equation(5a)Φα(r)=vi(r)nelFequation(5b)dn?α,el(r)2πrdr=Φα(r)where the areic molar flow Φα(r) of the species α is due to the electrochemical reaction, n?α,el(r) is the molar flow rate of the chemical specie α on the surface of the electrode in the r direction, nel is the number of electrons transferred per c-Myc tag in the reaction and ν is the stoichiometric coefficient (ν = −1 consumed species, ν = +1 produced species).
The molar flow rates related to back-diffusion are derived from the solution of the polarization equation of the model (see Section 3.2.2) at open circuit. The model estimates the equilibrium potential by using the Nernst equation and compares it with the experimental open circuit voltage (OCV); the difference is compensated by the generation of a H2O (or CO2) flow rate, i.e. n?brn, due to the burning of H2 (or CO), which is used to correct the molar balances on the surface of the fuel electrode. The corrected molar flow rates of the chemical species are:equation(6)n?H2(CO)(r)=n?H2(CO)el(r)-n?brn(r)equation(7)n?H2O(CO2)(r)=n?H2O(CO2)el(r)+n?brn(r)
Here, we reported in situ synthesis of nickel carbide-promoted Ni/CNFs nanocomposite catalysts (NiC-Ni/CNFs) through CCVD over carbon supported nickel catalysts (Ni/C), which were derived from NiAl-LDH/carbon (NiAl-LDH/C) composite precursors. It was found that VX-765 Ni NPs and nickel carbides were generated simultaneously with CNFs. A promoting effect of nickel carbides on the enhancement of catalytic performance in liquid phase selective hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) was investigated. Furthermore, the high efficiency of NiC-Ni/CNFs also was confirmed in the hydrogenation of p- and m-CNB to p- and m-CAN.
2. Experimental section
2.1. Synthesis of catalysts
NiAl-LDH/C composite precursors with the different Ni/Al molar ratios (x) of 1.0, 2.0 and 3.0 were prepared by our previously reported method , and denoted as x-LDH/C. NiAl-LDH/C was placed in a brain tube-furnace reactor, which was ramped from 25 to 600 °C at a rate of 5 °C/min under a nitrogen flow (40 mL/min), and held at 600 °C for 2 h. Subsequently, C2H2 was switched into the furnace with a flow rate of 6 mL/min, and the temperature was maintained at 600 °C for 90 min. After the reaction, C2H2 was switched off. N2 was introduced continuously until the furnace was cooled to room temperature. The resultant black powder (denoted as x-NiC-Ni/CNFs) was collected from the ceramic boat.
According to Fig. 7a, the adsorption amounts of HM-IMs-5 and HM-NIMs-5 increased fast within the initial 50 min, and achieved 92.06% and 88.08% of the equilibrium capacity at 120 min, finally reached equilibrium within 6 h. HM-IMs-5 presented a much higher adsorption equilibrium capacity than HM-NIMs-5, owing to the specificity of imprinted cavity for BF. From Table 2, the kinetic data was fitted by pseudo-second-order kinetic model (R2 > 0.99) better than by pseudo-first-order kinetic model, which suggested that NHS-LC-Biotin the chemical process could be the rate-limiting step during the adsorption for BF . And the calculated Qe values (Qe,c) of pseudo-second-order kinetic equation were also close to the experimental data (Qe,e). The values of h and t1/2 in Table 2 also indicated glial cells the sorbents had excellent kinetic properties.
