氧化物对3CaO·3Al_2O_3·CaSO_4形成的影响

借助XRD测试手段研究了Al_2O_3、SiO_2、Fe_2O_3以及MgO几种生料中常见氧化物对高温固硫物相3CaO·3Al_2O_3·CaSO_4形成的影响。结果表明,改变Al_2O_3的含量,不会对3CaO·3Al_2O_3·CaSO_4的形成产生明显影响; Fe_2O_3及MgO的存在能降低3CaO·3Al_2O_3·CaSO_4的形成温度,但也使其分解温度提前;SiO_2的大量存在则会抑制3CaO·3Al_2O_3·CaSO_4的形成。

Enhanced Biological Nutrients Removal in Modified Step-feed Anaerobic/Anoxic/Oxic Process

In order to enhance phosphorus removal in traditional step-feed anoxic/oxic nitrogen removal process,a modified pilot-scale step-feed anaerobic/anoxic/oxic(SFA 2/O) system was developed,which combined a reactor similar to UCT-type configuration and two-stage anoxic/oxic process.The simultaneous nitrogen and phosphorus removal capacities and the potential of denitrifying phosphorus removal,in particular,were investigated with four different feeding patterns using real municipal wastewater.The results showed that the feeding ratios(Q1)in the first stage determined the nutrient removal performance in the SFA 2/O system.The average phosphorus removal efficiency increased from 19.17% to 96.25% as Q1 was gradually increased from run 1 to run 4,but the nitrogen removal efficiency exhibited a different tendency,which attained a maximum 73.61%in run 3 and then decreased to 59.62%in run 4.As a compromise between nitrogen and phosphorus removal,run 3 (Q1=0.45Qtotal) was identified as the optimal and stable case with the maximum anoxic phosphorus uptake rate of 1.58 mg·(g MLSS)-1 ·h-1.The results of batch tests showed that ratio of the anoxic phosphate uptake capacity to the aerobic phosphate uptake capacity increased from 11.96% to 36.85% with the optimal influent feeding ratio to the system in run 3,which demonstrated that the denitrifying polyP accumulating organisms could be accumulated and contributed more to the total phosphorus removal by optimizing the inflow ratio distribution.However,the nitrate recirculation to anoxic zone and influent feeding ratios should be carefully controlled for carbon source saving.

Influence of Zirconia on Hydroxyapatite Coating on Ti-Alloy by Laser Cladding

Coating titanium alloy with the bioceramic material hydroxyapatite(HAP) has been used to improve the poor osteoinductive properties of pure titanium alloy. But in clinical applications, the mechanical failure of HAP-coated titanium alloy implant suffered at the interface of the HAP coatings and titanium alloy substrate will be a potential weakness in prosthesis. Yttria-stablized zirconia (YSZ) is expected to enhance the mechanical properties of the HAP coating and reduce the coefficient of thermal expansion difference between the coated layer and the substrate. These may reinforce the bonding strength between the coatings and the substrate. In this paper, HAP/YSZ composite coatings were cladded by laser. The effects of zirconia on the microstructure, mechanical properties and formation of tricalcium phosphate (TCP, Ca 3(PO 4) 2) of the HAP/YSZ composite coatings were evaluated. XRD, SEM and TEM were used to investigate the phase composition, microstructure and morphology of the coatings. The experimental results showed that adding YSZ in coatings was favorable to the composition and stability of HAP, and to the improvement of the adhesion strength, microhardness and microtoughness. A well uniform, crack-free coating of HAP/YSZ composites was formed on Ti-alloy substrate by laser cladding.

Ferroelectric solid solution Li1-xTa1-xWxO3 as potential photocatalysts in microbial fuel cells:Effect of the W content

Microbial fuel cells(MFCs)are bio-electrochemical systems that can directly convert the chemical energy contained in an effluent into bioelectricity by the action of microorganisms.The performance of these devices is heavily impacted by the choice of the material that forms the cathode.This work focuses on the assessment of ferroelectric and photocatalytic materials as a new class of non-precious catalysts for MFC cathode construction.A series of cathodes based on mixed oxide solid solution of LiTaO_3with WO_3formulated as Li_(1-x)Ta_(1-x)W_xO_3(x=0,0.10,0.20 and0.25),were prepared and investigated in MFCs.The catalyst phases were synthesized,identified and characterized by DRX,PSD,MET and UV–Vis absorption spectroscopy.The cathodes were tested as photoelectrocatalysts in the presence and in the absence of visible light in devices fed with industrial wastewater.The results revealed that the catalytic activity of the cathodes strongly depends on the ratio of substitution of W^(6+)in the LiTaO_3matrix.The maximum power densities generated by the MFC working with this series of cathodes increased from60.45 mW·m^(-3)for x=0.00(LiTaO_3)to 107.2 mW·m^(-3)for x=0.10,showing that insertion of W^(6+)in the tantalate matrix can improve the photocatalytic activity of this material.Moreover,MFCs operating under optimal conditions were capable of reducing the load of chemical oxygen demand by 79%(COD_(initial)=1030 mg·L^(-1)).

