Carbon Resources Conversion最新文献

Food waste is a significant contributor to greenhouse gas emissions when it ends up in landfills. Composting turns out to be a sustainable solution to this problem, but it requires controlled and continuous airflow for optimal performance. This study focused on the effect of aeration rates and airflow directions on food waste composting using a closed system with forced aeration. Air was entered into the composting vessel in three directions, which were upward, downward, and a combination of both directions. Each direction was run at aeration rates of 0.1, 0.4, and 0.7 L/min. The findings showed that the compost pile aerated at 0.4 L/min by using two-directional airflow can reach the thermophilic temperature within half of the day. The compost pile achieved temperature of 40.94 °C after 10.5 h. Although the compost experienced slightly high in moisture loss (4.3%), the compost still attained the standard values for maturity. The compost produced from food waste could be applied in soil to improve its fertility.

A lignocellulosic biomass, durian shell, modified by radiolytic oxidizing species from gamma and electron beam irradiations, has been used as a starting material for activated carbon (AC) production. Facile hydrothermal carbonization with ZnCl₂/FeCl₃ and physical activation were employed in addition. The physicochemical and energy storage properties of the graphitic carbons were investigated using Field Emission Scanning Electron Microscope (FESEM), N₂ adsorption-desorption, Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Raman spectroscopy, Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS). Biomass modification by radiolytic oxidizing species aided in improving the energy storage properties of the resultant ACs without significantly changing the textural qualities. The radiation type played an important role on the surface functional groups, basal plane, and pore structures of the graphitic materials. The energy storage mechanism was based on a combination of EDLC and pseudo capacitances with high Coulombic efficiency. The highest specific capacitance obtained was 325.20 F/g providing capacity retention of 94.79 % after 10,000 cycles. A promising method of AC production for energy storage application has therefore been successfully demonstrated.

In this work, Daylily Stalks derived N doped carbon material (N-DSC) with a high specific surface area was firstly prepared by a chemical activation method, and then cubic Cu₂O nanoparticles were combined with the prepared N-DSC to obtain N-DSC/Cu₂O composite as the catalyst for the photocatalytic degradation of tetracycline (TC) antibiotics under visible light. It is found that the obtained composite had higher photocatalytic activity than pure Cu₂O. Particularly, 25 wt% N-DSC/Cu₂O composite showed the highest photocatalytic performance with 95 % of TC degradation within 100 min and more excellent stability. Combined with various characterizations, it is confirmed that carbon bonds should be conducive to the separation of photoelectron and hole, and the carbon layer with an excellent electrical conductivity on Cu₂O can reduce the charge transfer resistance between N-DSC and Cu₂O, thereby improving the absorption of visible light and enhancing the photocatalytic activity. Moreover, it is considered that the synergistic effect of photo-generated electron pair in Cu₂O and N-DSC could promote the photodegradation efficiency of N-DSC/Cu₂O composite. In addition, the active species capture experiment confirmed that •OH and •O₂⁻ should be the main active species for TC degradation under visible light. This study is expected to provide a novel low-cost photocatalysts for pollutants removal.

The oligomerization of light olefins is an alternative for generating clean liquid fuels. In this study, the MCM-22 zeolite featuring a partially disordered layered structure with framework combined 10 membered ring (10 MR) was discussed for 1-hexene oligomerization. MCM-22 and Y zeolite were compared to investigate the influences of the framework and acidity strength on the activity and yield in the 1-hexene oligomerization. The results indicated that the MCM-22 zeolite was an efficient catalyst for oligomerization compared to Y zeolite. The MCM-22 zeolite was characterized in detail by NMR, Py-FTIR, and TG analyses. The catalytic performance and deactivation properties of MCM-22 zeolite in the oligomerization reaction of 1-hexene were investigated. Structure–activity relationships were established through the kinetic study. Although the density of strong acid sites was essential for the oligomerization of 1-hexene, the presence of low pressure was also necessary for the formation of dimers. Thus, MCM-22 zeolite demonstrates a substantial improvement in initial conversion and catalyst lifespan for 1-hexene oligomerization.

In this study, lipid extraction and CO₂ capture are combined using N, N-dimethylcyclohexylamine (DMCHA) as switchable polarity solvent. The effects of operation parameters are discussed according to the CO₂ absorption/desorption and lipid/DMCHA recovery results. A triphasic models considering lipid, water, and gas phases are established to analyze the kinetic behaviors. The results show that DMCHA is reversible through CO₂ absorption/desorption, and the enhanced dispersion of droplets and bubbles in water phase improves the lipid/DMCHA recovery and CO₂ absorption/desorption. The triphasic kinetic models fit well with experimental data, and gas–liquid mass transfer is regarded as the rate-determining step. The lower interfacial areas result in the poorer gas–liquid mass transfer for the DMCHA recovery than lipid recovery process.

