The effects of homogenization treatments on the precipitation behavior of Al3(Er,Zr) particles and theirs effects on recrystallization resistance in a new type Al-Zn-Mg-Er-Zr alloy have been investigated. Four different homogenization treatments, conventional one-stage homogenization, double-stage homogenization and ramp heating homogenization are carried out. Compared with that in the conventional one-stage homogenization, a finer particle size, higher number density and volume fraction of Al3(Er,Zr) particles can be obtained in other three homogenization treatments. In addition, the double-stage homogenization and the ramp heating homogenization can improve the Al3(Er,Zr) particles distribution and minimize the width of precipitation free zone in the region near the grain boundary, and provide an additional but nonnegligible strengthening effect for the Al-Zn-Mg-Er-Zr alloy. The difference in precipitation behavior of Al3(Er,Zr) particles lead to different recrystallization resistance. The high recrystallization resistance can be attributed to the larger fV/r ratio of Al3(Er,Zr) particles, which resulting in a higher Zener drag to effectively resist the recrystallization in Al-Zn-Mg-Er-Zr alloy during hot deformation and the subsequent thermal processing. Therefore, under the same annealing time, the double-stage homogenized and the ramp heating homogenized samples can achieve a significant lower recrystallized fraction compared with the conventional one-stage homogenized samples.

A strategy that visible-light responsive zeolitic-imidazolate-framework-67 (ZIF-67) encapsulates noble-metal sensitized semiconductors, ZnO@M (M = Au, Pt, and Ag) to fabricate composite catalysts for photoelectrochemical (PEC) water splitting is proposed. The obtained ZnO@M@ZIF-67 catalysts have good catalytic performance, particularly, the ZnO@Au@ZIF-67 exhibits quite improved photoconversion efficiency and photocurrent density, superior to most of the reported photoelectrode catalysts. This can be attributed to the wider solar spectra harvesting capability originating from visible-light responsive ZIF-67 and UV-light active ZnO. Simultaneously, their integration enables interfacial electrons in the ZIF-67 shell to easily transfer to the ZnO@Au core, providing good electron–hole separation. In addition, the porous ZIF-67 as a protective shell ensures structural robustness, while maintaining fast ion or gas bubble diffusion through its pores, accounting for stable and excellent PEC performance.

CoAl-based layered-double-hydroxide@zeolitic-imidazolate-framework-67 (LDH@ZIF-67) was fabricated via a hydrothermal synthesis of LDH film on Ni substrate followed by the in situ growth of ZIF-67. Its derivatives, MMO@Co3O4, spinelle@C and LDH@CoS with hierarchical structures were obtained by the subsequent oxidation, carbonization and sulfurization of LDH@ZIF-67, respectively, which exhibit distinct specific capacitances of 692, 781 and 1205 F g−1 at a discharge current density of 1 A g−1. Interestingly, these derivatives retained hierarchical structures with large surface area, which ensures that the majority of exposed active species can participate in the charge–discharge process and thus effectively contribute to total capacitances. The synergistic effect from fast electronic transfer reduces reversible ion accumulation at the interface, which imparts LDH@ZIF-67 derivatives improved electrochemical activities, in contrast to conventional bulk MOF derivatives. In addition, it was found that the combination of the remarkable electrical conductivity of sulfides (compared with their oxide counterparts) and the strong electronic coupling between LDH and CoS can facilitate fast electron transfer. As a result, LDH@CoS exhibits an excellent specific energy of 44.5 W h kg−1 at a current density of 20 A g−1, as well as good capacitance retention of 88.5% after 2000 cycles. This work thus demonstrates a feasible strategy for the design and fabrication of LDH@MOF derived composites as SCs components, which is applicable in constructing other novel electrode materials with hierarchical structures for applications in energy storage systems.

Isothermal compression tests of a new type Al–Zn–Mg–Er–Zr alloy are carried out on a Gleeble-3800 thermal simulator at temperatures varying from 300 to 460 °C and strain rates ranging from 0.001 to 10 s−1. A comprehensive and scientific constitutive models based on the Arrhenius type equation have been developed from the experimentally measured data. The deformation temperature and strain rate have significant effect on flow stress and the material constants, such as α, β, n, ln A and Q are the functions of the strain. The flow stress calculated by the developed constitutive equation shows a close agreement with the experimental value, which indicates that the proposed constitutive equation can precisely analyze the hot deformation behavior of the Al–Zn–Mg–Er–Zr alloy. Due to the presence of coherent L12-structured Al3(Er,Zr) precipitates, the dominant softening mechanism is dynamic recovery during isothermal compression.

Silica aerogels from wheat husk ash (WHA) were prepared via a sol–gel process by ambient pressure drying. Silica was extracted from WHA by NaOH solution to form sodium silicate, which was used as precursor for aerogels. Silica wet gels were synthesized by resin-exchange-alkali-catalysis of the sodium silicate solution, followed by solvent exchange with ethanol (EtOH) and hexane in turn. Consequently, a mixture of trimethylchlorosilane, EtOH and hexane was used for surface modification of the wet gels in order to obtain hydrophobic silica aerogels. The density, pore structure, hydrophobic property and thermal insulation property of the obtained silica aerogels were investigated in detail. The results show that the formation of silica aerogels can be successfully realized at a SiO2/H2O weight ratio varying from 0.065 to 0.167. Silica aerogels possess a desirable pore structure with a surface area ranging from 513 ± 5 to 587 ± 6 m2/g, a pore volume from 2.3 ± 0.3 to 4.0 ± 0.1 cm3/g and a pore size from 9 ± 2 to 15 ± 1 nm, an outstanding hydrophobic property with a water contact angle of 147 ± 0.1° and a distinguished thermal insulation property with a low thermal conductivity ranging from 0.009 ± 0.0001 to 0.012 ± 0.0002 W/(m·K).