Surface characteristics and structure of oxide films containing Ca and P on Ti substrate

The oxide films were obtained in an electrolyte of calcium glycerphosphate (Ca-GP) and calcium acetate (CA) by microarc oxidation (MAO). The oxide films displayed a porous and rough structure on the film surface, and the roughness tended to increase with increasing voltage of microarc oxidation. The oxide film exhibited a uniform coating and tends to be well boned to the substrate. The thickness of oxide films depended on the final voltage at a constant concentration of electrolyte solution. Ca and P were also incorporated into the oxide film during the microarc oxidation process. It was found that the electrolyte of calcium glycerphosphate (Ca-GP) and calcium acetate (CA) was suitable for microarc oxidation to form oxide film containing Ca and P on Ti substrate. The concentration of Ca and P were 11.6 at% and 6.4 at%, respectively, when microarc oxidation was performed in the electrolyte of 0.06 M Ca-GP and 0.25 M CA at current density 50 A/m^2 and final voltage 350 V. The composition of the Ca, P and Ti changed during depth profiling. The crystalline phases were only anatase when final voltage was below 300 V and rutile was presented when voltage was up to 350 V. The microstructure, phase structure and phase composition were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), energy dispersive X-ray microanalyser (EDX), and X-ray diffraction (XRD).

Microalgae for Renewable Energy： Is it a Solution for Global Warming？

Microalgae could be a new sustainable energy source substituted for petroleum. They can produce high value biodiesel, bioethanol, bio-hydrogen, biogas, and that they are able to use waste water and nutrients, allowing for integration of such processes with waste treatment. Open ponds in hectares of area, could remove excess CO2 in atmosphere with photosynthesis. Large scale microalgal production in fields which are not suitable for agriculture could be a solution for CO： capturing from the atmosphere. Sea water could be used for the culture medium not to consume the fresh water. However microalgae reduce the atmospheric CO： while producing the organic material, using the biomass for either fuel production or food, feed, fertilizer, come out with CO2 release to the atmosphere, when burned by the engine, body and/or bacterial activities. So, microalgal growth can＇t reduce the CO2 however makes an important contribution to keep the atmospheric CO2 level stable. Long term solution for removing the CO2, could be possible with making durable biomaterials with microalgal biomass and capture the atmospheric CO2 by fixing into the materials and interrupt the carbon cycle for a long while.

Combustion of Renewable Biogas Fuels

Biogas fuel is a sustainable and renewable fuel produced from anaerobic digestion of organic matter. The biogas fuel is a flammable mixture of methane and carbon dioxide with low to medium calorific values. Biogas is an alternative to conventional fossil fuels and can be used for beating, transportation and power generation. CFD （computational fluid dynamic） analysis of the combustion performance and emissions of biogas fuel in gas turbine engines is presented in this study. The main objective of this study is to understand the impact of the variability in the biogas fuel compositions and lower heating values on the combustion process. Natural gas, biogas from anaerobic digester, landfill biogas, and natural gas/biogas mixture fuels combustion were investigated in this study. The CFD results show lower peak flame temperature and CO mole fractions inside the combustor and lower NOx emissions at the combustor exit for the biogas compared to natural gas fuel. The peak flame temperature decreases by 37% for the biogas landfill （COJCH4 = 0.89） and by 22% for the biogas anaerobic digester （CO2/CH4 = 0.54） compared to natural gas fuel combustion. The peak CO mole fraction inside the combustor decreases from 9.8 × 10-2 for natural gas fuel to 2.22 × 10-4 for biogas anaerobic digester and 1.32 × 10-7 for biogas landfill. The average NOx mole fraction at the combustor exit decreases from 1.13 × 10-5 for natural gas fuel to 0.40 × 10-6 for biogas anaerobic digester and 1.06 × 10-6 for biogas landfill. The presence of non-combustible constituents in the biogas reduces the temperature of the flame and consequently the NOx emissions.

Surface modification of Ti O2 nanosheets with fullerene and zinc-phthalocyanine for enhanced photocatalytic reduction under solar-light irradiation

High-efficiency photocatalysts are of great importance to satisfy the requirements of green chemistry nowadays.Here we reported a novel solar-driven photocatalyst fabricated by a facile surface modification method,with the two-dimensional carboxylated zinc phthalocyanine-carboxylated C60-titanium dioxide(Zn Pc-C3-Ti O2)nanosheets,in which the surface modifications of Zn Pc and C60derivative were designed to extend the absorption range and promote charge separation,respectively.Benefiting from the unique structure and positive synergetic effect,the Zn Pc-C3-Ti O2 nanocomposite shows promising applications in selective reduction of nitroarenes for high-value-added aromatic amines under solar light.Especially,for the photocatalytic reduction of nitrobenzene to aniline,the Zn Pc-C3-Ti O2 nanocomposite possesses both high efficiency and selectivity(up to 99%).

