ChemBioEng Reviews最新文献

The abundance and renewability of lignocellulosic biomass have made it a suitable alternative to fossil fuels in the reduction of global warming. The complex nature of the cellulose–hemicellulose–lignin bonds in the biomass makes it difficult to directly obtain platform chemicals. Pretreatment of the biomass has become a solution to remove lignin and obtain cellulose and or hemicellulose to produce platform chemicals. Platform chemicals such as hydroxymethylfurfural, furfural, and levulinic acid are viable feedstocks for aldol condensation to produce C₈–C₁₅ fuels. This review reports on deep eutectic solvents and microwave-assisted pretreatment as green techniques for the delignification and platform chemicals production. Emphasis is placed on the use of hydrotalcites (HTs) as catalysts in platform chemicals production and aldol condensation for C₈–C₁₅ alkane fuels. Additionally, the hydrogenation of furfural into cyclopentanone and successive conversion into C₁₀ and C₁₅ alkanes with HTs was reviewed.

Electrochemical wastewater treatment technologies are gaining attraction as sustainable alternatives for industrial and municipal wastewater management. This study conducts a comprehensive life cycle assessment to assess the environmental and economic sustainability of electrochemical methods such as electrocoagulation, electrooxidation, and electroreduction. By analyzing key stages, from raw material extraction to end-of-life disposal, the review aims to provide insight into their overall sustainability performance. The study also delves into environmental impact categories and utilization of methods used in quantifying the environmental implications. Moreover, a cost structure analysis and cost-effectiveness evaluation offer insights into the economic viability of these technologies. Despite facing challenges like high initial costs and regulatory constraints, electrochemical technologies demonstrate competitive advantages in treatment efficiency and energy savings. Collaborative efforts and supportive policy frameworks are deemed crucial for overcoming barriers and fostering the widespread adoption of electrochemical technologies, thereby advancing sustainable wastewater management practices.

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

The increasing global population has led to a surge in waste production across various fields including agriculture, industry, marine, and household, posing significant waste management challenges. Concurrently, the world is facing an energy crisis, emphasizing the crucial need for sustainable and renewable energy sources. This comprehensive review examines the potential of biomethane production from diverse waste biomass. Feedstock characteristics; anaerobic digestion (AD); biochemical pathways; factors influencing AD; various pretreatment methods such as physical, chemical, biological, and combined; existing policies supporting biomethane production; and potential new policy implications are discussed in this review along with the significance of waste-to-energy integration. Our findings indicate that lignocellulosic wastes, primarily agricultural waste, stand out as the most efficient biomass source for biomethane production due to their characteristics such as high carbon/nitrogen ratio, low ash content, and their abundant availability. Among pretreatment methods, combined pretreatment emerges as the most promising option, offering flexibility and effectiveness in enhancing biomethane production. Additionally, the two-stage digester configuration proves advantageous in overcoming limitations associated with single-stage digesters such as pH inhibition. Altogether, the review highlights that biomethane production from waste biomass through AD offers a sustainable solution.

A comprehensive understanding of the inter-bubble dynamics and the cluster formations in non-Newtonian fluids is pivotal for chemical and biomedical engineering applications. In this review, we summarize current research efforts to provide a fundamental understanding and engineering principles of the interactions between bubbles and the dynamics of bubble clusters in non-Newtonian fluids. Although the majority of research is still predominantly conducted through experimentation, the significance of computational fluid dynamics in elucidating interaction mechanisms has become increasingly prominent in recent years. Moreover, the gas-liquid systems reviewed in this paper are driven by gravity, which is closer to the actual industrial processes. We indicate the effects of non-Newtonian fluid special rheological properties (especially viscoelasticity and shear-dependent viscosity) on the interaction between multiple bubbles and the formation of clusters. We summarize the main empirical correlations in related research, which are useful for the optimization of industry. Ultimately, we address the current trends, limitations, and future directions in this research field.

Exploring alternative energy sources is vital amid increasing human fuel consumption. Globally, biogas, rich in methane, hydrogen sulfide, and carbon dioxide, addresses energy demands through biomass anaerobic digestion (AD). Efficient digestate management, employing techniques like solid-liquid separation and composting, is crucial for environmental protection. The goal is to optimize nutrient-rich byproduct utilization while minimizing negative impacts. This review analyzes diverse substrates, emphasizing challenges and benefits. Key considerations include nutrient ratios, moisture content, co-digestion, organic loading rate, and retention time. The study explores temperature's impact on microbial growth, biogas impurities, and upgradation techniques, including biological methods. Fermentation, microbial electrochemical techniques, and biochar use for enhanced AD are introduced. Discussing digestate's multifaceted aspects, the review highlights its nutrient value and diverse applications in aquaculture, animal feed, fermentation, bioremediation, and fine chemical production.

Despite the increasing global need for sustainable energy, biomass gasification is becoming a highly promising method for transforming raw biomass into usable energy. The present review article analyzes the essential aspects of biomass-based energy production, starting with an assessment of existing energy needs and the crucial contribution that biomass can make in fulfilling these demands. The research investigates recent advancements in several biomass gasification methods, explaining their mechanics and discussing the related difficulties. The research conducts a thorough evaluation of the efficiency, yield, and environmental consequences of biomass gasification, aiming to determine the feasibility of the technique. In addition, the study rigorously assesses the techno-economic factors of energy generation from biomass, providing valuable information on the economic viability and scalability of various biomass gasification techniques. The present study is focused on providing a comprehensive understanding of biomass gasification by analyzing current improvements and conducting a techno-economic comparison to make well-informed decisions for a sustainable energy future.

Carbon dioxide (CO₂) is a greenhouse gas which is mainly found in natural gas (NG), biogas, and flue gas. Anthropogenic CO₂ emissions are the direct result of burning fossil fuels. Meanwhile, pre- and postcombustion CO₂ separation is a current state of CO₂ removal method in an extensive manner. From environmental, economic, and transportation perspectives, removal of CO₂ has driven the development of its separation process technology. Among the reported technologies, membrane-based gas separation technologies have grown substantially, breakthroughs and advances in past decades. This review paper aims to provide an overview on competitive gas separation processes, different types of membranes available, gas transport mechanisms, and fabrication process of hollow fiber membranes, particularly dual-layer hollow fiber membrane. The performance of the membranes in CO₂ separation and effect of spinning parameters on the formation of hollow fiber membranes are highlighted. In addition, approaches to improve the dual-layer adhesion, strategies to enhance the filler compatibility in the development of dual-layer hollow fiber mixed-matrix membranes, and effect of post-treatments on the gas separation performance of membrane are also discussed. Finally, challenges and future perspectives of dual-layer hollow fiber mixed-matrix membranes toward CO₂ capture, particularly on CO₂/CH₄ and CO₂/N₂ separation, are also included, due to its substantial and direct relevance to the gas separation industry.