Mesoporous organic–inorganic hybrid silica with ethylidene bridging group between two silicon atoms was prepared via a sol–gel and hydrothermal synthesis process by using silsesquioxane (1,2-bis(triethoxysilyl) ethane, BTESE) as silicon source and triblock copolymer poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (P123) in combination with dodecyltrimethylammonium bromide (DTAB) as template. Factors that affect the morphology and pore structure of silica particles were investigated in detail by means of scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption. The results show that the sphericity and surface smoothness of organic–inorganic hybrid silica are distinctly enhanced with increasing amount of DTAB and hydrochloric acid. Meanwhile, suitable synthesis time and crystallization temperature are beneficial to the formation of silica spheres with improved sphericity. The organic–inorganic hybrid silica spheres prepared with a DTAB/BTESE molar ratio of 0.8, a HCl/BTESE molar ratio of 6, an aging time of 24 h and a crystallization temperature of 100 °C exhibit a particle size of around 1.7 µm, a high surface area of 1063.35 m2 g−1 and a narrow pore size distribution centered at 3.12 nm.

As-annealed commercial pure titanium was selected as a model material with hexagonal close-packed (hcp) crystalline structure. Dislocation boundaries with different spacing values were prepared by cold rolling at various reductions. The influence mechanism of the initial dislocation boundaries on the adiabatic shear sensitivity of commercial pure titanium was investigated from two aspects: related dynamic mechanical response and dislocation boundary configuration. The geometrically necessary dislocation boundaries (GNBs) with spacing values of 550 nm, 340 nm and 107 nm were induced by cold rolling. The narrower the spacing of the GNBs was, the more sensitive the adiabatic shearing behavior was, which was attributed to the shear stress and adiabatic temperature rise. A narrow spacing of GNBs shortened the mean free path of dislocation slipping; as a result, the deformed resistance and accumulated plastic deformation work became larger. Therefore, the adiabatic temperature rise that was converted from plastic deformation work increased, thereby strengthening the material's adiabatic shear sensitivity.

A study on the precipitation hardening and recrystallization behavior of dilute Al–Er–Hf and Al–Er–Hf–Zr alloys has been carried out. The results show that both Al–0.045Er–0.18Hf and Al–0.045Er–0.08Zr–0.1Hf alloys can obtain remarkable age strengthening effect and recrystallization resistance. The precipitation hardening rate of Al–0.045Er–0.08Zr–0.1Hf is accelerated compared with that of the Al–0.045Er–0.18Hf alloy due to substituting 0.08 at% Zr for Hf, which can be ascribed to the sequential precipitation of solute elements on the basis of the disparity in their intrinsic diffusivities (DEr>DZr>DHf). The peak hardness values for the Al–0.045Er–0.08Zr–0.1Hf are 644 MPa and 662 MPa after isochronal aging to 450 °C and isothermal aging at 350 °C for 84 h, respectively, which are higher than those of the Al–0.045Er–0.18Hf alloy. The recrystallization temperature of Al–Er–Hf–Zr alloy is 450 °C, about 25 °C higher than that of the Al–Er–Hf alloy due to the larger f/r ratio of precipitates in Al–Er–Hf–Zr alloys.

The purposes of this study are to quantify the natural resource consumption of primary aluminum production in China and to determine the resource-saving potential of aluminum in the transportation sector relative to steel.In this study, exergy, which expresses both the quantity and the quality of a resource, was adopted for natural resource accounting. The cumulative exergy demand (CExD) of primary aluminum was calculated by the process analysis method, which begins in the final link of the fabrication of the considered product and runs through the production of semifinished products. This method can provide detailed information about each process.The CExD value of 1 t of primary aluminum produced in China is 246,778 MJex, and the largest contributor to the CExD is electricity, which is mainly consumed in the electrolytic process. Compared with the CExD derived from the national average resource consumption data of alumina production (three techniques), if alumina was only produced by the Bayer process, the CExD of primary aluminum would decrease by 10 %. Taking wheel hubs as a case study, although aluminum wheel hubs have a lower natural resource consumption rate during the use phase relative to steel wheel hubs, no natural resource savings are obtained before a certain driving distance (breakeven distance) is reached because of higher resource consumption in the production phase. The total amount of natural resources that aluminum wheel hubs could save (relative to steel wheel hubs) over its lifetime driving distance is 3,652 MJex. In contrast, the breakeven distance derived from the CML model is approximately 80 % lower than that derived from the CExD model.A determination of the advantages of the Bayer process in terms of resource saving suggests that importing high-grade bauxite from abroad to promote the application of the Bayer process is an effective way to reduce primary aluminum’s CExD, i.e., resource intensity, in China. A comparison of the characterization results between the CML model (China’s own factors) and the CExD model shows that the CExD model assigns more weight to coal than to minerals, whereas the CML model assigns more weight to minerals.

Precipitation strengthening was investigated in dilute Al–Er, Al–Hf and Al–Er–Hf alloys. Combined addition of 0.045 at.% Er and 0.18 at.% Hf in Al gives a maximum hardness of 640 MPa, which is significantly higher than that of the Al–0.18Hf and Al–0.045Er alloys. The remarkable strengthening can be attributed to the addition of Er, which accelerates the precipitation kinetics and stimulates the decomposition of Al–Hf. The effect of Er and Hf on precipitation strengthening in Al–Er–Hf alloys is discussed.

