Green Carbon最新文献

Plasticizers are essential to reduce processing difficulties and improve plastic properties. However, petroleum-based phthalate plasticizers, which are mostly used at present, urgently require alternatives due to their confirmed and serious health risks. In this study, the green mass production of trans-aconitic acid was achieved via synthetic biotechnology and microbial fermentation, which was further expanded to multiple application scenarios using chemical esterification, resulting in trans-aconitate plasticizers that are biosafe and environmentally friendly and have high plasticizing efficiency and long-term stability. Different plasticizers with various core structures and alkyl chains were studied to determine their properties as polyvinyl chloride (PVC) plasticizers, and tributyl trans-aconitate displayed the best comprehensive performance with up to 1.24 plasticizing efficiency. The possible PVC plasticization mechanism with synergistic solvent, support, and shielding effects was discussed and summarized. Tributyl trans-aconitate has significant potential to replace traditional PVC plasticizers in general merchandise, food packaging, medicinal materials, and other products, further promoting the development of the high-quality plastic industry with greener technology and safer applications.

Current global energy and environmental crisis have spurred efforts towards developing sustainable biotechnological solutions, such as utilizing CO₂ and its derivatives as raw materials. Formate is an attractive one-carbon source due to its high solubility and low reduction potential. However, the regulatory mechanism of formate metabolism in yeast remains largely unexplored. This study employed adaptive laboratory evolution (ALE) to improve formate tolerance in Saccharomyces cerevisiae and characterized the underlying molecular mechanisms. The evolved strain was applied to produce free fatty acids (FFAs) under high concentration of formate with glucose addition. The results showed that the evolved strain achieved a FFAs titer of 250 mg/L. Overall, this study sheds light on the regulatory mechanism of formate tolerance and provides a platform for future studies under high concentration of formate.

Electrochemical methodologies provide a wide arsenal of options for analytical sensors, providing a high sensitivity, short analysis time, low-cost, possibility for miniaturization, and are readily portable solutions. One common theme within the literature is the use of the word “green”. The use of this terminology is intended to demonstrate the development of electroanalytical sensing platforms utilizing biodegradable and sustainable materials. In many cases, the claims of “green” electroanalytical platforms is questionable. This minireview looks to address the green credentials that are utilized in the pursuit of electroanalytical sensors, offering insights into future research opportunities.

The diffusion of chemical species down concentration gradient is a ubiquitous phenomenon that releases Gibbs free energy. Nanofluidic materials have shown great promise in harvesting the energy from ionic diffusion via the reverse electrodialysis process. In principle, any chemicals that can be converted to ions can be used for nanofluidic power generation. In this work, we demonstrate the power generation from the diffusion of CO₂ into air using nanofluidic cellulose membranes. By dissolving CO₂ in water, a power density of 87 mW/m² can be achieved. Using monoethanolamine solutions to dissolve CO₂, the power density can be increased to 2.6 W/m². We further demonstrate that the waste heat released in the industrial processes and carbon capture processes, etc., can be simultaneously harvested with our nanofluidic membranes, increasing the power density up to 16 W/m² under a temperature difference of 30 °C. Therefore, our work should expand the application scope of nanofluidic osmotic power generation and contribute to the carbon utilization and capture technologies.

The negative effect of fossil-based industrial processes on the environment, especially the contribution to global warming by emitting greenhouse gases such as CO₂ causes a global threat to mankind. Therefore, technologies are demanded by the society for a sustainable and environmental friendly economy. The biotechnological use of sugar-based feedstocks to produce valuable products are in conflict with, for example, food production. In order to overcome this issue, waste products such as syngas (H₂, CO and CO₂) or CO₂ taken from the atmosphere are of increasing interest for biotechnological applications. Acetogenic bacteria are already used at industrial scale to produce sustainable and environmentally friendly biofuels from syngas. A promising candidate due to its physiological flexibility is the thermophilic acetogen Moorella thermoacetica. In contrast to most acetogens M. thermoacetica is not restricted to one energy conserving system. In addition to the Ech complex, cytochromes and quinones maybe involved in energy conservation by, for example, DMSO respiration. The extra energy conserved can be used to form highly valuable but energy demanding products. In this review we give insights into the physiology of this acetogen, the current state of the art of M. thermoacetica as a platform for biotechnological applications and discuss future perspectives.

The thermal conductivity of carbon-based nanomaterials (e.g. carbon nanotubes, graphene, graphene aerogels, and carbon fibers) is a physical property of great scientific and engineering importance. Thermal conductivity tailoring via structure engineering is widely conducted to meet the requirement of different applications. Traditionally, the thermal conductivity∼temperature relation is used to analyze the structural effect but this relation is extremely affected by effect of temperature-dependence of specific heat. In this paper, detailed review and discussions are provided on the thermal reffusivity theory to analyze the structural effects on thermal conductivity. For the first time, the thermal reffusivity-temperature trend in fact uncovers very strong structural degrading with reduced temperature for various carbon-based nanomaterials. The residual thermal reffusivity at the 0 K limit can be used to directly calculate the structure thermal domain (STD) size, a size like that determined by x-ray diffraction, but reflects phonon scattering. For amorphous carbon materials or nanomaterials that could not induce sufficient x-ray scattering, the STD size probably provides the only available physical domain size for structure analysis. Different from many isotropic and anisotropic materials, carbon-based materials (e.g. graphite, graphene, and graphene paper) have Van der Waals bonds in the c-axis direction and covalent bonds in the a-axis direction. This results in two different kinds of phonons whose specific heat, phonon velocity, and mean free path are completely different. A physical model is proposed to introduce the anisotropic specific heat and temperature concept, and to interpret the extremely long phonon mean free path despite the very low thermal conductivity in the c-axis direction. This model also can be applied to other similar anisotropic materials that feature Van der Waals and covalent bonds in different directions.

The study reports progress in developing a molybdenum carbide-based catalyst for co-processing ethane and CO₂. The cobalt promoting of molybdenum carbide improved the activity and stability of ethane transformation in the presence of CO₂ substantially without any impact on ethylene selectivity. The Mo-Co supported catalyst also showed interesting performance in catalyzing ethane dry reforming and that application could be a perspective further use for this system. In addition, the comprehensive analysis of mono- and bi-metallic catalysts revealed that Co-promoting prevented rapid Mo-carbide oxidation. Further, tuning operation conditions allowed to control catalyst’s selectivity and maximize CO₂ utilization or ethylene formation.

Biorefinery production of fuels and chemicals represents an attractive route for solving current energy crisis, as well as reducing green-house gas (GHG) emissions from ships, planes, and long-haul trucks. The current biorefinery industry is under transition from the use of food (1G, 1st generation), to the use of biomass (2G, 2nd generation). Moreover, the use of atmospheric CO₂ (3G, 3rd generation) has caught increased attention as the possible next-generation biorefinery. Here we discuss how microorganisms can be engineered for CO₂-based biorefineries to produce fuels and chemicals. We start through reviewing different metabolic pathways that can be recruited for CO₂ fixation, followed by different opportunities for CO₂ fixation, either through co-consumption with sugars or used as the sole carbon source. Key challenges and future research directions for advancing 3rd-generation biorefineries are also be discussed.