Bacterial cellulose-regulated synthesis of metallic Ni catalysts for high-efficiency electrosynthesis of hydrogen peroxide

The decentralized production of H_(2)O_(2) via a twoelectron oxygen reduction reaction(2e^(-)ORR)has emerged as a promising alternative to the energy-intensive anthraquinone(AQ)process.However,its practical application requires 2eORR electrocatalysts with high activity and selectivity.Herein,we report the synthesis of metallic Ni nanoparticles anchored on bacterial cellulose-derived carbon fibers(Ni-NPs/BCCF)via a facile impregnation-pyrolysis method as efficient electrocatalysts for 2 e-ORR to H_(2)O_(2).By tuning the amount of Ni precursor,the best electrocatalytic performance toward 2 eORR was achieved for Ni-NPs/BCCF-20.7,affording a high H_(2)O_(2) selectivity of ~90% and an onset potential of 0.75 V vs.reversible hydrogen electrode(RHE)in an alkaline electrolyte.Ni-NPs/BCCF-20.7 achieved the largest H_(2)O_(2) yield rate of 162.7±13.7 mmol gcat^(-1)h^(-1) and the highest Faradaic efficiency of 93.9%±4.2% at 0.2 and 0.5 V vs.RHE from the bulk ORR system,respectively.Theoretical calculations revealed the more favorable"end-on"adsorption configuration of molecular oxygen on the exposed Ni(111)plane,which can effectively suppress the O-O bond dissociation,resulting in high selectivity for H_(2)O_(2) generation.

Spontaneously producing syngas from MFC-MEC coupling system based on biocompatible bifunctional metal-free electrocatalyst

The preparation of high-value fuels and chemicals through the electrochemical carbon dioxide reduction reaction(CDRR)is of great significance to the virtuous cycle of carbon dioxide.However,due to the high overpotential involved in this reaction,high power consumption and high-cost noble-metal-based catalysts are required for driving this process.Herein,the electrochemical CDRR was achieved on biocompatible metal-free nitrogen,phosphorus co-doped carbon-based materials(NP-C)in the microbial fuel cell-microbial electrolysis cell(MFC-MEC)coupling system.As the bioelectrochemistry in MFC supplied power to drive the electrocatalysis in MEC,syngas was spontaneously produced from this coupling system without external energy input.With the NP-C materials as the excellent bifunctional electrocatalyst for the CDRR and oxygen reduction reaction(ORR),the current density of the MEC reached−0.52 mA cm^−2,and the Faradaic efficiencies(FEs)of CO and H2 were 60%and 40%,respectively,at a load resistance of 10Ω.Moreover,the CO/H2 product ratio can be changed by adjusting the load resistance,which will widely meet various demand of syngas usage in further reactions.This study provides a spontaneous and tunable production of syngas in biogas digesters via a electrochemical strategy.

Effect of treatment process on consolidation efficiency of fugitive dust cemented by bio-activated cementitious material based on CO2 capture

As a new green and environmental material, bio-activated cementitious material is attracting extensive attention. This study confirmed that the bio-activated cementitious material could mineralize and cement fugitive dust into the cal- cite-consolidation-layer based on CO2 capture and utilization. The results illustrated that treatment processes （non-pressure spraying, pressure spraying, non-pressure blending and pressure blending） had a strong effect on the microstructure and prop- erties of calcite-consolidation-layer. According to the analysis of X-ray diffraction （XRD） and Fourier transform infrared （FTIR）, calcite was prepared by bio-activated cementitious material during the cementation process. Meanwhile, scanning electron microscopy （SEM） and thermogravimetric-differenfial scanning calorimetry （TG-DSC） were adopted to measure the corresponding variation of porous characteristics and calcite content caused by different treatment processes. The results indi- cated that the microstructure of calcite-consolidation-layer from the spraying process had lower porosity and higher content of calcite than from blending processes. In addition, the mechanical properties of calcite-consolidation-layer were also tested. The hardness and compressive strength, which reached 19.5 GPa and 0.6 MPa, respectively, of calcite-consolidation-layer from the pressure spraying process were higher than those from the other three treatment processes. Compared with the non-treatment process, the four treatment processes had superior wind erosion resistance. Under the wind speed of 12 m/s, the mass loss of calcite-consolidation-layer from the pressure spraying process decreased from 2150.2 to 23.8 g/（m^2 h）.