Recovery processes of secondary resources usually encounter problems because of the diverse compositions of wastes. To enhance the applicability of traditional hydrometallurgical process toward secondary resources, the adjustment of components is necessary. In traditional hydrometallurgical separation, precipitation and complexation are extensively used. However, their combination as a specific metal separation method has not yet been studied in detail. This approach is very promising for solving problems caused by changeable components during recycling processes of secondary resources. This paper reviews the effects of precipitation and complexation in metal separation processes, and a metal separation method system of “complexation–precipitation” developed to adjust the components of secondary resources is introduced.

The theoretical simulations and experiments on metal separation in complexation–precipitation system of Me(Ni, Co, Mn)–OH−–NH3–CO32- were carried out. The Gibbs free energy change ΔG for metal precipitation reactions was calculated. The ΔG–pH curves showed that the precipitation difficulty order was Mn > Co > Ni at pH range of 8–11. Separation experiments indicated that Mn and Co were able to precipitate successively in solution of different compositions mainly in the forms of carbonates. pH, initial carbonate concentration [C] and initial ammonia concentration [N] had different influence on Ni, Co and Mn precipitation behaviors: the separation effect was best at about pH 10; [C] had little effect on the metal separation in the [C] range of 0.05–0.4 mol/L; changing [N] could regulate precipitation step by step, as Ni in solution and Mn/Co in precipitate at [N] 1 mol/L, and Ni/Co in solution and Mn in precipitate at [N] 2.5 mol/L. The experimental results basically consisted with the theoretical predictions. The Ni solution after Mn/Co precipitation could be electrodeposited to obtain Ni metal. Finally a separation process in complexation–precipitation system of Me(Ni, Co, Mn)–OH−–NH3–CO32- characterized by the theoretical simulation was proposed, of which the Ni, Co and Mn precipitation could be predicted or controlled by flexibly importing parameters of [C], [N], pH, etc. The process can provide a reference to metal comprehensive recovery from similar nickel–cobalt secondary resources.Highlights► Ni, Co and Mn separation was studied in complexation–precipitation system of OH−–NH3–CO32-. ► Theoretical simulation combined experimental method were employed. ► Mn and Co were precipitated mainly as carbonates step by step. ► Ni was electrodeposited from the solution after Mn and Co precipitation.

The carbon-based lead foam was produced by electrodepositing a uniform and dense lead coating on lightweight carbon foam in fluoborate system under appropriate conditions. The cyclic voltammetry showed that its electrochemical properties resembled the metallic pure lead. A lead acid battery equipped with the carbon-based lead foam as positive current collector undergone a charge–discharge test. The battery had a high discharge capacity and a good cycling stability, which indicated that the carbon-based lead foam could serve as positive current collector. The three-dimensional net structure of carbon-based lead foam provides larger surface area than traditional lead alloy grids, thus enhances the specific capacity of lead acid battery. The carbon-based lead foam might be a promising substitute for lead alloy grids.

Siliceous mesocellular foam (MCF) with tunable cell and window size was synthesized by the acid catalyzed sol–gel reaction of tetraethoxysilane in the presence of triblock copolymer Pluronic P123 (EO20PO70EO20) as structure-directing agent. The cell’s size of MCF is increased with the increase of 1,3,5-trimethylbenzene amount, while the window’s size of MCF could be tailored between 4 and 18.2 nm without affecting the cells size by adding of NH4F. The obtained MCF materials were employed as carriers for catalase immobilization. FT-IR spectra and N2 sorption show that the catalase is immobilized into the mesopores of MCF. MCF with window size of 12.9 nm shows high catalase loading and activity, suggesting that matching the window’s size with enzyme molecular diameter is a critical factor in attaining efficient immobilization since smaller window size prevents larger enzyme from entering the pore and larger window size causes the leakage of enzyme. The thermal and storage stabilities of the immobilized catalase were also improved due to the shield of the mesopores of MCF.

Cobalt is widely used in batteries, carbide, and many other industries due to its good performance. Secondary cobalt powder is an important source of cobalt. The performance of secondary cobalt and ore cobalt are studied in this paper. Secondary cobalt carbonate and ore cobalt carbonate possess monoclinic structures, but the secondary cobalt carbonate XRD diffraction peak half-width is more than twice the ore cobalt carbonate. In addition, the continuity of lattice fringes of secondary cobalt carbonate is poorer than the ore cobalt carbonate, so the crystallization of secondary cobalt carbonate is not as good as the ore. One-step production of the metal produces cobalt with a face-centered cubic structure. However, even though the structure performance of the secondary cobalt has greatly improved, the crystallization of ore cobalt remains better than that of secondary cobalt. The two-step product is close-packed hexagonal metal cobalt, and the ore cobalt product prepared using a two-step (air + H2) method is better than that from secondary cobalt. The structure and properties of secondary cobalt product prepared using a two-step (N2 + H2) method can achieve structural performance equal to that of the ore. The optimum sintering temperature for Co powders is 825–850 °C, and the relative density can be greater than 97%. The hardness of secondary cobalt is higher than that of ore cobalt.Highlights► The FWHM values of the secondary cobalt are more than twice the ore. ► The structural performance of the secondary cobalt has reached that of the ore cobalt. ► The relative density above can achieve 97% in 825–850 °C. ► The hardness of secondary cobalt is higher than that of the ore cobalt.

Core-shell nanospheres with a nanosize Co3O4 core and a periodic mesoporous organosilica (PMO) shell were fabricated by the packing and self-assembly of nanosize Co3O4 particles–surfactant–organosilica complexes based on the S+I− pathway under basic conditions. The amount of Co3O4 nanoparticles is crucial to the formation of core–shell nanospheres. The obtained nanospheres possess a uniform particle size of 130 nm, a high surface area of 474.1 m2g−1 and a large pore volume of 0.68 cm3g−1, which are highly advantageous to the immobilization of Microperoxidase-11 (MP-11). The presence of Co3O4 nanoparticles could enhance the activity of immobilized MP-11, probably due to their peroxidase activity.

