Carbon Resources Conversion最新文献

The present study numerically investigates the distinct combustion characteristics of a one-dimensional premixed laminar flame of gaseous ammonia under traditional, MILD, and high-temperature combustion regimes. Specifically, we examine the flames diluted by N₂ and H₂O, respectively, analyzing the flame structure, heat release rate, temperature, main species concentrations, and NO_x emissions. The fictitious gaseous diluents of FH₂O and FN₂ are applied to quantitatively distinguish physical and chemical effects. Results show that the chemical effect of dilution by N₂ is negligible while both physical and chemical effects by H₂O dilution significantly increase the flame thickness and hence reduce the heat release rate and temperature. Furthermore, both effects of H₂O dilution diminish as the burning regime transitions from MILD to traditional or high-temperature combustion. In particular, the H₂O dilution physically reduces the concentrations of the main species. On the other hand, the chemical effect raises the concentrations of H₂, OH, and NO in the traditional and high-temperature combustion, contrasting to that under the MILD regime. As for NO_x emissions, the H₂O dilution reduces NO emission in the MILD and high-temperature combustion but influences negligibly in traditional combustion. Additionally, the chemical effect of H₂O shows a contrasting influence on the NO emission under the MILD and high-temperature regimes. Comprehensive explanations are provided for the observed phenomena, shedding light on the intricate interplay of dilution and combustion.

Activated carbon (AC) possesses several versatile properties that make it a valuable material, including a higher surface area, high adsorption capacity, microporous structure, and increased surface reactivity. AC generation from pyrolysis of biomass can be economical and environmentally responsible using varied conversion technologies (thermochemical and biological processes). This review paper studied the effects of pre-treatment technology, activation process, and heating rates during the AC production stage. Also, the properties and abilities of AC generated from biomass were revealed. It also examined the catalytic performance of commercial compounds obtained from biomass and their combinations with other materials to improve bio-oil. Additionally, this paper deals with catalytic pyrolysis of biomass (phenol and hydrocarbon generation), adsorption of organic and pharmaceutical pollutants, and absorption of gases using AC. This comprehensive review offers a new perspective on creating biomass-derived activated carbon with superior characteristics for enhancing the absorption capacity of gases and organic and pharmaceutical pollutants.

The lignocellulose reinforced composites are commonly used sustainable materials with good mechanical and physical properties. Aiming to properly dispose and recover the potential value of discarded lignocellulose reinforced composites, the pyrolysis behaviour and kinetics of reed straw processing residual/polylactic acid (RSPR/PLA) composites, a typical 3D printing material, was investigated. Based on the TG-FTIR results, the synergistic effects between RSPR and PLA during the pyrolysis process were clarified. Compared with the FTIR spectra of PLA, the absorption peaks of CO and CO₂ disappear in the FTIR spectra of RSPR/PLA composite, which indicates RSPR provides additional free radicals for the free radical reaction of PLA, and further promoting the decomposition. The apparent activation energy of the RSPR/PLA composite pyrolysis was calculated by two iso-conversional methods including Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS). The average E_a of the RSPR/PLA composite (122.6 kJ mol⁻¹ (FWO) and 117.9 kJ mol⁻¹ (KAS)) was lower than that of solo pyrolysis of RSPR (138.5 kJ mol⁻¹ (FWO) and 135.4 kJ mol⁻¹ (KAS)) and the pure PLA (197.0 kJ mol⁻¹ (FWO) and 196.6 kJ mol⁻¹ (KAS)). The master plot method results suggested the pyrolysis of RSPR/PLA composite followed the one-dimensional (D1) diffusion model. This work provides an environmentally friendly strategy to effective thermo-chemical upgrading of the value of discarded lignocellulose reinforced composite material.

