For metal-free carbocatalysts, heteroatom doping and hierarchically porous structure are the significant factors to improve their catalytic performances. Herein, N-, P-co-doped hierarchically porous carbon fiber (NPC–2–800) was prepared by pyrolyzing bamboo pulp in combination with ( NH4)2HPO4 and activator K2CO3. It was found that ( NH4)2HPO4 not only provides N and P atoms, but also significantly affect the morphology and pore structure of the porous carbon. An appropriate dosage of ( NH4)2HPO4 facilitates the formation of hierarchically porous carbon fiber in NPC-2–800. Whereas, the carbon fragments with only micropores were obtained in absence of ( NH4)2HPO4. The hierarchical porosity and the co-doping of N and P atoms in the NPC-2–800 contribute to its outstanding catalytic performances in the 4-Nitrophenol (4-NP) reduction assisted by NaBH4. The NPC-2–800 exhibits an attractive turnover frequency (TOF) value of 4.29 × 10– 4 mmol mg− 1 min− 1, a low activation energy (Ea) of 24.76 kJ/mol, and an acceptable recyclability for 7 cycles without obvious decrease in activity. Kinetics analyses suggest that the 4-NP reduction proceeds through the Langmuir–Hinshelwood model. In addition, the NPC-2–800 can also efficiently catalyze the 2-NP and 3-NP reduction. Moreover, in the real water body, the NPC-2–800 also showed superior catalytic activity to catalyze 4-NP reduction. This study provides an efficient catalyst for pollutant conversion and elimination as well as guidelines for designing versatile carbon-based catalysts.
Novel ionic liquid-functionalized carbon quantum dots (IL-CDs) were prepared by hydrothermal method, and characterized with FT-IR, TEM and XPS. The IL-CDs exhibited narrower particle size distribution with more uniform dispersion and the surface potential changes from negative to positive due to the function of IL. IL-CDs could be quenched (“turned off”) after adding ascorbic acid (AA), and as an “on–off”, fluorescent probe could be established for direct analysis AA. The linear range of AA was 0.34–30.00 μg/mL and the LOD was 0.11 μg/mL. The method was successfully applied to the determination of AA in real samples with satisfactory results.
Whole plant com fertilized with or without nitrogenous fertilizer during its growth was harvested at milk matured stage for silages. The lactic acid bacteria inoculants Lactobacillus>6×10¹? cfu/g, Pediococcus>2×10¹? cfu/g) was used at 0.01 g/㎏ of fresh matter. Cellulase (CF) (concluding cellulase, acremmoocium and trichioderma) was used at 0.033 g/㎏ of fresh matter. And the mixture of lactobacillus and enzyme (LF+CF) were used respectively 0.01 g/㎏ and 0.033 g/㎏ of fresh matter. After 45 days, when the silages had been made, opened to air and sampling for the analysis of nitrate contents and nitrite contents at 0, 1, 3, 6 and 10 days. The results showed that, the nitrate content of fertilized com silages was higher (p<0.05) than that of unfertilized com silages significantly at the beginning of opening the silages. As the day's extension, the nitrate content of all silages trended to decline. For the fertilized com silages, the nitrate content of untreated silages higher (p<0.05) than that of treated silages and declined sharply throughout the process. This phenomenon appeared from 3 day point to 10 day point for treated silages. For unfertilized com silages, there was no significant difference between untreated silages and treated silages at 0 day point. The nitrate content of untreated silages sharply declined from 0 day to 10 day point, which of treated silages began at 3 day point. From above, we can conclude that nitrogenous fertilizers can affect the nitrate content of com silages, and adding LAB and enzyme can retard the nitrate transforming into nitrite.
Research on alfalfa root morphology and health is very important in development of technology for efficient improvement and production of alfalfa. The objectives of this study were to evaluate the root morphology and health of two alfalfa varieties, Algonquin and Golden Queen, to determine relationships among root morphology traits and root health. Results from these analyses indicated t㏊t yield was 6.77-43.93 t/h㎡, total root length ranged from 215.17-708.89 ㎜, root surface area ranged from 93.61-717.06 ㎠, volume ranged from 3.24-57.72㎤. Results from these analyses indicated t㏊t root infestation score was the lowest averaged over age of alfalfa stand in Algonquin. Yield in 2-yr old stands was greater in Golden Queen compared to Algonquin.
In this study, we determinated the dynamic changing of soluble sugar, total nitrogen and malondialdehyde, so t㏊t found out their relationships with cold resistance. The result indicates: the content of soluble sugar and total nitrogen increased from late autumn and early winter, and kept higher level during the entire winter, then decreased in regreen time in the next spring. The content of malondialdehyde was high in Sep., then decreased gradually and reached the minimum in Jan., thereafter the content of malondialdehyde represented increasing trend.
Cold acclimation of plants is a highly active process resulting from the expression of a number of physiological and metabolic adaptations to low temperature. Major metabolic changes in carbohydrates, protein, nucleic acids, amino acids, and growth regula