A Cu-Ce0.8Zr0.2O2 (Cu-CeZr) catalyst was synthesized by a facile ball-milling technique and its performance towards to CO2 reforming of ethanol was deeply studied. Noticeably, syngas production from ethanol dry reforming is regarded as one of the efficient routes to minify the undesirable CO2 discharge. Various characterization and detailed experimental tests were conducted to probe the influence of catalyst preparation method. Hence, the as-prepared Cu-CeZr sample presented a better activity compared with Cu/CeZr prepared by precipitation method. Full ethanol conversion was achieved at as low as 550 °C under the conditions where only 49 mol% H2, 41 mol% CO and 10 mol% CH4 were formed as main products. Additionally, Cu-CeZr catalyst exhibited satisfactory stability even under severe stoichiometric feed composition (ethanol/CO2 = 1) during 90 h on-stream aging tests. Herein, the remarkably superior catalytic performance of Cu-CeZr was interpreted in terms of the improved Cu dispersion and the intimated metal-support interaction. This might shed light on syngas production from an sustainable process instead of conventional methane dry reforming.
Coprinus comatus is an edible mushroom and its fermented product possesses antioxidant activity. In this study, to further enhance the antioxidant activity and improve the reusability of the strain, calcium alginate hydrogel was used as the carrier for embedding and immobilizing Coprinus comatus. The effects of CaCl2 concentration, sodium alginate concentration, microsphere diameter, and the amount of magnetic particle on the antioxidant activity of fermented products were investigated. The results showed that the magnetic immobilized microsphere prepared by 2.50% CaCl2, 2.00% sodium alginate and 0.50% Fe3O4 had the best fermentation antioxidant activity (EC50 was 0.43 ± 0.01 mg/mL) when the diameter was 5 mm, which increased by 24.56% compared to the initial activity. Besides, the microsphere showed strong reusability, the antioxidant activity was still better than the free strain after being used five times. This study not only enhanced the antioxidant activity of Coprinus comatus fermented product through immobilization, but also provided an effective method for microbial fermentation.
Toona sinensis is a traditional vegetable with rich nutrition and wide biological activity. In our previous study, an active composition against α-amylase was screened from T. sinensis by ligand fishing. To investigate the effect of T. sinensis on other targets of antidiabetes, in this work, α-glucosidase was immobilized on polydopamine-coated magnetic nanoparticles to further screen the compounds against α-glucosidase by ligand fishing. The enzyme activity test showed that the 70% ethanol extract of T. sinensis (crude sample) had weak α-glucosidase inhibitory activity, but after extraction with different solvents, the ethyl acetate extract showed the highest α-glucosidase inhibitory activity. After immobilization of α-glucosidase on polydopamine (PDA)-coated magnetic nanoparticles, the properties of the enzyme were characterized and determined, and then quercetin-3-O-α-L-rhamnopyranoside was screened by ligand fishing and isolated by high-speed counter-current chromatography using the two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:5:1:5, v/v). The results of enzymes assay showed that the screened compound (IC50 value of 374.94 ± 4.35 μg/mL) possessed moderate α-glucosidase inhibitory activity. The presented results not only proved that ligand fishing based on polydopamine-coated magnetic α-glucosidase was an effective method for the rapid discovery of natural active substances, but also further strengthened the evidence of antidiabetic effect of T. sinensis.
The Ir-catalyzed asymmetric hydrogenation of β-keto esters with chiral ferrocenyl P,N,N-ligands has been developed, providing the corresponding β-hydroxy esters in good to excellent enantioselectivities.
Ellagic acid is one of the most representative natural antioxidants, and is rich in pomegranate peel. In this study, a consecutive countercurrent chromatographic (CCC) separation method was established to improve the preparative efficiency of ellagic acid from pomegranate peel. By optimizing the solvent system, sample size and flow rate, 280 mg of ellagic acid was obtained from 5 g of crude sample from pomegranate peel by CCC after six consecutive injections. Moreover, the values of EC50 for ellagic acid in scavenging ABTS·+ and DPPH· were 4.59 ± 0.07 and 10.54 ± 0.07 μg/ml, respectively, indicating a strong antioxidant activity. This study not only established a high-throughput method for the preparation of ellagic acid, but also provided a successful example for the development of and research on other natural antioxidants.
The effects of Zn ion on magnetic properties Fe3O4 magnetic colloids were investigated in this study. Fe3O4 magnetic colloids were produced by the chemical coprecipitation method, i.e., mixing an acidic solution containing FeCl2⋅4H2O, FeCl3⋅6H2O, ZnCl2⋅4H2O, with a NaOH alkali solution at 70 °C, and then centrifuging them from the mixed solution. Various reaction times, solution pH values, and Zn ion contents were also used. Fe3O4 magnetic fluid was obtained by adding ammonium oleate into the mixed solution, precipitating the colloids from the solution, neutralizing the colloids by hydrochloric acid, and dispersing the colloids in n-hexane. XRD, EDX, TEM, and VSM were used to determine the structure, chemical compositions, particle sizes, and magnetic properties of the colloids and the magnetic fluid. The spinel colloids was easily form at a higher pH value in solutions where the pH value ranged from 7 to 12. Fe3O4 colloids were completely formed within the first minute of mixing and the particle size of Fe3O4 colloids did not increase with time after the first minute. The lattice parameter of Fe3O4 colloids increased linearly with the Zn ion content because the diameter of Zn ion is larger than that of Fe ions. The particle size of Fe3O4 colloids was found to be 10 nm by TEM. For an initially fixed Zn content of 8 wt % in solutions, the Zn content in the Fe3O4 colloids ranged from 3.32 wt % at pH=5 to a maximum value of 7.85 wt % at pH=10. Later, it reduced to 7.51 wt % at pH=12 because Zn ion has the lowest solubility at pH=10. At 8 wt % of zinc ion in the solution, the σs of the Fe3O4 colloid increase sharply from 0 at pH=3 to 92 emu/g at pH=8 and then reach a maximum value of 94 at pH=10. The σs value and Hc value of the Fe3O4 colloid were found significantly improved by adding a suitable amount of Zn ions, e.g., ranging from 70 emu/g and 48 Oe at Zn=0 wt % to a maximum 94 emu/g and 50 Oe at Zn=7.14 wt %. Later they reduced to 70 emu/g and 44 Oe at Zn=12.52 wt % when prepared at pH=10. The σs value of the magnetic fluid was found linearly proportional to the colloid content in the magnetic fluid. For a colloid containing 7.51 wt % of Zn ion, the σs value of the magnetic fluid is 9.8 emu/g at 25 wt % of colloid.
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