effectively treat radioactive wastewater and enrich various radionuclides in a more energy-saving manner.

Biochar from pyrolysis/gasification is relatively poor in oxygen-containing groups and low in micro/mesoporosity, which constrains its adsorption performance. Here, thermal air treatment (TAT) at a mild condition (300 °C in air) was applied to oxygenate the surfaces of various biochars and modify their pore structures for the promotion of their uranium (U(VI)) adsorptions. Results showed that TAT had a high product yield (>76%), increased the O contents, O/C ratios and O-containing groups in biochars, and substantially developed the micro/mesoporosities of biochars. Batch adsorption results showed that TAT remarkably improved U(VI) adsorption capacities of various biochars. Specifically, the maximum U(VI) adsorption capacities of ash-poor corn cob biochar and ash-rich sewage sludge biochar were increased by 137% to 163 mg/g and 23% to 97 mg/g, respectively. Thus, TAT might be a promising strategy to engineer various biochars for adsorptive applications.

Increasing the mass loading of transition metal single atoms coordinated with nitrogen in carbon-based materials (M-N-C) is still challenging. Herein, inspired by the bioconcentration effect in the living body, a biochemistry strategy for the synthesis of Fe-N-C single atoms is demonstrated. Through introducing ferrous glycinate into the growth of fungus, the Fe atoms are bioconcentrated in hyphae. The highly dispersed Fe-N-C single atoms in hyphae-derived carbon fibers (labeled as Fe-N-C SA/HCF) are prepared by the pyrolysis of Fe-riched hyphae. In the bioconcentration process, the uptake of Fe ions by hyphae promotes the secretion of glutathione and ferritin, which provides additional coordination sites for Fe ions. Accordingly, the mass content of Fe in bioconcentrated Fe-N-C SA/HCF reaches 4.8%, which is 5.3 times larger than that of the sample prepared by the conventional pyrolysis process. The present bioconcentration strategy is further extended to the preparation of Co, Ni, and Mn single atoms. Owing to the high content of Fe-N-C single atoms, Fe-N-C SA/HCF shows the onset potential (Eonset ) of 0.931 V versus reversible hydrogen electrode (RHE) and half-wave potential (E1/2 ) of 0.802 V versus RHE in oxygen reduction reaction measurements, which is comparable to the commercial Pt/C catalysts.

The pressure-induced structural, elastic, vibrational, thermodynamic properties and the hardness of C11N4 polymorphs were investigated by first-principles calculations based on the density functional theory. Our calculations reveal that the g-C11N4 is the most stable structure at ambient pressure among the four C11N4 polymorphs and that α-C11N4 and d-C11N4 are the most energetically preferred structures. The transition from g-C11N4 to α-C11N4 and d-C11N4 with low pressure phases occurs around 3.557 and 9.468 GPa, respectively, and the transition from g-C11N4 to β-C11N4 with high pressure phase occurs around 46.032 GPa. The elastic properties and anisotropic mechanical properties of C11N4 polymorphs are then discussed in detail. Importantly, the hardnesses of C11N4 polymorphs are estimated using a semi-empirical model for the hardness, and the results indicate that α-C11N4, β-C11N4, and d-C11N4 are superhard materials. Finally, the mechanical and thermodynamic properties, including the bulk moduli, heat capacity and the thermal expansion coefficient, of C11N4 polymorphs depending on pressure are predicted. Keywords: Phase transitions, Mechanical property, Hardness, Thermal properties

Integrating the defect engineering and conductivity promotion represents a promising way to improve the performance of CO

With the development of nuclear energy, the removal/recovery of radionuclides has attracted increasing attention. Here, an ultra-light, super-elastic, konjac glucomannan/graphene oxide composite aerogel (KGCA) as a high performance adsorbent for radionuclide removal/recovery was fabricated by a three-step process of freeze-casting, freeze-drying, and carbonization. The as-prepared bionic structured KGCA showed ultralow density, high specific surface area, desirable super-elasticity, and abundant oxygen-containing functional groups. Batch adsorption results demonstrated the maximum adsorption capacity of uranium (U(VI)) on KGCA is as high as 513.4 mg g-1, far exceeding other biomass carbon aerogels. Furthermore, KGCA showed good radiation stability, selective adsorption of U(VI), and high recycling performance. The KGCA also showed good adsorption properties even under simulated seawater or high salt concentration. Thus, these ultra-light and super-elastic biomass-derived composite aerogels could have a wide range of applications for nuclear wastewater treatment in the future.