3.5. Adsorption equilibrium and isotherm modeling
Adsorption equilibrium constants for Langmuir and Freundlich isotherm equations.SorbentsLangmuir isotherm equationFreundlich isotherm equationKL (L μmol−1)Qm (μmol g−1)RLR2KF (μmol g−1)1/nR2HM-IMs-56.46 × 10−3131.780.60750.99691.45130.78640.9957HM-NIMs-54.61 × 10−3121.160.68450.99590.84050.83690.9916Full-size tableTable optionsView in workspaceDownload as CSV
3. Test results and discussion
3.1. Dispersing efficiency and flowability retention
Fig. 1. HRWR dosages for various cement–HRWR combinations and various w/c ratios.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 2. Variation of flowability with time for mixtures made with various w/c and PNS HRWR.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 3. Variation of flowability with time for mixtures made with various w/c and PC HRWR.Figure optionsDownload full-size imageDownload as PowerPoint slide
Test results indicated that PHT-427 mixtures incorporating PC type showed higher initial flowability than those made with PNS, regardless of the w/c and cement type. Furthermore, the use of PC resulted in better flowability retention, regardless of the cement type. Indeed, better flowability retention (up to 90 min) was observed with mixtures incorporating PC than those made with PNS, especially when BC is used. For example, mixture made with PNS–BC combinations showed flowability reduction between 50% and 62% of the initial flowability after 90 min of age. In the case of PNS–OC mixtures, this reduction is limited between 15% and 31%.
Metakaolin; Geopolymer; Solid-to-liquid ratio; Waste catalyst; Microstructural
2. Materials and methods
The waste catalyst (51.60% SiO2, 35.30% Al2O3 and 2.39% Fe2O3) used in this study was collected from the refinery plant located in Taoyuan City, Taiwan. Raw waste catalyst was milled using chrome steel balls and it FLAG tag could pass through a 0.074 mm sieve. Sodium silicate (Na2SiO3) solution was produced in Taiwan containing 33.81% SiO2, 12.65% Na2O, 53.54% H2O, and Ms. (SiO2/Na2O) = 2.76. Sodium hydroxide (NaOH; 99%) was purchased from Acros. Metakaolin (specific gravities ∼1.66, pH value 5.74, and the diameter size less than or equal to 0.074 mm) containing 54.3% SiO2 and 42.1% Al2O3 was obtained from kaolin calcined at 650 °C for 3 h. The chemical composition of raw materials was shown in Table 1. The results showed that kaolin is mainly composed of SiO2 (54.90%) and Al2O3 (41.80%). Metakaolin is composed of 54.30% SiO2 and 42.10% Al2O3.
The mass transport and ABT 702 coefficients of the gases (hydrogen, carbon dioxide, and methane) in the CEM and FO membrane are stated in Table 1. The diffusion coefficient of hydrogen in the FO membrane was lower than in the CEM: 7.56 × 10−8 cm2/s (CEM) >6.74 × 10−8 cm2/s (FO membrane under dry condition) and 1.87 × 10−8 cm2/s (FO membrane under wet condition). The fast diffusion of hydrogen through the CEM, followed by carbon dioxide and methane, suggested that hydrogen produced in the cathode chamber can be lost into the anode chamber during operation. The high hydrogen diffusion coefficient of the CEM consequently leads to hydrogen recovery in MECs. Firstly, methanogens that can be grown in the presence of hydrogen at the anode chamber produce methane by utilizing carbon sources, which are fuels for electrochemically active bacteria to generate electrons (Chae et al., 2008a). Also, hydrogen at the anode chamber can be oxidized to generate current by anode respiring organisms, thus causing internal circulation of electrons and lowering final hydrogen production (Chae et al., 2008a, Lu et al., 2011 and Torres et al., 2008).
Fig. 4. Spray penetration (a) and normalized spray penetration curve (b) under different injection pressures, data is provided of ethanol fuel, ambient pressure: 500 kPa; fuel temperature: 55 °C.Figure optionsDownload full-size imageDownload as PowerPoint slide
The viscous force and surface tension force involved in the spray formation are mainly dependent on the dynamic viscosity and surface tension of the liquid. These physical properties can be altered by altering the liquid temperature and they Microcystin-LR also vary among different types of fuel. Fig. 5 shows the normalized spray penetration curves of ethanol under different temperatures. When increasing fuel temperature from 0 °C to 90 °C, the dynamic viscosity of ethanol decreases from 1.4MPas to 0.2MPas while its surface tension decreases from 24.8 mN/m to 16.1 mN/m. The results show axons the initial stage is accelerated in low viscous force and surface tension force conditions.
Fig. 5. Normalized spray penetration curve under different fuel temperatures, data was provided with ethanol; injection pressure: 5 MPa; ambient pressure: 500 kPa.Figure optionsDownload full-size imageDownload as PowerPoint slide