Despite lignin nanoparticles (LNPs) being extensively employed as assistant agents to improve the UV-blocking performance of sunscreens, there is a lack of information addressing how and to what extent the chemical and structural features of these particles relate to the improvements observed in the Sun Protection Factors (SPF) of the sunscreens. In this study, lignin oligomers were prepared by a solvothermal extraction process of five typical biomasses in a water–acetone co-solvent without noticeable degradation of the cellulose fraction. Afterward, LNPs were produced from the self-assembly of these lignin oligomers via the solvent-shifting methodology. When incorporated into the sunscreen, these had different morphologies, and exerted different UV-blocking capacities. The effects of the chemical structure and size distribution of the LNPs were systematically studied and compared to those of the original lignin oligomers. LNPs exhibited better UV-blocking ability than soluble lignin oligomers due to the more exposed chromophore on the surface. Besides, compact LNPs with conjugating CO and β-O-4 linkages, as well as the presence of the syringyl unit rich in the methoxyl group in the structures, were beneficial in boosting the UV resistance of the sunscreens. Even though smaller LNPs with higher surface area favored the UV shielding performance, LNPs with widely distributed sizes could further help decrease the UV transmittance. These findings provide an excellent basis for using lignin-derived materials as sunscreen additives and pave the way to developing new environmentally friendly materials for the cosmetic industry.

In this study, we introduce a straightforward and effective approach to produce P-doped hard carbon using coffee grounds as the precursor, with H₃PO₄ serving as the doping agent. By varying the concentrations of H₃PO₄ (1 M, 2 M, and 3 M), we aimed to determine the optimal doping level for maximizing the incorporation of phosphorus ions into the carbon framework. Our investigation revealed that using 2 M of H₃PO₄ as the dopant material for hard carbon led to promising electrochemical performance when employed as an anode material for sodium-ion batteries. The P-doped hard carbon, carbonized at 1300 °C, exhibited an impressive reversible capacity of 341 mAh g⁻¹ at a current density of 20 mA g⁻¹, with an initial Coulombic efficiency (ICE) of 83 %. This outstanding electrochemical performance of P-doped hard carbon can be attributed to its unique properties, including a porous agglomerated structure, a significant interlayer spacing, and the formation of C–P bonds.

The present study reports a successful attempt to produce single cell oil (SCO), heterogeneous base catalyst and yeast-based biodiesel from durian peel as a promising carbon feedstock by means of the waste-to-energy concept. For this purpose, first, durian peel (DP) was hydrolyzed by dilute sulfuric acid to obtain xylose-rich DP hydrolysate (XDPH) and post-hydrolysis DP solid residue (DPS). Candida viswanathii PSY8, a newly isolated oleaginous yeast, showed high SCO accumulation (5.1 ± 0.1 g/L) and SCO content (35.3 ± 0.13 %) on undetoxified XDPH medium. A novel heterogeneous base catalyst (DPS-K) prepared from DPS by wet impregnation technique with KOH, exhibited considerable catalytic activity to convert SCO-rich wet yeast of C. viswanathii PSY8 into yeast-based biodiesel (FAME) via direct transesterification with a maximum FAME yield of 94.3 % under optimal conditions (6 wt% catalyst, 10:1 methanol to wet yeast ratio, 75 °C, and 2 h). Moreover, most of the yeast-based biodiesel properties obtained from the FAME profiles were correlated well with the biodiesel standards limit of Thai, ASTM D6751 and EN 14214. Additionally, the energy output of FAME produced about 37.5 MJ/kg was estimated. Thus, this present finding demonstrated the favorable strategy for sustainable and eco-friendly production of new generation biodiesel.

The pyrolysis behaviors and temperature evolution history of lignocellulosic biomass (Beech, BH) were characterized using a novel pyrolysis model—C-DAEM. The simulation results were validated through corresponding experimental data. Based on the simulation results, two distinct peaks were observed in the temperature difference between the surface and center (TDSC) curve, namely the thermal disturbance peak (TDP) and the pyrolysis reaction peak (PRP). The presence of TDP and PRP was confirmed by examining the heat flux ratio between the pyrolysis rate and the temperature rise rate. Moreover, the results indicated that three factors, namely heating temperature, particle size, and pyrolysis rate, influenced the relative intensity between TDP and PRP. By changing the values of each impact factor, conditions where TDP owns the same height with PRP were obtained under different working conditions. These findings have led to the development of a dimensionless number, naming the pyrolysis-heating surface-center number (PH_SC number). This number could provide a comprehensive indication of the collective impact of the aforementioned factors when TDP and PRP exhibit equal peak heights.

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