Carbon Resources Conversion最新文献

In this study, we aimed to synthesise and evaluate the antimicrobial activity of sulphanilamide-condensed pyrimidine derivatives. The compounds were synthesised using a one-pot, three-component reaction. The structures of the synthesised compounds were confirmed using spectroscopic techniques such as FT-IR, 1H NMR, mass spectrometry, and elemental analysis. The antibacterial activity of all the synthesised compounds was tested against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis), two types of Gram-positive bacteria. The thiamine-pyrophosphate riboswitch E. coli and the purine riboswitch B. subtilis were chosen as targets to determine how compounds bind to them. The molecular docking data showed that compound 6f bound well and had the lowest binding energy in the active site areas of both targets. This was in line with the tests done in vitro. The majority of the compounds have been demonstrated to be antibacterial.

Crude glycerol, the principal by-product of biodiesel production process, was employed as substrate by three wild-type Yarrowia lipolytica strains (ACA-YC 5030, LMBF 20 and NRRL Y-323). Stressful conditions (low pH value = 2.0 ± 0.3, low incubation temperature T = 20 ± 1 °C, non-aseptic conditions) were employed. Interesting production of yeast biomass and polyols (viz. erythritol, mannitol and arabitol) was noted at pH = 2.0 ± 0.3 and T = 20 ± 1 °C. Strains failed to produce significant quantities of cellular lipid, while variable quantities of intra-cellular polysaccharides were produced. Fermentations under previously pasteurized media supported significant biomass and polyols production for most of the tested strains, while only one strain (NRRL Y-323), managed to produce polyols at media that were not previously thermally treated at all. The production of mannitol was favored at low initial glycerol (Glol₀) concentrations, whereas higher Glol₀ quantities favored the biosynthesis of erythritol. For the strain NRRL Y-323, highly aerated / agitated bioreactor trials showed different physiological profiles as compared to the respective flask experiments. Finally, in flask experiments with the strain NRRL Y-323 at high Glol₀ amounts (≈140 g/L) at low medium pH (=2.0 ± 0.3), a significant production of polyols (=84.2 g/L) with the corresponding remarkable conversion yield on glycerol consumed = 62 % w/w was achieved.

Practical application

Renewable and biodegradable fuels, such as biodiesel, are safer and environmentally friendlier than the conventional petroleum diesel. Glycerol is a cost-effective substrate obtained as the main side-product from biodiesel production process and is currently being employed in the realm of Industrial Microbiology and Biotechnology to produce metabolic products with added value. Current research focuses on using glycerol as a starting substrate for biotechnological conversions aiming at producing, amongst other compounds, polyols, microbial biomass, citric acid, etc. from selected strains of the Generally Recognized Αs Safe (GRAS) yeast Yarrowia lipolytica. In the current investigation therefore, we examined the capacity of new wild-type non-extensively studied strains of this yeast to grow and assimilate this inexpensive substrate. Specifically, we have performed the acclimatization of the mentioned strains to stressful environments (i.e., low pH, low incubation temperature, non-aseptic conditions, etc.) and remarkable quantities of the added-value compounds (polyols, yeast mass, citric acid) were produced.

In this paper, refuse derived fuel (RDF) and bituminous coal were co-fired to investigate the particulate matter (PM) yields and the interaction between the inherit minerals in a lab-scale drop tube furnace (DTF). The PM_1-10 yields during the co-firing of coal and RDF dramatically decreased by 16.29 %∼28.5 % of the combustion of coal alone. In addition, methane auxiliary combustion inhibited the PM₁ yields by 7.95 % at air atmosphere. The Si-rich minerals in coal interreacted with the organic alkali (earth) metals in RDF, massively generating sticky particles with high liquid amount of K-Al-Si and Ca-Al-Si, promoting the transformation of fine grains into coarser mode. Moreover, it was proved that both methane auxiliary combustion and co-firing can reduce the emission of fine particles. The additional heat accelerated the burn of the char at the early stage of combustion, providing adequate time for the interaction between the inorganic species. Through thermodynamic equilibrium calculations of 1500 ∼ 3000 fly ash grains, it was found that co-firing increased the formation of sticky particles by 64.8 %∼70.3 %, resulting in a significant enhancement in capturing fine particles and Na, K vapor. Therefore, the co-firing of coal with RDF offers a promising approach to realize the harmless and resourceful treatment of municipal solid waste (MSW), and inhibit land resource losses caused by landfill