The presence of organics in radioactive wastewater decreased the extraction efficiency in traditional adsorption treatment of nuclide. Herein, we developed g-C

Carbon nanotube (CNT)-based materials have attracted tremendous interest for their high performance in oil separation. However, the preparation of CNT based materials always require harmful and expensive chemicals. Here, a biological assembly route was applied to assemble CNTs onto a fungal hyphae (FH) to produce FH/CNTs composites, followed by pyrolysis to obtain a hydrophobic CNT based aerogel for oil separation, which is a more environmentally friendly process. The as-prepared FH/CNTs-800 aerogel (pyrolyzed at 800 °C) showed hydrophobicity with a water contact angle of 143° and high specific surface area (1041.2 m2 g-1). The oil absorption results showed that the as-prepared FH/CNTs aerogels could absorb a wide range of oils with high absorption capacities ranging from 48 to 138 times their own weight. Furthermore, the oil-loaded aerogel was recycled through burning with little reduction in the oil absorption capacity. In addition, FH/CNTs-800 provided a high specific capacitance of 232 F g-1 at 1 A g-1 and maintained a capacity retention of 70.62% at 20 A g-1. Therefore, this study offers a simple, low-cost and environmentally friendly bioassembly route for large-scale assembly of CNTs into macroscopic 3D hydrophobic aerogels for highly efficient water-oil separation.

Photoreduction of soluble U(VI) into insoluble U(IV) servers as a novel and efficient approach for U(VI) enrichment, where semiconductors are generally applied as the photocatalysts. Unfortunately, only a part of sunlight is utilized during the photoreduction process, significantly limiting the treatment performance for U(VI). Herein, we successfully constructed highly active and stable photocatalysts for the photo-assisted treatment of U(VI) by depositing Cu80Co5Ni5Cd5In5 nanocrystals on porous ZnO (CCNCI/ZnO) to efficiently expand the response region of sunlight. Impressively, the U(VI) enrichment capacity of CCNCI/ZnO was up to 2405.3 mg/g within 60 min. Moreover, CCNCI/ZnO exhibited excellent stability during photocatalysis due to the enhanced entropy of Cu80Co5Ni5Cd5In5 nanocrystals. Further mechanistic studies indicated that Cu80Co5Ni5Cd5In5 nanocrystals in CCNCI/ZnO generated hot electrons under visible light, followed by the transformation of hot electrons to porous ZnO via the Schottky barrier. Hot carriers efficiently reduced U(VI) over CCNCI/ZnO, contributing to the remarkable performance during U(VI) enrichment.

Three kinds of nano-manganese oxide materials were prepared at different temperature (500, 600 and 700 °C) using chitosan as the template agent. The results showed that there was no sintering and agglomeration in the calcination of nano-manganese oxide at 600 °C, while the manganese oxide material calcined at 700 °C showed pore collapse and agglomeration and the template agent was incompletely removed in the manganese oxide material calcined at 500 °C. The adsorption properties of uranium (VI) on the three manganese oxide materials were investigated. The experimental results showed that the adsorption behavior conformed to the pseudo-second-order kinetics and Langmuir isotherm models, revealing that the adsorption behavior of uranium (VI) on manganese oxide materials was a uniform and monolayer chemical adsorption process. The adsorption capacity of MnO-600 was 635.4 mg/g and the adsorption efficiency was above 90% after five cycles. In conclusion, the novel manganese oxide materials would have a prospect for application in wastewater treatment.

