Silica-silver nanocomposites (Ag-SBA-15) are a novel class of multifunctional materials with potential applications as sorbents, catalysts, sensors, and disinfectants. In this work, an innovative yet simple and robust method of depositing silver nanoparticles on a mesoporous silica (SBA-15) was developed. The synthesized Ag-SBA-15 was found to achieve a complete capture of Hg0 at temperatures up to 200 °C. Silver nanoparticles on the SBA-15 were shown to be the critical active sites for the capture of Hg0 by the Ag–Hg0 amalgamation mechanism. An Hg0 capture capacity as high as 13.2 mg·g–1 was achieved by Ag(10)-SBA-15, which is much higher than that achievable by existing Ag-based sorbents and comparable with that achieved by commercial activated carbon. Even after exposure to more complex simulated flue gas flow for 1 h, the Ag(10)-SBA-15 could still achieve an Hg0 removal efficiency as high as 91.6% with a Hg0 capture capacity of 457.3 μg·g–1. More importantly, the spent sorbent could be effectively regenerated and reused without noticeable performance degradation over five cycles. The excellent Hg0 removal efficiency combined with a simple synthesis procedure, strong tolerance to complex flue gas environment, great thermal stability, and outstanding regeneration capability make the Ag-SBA-15 a promising sorbent for practical applications to Hg0 capture from coal-fired flue gases.

Molecular dynamics simulation was used to investigate the adsorption of a polyaromatic compound (C5Pe) on silica surfaces from organic solvents. Heptane and toluene were used as oil phase to probe the effect of solvent properties on C5Pe adsorption. The results showed that C5Pe molecules tend to adsorb rapidly on silica surface in heptane and assemble to form long strip shaped aggregates, while in toluene C5Pe prefers to form aggregates which remain mostly in bulk oil phase. The van der Waals interactions were found to provide the largest contribution for driving the adsorption of C5Pe from heptane solutions due to the protonated state of C5Pe molecules. The calculated lower system free energy of C5Pe adsorption from heptane than from toluene corresponded well with the observed stronger adsorption of C5Pe from heptane than from toluene. AFM imaging confirmed the observed trend of C5Pe adsorption on silica from heptane and toluene.

•Porous membrane based on hydroxymethyl modified PEEK was fabricated as LIB separator.•The OHPEEK membrane exhibits 0% shrinkage until 160 °C.•The OHPEEK membrane shows 2.3-fold higher electrolyte uptake compared to PP membrane.•The LIB with OHPEEK membrane shows satisfactory rate and cycling performances.Hydroxymethyl functionalized poly(ether ether ketone) (OHPEEK) was exploited as the separator of lithium ion battery (LIB). The stable OHPEEK backbone endows the membrane with high anti-shrinkage property (0% until 160 °C and only 18.3% at 240 °C) and high thermal stability (degradation temperature up to 282 °C). Due to the abundant polar groups of the OHPEEK, the wettability of OHPEEK membrane is improved, reflected by that the contact angle reduces to 24.6 °C, and the electrolyte uptake rises to 204% at 30 °C. The OHPEEK membrane shows a higher conductivity in the electrolyte (1 M LiPF6/EC/DME) compared with the Celgard 2400 PP separator. As a result, the LIB with the OHPEEK membrane possesses 0.3%–36.8% higher discharge capacity at the C-rate from 0.1 to 4 C and satisfactory cycling performance.

•A novel process for combining Li and cathode material recycling is developed.•Ni, Co and Mn are co-extracted and separated with Li.•Li recovered as Li2CO3 with the purity of 99.2% is achieved.•The spherical cathode material LiNi1/3Co1/3Mn1/3O2 is directly regenerated.A novel process for extracting transition metals, recovering lithium and regenerating cathode materials based on facile co-extraction and co-precipitation processes has been developed. 100% manganese, 99% cobalt and 85% nickel are co-extracted and separated from lithium by D2EHPA in kerosene. Then, Li is recovered from the raffinate as Li2CO3 with the purity of 99.2% by precipitation method. Finally, organic load phase is stripped with 0.5 M H2SO4, and the cathode material LiNi1/3Co1/3Mn1/3O2 is directly regenerated from stripping liquor without separating metal individually by co-precipitation method. The regenerative cathode material LiNi1/3Co1/3Mn1/3O2 is miro spherical morphology without any impurities, which can meet with LiNi1/3Co1/3Mn1/3O2 production standard of China and exhibits good electrochemical performance. Moreover, a waste battery management model is introduced to guarantee the material supply for spent battery recycling.Download high-res image (220KB)Download full-size image