Formic acid is regarded to be one of the most prospective hydrogen carriers. Effective screening of the fitting non-noble-metal-based heterogeneous catalysts to substitute the expensive noble-metal-based ones for FA dehydrogenation is considered as a key to the commercial application for hydrogen economics. Herein, dehydrogenation of liquid neat FA achieved a gas production value of 1753.5 mL/g_cat./h at 94 °C by using a biomass-derived γ-Mo₂N based catalyst synthesized from the earth-abundant molybdenum and soybean with a facile pyrolysis process. The effect of material ratio, pyrolysis temperature on the catalytic performance of FA dehydrogenation were studied in details. In particular, the catalyst obtained at a pyrolysis temperature of 700 °C, weight ratios of ammonium molybdate to soybean of 0.2/1 exhibited the highest activity. In addition, the catalytic activity increased with the increase of FA concentration, but conversely, the dehydrogenation selectivity decreased with the increasing FA concentration. Moreover, it was found that the Bio-Mo₂N catalyst was rather stable over the 40 h continuous reaction period.

Photocatalytic technology could utilize solar energy to reduce CO₂ into high-value-added fossil fuels, providing promising solutions for global energy and environmental issues. Metal-organic frameworks (MOFs) are a class of crystalline porous solids with high porosity and flexible structure. MOF-based photocatalysts have excellent CO₂ capture ability, photochemical and structural characteristics and have shown infinite development potential in CO₂ reduction. However, in practical large-scale applications, MOF-based photocatalysts still have some urgent problems to be solved, such as high composite rate of photogenerated carriers, limited response range to visible spectrum, poor photocatalytic activity and weak reduction ability. This paper introduces series of MOF-based photocatalysts, including pure MOF materials, compounds, and derivatives, were reviewed based on recent reports. Emphasis was placed on the modification strategy of photocatalysts, the photocatalytic reaction's key physical and chemical parameters, and the mechanism of synergistic improvement of chemical fuel yield. Ultimately and most importantly, the future development trends and prospects of MOF-based catalysts for photocatalytic CO₂ reduction were discussed.

We report the controlled fabrication of nitrogen doped graphene (NG) nanoplates, which are uniformly decorated with iron nitride (Fe₃N) nanoparticles, via ball milling of mixtures of graphite and iron nitrates and the following ammonia annealing. The obtained Fe₃N@NG composites demonstrate excellent electrocatalytic activity and durability for oxygen evolution reaction, both of which outperform those of the state-of-the-art iridium oxide catalysts. This may be attributed to nitrogen doping as well as the synergistic effect between Fe₃N and graphene nanoplates.

Carbon dots (CDs) have been attracted to nanocarbon materials for metal ion sensing, biological activity, and plant phytotoxicity due to their excellent photophysical properties, such as low cytotoxicity, high quantum yield, tunable fluorescence emission, and biocompatibility. Cassava pulp, which consists mainly of starch, has been identified as a low-cost biomass waste from the cassava starch industry. Therefore, this research developed CDs and nitrogen-doped CDs (NCDs) from cassava pulp using a one-step hydrothermal process in deionized water at 200 °C. The effects of the synthesis conditions, including reaction time (6–24 h) and the nitrogen doping derivatives, were also investigated. CDs and ethylenediamine doped-NCDs exhibited tunable fluorescence emission, strong quantum yield, high photostability, and tolerance to photobleaching. Furthermore, the potential applications of CDs-12 h were demonstrated such as fluorescent sensors for metal ion sensing, antioxidant activity, and mercury detoxification in plants. Fluorescence quenching of the CDs-12 h via both static and dynamic quenching mechanisms was observed in the presence of several metal ions such as Hg²⁺, Cu²⁺, and Fe³⁺ with the detection limit in micromolar levels and further applied to real water samples with good recovery and acceptable relative standard derivation. The paper test strip coated with CDs-12 h could also detect these metal ions under UV light. CDs and NCDs-EDA also showed potential DPPH radical scavenging activity and alleviated mercury toxicity in the Chinese cabbage seedlings with the incubation of CDs-12 h and NCDs-EDA-12 h (30 mg/L).