With the continuous increase in the demand for energy storage equipment, it is imperative to develop new electrode materials with high specific capacitance. In this study, yak dung derived carbon materials (N-YD) were prepared by a simple, economical, and effective method, and it was applied as a supercapacitor electrode material. The N-YD-800 material exhibited high nitrogen content, as well as a large number of multipore structures, which were beneficial to improve the capacitance performance. N-YD-800 exhibited an excellent specific capacitance (346.3[Formula: see text]F[Formula: see text]g[Formula: see text] at 1[Formula: see text]A[Formula: see text]g[Formula: see text], good rate performance (56.6% from 0.5[Formula: see text]A[Formula: see text]g[Formula: see text] to 10[Formula: see text]A[Formula: see text]g[Formula: see text], and excellent cycling stability (93.3% after 5000 cycles). This study provided a new method for the treatment of livestock and poultry manure resources, affording a cost-effective, easy-to-use carbon source to solve the problem of nonrenewable energy.

As a safe, reliable, and strongly electromagnetic resistant initiation method, laser initiation shows great promise in military blasting applications. Many obstacles exist when delivering a high-energy laser through optical fibers, directly influencing the energetic explosives under low-initiation conditions. Herein, we developed silver nanoplates as a laser energy absorber to reduce the laser initiation threshold and delay time. During the growth process of the silver seed nanoplates, mechanical disturbance was applied to provoke the nanoplates to develop more internal hotspots. Meanwhile, in ultraviolet visible near-infrared (UV–VIS-NIR) testing, the absorption peak was regulated to 808 nm by tailoring the size of the nanoplates. Results showed that the maximum temperature of the cracking nanoplates could reach 100 °C within 10 s, under the irradiation of an 808 nm diode laser at a power density of 1 W·cm−2. Through their use as a laser energy absorber, the silver nanoplates can effectively reduce the initiation threshold of cyclotrimethy lenetrinitramine (RDX) by 58.33% and reduce the delay time of B/KNO3 by 51.00%. This result provides potential applications for initiation energetic explosives at low laser energy.

The efficient, safe, and low-cost treatment of uranium-containing wastewater is still an urgent and meaningful problem. The uranium-containing wastewater system commonly contains a variety of soluble organics, which complex with hexavalent uranium (U(VI)) and thus increase the difficulty for U(VI) treatment. Herein, we introduced oxygen vacancy into WO3 nanosheets to achieve highly efficient photocatalytic reduction of U(VI) and photo-degradation of organics. The WO2.78 nanosheets showed U(VI) removal ratio of 95.6% with the reduction ratio of 84.5% in 8 mg/L of U(VI). Additionally, the maximum extraction capacity of U(VI) on WO2.78 nanosheets reached 507.2 mg/g at 200 mg/L of U(VI). Meanwhile, the presence of excessive interfering ions and the cycle use of the WO2.78 nanosheets hardly decreased the removal ratio of U(VI). The mechanistic study demonstrated that the introduction of oxygen vacancies not only broadened the response range of visible light, but also increased the adsorption of U(VI) over WO3 nanosheets. Moreover, the decreased reduction potential of WO2.78 nanosheets to U(VI) verified the enhanced photocatalytic activity of WO2.78 nanosheets. Our work provided a successful example for the promotion of reduction efficiency toward U(VI) pollutants by the vacancy engineering in metal oxides.

The electronic configuration plays a crucial role in the activity of catalyst toward OER according to Shao-Horn’s principle. Herein, we demonstrated a facile strategy to modulate the electrons of doubly degenerated (eg) orbital for Co ions in Co4Nx (0

Nano-scale zero-valent iron (NZVI) is easy to be agglomerated and passivated in the process of U(VI) reduction and fixation. Herein, a facile one-step process for titanium modified beaded segments like nano-zero-valent iron nanoparticles (FTNP) was designed and prepared for U(VI) adsorption-reduction from aqueous solution. The as-prepared NZVI, FTNP were characterized by Fourier transform infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), X-Ray photoelectron spectra (XPS), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and Energy dispersive X-ray spectrum (EDS). Results indicated that the beaded segments like FTNP were successful prepared. Furthermore, the uranium removal performance of FTNP with the effect of adsorption and reduction were investigated and showed excellent adsorption and reducibility for U(VI) from aqueous solution. Batch adsorption for U(VI) shown the U(VI) adsorption capacity of FTNP reached 734.4 mg g–1 (pH = 5.0). In the Fe-U reaction system, Fe2+ was generated as the primary reducing agent to reduce U(VI) from Fe0. Therefore, part of U(VI) was removed and reduced to U(IV), while others was precipitation hydrolyzed to schoepite, which also reduced to U(IV) and precipitated. This study may provide a novel and significant method for using nano-zero-valent iron to develop for wastewater decontamination.