The microstructure and microstructural evolution were investigated near crater wall in Al–Cu–Mn alloy using optical and transmission electron microscopy (TEM) after projectile impaction. The results show that three characteristic zones around the crater can be classified based on the different microstructure, i.e. deformation bands, dynamic recovery zone and adiabatic shear bands (ASBs). The TEM observation indicates that the dislocation glide plays a crucial role in the formation of that microstructure during projectile impact. The adiabatic shear bands were formed near the crater wall and extend into matrix. It can be found that fine grains were formed within the adiabatic shear bands by dynamic recrystallization occurring during projectile impact. The micro-cracks have been developed along the adiabatic shear bands. However, It is demonstrated that the formation of deformation bands are favorable for improving anti-impact property of Al–Cu–Mn alloy, but adiabatic shear bands are easily to initiate micro-cracks, leads to the failure of target material.Graphical abstractThe TEM image of the characteristic microstructure around the crater in 2519-T87 aluminum alloy target impacted at a velocity of 584 m/s. (a) subgrains, (b) dynamic recrystallization grains, and (c) micro-bands.Highlights► Three characteristic zones around the crater were classified. ► Dynamic recrystallization behavior were found in the adiabatic shear bands. ► The micro-cracks formed in the adiabatic shear bands. ► The dislocation slipping plays a critical role in the microstructure evolution.

AbstractLife cycle assessment (LCA) is a technique for systematically analyzing the environmental impacts and resources used throughout a target's life cycle, i.e. from raw material acquisition, via production and use phases, to waste management. It is an effective tool that gives a detailed information of environmental profiles of a material or a product. More importantly, the value of life cycle thinking lies in its ability to provide the decisionmaking basis for sustainable development, making the products, industries and even the whole industry chain act more in line with the principles of sustainable development. The recent developments of LCA methods and applications of materials life cycle assessment in China were reviewed. In the sections on LCA methodology, the data quality analysis, the impact of land use and abiotic resource depletion as well as the weakness in life cycle impact assessment were discussed. In relation to the applications, the Chinese materials database (SinoCenter Database) and several representative case studies such as life cycle analysis of civilian buildings and metal production in China were introduced.

The annealing behavior of a modified 5083 aluminum alloy was studied in the temperature range of 125–375 °C with different holding times. The results shown that the annealing temperature was more sensitive to the mechanical and corrosion resistance properties compared with the annealing holding time. The mechanical and corrosion resistance properties depend on annealing treatment due to different dislocation configuration in the matrix and the second phase interface, annealing temperature and time have been optimized for both of those properties improvement.

Large pore ordered mesoporous organosilicas (OMOs) with distinct mesophase structure was synthesized under low temperatures by the co-condensation of 1,2bis(triethoxysilyl)ethane (BTESE) and tetraethyl orthosilicate (TEOS) in acidic solution, using triblock copolymer F127 as a template and 1,3,5-trimethylbenzene (TMB) as a swelling agent. With the decrease of temperature, a mesophase transformation from 2D hexagonal structure (p6mm) via mesostructured cellular foam to a highly ordered 3D cubic structure (Fm3m) was evidenced by small angle X-ray diffraction (SAXS), transmission electron microscopy (TEM) and N2 sorption. It reveals that the lower synthesis temperatures may influence the hydrolysis and condensation of silica species and the hydrophilic–hydrophobic property of F127, as well as the swelling capacity of F127 micelles with TMB, which resulting in a formation of large pores ordered mesoporous organosilicas with various mesostructures materials. Finally, the enzyme adsorption properties of the OMOs were investigated and the results showed that the OMOs with a 3D large pore structure and regular morphology is much more qualified for enzyme adsorption.Ordered mesoporous organosilicas materials with ultra-large pores were synthesized by the modified low temperature route and a mesophase transformation from p6mm to Fm3m with the temperatures decreasing from 20 to 8 °C can be observed.

Bifunctional periodic mesoporous organosilicas (PMOs) with ethane bridging groups within the framework and various amounts of terminally bonded groups in the pore channels was synthesized by the co-condensation of 1,2-bis(triethoxysilyl)ethane (BTESE) and 3-glycidoxypropyltrimethoxylsilane (GPTMS) in the presence of triblock copolymer poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (P123) surfactants under acidic conditions and utilized as supports for enzyme immobilization. It is revealed that glycidoxypropyl groups have been successfully covalently attached to the pore wall of PMOs and a fraction of them have experienced epoxy ring opening reaction to form diol groups. The functional materials still preserve a mesoscopic ordering at a concentration of GPTMS as high as 10% in the reaction mixtures. The BET surface area, pore volume and pore size of the functionalized materials decrease with increasing amount of GPTMS, but a desirable pore structure remains when the GPTMS amount increases to 10%. The coexistence of the epoxy groups and the diol groups provides an efficient two-step covalent enzyme immobilization mechanism. The bifunctional PMOs materials exhibit higher papain immobilization efficiency and stability than pure PMOs because of the covalent interaction between the amino groups of papain and the epoxy groups of functionalized PMOs.