(2,3-Dimethylbutyl)(2,4,4′-trimethylpentyl)phosphinic acid (INET-3) was impregnated onto dry macroporous resins XAD-16 and pretreated XAD-16 with ethyl alcohol and HCl (Pre-XAD-16) to prepare the solvent impregnated resins SIRs-INET-3/XAD-16 and SIRs-INET-3/Pre-XAD-16. The molecular weight distribution of the low molecular weight (LMW) polymers washed off by ethyl alcohol during XAD-16 pretreatment was determined by gel permeation chromatography (GPC). The macroporous resins (XAD-16 & Pre-XAD-16), the corresponding solvent impregnated resins (SIRs-INET-3/XAD-16 & SIRs-INET-3/Pre-XAD-16) and the PVA coated SIRs-INET-3/Pre-XAD-16 with boric acid as cross-linking agent were characterized by FT-IR, SEM-EDS and TGA. The effects of XAD-16 pretreatment and PVA coating technology on RE(III) adsorption equilibrium time, INET-3 losses during extraction and adsorption capacity were investigated. The adsorption kinetics, selectivity and stripping behaviors of SIRs-INET-3/XAD-16 were further studied. The washed off LMW polymers had the Mn of 36,656, Mw of 40,310 and polydispersity coefficient of 1.10. The SIRs-INET-3/XAD-16 had shorter equilibrium time, less INET-3 loss and more Tm(III) adsorption capacity than the SIRs-INET-3/Pre-XAD-16. The PVA coated SIRs-INET-3/Pre-XAD-16 had less INET-3 loss and more Tm(III) adsorption capacity but longer equilibrium time than the uncoated SIRs-INET-3/Pre-XAD-16. The adsorption of RE(III) on the SIRs-INET-3/XAD-16 followed the pseudo-second-order kinetic model. The Tm(III) accumulative adsorption amounts onto SIRs-INET-3/XAD-16 after eight extraction stages was 23.6 mg/g. The separation factors of adjacent heavy RE(III) βEr/Ho, βTm/Er, βYb/Tm and βLu/Yb values were 1.76, 2.59, 2.56 and 1.19, respectively. The adsorbed Lu(III) onto the SIRs-INET-3/XAD-16 can be stripped completely by 1.0 mol/L H2SO4.

•A magnetically responsive catalytic sorbent is designed and synthesized.•The catalytic sorbent shows excellent performance of Hg0 and NO removal at 150 °C.•The catalytic sorbent can maintain good stability after repetitive regeneration and recycle.•The possible mechanism of simultaneous removal of Hg0 and NO is proposed.•The silica coating method has been improved to form a densely packed silica films on the surfaces of Fe3O4 particles.A novel class of magnetically responsive catalytic sorbents are proposed and synthesized with a potential application to simultaneous removal of Hg0 and NO at low temperature from the flue gases of coal-fired power plants. The catalytic sorbent consists of magnetite (Fe3O4), molecular sieve (HZSM-5), supported silver nanoparticles and catalytically reactive component of V2O5. Each of these materials provides a unique function for the purpose of capturing mercury, removing NO, and separation from fly ash. After separation from the fly ash, the spent sorbent can be regenerated and reused, leaving an uncontaminated fly ash product. The successful synthesis as designed was confirmed and properties of the catalytic sorbent were characterized by several methods. The synthesized catalytic sorbent was able to completely capture Hg0 at 150 °C with a capture capacity as high as 32.4 μg·g−1, while achieving 84% removal of NO at 150 °C. Even at a relatively high space velocity, the catalytic sorbent achieved 97% Hg0 and 80% NO removal simultaneously, while maintaining a good stability after repetitive regeneration and recycle. The magnetically responsive catalytic composite was shown to be a promising candidate for multi-pollutant emission control from coal-fired power plants.Download high-res image (391KB)Download full-size image

