Volume 38, Issue 3

Conventional biorefinery processes are complex, engineered and energy-intensive, where biomass fractionation, a key functional step for the production of biomass-derived chemical substances, demands industrial organic solvents and harsh, environmentally harmful reaction conditions. There is a timely, clear and unmet economic need for a systematic, robust and affordable conversion method technology to become greener, sustainable and cost-effective. In this perspective, deep eutectic solvents (DESs) have been envisaged as the most advanced novel polar liquids that are entirely made of natural, molecular compounds that are capable of an association via hydrogen bonding interactions. DES has quickly emerged in various application functions thanks to a formulations’ simple preparation. These molecules themselves are biobased, renewable, biodegradable and eco-friendly. The present experimental review is providing the state of the art topical overview of trends regarding the employment of DESs in investigated biorefinery-related techniques. This review covers DESs for lignocellulosic component isolation, applications as (co)catalysts and their functionality range in biocatalysis. Furthermore, a special section of the DESs recyclability is included. For DESs to unlock numerous new (reactive) possibilities in future biorefineries, the critical estimation of its complexity in the reaction, separation, or fractionation medium should be addressed more in future studies.

The emission of large amounts of CO 2 into the atmosphere is believed to be a major reason behind climate change, which has led to increased demand for CO 2 capture. Postcombustion CO 2 capture with chemical solvent is considered one of the most important technologies in order to reduce CO 2 emission. Amino acid salt solutions have attracted special attention in recent years due to their excellent physicochemical properties, e.g., low volatility, less toxicity, and high oxidative stability, as well as capture performance comparable with conventional amines. In this study, physicochemical properties of 20 amino acids are reported and their CO 2 absorption performance discussed. The topics covered in this review include the most relevant properties of amino acids including CO 2 loading capacity, cyclic capacity, equilibrium constant, density, viscosity, dissociation constant, CO 2 solubility, CO 2 diffusivity, reaction kinetic between CO 2 and amino acid salts, reaction rate constant, surface tension, heat of CO 2 absorption, precipitation, toxicity, solvent degradation, and corrosion rate. This review provides the most recent information available in the literature on the potential of using amino acid salts as a solvent for CO 2 capture which can help improve the performance of the CO 2 capture process from flue gas streams.

The world is faced with several problems as regards water pollution. This is due to several factors, including the discharge of effluents into the environment with no prior treatment. This wastewater, therefore, contains significant levels of pollutants, including numerous toxic organic contaminants and others that are similarly undesirable. Several studies have attempted to find ways of removing wastewater contaminants using pillared interlayered clays (PILC) as adsorbents. In this work, we present a summary of those studies that have used PILC as adsorbents for the removal of organic compounds from aqueous solutions while simultaneously illustrating their potential for this purpose. A general overview is provided so that the reader can acquire a basic understanding of the PILC and their modified counterparts that have been used, and some of the characteristics that can directly affect their adsorption behavior, especially their textural and surface properties.

The high-temperature proton exchange membrane fuel cell (HT-PEMFC) offers several advantages, such as high proton conductivity, high CO tolerance, good chemical/thermal stability, good mechanical properties, and low cost. The proton exchange membrane (PEM) is the critical component of HT-PEMFC. This work discusses the methods of current PEMs development for HT-PEMFC including modifications of Nafion® membranes and the advancement in composite PEMs based on non-fluorinated polymers. The modified Nafion®-based membranes can be used at temperatures up to 140 °C. Nevertheless, the application of Nafion®-based membranes is limited by their humidification with water molecules acting as proton carriers and, thus, by the operation conditions of membranes under a relative humidity below 20%. To obtain PEMs applied at higher temperatures under non-humidified conditions, phosphoric acid (PA) or ionic liquids (ILs) are used as proton carriers in PEMs based on non-fluorinated polymers. The research discussed in this work provides the approaches to improving the physicochemical properties and performance fuel cell of PEMs. The effects of polymer blending, crosslinking, and the incorporation of inorganic particles on the membrane properties and fuel cell performance have been scrutinized. The incorporation of inorganic particles modified with ILs might be an effective approach to designing high-performance PEMs for HT-PEMFC.

Tissue engineering, after decades of exciting progress and monumental breakthroughs, has yet to make a significant impact on patient health. It has become apparent that a dearth of biomaterial scaffolds which possess the material properties of human tissue while remaining bioactive and cytocompatible, has been partly responsible for this lack of clinical translation. Herein, we propose the development of interpenetrating polymer network (IPN) hydrogels as materials that can provide cells with an adhesive extracellular matrix-like 3D microenvironment while possessing the mechanical integrity to withstand physiological forces. These hydrogels can be synthesized from biologically derived or synthetic polymers, the former polymer offering preservation of adhesion, degradability, and microstructure and the latter polymer offering tunability and superior mechanical properties. We review critical advances in the enhancement of mechanical strength, substrate-scale stiffness, electrical conductivity, and degradation in IPN hydrogels intended as bioactive scaffolds in the past 5 years. We also highlight the exciting incorporation of IPN hydrogels into state-of-the-art tissue engineering technologies, such as organ-on-a-chip and bioprinting platforms. These materials will be critical in the engineering of functional tissue for transplant, disease modeling and drug screening.