A model with Chinese characterization factors for quantifying the damages to environment by land use in terms of the change in net primary productivity (NPP) of ecosystem was developed in the framework of life cycle assessment (LCA). In this method, the forms of land utilization were divided into two aspects involving long-term use of land (e.g., for arable farming), namely “land occupation“, and the change of land properties (e.g., from agricultural area to urban area), namely “land transformation”. Furthermore, the land use elementary flows (occupation and transformation) and parameters were linked to the impact indicators, and the characterization formulas of the two forms of land utilization were derived respectively according to the ecological theory. Moreover, based on this method, the characterization factors of both land occupation and land transformation were calculated using Chinese empirical information on NPP, which can be incorporated into LCA framework and applied to Chinese LCA case study to fill up the important gap in life cycle impact assessment (LCIA) of land use.

A modified external passivation route was performed to control the distribution of gold nanoparticles in periodic mesoporous organosilica (PMOs). The surfactants were first removed completely to ensure enough space in the mesopores. The external surface was then functionalized with n-octadecyltrimethoxysilane (C18TMS), and finally the internal surface was modified with aminopropyltrimethoxysilane (APTMS) to enhance the adsorption of (HAuCl4)− complex, followed by the reduction under hydrogen atmosphere. The external passivation aims to prevent the formation of large aggregated gold particles on the exterior surface. The aminopropyl groups at the internal surface ensure the incorporation of gold nanoparticles with a size about 5 nm inside the pore channels of PMOs. A combination of high-resolution TEM/STEM and SEM shows that the selective surface functionalization can effectively avoid the growth of large gold particles at the external surface and strictly confine the gold nanoparticles within the pore channels of PMOs. The confined gold nanoparticles in PMOs exhibit good catalytic properties in the reduction of methylene blue (MB) dye with sodium boron hydride as reducing agent.

Ultrafine cobalt powders have been prepared by the freeze-drying method and supported cobalt catalysts have been prepared by a new freeze-drying immersion method. The results of XRD and SEM showed that the precursors were amorphous and most were massive with a size range of 2–5 µm. In the cobalt powders synthesized by freeze-drying, the grains were spherical in shape and with sizes ranging from 30 to 50 nm. IR analysis showed that Co existed in the precursor in the form of [Co(NH3)x]2(C2O4)3. EDS line scanning results indicated that catalysts prepared by freeze-drying could load more cobalt powders and the distribution was more homogeneous. Catalyst activity was also tested in the system of carbon monoxide oxidation. The catalysts in this research can lower the ignition temperature of CO and have increased catalytic properties.Graphical AbstractSpherical cobalt nanopowders with a grain size of 30–50 nm were prepared by the freeze-drying method. Catalysts prepared by freeze-drying can load more cobalt powder and the distribution is more homogeneous. Catalyst activity was also tested in the system of carbon monoxide oxidation; the catalysts in this research can lower the ignition temperature of CO and have increased catalytic properties.

China has been the largest primary magnesium producer in the world since year 2000 and is an important part of the global magnesium supply chain. Almost all of the primary magnesium in China is produced using the Pidgeon process invented in the 1940s in Canada. The environmental problems of the primary magnesium production with the Pidgeon process have already attracted much attention of the local government and enterprises. The main purposes of this research are to investigate the environmental impacts of magnesium production and to determine the accumulative environmental performances of three different scenarios. System boundary included the cradle-to-gate life cycle of magnesium production, including dolomite ore extraction, ferrosilicon production, the Pidgeon process, transportation of materials, and emissions from thermal power plant. The life cycle assessment (LCA) case study was performed on three different fuel use scenarios from coal as the overall fuel to two kinds of gaseous fuels, the producer gas and coke oven gas. The burden use of gaseous fuels was also considered.The procedures, details, and results obtained are based on the application of the existing international standards of LCA, i.e., the ISO 14040. Depletion of abiotic resources, global warming, acidification, and human toxicity were adopted as the midpoint impact categories developed by the problem-oriented approach of CML to estimate the characterized results of the case study. The local characterization and normalization factors of abiotic resources were used to calculate abiotic depletion potential (ADP). The analytic hierarchy process was used to determine the weight factors. Using the Umberto version 4.0, the emissions of dolomite ore extraction were estimated and the transportation models of the three scenarios were designed.The emissions inventory showed that both the Pidgeon process of magnesium production and the Fe–Si production were mainly to blame for the total pollutant emissions in the life cycle of magnesium production. The characterized results indicated that ADP, acidification potential, and human toxicity potential decreased cumulatively from scenarios 1 to 3, with the exception of global warming potential. The final single scores indicated that the accumulative environmental performance of scenario 3 was the best compared with scenarios 1 and 2. The impact of abiotic resources depletion deserves more attention although the types and the amount of mineral resources for Mg production are abundant in China. This study suggested that producer gas was an alternative fuel for magnesium production rather than the coal burned directly in areas where the cost of oven gas-produced coke is high. The utilization of “clean” energy and the reduction of greenhouse gases and acidic gases emission were the main goals of the technological improvements and cleaner production of the magnesium industry in China.This paper has demonstrated that the theory and method of LCA are actually helpful for the research on the accumulative environmental performance of primary magnesium production. Further studies with “cradle-to-cradle” scheme are recommended. Furthermore, other energy sources used in magnesium production and the cost of energy production could be treated in further research.

The hot deformation behavior of an Al–5.7 wt.%Mg alloy with erbium was studied by compressive deformation tests in the strain rate range of 0.001–10 s−1 and temperature range of 300–500 °C. The constitutive equations were presented considering the values of A and β as a function of strain in the exponential function form. The error of predicted and measured data was less than 9%. Dynamic recrystallization was restrained by precipitate with Er and dynamic recovery dominated in the hot deformation. The mechanism of dynamic recovery was dislocation movement and the development of microstructure during deformation can be characterized by the Z parameter, and then the relationship between subgrains and deformation parameters have been also established.