•Anion exchange membranes with efficient ion transport channels are fabricated.•Membrane ion channels are formed due to the aggregation of imidazolium groups.•The hydroxide conductivity of membranes is correlated with effective ion mobility.•The nano-size of filler particles allows precise tuning of membrane ion channels.Imidazolium-functionalized octaphenyl polyhedral oligomeric silsesquioxane nanoparticles were incorporated into imidazolium-functionalized poly(ether ether ketone) (ImPEEK) to fabricate high-performance anion exchange membranes with tuneable microphase separation structures and efficient ion transport channels. High-resolution transmission electron microscopy observations revealed the formation of ion channels in the membranes due to the aggregation of imidazolium groups. The transport of hydroxide ions in the composite membranes was facilitated by the increase in the effective ion mobility from 2.27×10−4 to 3.09×10−4 cm2 s−1 V−1, while their hydroxide conductivity at 30 °C (36.22–44.11 mS cm−1) was significantly higher than that of an ImPEEK control membrane (30.66 mS cm−1).

As a relatively new extractant, di-(2,3-dimethylbutyl)-phosphinic acid (HYY-2) is more efficient to separate heavy rare earths Tm/Yb/Lu than Cyanex 272 and P507. In this paper, HYY-2 was synthesized in our lab, and the extraction equilibrium, thermodynamics and stripping acidity for La, Gd and Y, which stood for light rare earth elements (REE), middle REE and heavy REE respectively, from nitrate media with this extractant were investigated. Meanwhile, extraction ability, capacity and stripping acidity of HYY-2 were investigated and compared with those of Cyanex 272 and P507. The separation performance for rare earth element couples Gd/Eu and Er/Y were also studied. Compared to Cyanex 272, it possessed higher extraction capacity; while compared with P507, it has lower stripping acidity. The maximum βGd/Eu 1.46 occurred at pHequilibrium=2.78 and the maximum βEr/Y was 1.47 when pHequilibrium= 2.01.Extraction percentages E of rare earth ion Er3+ by HYY-2, P507 and Cyanex 272 under different pH values (CEr3+: 4×10−4 mol/L; CNaNO3=0.1 mol/L; CHL=1.0×10−2 mol/L)

In this paper, ZnO microspheres, which are composed of irregular nanoparticles, have been synthesized successfully from a metal-organic precursor. The average diameter is about 3.5 μm and the specific surface area is 7.53 m2 g−1. Measured by electrochemical tests as electrode materials for supercapacitors, the ZnO powders show high specific capacitances (1017.5 Fg−1 at 5 Ag−1 and 562.5 Fg−1 at 50 Ag−1, respectively) and excellent cycling stability (the specific capacitance was kept at 631.2 Fg−1 and 89.2 % retention after 3000 cycles at 18 Ag−1). These results show that the microspherical ZnO could be a potential electrode material for supercapacitors.

A carbon black/MnO2 nano-composite (CB/MnO2) of coral-like architecture was synthesized from a commercially available conductive carbon black (CB) using an in situ method. The morphology and structural analysis of the synthesized CB/MnO2 revealed 10 nm thick MnO2 nano-sheets grown on the CB. The MnO2 nano-sheets of poorly crystalline δ-MnO2 birnessite structure assembled into a coral-like architecture. Energy dispersive X-ray (EDX) microanalysis showed high Mn content in the composite. Electrochemical tests using the synthesized CB/MnO2 showed a specific capacitance of 946 F g−1 at a current density of 0.3 A g−1, which was much higher than that of the composites reported in the literature. Under a current density of 30 A g−1, the CB/MnO2 electrode was shown to retain a high specific capacitance after 5000 charge/discharge cycles. The results from this study demonstrate that the CB/MnO2 nano composite materials of coral-like architecture fabricated with commercially available CB and MnO2 achieved a good electrochemical performance, exhibiting promising application prospects.