The basic structure of aromatic compounds that are abundant in coal is the carbonaceous precursor derived from carbon microspheres. However, it remains to be a huge challenge to prepare carbon microspheres using coal due to the complex construction and composition of coal. Herein, a simple and viable way to obtain coal-based microporous carbon microspheres was developed by means of ethanol pyrolysis and a sequential extraction strategy. The as-prepared carbon microsphere featured aspherical micron particles of a uniform size (0.6–1.6㎛), abundant O-functional groups, excellent thermal stability, high SBET(415.5–983.2 m²/g), and plentiful ultramicropores(63.15–72.72 %). The coal-based carbon microsphere exhibited a noteworthy CO₂ uptake (3.19–4.97 mmol/g at 273 K and 1.0 bar), acceptable CO₂/N₂ selectivity (IAST: 23–46) and moderate isosteric heats (20–32 kJ/mol). This synthetic strategy is important for the preparation of ultramicroporous carbon microspheres using coal, and the synthetic carbon microspheres have promising prospects for highly efficient CO₂ capture.

The NO formation experiments simulating moderate and intense low-oxygen dilution (MILD) oxy-coal combustion conditions were conducted on a laminar diffusion flame burner with the coflow temperatures of 1473–1873 K and the oxygen volume fractions of 5 %–20 % in O₂/CO₂, O₂/Ar and O₂/N₂ atmospheres. The flame images of pulverized coal combustion were captured to obtain the ignition delay distances, and the axial species concentrations were measured to obtain the variation of NO formation and reduction. The NO yield in O₂/Ar atmosphere decreased by nearly 0.2 when the oxygen volume fraction decreased from 20 % to 5 % and by about 0.05 when the coflow temperature decreased from 1873 K to 1473 K. The NO yield in O₂/CO₂ atmosphere was 0.1–0.15 lower than that in O₂/Ar atmosphere. The optimal kinetic parameters of thermal NO and fuel NO formation rate were obtained by a nonlinear fit of nth-order Arrhenius expression. Finally, the relative contribution rates of thermal NO to total NO (R_th) and NO reduction to fuel NO (R_re) were quantitatively separated. R_th decreases with the increase of oxygen volume fraction, below 6 % at 1800 K, 25 % at 2000 K. R_re is almost unaffected by the coflow temperature and affected by the oxygen volume fraction, reaching 30 % at 5 % O₂.

The global impact of greenhouse gas emissions requires concerted efforts to reduce emissions and energy use, and to increase carbon capture and sequestration. Promoting the circular economy in CO₂ sequestration systems optimises resource use and reduces the emissions burden throughout the supply chain. Carbon capture from anaerobic digestion, composting and fermentation (particularly ethanol) processes offers great opportunities for climate change mitigation. The waste/by-products generated from these processes can limit the need to source nutrients from outside the system and increase the potential for circular economy. The integration of microalgae cultivation with each of anaerobic digestion, composting and ethanol fermentation processes provides a new model for climate change mitigation of biogenic CO₂ and circular economy. While this model is limited by high energy consumption and nutrient demand, seasonal variability, operational efficiency and end-user requirements, further research and policy support will go a long way in realising the associated benefits, including in CO₂ fixation, nutrient recovery, waste remediation and as an alternative source of animal feed.