The hot deformation behavior of an Al–5.7 wt.%Mg alloy with erbium has been investigated. Compression tests are performed in the temperature range of 300–500 °C and in the strain rate ranging from 0.001 s−1 to 50 s−1 up to a true strain of 0.7. The processing maps are developed at different strains and the standard kinetic analysis has been applied to evaluate the rate controlling mechanisms. The processing maps have exhibited two domains of 350–450 °C at 0.001–0.03 s−1 and 450–500 °C at 0.01–1 s−1, representing dynamic recovery of Al–5.7 wt.%Mg with erbium. The apparent activation energies estimated in these two domains are 180 kJ/mol and 163 kJ/mol respectively, which suggests that cross-slip of dislocation and lattice self-diffusion are the deformation mechanisms. At strain rates higher than 10 s−1, the flow curves demonstrate flow softening behavior, and the flow instability regions reveal mixed microstructure of local deformation and dynamic recrystallization.

The influences of erbium (Er) on the microstructure and mechanical properties of Al–Mg–Mn–Zr alloys have been investigated. It has been found that about 0.2 wt.% Er can be dissolved in the matrix, excess Er atoms segregate at grain boundaries to form primary Al3Er. Addition of 0.4 wt.% Er refines the grain size of the as-cast alloy due to the formation of primary Al3Er. The solid solution decomposes to form a dispersion of secondary Al3Er, with facets parallel to {1 0 0} and {1 1 0} planes, during homogenization at 470 °C. The secondary Al3Er precipitates improve strength, especially the elevated temperature strength. The yield strength, at 150 °C, of the alloy with 0.2 wt.% Er is 50% higher than that of the Er-free alloy. The recrystallization temperature of the alloy with 0.4 wt.% Er is about 25 °C higher than that of the alloy without addition of Er.

Nanostructured Ni(OH)2 thin films were prepared by a simple solution growth process with F− and NH3 used as Ni2+ coordination agents, and ammonia hydroxide solution used as OH− supplier to accelerate the hydrolyzation of nickel complex species. The results showed Ni(OH)2 thin films were constructed mainly with hexagonal β-Ni(OH)2β-Ni(OH)2 nanorods; the F− and NH3 in reactive solutions played important roles in the film growth process; and solution pH had great influence on the morphologies of thin films, which was explained by the competition of Ni(OH)2 nucleation and growth in solutions. NiO crystallinity thin films were obtained by annealing Ni(OH)2 thin films at 400 °C for 2 h and the morphologies of the Ni(OH)2 thin films were sustained well during the annealed process.It was unique that Ni(OH)2 films were constructed with Ni(OH)2 nanorods and there were a lot of open pores resulted from the interconnection of the Ni(OH)2 nanorods in the thin films. The film from the SEM cross-sectional view, the thickness of the films synthesized with pH 8.0 was about 550 nm.

The ethylene-modified silica membranes were prepared by the acid-catalyzed co-hydrolysis and condensation reaction of tetraethylorthosilicate (TEOS) and ethylenetriethoxysilane (TEVS) in ethanol and the final materials were characterized by scanning electron microscope (SEM), water contact angle measurement, solid-state 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR), and N2 adsorption. The modification leads to a transform from superhydrophilicity for the unmodified silica membranes to hydrophobicity for the modified materials. The ethylene-modified silica membranes are much less water sensitive than the unmodified materials because the hydrophobic ethylene groups replace a portion of the hydrophilic hydroxyl groups on the pore surface. The modified materials process a microporous structure with a narrow pore size distribution centered at 1.1 nm. Such a microporous structure can be stabilized after exposured to humid atmosphere for 450 h, in intense contrast to the collapse of the micropores in the unmodified silica membranes.

A mesoporous HOM-5 with a structure of 3D cubic monoliths was synthesized by a method of direct-templating, where tetraethyl orthosilicate (TEOS) and Pluronic P123 were used as precursor and surfactant template, respectively, and the concentration of surfactant templates was very low. Our experiments show that a low hydrolysis rate of TEOS facilitates the fabrication of 3D mesoporous structure. The obtained HOM-5 has a high surface area of 746.5 m2/g, a large pore volume of 1.3 cm3/g and a narrow pore size distribution around 7.7 nm. The capacity of immobilization of papain in the HOM-5 is 181 mg/g and the immobilized papain shows high thermal and chemical stability compared to the free papain.

Fluorocarbon-modified silica membranes were deposited on γ-Al2O3/α-Al2O3 supports by the sol−gel technique for hydrogen separation. The hydrophobic property, pore structure, gas transport and separation performance, and hydrothermal stability of the modified membranes were investigated. It is observed that the water contact angle increases from 27.2 ± 1.5° for the pure silica membranes to 115.0 ± 1.2° for the modified ones with a (trifluoropropyl)triethoxysilane (TFPTES)/tetraethyl orthosilicate (TEOS) molar ratio of 0.6. The modified membranes preserve a microporous structure with a micropore volume of 0.14 cm3/g and a pore size of ∼0.5 nm. A single gas permeation of H2 and CO2 through the modified membranes presents small positive apparent thermal activation energies, indicating a dominant microporous membrane transport. At 200 °C, a single H2 permeance of 3.1 × 10−6 mol m−2 s−1 Pa−1 and a H2/CO2 permselectivity of 15.2 were obtained after proper correction for the support resistance and the contribution from the defects. In the gas mixture measurement, the H2 permeance and the H2/CO2 separation factor almost remain constant at 200 °C with a water vapor pressure of 1.2 × 104 Pa for at least 220 h, indicating that the modified membranes are hydrothermally stable, benefiting from the integrity of the microporous structure due to the fluorocarbon modification.