The conversion of glycerol to acrylic acid was carried out by the one-pot process method. The catalyst used in this conversion is Cu-modified HY zeolite synthesized using pro-analytical precursors and alternative precursors from natural resources i.e., Indonesian natural zeolite and kaolin. The crystal structure and physicochemical properties of catalysts were determined by various characterization techniques such as XRD, FTIR, SEM-EDX, TEM, SAA, and TPD-NH₃. Based on XRD analysis, it shows that HY and CuHY, both from synthetic and alternative precursors, are confirmed to have typical peaks of Y zeolite. EDX mapping images show a uniform distribution of Cu on the HY surface. In addition, the TEM analysis also shows uniform particle size distribution. The results of catalytic glycerol conversion show that Cu-modified HY catalysts give a higher acrylic acid yield than HY. The results also show that the highest yield of acrylic acid was obtained in 27.5% and 25.8% at a dehydration time of 3 h using pro-analytical and natural resources CuHY catalyst, respectively. The Cu-modified HY catalysts having weak acid sites show the best catalytic activity in the conversion of glycerol to acrylic acid.

Replacing fossil carbon sources with green bio-oils is a promising route to switch to a sustainable chemical industry, although their high oxygen contents are challenging. Catalytic hydrodeoxygenation is a favored route to upgrade bio-oils to renewable fuels and basic chemicals. In this work, we investigated Ni/SiO₂ catalysts with differing metal dispersity in continuous mode conversion of guaiacol with a statistical experimental design for 250 °C to 400 °C, 2 h up to 5 h time on stream (ToS) and subsequently different residence time besides other parameters. While low temperature (250 °C) promotes cyclohexanol formation from guaiacol, high temperature (400 °C) inhibits hydrogenation, leading to phenol and methane. For medium temperature (340 °C), the selectivity for cyclohexanone increases. Cyclohexanol and cyclohexanone (KA-oil) are the industrial basis for polyamide 6. Furthermore, we clarified the role of 2-methoxycyclohexanol (2MC) in the reaction network towards KA-oil for continuous-mode operation. Statistical analysis was used to predict and optimize product selectivity and yield, leading to the best yield of cyclohexanone/-ol at 327.5 °C, low ToS, medium residence time, high particle dispersity, and medium hydrogen pressure (15 bar(g)).

In recent years, hydrothermal treatment has been considered as among the most promising option for sludge solubilisation and carbon recovery in terms of sludge management. In this study, the effect of different individual hydrothermal operating conditions like temperature (110–250 °C), sludge pH (6–13) and reaction time (0.5–3 h) were varied to understand their influence on sludge solubilisation. The most effective hydrothermal conditions (severity factor of 9.7) were found to be at 200 °C, sludge pH of 12 and reaction time of 1 h which solubilised about 1743 mg/g and 131 mg/g of COD and carbohydrates respectively into the aqueous phase. Also, gas chromatography- mass spectrometry (GC–MS) analysis was done that identified the organic compounds in the treated liquid phase to be mainly carboxylic acids, phenols, esters, and their derivatives. Although further studies are required to efficiently separate and recover the different organic compounds present, this work provides more insights for future valorisation of the organic rich hydrothermally treated liquid phase.

The sorption-enhanced method can change the thermodynamic equilibrium by absorbing CO₂. However, it also brings about the problems of high regeneration temperature of adsorbent and large regeneration energy consumption. In order to study the impact of enhanced adsorption methods on the overall energy cost of the system in the hydrogen production process, this paper analyzes and compares steam methane reforming and reactive adsorption-enhanced steam methane reforming with the energy consumption of hydrogen production products as the evaluation index. The results showed that the energy consumption per unit hydrogen production decreased from 276.21 MJ/kmol to 131.51 MJ/kmol, and the decomposition rate of H₂O increased by more than 20% after the addition of adsorption enhancement method. It is proved that the advantage of sorption enhanced method on pre-separation of CO₂ in the product makes up for the disadvantage of energy consumption of adsorbent regeneration. In addition, the ability of the process to obtain H element is improved by the high decomposition rate of H₂O, which realizes a more rational distribution of the element.