Al2O3 aerogels have been synthesized by in situ water formation method using different agents including phenylenediamine, aniline, thiourea and urea for in-situ water formation. Then, various of techniques were implemented to analyze the structure of these as-prepared Al2O3 aerogels. The results showed that the Al2O3–Th possessed the uniform porous morphology, which might provide the large specific surface area and a large number of active sites to dislodge U(VI) species. Additionally, the adsorption properties of the as-prepared Al2O3 aerogels to U(VI) from solution were investigated. It could be concluded that the removal of U(VI) on Al2O3 aerogels were independent on ionic strength and strongly reliant on the initial pH. The adsorption isotherms of Al2O3–Th to U(VI) could be imitated using the Langmuir model and the maximum adsorption capacities in simulated seawater and aqueous solution were 270.9 and 634.0 mg/g, respectively, which showed that the adsorption property of Al2O3–Th was much better than that of other reported Al2O3-based adsorbents. In addition, the adsorption efficiency of Al2O3–Th reached 70% within 5 min and the equilibrium of U(VI) adsorption was achieved within 100 min (C0 = 10 mg/L). Meanwhile, the adsorption efficiency of Al2O3–Th to U(VI) maintained quite good and the value still reached about 93% after five consecutive cycles. These results indicated that the Al2O3 aerogels would be applied as potential materials for wastewater treatment.

A novel health hazard assessment model of fine particles generated from five groups of coal-fired boilers is built based on AHP. In our assessment model, some important factors are taken into account, including the number from uncontrolled emission, and mass from uncontrolled emission, the particle size distribution of Rosin-Rammler function of fine particles, and the total content of toxic chemical compositions (including Cr, V, Mn, Ni, Pb, Cd, As, Se, Hg, OC and EC). By calculation, PM2.5 from the industrial grate-fired boilers are much more harmful to human health than those from the other types of coal-fired boilers, which is not recommended to choose grate-fired burners as a burner of a new boiler or a modification boiler. PM2.5 from industrial fluidized-bed boilers are more harmful to human health than that of utility CFB boilers; PM2.5 from the large-capacity utility pulverized coal boilers (⩾450MW) are more harmful to human health than those from the small-capacity utility pulverized coal boilers (

Integration of the schottky junction and defect engineering over the adsorbent-semiconductors is a perspective strategy for the photocatalytic reduction of hexavalent uranium (U(VI)), which not only effectively avoid the limited active sites on semiconductors, but also promote photogenerated electrons are transferred to the adsorbent through the schottky junction. Here, we developed a bacterial cellulose-defective molybdenum disulfide (BC-MoS2-x) heterojunction by integrating schottky junction and sulfur vacancy (S-vacancy), targeting at simultaneous selective U(VI) removal. The carbonized BC served as not only a confined framework for the growing of MoS2, but also an ideal electron acceptor and transporter for improving the charge carrier separation efficiency. Specifically, the Schottky Junction and S-vacancy had been proven to effectively synergistically enhance the photoelectrons transfer from MoS2 to carbonized BC. Accordingly, the BC-MoS2-x heterojunction presented high removal efficiency for U(VI) with a removal rate of up to 91% in a wide range of U(VI) concentrations. The BC-MoS2-x heterojunction possessed excellent cycle stability in multiple U(VI) capture test cycles, and exhibited a highly selective U(VI) removal in the system containing an abundant of non-redox-active competing metal cations. Interestingly, organic matter, as an unfavorable factor for U(VI) removal in the traditional radioactive wastewater, had been proven to be used as the hole trapping agent to improve the U(VI) removal efficiency. This strategy may open a paradigm for the development of rationally designed heterojunctions as the photocatalysts for selective U(VI) removal.