Ureidopropyl groups were used to functionalize the pore channels of ethane-bridged periodic mesoporous organosilica by the co-condensation of 1,2-Bis(triethoxysilyl)ethane (BTESE) and ureidopropyltriethoxysilane (UPTES) in the presence of Poly(ethylene glycol)-B-Poly(propylene glycol)-B-Poly(ethylene glycol) (P123) surfactants under acidic conditions. The final materials were investigated in detail by means of XRD, TEM, solid-state NMR, FT-IR and N2 adsorption, in order to study the effect of ureidopropyl groups concentration on their mesoscopic order and pore structure. The results show that bridging groups in the framework do not cleave and ureidopropyl groups are attached covalently to the pore wall of periodic mesoporous organosilica after functionalization. The mesoscopic order decreases with increasing amount of UPTES except for the sample with 20 mol% UPTES concentration, which exhibits a highly ordered two-dimensional hexagonal symmetry. The surface area and pore size decrease as the concentration of UPTES increases, but the materials with 20 mol% UPTES still preserve a desirable pore structure, with a surface area of 565 m2/g, a pore volume of 1.1 cm3/g and a mean pore size of 10.1 nm.

The objective of this study was to produce detailed a life cycle inventory (LCI) for the provision of 1 kWh of electricity to consumers in China in 2002 in order to identify areas of improvement in the industry. The system boundaries were processes in power stations, and the construction and operation of infrastructure were not included. The scope of this study was the consumption of fossil fuels and the emissions of air pollutants, water pollutants and solid wastes, which are listed as follows: (1) consumption of fossil fuels, including general fuels, such as raw coal, crude oil and natural gas, and the uranium used for nuclear power; (2) emissions of air pollutants from thermal power, hydropower and nuclear power plants; (3) emissions of water pollutants, including general water waste from fuel electric plants and radioactive waste fluid from nuclear power plants; (4) emissions of solid wastes, including fly ash and slag from thermal power plants and radioactive solid wastes from nuclear power plants.Data were collected regarding the amount of fuel, properties of fuel and the technical parameters of the power plants. The emissions of CO2, SO2, NOx, CH4, CO, non-methane volatile organic compound (NMVOC), dust and heavy metals (As, Cd, Cr, Hg, Ni, Pb, V, Zn) from thermal power plants as well as fuel production and distribution were estimated. The emissions of CO2 and CH4 from hydropower plants and radioactive emissions from nuclear power plants were also investigated. Finally, the life cycle inventory for China’s electricity industry was calculated and analyzed.Related to 1 kWh of usable electricity in China in 2002, the consumption of coal, oil, gas and enriched uranium were 4.57E-01, 8.88E-03, 7.95E-03 and 9.03E-08 kg; the emissions of CO2, SO2, NOx, CO, CH4, NMVOC, dust, As, Cd, Cr, Hg, Ni, Pb, V, and Zn were 8.77E-01, 8.04E-03, 5.23E-03, 1.25E-03, 2.65E-03, 3.95E-04, 1.63E-02, 1.62E-06, 1.03E-08, 1.37E-07, 7.11E-08, 2.03E-07, 1.42E-06, 2.33E-06, and 1.94E-06 kg; the emissions of waste water, COD, coal fly ash, and slag were 1.31, 6.02E-05, 8.34E-02, and 1.87E-02 kg; and the emissions of inactive gas, halogen and gasoloid, tritium, non-tritium, and radioactive solid waste were 3.74E+01 Bq, 1.61E-01 Bq, 4.22E+01 Bq, 4.06E-02 Bq, and 2.68E-10 m3 respectively.The comparison result between the LCI data of China’s electricity industry and that of Japan showed that most emission intensities of China’s electricity industry were higher than that of Japan except for NMVOC. Compared with emission intensities of the electricity industry in Japan, the emission intensities of CO2 and Ni in China were about double; the emission intensities of NOx, Cd, CO, Cr, Hg and SO2 in China were more than 10 times that of Japan; and the emission intensities of CH4, V, Pb, Zn, As and dust were more than 20 times. The reasons for such disparities were also analyzed.To get better LCI for the electricity industry in China, it is important to estimate the life cycle emissions during fuel production and transportation for China. Another future improvement could be the development of LCIs for construction and operation of infrastructure such as factory buildings and dams. It would also be important to add the information about land use for hydropower.

A coupled thermo-mechanical 3D finite element model is developed to simulate the cogging-down rotary swaging (RS) processing of pure magnesium square billet in this paper. Through simulation, the effects of high-frequency pulse stroking, special to RS, on the distributions and histories of different field-variables such as stress, strain, temperature and so on are clarified. The effect of the cogging-down RS on the subsequent RS passes is also analyzed. It is shown that the strain of each node increases stepwise with pulse stroking. The equivalent strain of nodes at the corner of the square billet is much higher than that at the center by 1.48. The stresses fluctuate periodically with the pulse stroking. The axial component σz of the residual stress at the corner of the cogging-down RS bar is as high as 32 MPa that it becomes one of the main factors causing the transverse surface crack in the subsequent RS passes. The temperature rising owing to the heat translation from plastic deformation energy is only 1 °C in the cogging-down RS. Compared the calculated results with experimental data, the consistency is demonstrated.

In the W/O microemulsion system of cetyltrim ethylamine bromide (CTAB) + butanol / cyclohexane / water solution, the microemulsion area was measured and cerium oxide nanoparticles were prepared according to the principle by two-phase liquid–liquid method. The samples were analyzed by means of transmission electron microscope, X-ray diffraction, thermogravimetric-differential scanning calorimetry, and infrared. And their morphology, phase, components were investigated. The results made clear that nanometer cerium oxide could be prepared in the measured area of microemulsion and it is an effective way to gain the well dispersed and uniformly distributed nanometer cerium oxide grains with the size of about 3 nm.

