Green Carbon最新文献

Gasification is one of the most significant and well-researched pathways to produce energy from biomass among the different options available. It is a conversion through thermo-chemical process that takes place within a gasifier, with interconnected factors that have an impact on how well the gasifier works. Gasification of carbonized biomass, which has a variety of effects on both the gasification process and the final product, is a significant method of producing energy from raw biomass that contains a lot of moisture or has non-homogeneous morphology. Although carbonized biomass has the potential to eliminate or significantly reduce tar formation, which is the most difficult aspect of biomass gasifier design and operation, it has not received the attention it merits even though gasification of biomass is a well-known conversion process with extensive research and development spanning all sectors of the process. This review gathers and analyzes the growing number of experimental and numerical modeling approaches in gasification of carbonized biomass based on exact conditions such as type of modeling considerations, feedstock, gasifier, and assessed parameters. The study also provides an overview of various models, such as equilibrium and kinetic rate models and numerical simulations of carbonized biomass gasification schemes based on computational fluid dynamics and Aspen Plus, while comparing the modeling approaches and results for each type of models that are described in the literature. Also, this review encompasses a broad variety of technologies, from laboratory reactors to industrial scale. Overall, this review offers a brief overview of the modeling decisions that must be taken at the beginning of a modeling research.

Methanol, produced from carbon dioxide, natural gas, and biomass, has drawn increasing attention as a promising green carbon feedstock for biomanufacturing due to its sustainable and energy-rich properties. Nicotinamide adenine dinucleotide (NAD⁺)-dependent methanol dehydrogenase (MDH) catalyzes the oxidation of methanol to formaldehyde via NADH generation, providing a highly active C1 intermediate and reducing power for subsequent biosynthesis. However, the unsatisfactory catalytic efficiency and cofactor bias of MDH significantly impede methanol valorization, especially in nicotinamide adenine dinucleotide phosphate (NADP⁺)-dependent biosynthesis. Herein, we employed synthetic NADH and NADPH auxotrophic Escherichia coli strains as growth-coupled selection platforms for the directed evolution of MDH from Bacillus stearothermophilus DSM 2334. NADH or NADPH generated by MDH-catalyzed methanol oxidation enabled the growth of synthetic cofactor auxotrophs, establishing a positive correlation between the cell growth rate and MDH activity. Using this principle, MDH mutants exhibiting a 20-fold improvement in catalytic efficiency (k_cat/K_m) and a 90-fold cofactor specificity switch from NAD⁺ to NADP⁺ without a decrease in specific enzyme activity, were efficiently screened from random and semi-rationally designed libraries. We envision that these mutants will advance methanol valorization and that the synthetic cofactor auxotrophs will serve as versatile selection platforms for the evolution of NAD(P)⁺-dependent enzymes.

Phase change materials (PCMs) are increasingly capturing the spotlight in the realm of building design and construction owing to their capacity to absorb and release thermal energy throughout phase transitions. This review provides a comprehensive overview of PCMs, outlining their properties and applications in improving energy efficiency, comfort, and sustainability in buildings. It delves into various types of PCMs, discussing their selection criteria, integration methods, and their impact on indoor climate and energy consumption. The exploration covers both passive and active PCM systems across diverse building components, including implications for walls, roofs, windows, and floors, and integrated heating, ventilation and air conditioning (HVAC) and solar energy storage. Additionally, the review addresses challenges associated with PCM implementation in building applications while considering future prospects in this field.

To understand the catalytic conversion of lignin into high-value products, lignin depolymerization was performed using a layered polymetallic oxide (CuMgAlO_x) catalyst. The effects of the conversion temperature, hydrogen pressure, and reaction time were studied, and the ability of CuMgAlO_x to break the C–O bond was evaluated. The CuMgAlO_x (Mg/Al = 3:1) catalyst contained acidic sites and had a relatively homogeneous elemental distribution with a high pore size and specific surface area. The β-O-4 was almost completely converted by disassociating the C–O bond, resulting in yields of 14.74% ethylbenzene, 47.58% α-methylphenyl ethanol, and 36.43% phenol. The highest yield of lignin-derived monophenols was 85.16% under reaction conditions of 280 °C and 3 Mpa for 4 h. As the reaction progressed, depolymerization and condensation reactions occurred simultaneously. Higher temperatures (> 280 ℃) and pressures (> 3 Mpa) tended to produce solid char. This study establishes guidelines for the high-value application of industrial lignin in the catalytic conversion of polymetallic oxides.

Considering the aim of carbon neutrality and reducing plastic pollution, lightweight porous materials with good thermal insulation and mechanical robustness derived from renewable resources are in high demand. Cellulose-based pulp foams (PFs) offer considerable potential applications in many fields; however, the cost-effective manufacturing of PFs with satisfactory properties remains challenging. Herein, we demonstrate a simple and low-cost strategy to prepare a novel pulp/natural rubber (PNR) foam by combining wood pulp fiber and natural rubber latex through wet foaming and oven drying, eliminating traditional freeze-drying and solvent exchange processes. The obtained PNR foam exhibited high porosity (98.4%-99.1%), low density (14.1–24.0 mg/cm³), and excellent water stability (without disintegration under magnetic stirring for 14 days). Moreover, montmorillonite (MMT) was easily incorporated into the PNR during the preparation process, improving the mechanical strength and heat insulation of the obtained PNR-MMT foam. The optimized PNR-MMT foam could be compressed more than ten times without losing its resilience, exhibiting a compressive strength of 2.7 MPa at 80% strain, five times higher than that of pristine PF. Moreover, the PNR-MMT foam exhibited excellent flame retardant, good “spill” oil absorption, and good antibacterial properties towards Escherichia coli and Bacillus subtilis. Overall, this study provides a facile, sustainable, and low-cost route for manufacturing PNR-MMT foams with high resilience, good thermal insulation, excellent flame retardancy, and strong antibacterial properties, thus highlighting their usage potential in a broad range of applications.

Carbon neutralization has been introduced as a long-term policy to control global warming and climate change. As plant photosynthesis produces the most abundant lignocellulosic biomass on Earth, its conversion to biofuels and bioproducts is considered a promising solution for reducing the net carbon release. However, natural lignocellulose recalcitrance crucially results in a costly biomass process along with secondary waste liberation. By updating recent advances in plant biotechnology, biomass engineering, and carbon nanotechnology, this study proposes a novel strategy that integrates the genetic engineering of bioenergy crops with green-like biomass processing for cost-effective biofuel conversion and high-value bioproduction. By selecting key genes and appropriate genetic manipulation approaches for precise lignocellulose modification, this study highlights the desirable genetic site mutants and transgenic lines that are raised in amorphous regions and inner broken chains account for high-density/length-reduced cellulose nanofiber assembly in situ. Since the amorphous regions and inner-broken chains of lignocellulose substrates are defined as the initial breakpoints for enhancing biochemical, chemical, and thermochemical conversions, desirable cellulose nanofibers can be employed to achieve near-complete biomass enzymatic saccharification for maximizing biofuels or high-quality biomaterials, even under cost-effective and green-like biomass processes in vitro. This study emphasizes the optimal thermal conversion for generating high-performance nanocarbons by combining appropriate nanomaterials generated from diverse lignocellulose resources. Therefore, this study provides a perspective on the potential of green carbon productivity as a part of the fourth industrial revolution.