Powdered modified TiO2 materials are commonly used for photocatalysis. They are easily dispersed in solution but difficult to recycle. In addition, the low light transmission and lack of oxygen in solution also cause a decrease of the photocatalytic efficiency for practical applications. Here we prepare a low-density circular slice which can be suspended on the surface of an aqueous solution and can be used to enrich methylene blue easily. The body of the circular slice is a kind of biomass carbon derived from fungus while the surface of the circular slice is coated with Fe/N co-doped TiO2 nanotubes and a N-doped graphene composite. The advantages are that the circular slice cannot only be convenient to recycle, but also be easy to receive light and oxygen. According to the photocatalytic activity test, the floatable material consisting of Fe/N-TNTs/NG and fungus shows superb performance on the degradation of methylene blue under simulated solar irradiation, which makes it a promising photocatalytic material.

As one of the materials having a bionic structure, nacrelike layered composites, inspired by their natural hybrid structures, have been studied via a variety of approaches. Graphene oxide (GO), which differed from inert graphene, was used as a new building block because it could be readily chemically functionalized. Rather than natural polymers, synthetic polymers were most commonly used to fabricate nacrelike GO-polymer materials. However, naturally occurring polymers complied more easily with the requirements of biocompatibility, biodegradability, and nontoxicity. Here, a simple solution-casting method was used to mimic natural nacre and fabricate a self-assembled and aging-resistant binary natural polymer, (κ-carrageenan (κ-CAR)-Konjac glucomannan (KGM))-GO nanocomposites, with varying GO concentrations. The investigation results revealed that κ-CAR-KGM and GO mostly self-assemble via the formation of intermolecular hydrogen bonds to form a well-defined layered structure. The mechanical properties of the natural polymer-GO films were improved significantly compared to those of pure natural polymer films. With the addition of 7.5 wt % GO, the tensile strength (TS) and Young's modulus were found to increase by 129.5 and 491.5%, respectively. In addition, the composite films demonstrated high reliability and aging resistance as well as a definite TS after cold and hot shock and ozone aging tests, especially showing a superior ozone resistance. The composite films can potentially be used as biomaterials or packing materials.

In this work, 3D hierarchical walnut-shaped, 2D nanosheet and 3D microspheres single phase CuO nanostructures are functioning as catalysts and supporting materials, differing from the conventional ways. The novel nanostructures were synthesized via hydrothermal method under a stainless steel autoclave. The as-prepared materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and H 2 temperature-programmed reduction (H 2 -TPR). The walnut-shaped structures with high O/Cu atomic ratio (1.22) exhibit high oxygen adsorption capacity and greatly enhanced catalytic activity. These results will be enrich the techniques for tuning the morphologies of metal oxide micro/nanostructures and open a new field in catalytic applications.

A new sustainable filamentous fungi-based process is reported to synthesize mycelium/bayberry tannin (BT) hybrid materials. The hybrid materials are produced with fungi growing in solution, where the cell wall interacted with BT by hydrogen-bond from the phenolic hydroxyl and amino in protein. In the adsorption experiment, This hybrid biologic material show excellent performances for strontium ions adsorption and experimental data obey a pseudo second-order model of the chemical adsorption process. This study reported a new method for the producing of bio-based materials, which had the potential applications in waste water treatment.

This paper investigated the oscillation characterization of volatile combustion of single coal particles using high-speed OH-PLIF and CH* chemiluminescence, meanwhile advanced data-driven algorithm as post-processing. The measurement region of in-situ 500 Hz OH-PLIF system was set to 53mm × 35 mm with a spatial resolution of ~23 µm per pixel, which was used to capture the continuous and whole volatile combustion process of single particle in a group of pulverized coal particles (SPGCP). A high-volatiles bituminous coal (30 wt%) burned at a gas temperature of 1700 K with oxygen mole fractions in the range of 10%–30%. The morphology of volatile flame and dynamic evolution was obtained. Dynamic mode decomposition (DMD) method can provide a new insight into combustion oscillation of pulverized coal. The oscillation frequency characteristics of pulverized coal flame were captured, and the red-shift phenomenon of dominant frequency with the increase of oxygen concentration was found. The particle aggregation might lead the low-frequency oscillation of pulverized coal combustion. On the contrary, individual or separated particle combustion could generate larger oscillation frequency.