Mesoporous thiol-functionalized SBA-15 silicas have been directly synthesized by co-condensation of tetraethyl orthosilicate and 3-mercaptopropyltrimethoxysilane with triblock copolymer poly(ethylene glycol)-B-poly(propylene glycol)-B-Poly(ethylene glycol) as structure-directing agent under hydrothermal condition. Mesoporous structure was obtained after the surfactant removal by Soxhlet ethanol extraction. These materials have been characterized by means of powder X-ray diffraction, nitrogen sorption, transmission electron microscopy, thermogravimetry analysis, elemental analysis and solid state 29Si nuclear magnetic resonance. The effect of 3-mercaptopropyltrimethoxysilane concentration in the initial mixture on the pore structure of functionalized SBA-15, including pore ordering, surface area, pore size and pore volume, is investigated in detail. In order to functionalize the SBA-15 silicas without a significant change of pore structure, the molar concentration of 3-mercaptopropyltrimethoxysilane should be limited to less than 20%.

The synthesis of Ce–W composite nanopowder plays an important role in the preparation of relevant alloys. In the paper, the Ce–W composite nanopowder were prepared by liquid–liquid mixing, freeze drying, and two-stage reduction. The particle size of the powder produced is in the range of 20 and 30 nm. Homogeneous microstructure and uniform distribution of Ce were found in this powder. The phase compositions during the producing process of nanopowder were studied by XRD. The appearances of the freeze-dried powder, the first-reduced treated powder, and the finally obtained nanopowder were analyzed by SEM, FESEM, as well as TEM. Research results showed that most of the powders existed in the non-hygroscopic and non-crystalline state. The final product of the experiments was the W–Ce2WO6 nanopowder, which existed in the form of crystalline state. IR analysis indicated that the freeze-dried powder remained a Keggin structure. In addition, the TG and DTA thermal analysis explained that the losing water contained in the powders could be processed in three stages.

A brief review of the recent advances in the field of ecomaterials in China is presented, giving opinions on the current activities and suggesting possible future courses of action. The past 10 years has seen the development of the concept of ecomaterials involving practical research and development of environmentally conscious materials, and the establishment of related systems including national programs and laws. It has been an important period for the development of materials science and the goal of creating a sustainable society in China. It has now become clear that ecomaterials, which exhibit high performance whilst being environmentally benign in their life cycle, are evolving from being only materials for end-of-pipe applications to include all materials being designed on the basis of life-cycle thinking.

The theoretical simulations and experiments on metal separation in complexation–precipitation system of Me(Ni, Co, Mn)–OH−–NH3–CO32- were carried out. The Gibbs free energy change ΔG for metal precipitation reactions was calculated. The ΔG–pH curves showed that the precipitation difficulty order was Mn > Co > Ni at pH range of 8–11. Separation experiments indicated that Mn and Co were able to precipitate successively in solution of different compositions mainly in the forms of carbonates. pH, initial carbonate concentration [C] and initial ammonia concentration [N] had different influence on Ni, Co and Mn precipitation behaviors: the separation effect was best at about pH 10; [C] had little effect on the metal separation in the [C] range of 0.05–0.4 mol/L; changing [N] could regulate precipitation step by step, as Ni in solution and Mn/Co in precipitate at [N] 1 mol/L, and Ni/Co in solution and Mn in precipitate at [N] 2.5 mol/L. The experimental results basically consisted with the theoretical predictions. The Ni solution after Mn/Co precipitation could be electrodeposited to obtain Ni metal. Finally a separation process in complexation–precipitation system of Me(Ni, Co, Mn)–OH−–NH3–CO32- characterized by the theoretical simulation was proposed, of which the Ni, Co and Mn precipitation could be predicted or controlled by flexibly importing parameters of [C], [N], pH, etc. The process can provide a reference to metal comprehensive recovery from similar nickel–cobalt secondary resources.Highlights► Ni, Co and Mn separation was studied in complexation–precipitation system of OH−–NH3–CO32-. ► Theoretical simulation combined experimental method were employed. ► Mn and Co were precipitated mainly as carbonates step by step. ► Ni was electrodeposited from the solution after Mn and Co precipitation.

CoAl-based layered-double-hydroxide@zeolitic-imidazolate-framework-67 (LDH@ZIF-67) was fabricated via a hydrothermal synthesis of LDH film on Ni substrate followed by the in situ growth of ZIF-67. Its derivatives, MMO@Co3O4, spinelle@C and LDH@CoS with hierarchical structures were obtained by the subsequent oxidation, carbonization and sulfurization of LDH@ZIF-67, respectively, which exhibit distinct specific capacitances of 692, 781 and 1205 F g−1 at a discharge current density of 1 A g−1. Interestingly, these derivatives retained hierarchical structures with large surface area, which ensures that the majority of exposed active species can participate in the charge–discharge process and thus effectively contribute to total capacitances. The synergistic effect from fast electronic transfer reduces reversible ion accumulation at the interface, which imparts LDH@ZIF-67 derivatives improved electrochemical activities, in contrast to conventional bulk MOF derivatives. In addition, it was found that the combination of the remarkable electrical conductivity of sulfides (compared with their oxide counterparts) and the strong electronic coupling between LDH and CoS can facilitate fast electron transfer. As a result, LDH@CoS exhibits an excellent specific energy of 44.5 W h kg−1 at a current density of 20 A g−1, as well as good capacitance retention of 88.5% after 2000 cycles. This work thus demonstrates a feasible strategy for the design and fabrication of LDH@MOF derived composites as SCs components, which is applicable in constructing other novel electrode materials with hierarchical structures for applications in energy storage systems.