Through a facile hydrothermal method with a special surfactant triethanolamine (TEA) followed by thermal treatment, monodispersed micro-/nanostructured Co3O4 powders with unique morphology (cube) have been synthesized successfully as anode material for Li-ion batteries (LIBs). The regular Co3O4 microcubes (∼2.37 μm in the average side length) consist of many irregular nanoparticles (20–200 nm in diameter, 30–40 nm in thickness) bonded to each other, which greatly inherit the morphology and size of the precursor CoCO3. The specific surface area of Co3O4 powders is about 5.10 m2·g–1 by the Brunauer–Emmett–Teller (BET) method, and the average pore size is about 3.08 nm by the Barrett–Joyner–Halenda (BJH) method. In addition, the precursor is verified as a single-crystal, while the mesoporous cubic Co3O4 is a polycrystalline characteristic assembled by numerous single-crystal nanoparticles. More remarkable, the high performance of the micro-/nanostructured cubic Co3O4 powders has been obtained by the electrochemical measurements including high initial discharge capacities (1298 mAhg–1 at 0.1 C and 1041 mAhg–1 at 1 C), impressive rate capability, and excellent capacity retention (99.3%, 97.5%, 99.2%, and 89.9% of the first charge capacities after 60 cycles at 0.1 C, 0.2 C, 0.5 C, and 1 C, respectively).Keywords: cobalt oxide; cube; enhanced rate capability; lithium-ion batteries; mesoporous; micro-/nanostructured;

In this study, novel core–shell ellipsoidal MnCo2O4 powders with desired micro/nano-structure and a unique concentration gradient have been synthesized as anode material for Li-ion batteries. The special porous ellipsoid (2.5–4.5 μm in the long axis, 1.5–2.5 μm in the short axis, 200–300 nm in the thickness of shell) is built up by irregular nanoparticles attached to each other, and corresponding to the ellipsoid with concentration gradient, the Co/Mn atomic ratios of core and shell are about 1.76:1 and 2.34:1, respectively. The good performance, including high initial discharge capacities (1433.3 mAhg–1 at 0.1 Ag–1 and 1248.4 mAhg–1 at 0.4 Ag–1), advanced capacity retention (∼900.0 mAhg–1 after 60 cycles at 0.1 Ag–1), and fair rate performance (∼620.0 mAhg–1 after 50 cycles at 0.4 Ag–1) has been measured by the battery test. Remarkably, the ellipsoidal shape and core–shell microstructure with concentration gradient are still maintained after 70 cycles of charge/discharge at 0.1 Ag–1.Keywords: concentration gradient; core−shell; electrochemistry; ellipsoidal; micro/nano-structure; MnCo2O4

Co3O4 is commonly used as a potential anode material for Li-ion batteries (LIBs). In this study, novel porous polyhedral and fusiform Co3O4 powders have been synthesized successfully through the hydrothermal method with different solvents followed by thermal treatment. It is shown that both of the polyhedrons (1.0-3.0 μm in side length) and the spindles (2.0-5.0 μm in length, 0.5-2.0 μm in width) are composed of similar irregular nanoparticles (20-200 nm in diameter, 20-40 nm in thickness) bonded to each other. Evaluated by electrochemical measurements, both of them have high initial discharge capacities (1374.4 mAhg−1 and 1326.3 mAhg−1) and enhanced cycling stabilities at the low rate (the capacity retention ratios at 0.1 C after 70 cycles are 91.6% and 92.2%, respectively). However, the rate capability of the spindles (93.8%, 90.1% and 98.9% of the second discharge capacities after 70 cycles at 0.5 C, 1 C and 2 C, respectively) is better than the polyhedrons’ (only 76.2%, 42.1% and 59.3% under the same conditions). Remarkable, the unique morphologies and special structures may be extended to synthesize other similar transition metal oxides (NiO, Fe3O4, et al.) as high performance anodes for LIBs.