Utilization of infrared (IR)/near-infrared (NIR) light paves an opportunity to improve the efficiency of N2 photofixation under full-spectrum irradiation, but remains as a grand challenge. Herein, a highly active photocatalyst toward NIR light-driven N2 photofixation was successfully developed by construction of plasmonic Ti3C2Tx MXene and TiO2 hybrid structures (Ti3C2Tx/TiO2-400). Impressively, Ti3C2Tx/TiO2-400 exhibited remarkable activity in N2 photofixation under full-spectrum irradiation of Xenon lamp, attaining an NH3 production rate of 422 μmol gcat.–1 h–1 without any sacrificial agents. More importantly, superior activity under NIR light was even achieved for Ti3C2Tx/TiO2-400 with the NH3 production rate up to 82 μmol gcat.–1 h–1 by applying 740-nm monochromatic light. Further mechanistic studies revealed that plasmonic Ti3C2Tx Mxene phase in Ti3C2Tx/TiO2-400 enabled the harvesting of NIR light. Moreover, oxygen vacancies in TiO2 phase of Ti3C2Tx/TiO2-400 served as the active centers to efficiently adsorb and activate N2.

A novel natural honey hydrothermal biochar (HHTB) was prepared using natural honey as raw material. The as-prepared adsorbent was applied to adsorb Pb2+ from aqueous solution and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy to investigate the structure and morphology change of the adsorbent before and after Pb2+ adsorption. The influence of the pH, initial Pb2+ concentration, temperature, and contact time on the adsorption of Pb2+ was systematically investigated. The results revealed that the adsorption capacity for Pb2+ is up to 133.2 mg&middot, g&minus, 1 at initial pH of 5.0 and adsorption temperature of 298 K. Meanwhile, the adsorption of Pb2+ on HHTB can be well fitted by the pseudo-second-order model and Langmuir isotherm model. The adsorbent had great selectivity for Pb2+ from the aqueous solution containing coexisting ions including Cd2+, Co2+, Cr3+, Cu2+, Ni2+ and Zn2+. Furthermore, the adsorption of Pb2+ on HHTB was attributed to complexation coordination, where it involved hydroxyl and carboxylic groups on HHTB in the process of adsorption of Pb2+.

An optical entrained flow reactor, based on a downward flat-flame, was established to explore the devolatilization and volatile combustion behaviours of coal particle streams with surrounding temperatures from 1600 K to 1800 K and oxygen mole fractions in the range of 10%–30%. The coal particle streams with particle sizes of 53–80 μm are two kinds of high-volatile pulverized bituminous coal and lignite. Using High-speed Planar Laser-Induced Fluorescence to diagnose OH (OH-PLIF), the planar sheet-imaging of OH-radicals was obtained to visualize the coal particle flames, and then, the normalized fluorescence signal intensity along the distance downstream from the burner and along the radial distance was obtained to investigate the volatiles combustion process. From the planar sheet-imaging, the ignition of tested high-volatile bituminous coal and lignite is dominated by the combustion of their volatiles. The combustion processes of volatiles can be divided into 4 stages: ignition, accelerating burning, stable burning and feeble burning, to investigate the intrinsic combustion correlation phenomena. The relative standard deviation (RSD) changes of the OH radial profiles can provide a new insight into flame stabilization, wherein the flame stability of the bituminous coal particle stream is higher than that of lignite under the same combustion conditions. The volatiles combustion of lignite is more sensitive to the oxygen concentration and temperature than that of bituminous coal, and the volatile releasing ratio of bituminous coal (65%–81%) was substantially less than that of lignite (92%–100%) by the analysis of the char residues.

