Nowadays there is a strong urge to replace the fossil-based chemicals and fuels with biobased ones. In this context, the 7th principle of the green chemistry, the Sustainable Development Goals (SDGs) and the recent Safe and Sustainable by Design (SSbD) approach are the main references. Among the various biorefineries, lignocellulosic biomasses represent the most abundant resource to explore. Considering the vast plethora of useful molecules produced from lignocellulosic biomasses, levulinic acid embodies a potential starting material for the preparation of high value-added chemicals. This review explores the preparation of levulinic acid form lignocellulosic biomasses and its further valorization to high-value added compounds (γ-valerolactone, ketals and methyl/ethyl levulinate), considering the current state of the art of the available synthetic strategies, in a life cycle perspective considering the adoption of the life cycle assessment (LCA) methodology.
Aromatic monomers are key building blocks for many polymer resins for coatings applications. The rigid structure results in improved thermal and mechanical properties of the coatings, such as high hardness or scratch-resistance to name but a few. However, most of the available aromatic building blocks are very inexpensive monomers obtained from petrochemical resources. To enhance the sustainability of coatings materials, bio-based alternatives are of high interest for both industry and academia. This short review aims to highlight very recent work on biobased aromatics for coatings applications.
The landscape of chemical production has undergone a paradigm shift towards sustainability, emphasizing catalytic procedures, renewable raw materials, and green chemistry principles. Chitin, the second most abundant global biomass, offers opportunities for synthesizing nitrogen-rich aromatics, crucial for reducing the reliance on energy-intensive nitrogen sources like ammonia. This review outlines the most recent advances in methodologies for preparing nitrogen-rich furans, focusing on 3-acetamido-5-acetylfuran (3A5AF), dihydroxyethyl acetamidofuran (diHAF), 3-acetamido-5-formylfuran (3A5FF), and 3-acetamidofuran (3AF) from N-acetylglucosamine (NAG) dehydration. In addition, the review encompasses other aromatic commodities currently obtained from chitin, either by derivatization of the aforementioned furans, by deacetylation-dimerization, or other strategies. Although challenges in scaling up, product stability, and low yields persist, these furans hold promise as sustainable synthons, driving innovations in chemical synthesis.
Sewage sludges (SS) are by-products of the wastewater treatment process and are considered critical source of contaminants as they contain a diverse range of microbial, organic, and inorganic pollutants that are concerning to public health and the environment. Hydrothermal processes are particularly suitable for treating SS; however, their viability for the effective degradation and potential destruction of persistent contaminants, such as heavy metals, microbial pathogens, microplastics, per- and polyfluoroalkyl substances, pharmaceuticals, and personal care products, among others in SS is still under rapid investigations. This article reviews the source, transformation, and fate of prominent contaminants in SS during hydrothermal treatment (HT). Most contaminants in SS are to a certain extent degraded or transformed into other products under typical HT at subcritical conditions. Transformation pathways can be complex due to the diverse physicochemical and biochemical properties, including thermal stability and hydrophobicity. Critical findings were summarised with conclusions and perspectives for future works provided.
Challenges related to economic viability and production processes to sustainable aviation fuel (SAF) have significantly hindered its widespread commercial adaptations. This mini review provides the current opinion on various feedstocks and conversion processes for low-cost SAF production. The primary emphasis lies on exploring alternatives to traditional feed crops with a shift toward utilizing lignocellulosic biomass, waste feedstocks, oil-seed crops, and microalgal oil. The Fischer–Tropsch process, hydroprocessed esters and fatty acids, and nonthermal plasma method, where lignocellulosic biomass, oil-based crops, microalgal oil, and waste oils are widely used are cost effective, have high potential to produce SAF. However, technical immaturity and high cost compel detailed investigation on the optimization process using various alternative feedstock. This mini review insights the critical factors effecting reaction efficiencies, including feedstock characteristics, reaction parameters, catalyst reusability, and supports that need systematic investigation. Conclusively, this outlook delves into the challenges, solutions, and opportunities associated to cost-effective SAF production.
Known for its high theoretical capacity and low cost, the commercialization of Li–S batteries is hindered by the notorious shuttle behavior of the intermediate lithium polysulfides in liquid electrolyte and the sluggish kinetics of the liquid-to-solid reaction. Recently, to improve the electrochemical performance, iron-based compounds with well-designed nanostructures have been developed and applied as host material for sulfur because they have strong chemisorption of polar polysulfide molecules and could reduce the nucleation energy of solid Li2S. Here, we have reviewed the latest research progresses (in the last three years) of various iron-based compounds as sulfur host materials and prospected the designing principles of efficient host materials with multiple functionalities to address the issues in sulfur cathode.
Metal–organic frameworks (MOFs) have been proposed to provide solutions for industrially-relevant gas separations due to their exciting structural and porosity attributes. Significant progress has been made in the past decade in the development of tailor-made MOFs for gas separation applications. However, most of the developed MOF sorbents, made from different metal salt and organic linker precursors, cannot be prepared following green chemistry principles. Accordingly, recent research has focused on green synthesis protocols for preparing MOFs for energy and environment applications. This short review delves into the lab-scale development of green MOF sorbents, showcasing their performance in selected gas separation applications. By summarizing key recently reported examples, we illustrate the potential of green MOFs to advance the transition to large/industrial scale synthesis and sustainable gas separation technologies. Our analysis also reveals a critical gap, i.e., the lack of quantitative data showing environmental impact and comprehensive Life Cycle Assessment (LCA) studies.
Flow chemistry is now a key technology for synthetic chemistry, with the different operating windows available allowing new chemistry to be optimised and discovered. The related area of flow biocatalysis is also becoming increasingly recognised as an integral aspect of bioprocess optimisation, with modularisation and technology integration some of the key drivers for this. This minireview will discuss some recent examples where flow has substantially improved the sustainability of a bioprocess. We also reflect on the increase in analytics, how it is starting to impact bioprocess optimisation, and what the implications of this will be moving forward.
This study highlights the extensive use of and full reliance on nonrenewable sources like fossil base fuels results in availability shortage, increased economy, depletion in the carbon sink, CO2 emission high, environmental pollution, drastic change in climate and mismanagement of waste. To overcome this problem, renewable resources together with nuclear advanced approaches resulted in fewer carbon sources and are used to decarbonize GHG/CO2 emissions, carbon storage technology and lower carbon pricing to achieve net-zero carbon sustainability in the environment. The proposed policies and their implementation occurrence at national and international levels also resulted in carbon-free production and enhanced consistency. On implementation of environmentally friendly policies, the problem could be solved by global contribution of government, stakeholders, public sectors, engagement policy coherence and integration towards making and implementing policies via advanced approaches for achieving net-zero carbon emissions.