•Micro monodispersed CoCO3 spheres (5.0 µm in diameter) have been synthesized through the hydrothermal method.•The micro-spherical CoCO3 powders show large initial discharge and charge capacities (1669.3 mA h g−1 and 1099.8 mA h g−1) at 200 mA g−1.•The micro-spherical CoCO3 powders show good cycle stability (the reversible capacity is about 600.0 mA h g−1 after 66 cycles at 200 mA g−1).In this paper, micro-spherical CoCO3 powders have been synthesized through the hydrothermal method. The specific surface area is 1.48 m2 g−1 and the average diameter is about 5.0 µm. Measured by the electrochemical tests as anode materials for lithium-ion batteries, the high performance has been proved: the initial discharge and charge capacities are 1669.3 mA h g−1 and 1099.8 mA h g−1 at 200 mA g−1, and the discharge capacity retention ratio (vs. the second discharge capacity) is about 64.5% after 20 cycles, then the reversible capacity nearly keeps a constant between 700.0 mA h g−1 and 600.0 mA h g−1 from the 20th cycle to the 66th cycle. It indicates that the CoCO3 powders maybe possess the potential application in this field.

Three 2-mercaptobenzimidazole derivatives, 1-ethyl-2-mercapto-benzimidazole (EMBI), 1-propyl-2-mercapto-benzimidazole (PMBI) and 1-benze-2-mercapto-benzimidazole (BMBI), were designed and synthesized in the paper, and their collecting behavior in flotation separation process of galena over pyrite was investigated by flotation tests on lab scale. Apart from this, density functional theory (DFT) calculation and molecular dynamics (MD) simulation were also used to elucidate their collecting mechanism. Results of flotation tests indicate that separation of galena over pyrite is feasible at pH 10, and BMBI has the best floatability among three collectors. DFT calculations show that BMBI has the highest occupied molecular orbital (HOMO) energy and strongest collecting efficiency. The adsorption mode of three collectors on mineral surface by MD method indicates that the combination processes of collectors with mineral are exothermic, and the higher the binding energy, the firmer the collector adsorbs on the mineral surface and the higher collecting capacity. The calculation results demonstrate that the floatability of three collectors follows the order: BMBI > PMBI > EMBI, which is highly consistent with the flotation tests.

The LiNi1/3Co1/3Mn1/3O2 is first obtained by the controlled crystallization method and then coated with Ni3(PO4)2 particles. The effects of the coating on rate capability and cycle life at high cut-off voltage are investigated by electrochemical impedance spectroscopy and galvanostatic measurements. The element ratio of Ni:Mn:Co is tested by inductively-coupled plasma spectrometer (ICP) analysis and it testified to be 1:1:1. It is indicated that Ni3(PO4)2-coated LiNi1/3Co1/3Mn1/3O2 has an outstanding capacity retention, where 99% capacity retention is maintained after 10 cycles at 5C discharge rate between 2.7 V and 4.6 V. The electrochemical impedance spectroscopy (EIS) results show that the current exchange density i0 of the coated sample is higher than that of LiNi1/3Co1/3Mn1/3O2, which is beneficial to its electrochemical performances. All the conclusions show that the Ni3(PO4)2 coating can prominently enhance the high rate performance of the LiNi1/3Co1/3Mn1/3O2, especially at high cut-off voltage.It is apparent from the figure that there are some cotton-like particles deposited on the surface of LiNi1/3Co1/3Mn1/3O2. These particles are identified as Ni3(PO4)2, and the Ni3(PO4)2 layer reaches about 20 nm. So the HRTEM can further demonstrate the existence of the surface coating of Ni3(PO4)2. The generated HF from the electrolyte attacks the surface of the cathode and accordingly the metal ions in the surface (Ni, Co, Mn) dissolve into the electrolyte. After coating, the existence of Ni3(PO4)2 coating can effectively prevent the fatigue of the particles during the continuously cycling at high voltage and keep the structural stability.Download full-size image