Graphene oxide (GO) is expected to be harmful to the environment due to the toxicity. Accordingly, this work aimed to assess the potential harm of GO to the environment by investigating the toxicity of GO to the M. sextelata, and the effects of M. sextelata to GO. The dry weights, IR spectra, morphology, ultra-structures of mycelia, pH, conductivities of culture media, the activity of superoxide dismutase (SOD) and malondialdehyde (MDA) contents were measured to display the potential hazards of GO to M. sextelata. Then the Raman spectroscopy, dispersibility, and X-ray photoelectron spectroscopy (XPS) of GO were measured to show the effect of M. sextelata on GO. The results indicated that the lower GO concentrations promoted the growth of M. sextelata while the high level of GO inhibited the growth process of M. sextelata. After 7 d of culture, the effect was suppressive, with the biomass significantly reduced by 10.10%, the MDA content of G200 increased by 69.06%. GO nanosheets covered the surface of mycelia which caused change of the mycelial microstructures. Correspondingly, M. sextelata induces more defects in GO, accompanied by poor dispersion of GO in ethanol. Based on the XPS analysis, in the G10, G50 and G200 treatments, their atomic percentage of nitrogen in GO increased by 3.03%, 4.28% and 2.2%, respectively, and the atomic percentage of oxygen in GO reduced by 8.61%, 9.42% and 4.09%, respectively. The effect of mycelia on GO is mainly in deoxygenated and nitrogen-doped. We expected that the above results would provide a reference for the environmental hazard of GO.

In this study, nano-zero-valent Fe/Ni particles (NZFNP) loaded on collagen fibers through the immobilization of bayberry tannin was prepared and used for uranium adsorption-reduction from aqueous solution. The effects of environmental conditions for uranium removal onto NZFNP were studied in detail. The as-prepared adsorbent was characterized by TEM, SEM, EDS, FT-IR to investigated the adsorption-reduction mechanism of uranium on NZFNP. The results indicated that the major removal reaction of uranium should be recognized as a process of adsorption and reduction, and the U(VI) was adsorbed onto NZFNP firstly under the effect of electrostatic interaction. Then the Fe0 in the inner layer of the metal sphere lost electrons to generate Fe(II) as a new reductant, and U(VI) could be reduced by the Fe(II) generated on the surface of sample at the interface between adsorbent and aqueous. In particular, a higher uranium reduction ratio of 70.6% have been obtained due to the introduction of Ni0, where a battery is formed between Fe0 and Ni0, thereby forming a continuous electron flow and an increase in Fe0 activity. Thus, the NZFNP is promising for the rapid and effective removal of uranium from waste water.

Agglomerate and reuse limit the promising application of silver nanoparticles (AgNPs) as catalyst. To eliminate those disadvantages, herein, Fe-containing silica nanowires (SiO2NWs) and reduced graphene oxide (RGO) are used as suitable substrates to prepare AgNPs/SiO2NWs/RGO nanocomposite via self-assembly approach. The nanocomposite mostly assembled with each other via intermolecular hydrogen bond and electrostatic adsorption to form a three-dimensional network structure. The AgNPs/SiO2NWs/RGO nanocomposite exhibit excellent photocatalytic activity for 4-nitrophenol reduction by NaBH4, originating from that the nearly mono-dispersed AgNPs are adhered on the surface of the SiO2NWs and RGO, allowing the effective contact of reactants with catalyst and facilitating the electron transfer between them in the reaction. The obtained nanocomposites exhibit the superior stability and can be easily recovered with their fully catalytic activities due to the hydrophobic and magnetic properties of the nanocomposites. It shows the great prospect for the 4-NP reduction in practice and is promising for wide applications in visible light catalytic reaction.

Adsorption is the common-used method to remove dyes from wastewater, and many efforts have been made to develop low-cost but excellent adsorbents. Here, calcium-rich biochar (CRB) as a low-cost adsorbent was directly prepared from crab shell via a simple pyrolysis process without any modification. Batch adsorption results suggested that CRB was among the dye adsorbents with highest adsorption capacities and fastest adsorption rate. Specifically, it showed high adsorption capacities of 12,502 and 20,317 mg/g for cationic malachite green and anionic Congo red, respectively. The adsorption equilibrium for Congo red onto CRB could be achieved as short as 2 min. Furthermore, the dye adsorption mechanism for CRB, as investigated by zeta potential and FTIR spectra, could be attributed to electrostatic attraction, hydrogen bonding and π-π interaction. Finally, this study suggested that, attributed to its cheap source, simple synthesis process and excellent adsorption performance, CRB was promising in dye removal.

