ChemBioEng Reviews最新文献

Algae for biofuels as an alternative to fossil fuels. Copyright: toa555@AdobeStock

Heat exchangers (HXs) are crucial in transmitting thermal energy in various industrial and domestic applications. Efforts to improve the design of HXs over the years have resulted in heat transfer enhancement with the penalty of pressure loss (∆P). Researchers have implemented various methods to enhance heat transfer. These methods have been categorized based on the need for external power. Active heat transfer methods require external energy, whereas passive heat transfer methods operate without an external power source. Increasing the effective surface area for heat transfer or inducing turbulence through surface alterations can improve passive heat transfer, leading to secondary flow. Of all the surface alterations, the corrugated tubes are particularly significant for enhancing the heat transfer in a turbulent flow, as they result in a reasonable increase in ΔP. Apart from an increase in ΔP, the initial cost of corrugated tube HX is higher than that of simple HX. Therefore, one should not write off the economic analysis of any passive enhancement technique. Various applications increasingly use corrugation in systems like the primary and secondary heat transport systems of nuclear reactors, refrigeration, and other industries. This paper critically reviews thermal investigations for improving heat transfer and a comprehensive economic analysis of corrugated tube HXs.

The current review article investigates the potential for producing highly valuable items solely from agricultural wastes treated with deep eutectic solvents (DES). A thorough explanation of the DES s’ reaction mechanism and biomass-treating capabilities is provided, shedding light on how green pretreatment methods can be applied to agricultural wastes in order to form high-value products. In view of that, the influences of crucial properties of DES like viscosity, density, and recycling ability of DES are well analyzed. This review article's next goal is to compile the most recent developments for the years 2018–2023 on DES-based valorization of agricultural wastes into a range of products, including biogas such as biohydrogen, liquid biofuels like bioethanol and butanol, and platform chemicals and reagents that are followed by novel materials. A discussion of the current criticalities and prospective avenues for further research concluded the paper. For this reason, having a thorough grasp of product value in one review paper from the potential of DES to agricultural wastes will be very helpful to the readers.

In recent decades, biodiesel has emerged as a renewable and environmentally benign fuel compared with its fossil counterpart. From an industrial perspective, homogeneously-catalyzed transesterification has been established as the principal method for biodiesel synthesis owing to the moderate reaction conditions. However, homogeneous catalysts cannot be reused, and large amounts of wastewater accompany their separation from the products, making the production process detrimental to the environment and contrary to the sustainable development objectives. This grim reality confronting green fuel can be avoided by using heterogeneous catalysts that can be recycled and reused several times. Metal elements have played a crucial role in the development of such catalysts. These species are readily available in the environment and provide solid catalysts with high activity. Due to their significant contribution to achieving a sustainable production method for biodiesel, this paper reviews the role of metallic elements in fabricating functional materials, including metal oxides, mixed metal oxides, and metal-doped porous frameworks. The optimized reaction conditions focused on reusability were reported and analyzed for each class of catalysts. Challenges and future requirements for boosting the catalysts’ activity and reusability in the production process were also discussed. Leaching of active sites and pore blockage were the primary factors detrimental to reusability. These issues could be minimized by supported metal atoms on porous materials, providing a stronger bond of the metal sites and the support, and utilizing membrane reactors to continuously remove the products from a reaction mixture.

New Zealand is known for its diverse population of flora and fauna, of which 80 % are endemic. Māori, the indigenous people of New Zealand, have profound and holistic knowledge of plants and utilize them in medicinal, spiritual, and ecological practices. Among these, kānuka has traditionally been used for medicinal purposes. Prior in vitro studies on kānuka extracts have demonstrated promising antioxidant, antimicrobial, anti-inflammatory, and antiproliferative properties. These studies further recommend the translation of these findings into new medicines and commercial products. However, a significant knowledge gap regarding their therapeutic potential hinders their application in various industries. A deeper understanding of the biochemical composition of the extract and the mode of interaction to exert its bioactivity in the host is vital for achieving this. Hence, this review evaluates the bioactivities of kānuka in association with its bioactive compounds (polyphenolics and terpenoids) reported in the current literature. Knowing the critical role of extraction methodologies in determining bioactive composition, we highlighted their efficiency in the bioactivities of kānuka.

Global energy consumption has drastically increased over the years due to population growth and industrialization. This has prompted an exploration for clean and renewable energy alternatives. Microalgae are widely recognized as a promising third-generation energy source because they have the capability to generate biofuels, including biochar. The utilization of microalgal biomass has been gaining traction because of their advantages, such as fast growth, a high rate of production, and high carbon-fixing efficiency. Thermochemical methods like hydrothermal carbonization, torrefaction, and pyrolysis can be employed to harness energy from microalgae. The different thermochemical methods employed for converting microalgal biomass into biochar have been discussed, as well as the factors affecting these methods. In addition, a dedicated section covered the components and properties of the generated biochar, including its thermal and surface properties. Furthermore, the economic analysis of the production of biochar from microalgae as well as the applications of microalgae-derived biochar were presented and discussed, along with suggestions for further research.

Effective biobased thermally insulating materials are crucial to addressing the escalating concerns surrounding climate change and plastic waste. Numerous experimental biobased foams have demonstrated properties that are either equal to or superior to those of traditional foams employed in the construction sector. The comprehensive review titled “Recent Advances in Biobased Foams and Foam Composites for Construction Applications” by DSouza et al. (DOI: https://doi.org/10.1002/cben.202300014) specifically focuses on the fabrication methods, advancements, and future prospects of biobased polyurethanes (BPU), biobased phenol formaldehyde (BPF), and cellulose nanofibers (CNF) foams for application in residential construction. To be a suitable material for construction, a biobased foam must be an excellent thermal insulator (possessing low thermal conductivity), a fire retardant (with high limiting oxygen index) and possess remarkable mechanical properties. The cover image thus depicts forest waste-based foams that meet the design criteria for construction applications. [Credits: Riddhi Gadre for the initial design and InMyWork Studio team for the final design]

Biobased Foams for Construction Applications. Copyright: Glen Cletus DSouza, Harrison Ng, Paul Charpentier, Chunbao Charles Xu