A three-dimensional (3D) MoS

Three-dimensional network structure of konjac glucomannan/graphene oxide (KGM/GO) sponges was successfully prepared by ice template method. The KGM/GO sponges was rich in functional groups, negatively charged under pH 2 to 10. Batch adsorption experiment was conducted to investigate the adsorption performance of the as-prepared KGM/GO sponges for organic dye (malachite green (MG)) and radionuclide (uranium U(Ⅵ)). The results showed that the maximum adsorption capacities of KGM/GO sponges were 266.97, 189.96 mg/g for U(Ⅵ) and MG, respectively. Moreover, the KGM/GO sponges exhibited an excellent selectivity for capturing U(Ⅵ) in multi-ion system. The adsorption process was fitted better to pseudo-second order model, while adsorption isotherms for these pollutants were well matched up to Langmuir models. In addition, KGM/GO sponges can be easily separated from the aqueous solution and could be effectively reused for 5 times without obvious loss in adsorption performance. The advantages of eco-friendliness, low cost, simple preparation process, controllable shape and size, as well as high adsorption capacities for MG and U(Ⅵ), suggested that KGM/GO sponges promising in water pollution control.

In this paper, cotton stalk is used as a low-cost raw material source to prepare activated carbon with a unique porous structure with the assistance of chemical treatment. Gold nanoparticles as a multifunction building block were in situ assembled onto the carbon material, endowing this hybrid more promising applications. The as-fabricated CS carbon/AuNPs hybrid materials have been demonstrated to behave with catalytic and photothermal conversion properties, indicating that AuNPs successfully functionalise the activated carbon. The catalytic activity of the hybrid showed a glucose concentration-dependent effect (as low as 5 × 10−6 M). The water temperature of the sample containing the CS carbon/Au NPs increased rapidly, and even reached 55 °C, only exposed to light for 5 min. When used as catalyst of reduction of p-nitrophenol, the hybrid showed a good reusability up to10 cycles.

Silver nanoparticles/silica nanowires (AgNPs/SiO2NWs) with the nearly uniform diameters of 35 ± 5 nm were successfully fabricated by two steps consisting of the preparation of the silica nanowires (SNWs) by chemical dispersing and acid leaching from the natural mineral chrysotile and an in situ reduction approach (for AgNPs). The highly dispersed AgNPs assembled on the surface of SiO2NWs through the in situ reduction of Ag+ by NaBH4 were confirmed by transmission electron microscopy (TEM) and UV–vis absorption spectra. The catalytic activities of the as-prepared Ag/SiO2NWs (silver nanoparticles/silica nanowires) nanocomposites with different concentrations were assessed via using a classical reaction based on the reduction process of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) in the presence of NaBH4 as the reductant. The results demonstrated that all the nanocomposite catalysts exhibited high catalytic activities because the nearly monodispersed AgNPs were embedded on the surface of SiO2NWs, allowing...

In the present work, a composite material formed by bacterial cellulose (BC) and graphene oxide (GO) was synthesized and characterized. GO was added in the bacteria culture media and then the bacteria was inoculated. The BC/GO pellets composite was prepared into the bacteria culture media and vibrated in Erlenmeyer flask. Characterization of the BC/GO composite showed GO nanosheets embedded in the nanofibers network of BC. The experiments in this study demonstrated BC and GO effectively interacted by hydrogen bonding. Moreover, the cytotoxicity assays showed the material had a better biocompatibility than the counterparts and promoted the cell proliferation excellently. The biocompatibility of BC/GO has the potential to be used for drug delivery.

Electrocatalysts for the oxygen reduction reaction (ORR) in acidic media are crucial in proton-exchange membrane (PEM) fuel cells and other electrochemical devices. Achieving ideal ORR activity and durability in acidic media remains a challenge. Here, we developed a new NFeCo-CNT/NC nanocomposite electrocatalyst from the highly available and recyclable plant biomass Typha orientalis using a readily scalable approach. The electrocatalyst exhibits excellent ORR activity, superior stability and tolerance to methanol poisoning effects in acidic media. The value of the onset potential and half-peak potential of the typical product is only 70 mV and 65 mV less than that of Pt/C, respectively. The NFeCo-CNT and NFeCo-NC in the nanocomposite have synergistically enhanced ORR activities. The catalyst may have practical applications in fuel cells. One of the important accomplishments of this work is the discovery that trace Fe3+ and Co2+ can synergistically catalyze the growth of the carbon nanotubes when melamine serves as the CNT precursor.