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Deep Eutectic Systems (DESs) are obtained by combining Hydrogen Bond Acceptors (HBAs) and Hydrogen Bond Donors (HBDs) in specific molar ratios. Since their first appearance in the literature in 2003, they have shown a wide range of applications, ranging from the selective extraction of biomass or metals to medicine, as well as from pollution control systems to catalytic active solvents and co-solvents. The very peculiar physical properties of DESs, such as the elevated density and viscosity, reduced conductivity, improved solvent ability and a peculiar optical behavior, can be exploited for engineering modular systems which cannot be obtained with other non-eutectic mixtures. In the present review, selected DESs research fields, as their use in materials synthesis, as solvents for volatile organic compounds, as ingredients in pharmaceutical formulations and as active solvents and cosolvents in organic synthesis, are reported and discussed in terms of application and future perspectives.

Films with different morphology can be obtained by mixing fish gelatin, Tara gum and glycerol in different ratio and by subjecting the Tara gum to a ball milling treatment before its use. The amount of the plasticizer glycerol, as well as the type of Tara gum employed (as received or milled) resulted, from SEM and AFM analyses, to strong influencing the morphology of the films and their density. Also, the morphological differences determine different thermal and mechanical behaviours. In particular, the employment of milled Tara gum allows to improve the thermal stability, as well as the mechanical properties of the polymers. A similar outcome can be obtained by increasing the glycerol content, which can be used up to 20 wt%. Glycerol amounts exceeding that percentage, are detrimental for the quality of the films and reduce their thermal and mechanical performances., FEDER (Fondo Europeo de Desarrollo Regional) and both the Spanish Agencia Estatal de Investigacióon (MAT2017–84501-R; MAT2017-88923-P) and the Consejería de Educación, Junta de Castilla y León (BU306P18)

The employment of used vegetable oils (UVOs) as raw materials in key sectors as energy production or bio-lubricant synthesis represents one of the most relevant priorities in the European Union (EU) normative context. In many countries, the development of new production processes based on the circular economy model, as well as the definition of future energy and production targets, involve the utilization of wastes as raw material. In this context, the main currently applied EU regulations are presented and discussed. As in the EU, the general legislative process consists of the definition in each State Member of specific legislation, which transposes the EU indications. Two relevant countries are herein considered: Italy and Spain. Through the analysis of the conditions required in both countries for UVOs&rsquo, collection, disposal, storage, and recycling, a wide panorama of the current situation is provided.

The optical properties of nine choline-based Deep Eutectic Solvents (DESs) of the type choline+X− (X− = chloride or acetate)/Y (Y = ethylene glycol, glycolic or levulinic acid) were studied by measuring their band gap through the UV-VIS-based Tauc method. All the considered systems showed a direct optical transition. A correlation between band gap and eutectic composition was discovered by plotting the variation of the band gap versus the molar fraction of choline+X−/Y in the parent systems containing 10 wt% of H2O. The main parameters influencing the energy of the optical transition in these “Deep Band Gap Systems” (DeBaGS) where studied through Design of Experiments (DoE) combined with multivariate analysis. The effect on the band gap of the anion (chloride or acetate), the acid (levulinic or glycolic), the water, and the stirring time, considered as single factor or in combination was clarified. Thus a multivariate model was implemented through surface responding analysis which allows engineering such kind of systems and opening to further applications in material science.

Recently, the interest in converting waste cooking oils (WCOs) to raw materials has grown exponentially. The driving force of such a trend is mainly represented by the increasing number of WCO applications, combined with the definition, in many countries, of new regulations on waste management. From an industrial perspective, the simple chemical composition of WCOs make them suitable as valuable chemical building blocks, in fuel, materials, and lubricant productions. The sustainability of such applications is sprightly related to proper recycling procedures. In this context, the development of new recycling processes, as well as the optimization of the existing ones, represents a priority for applied chemistry, chemical engineering, and material science. With the aim of providing useful updates to the scientific community involved in vegetable oil processing, the current available technologies for WCO recycling are herein reported, described, and discussed. In detail, two main types of WCO treatments will be considered: chemical transformations, to exploit the chemical functional groups present in the waste for the synthesis of added value products, and physical treatments as extraction, filtration, and distillation procedures. The first part, regarding chemical synthesis, will be connected mostly to the production of fuels. The second part, concerning physical treatments, will focus on bio-lubricant production. Moreover, during the description of filtering procedures, a special focus will be given to the development and applicability of new materials and technologies for WCO treatments.

The chemical composition and the color of samples of waste cooking oils (WCOs) were determined prior to and after filtration on two different pads of bentonite differing in particle size. The volatile fraction was monitored by headspace solid-phase microextraction (HS-SPME) coupled with gas-chromatography, while the variation of the composition of the main components was analyzed by 1H NMR. Both techniques allowed the detection of some decomposition products, such as polymers, terpenes, and derivatives of the Maillard process. The analysis of the chemical composition prior to and after bentonite treatment revealed a tendency for the clays to retain specific chemical groups (such as carboxylic acids or double bonds), independent of their particle size. A pair comparison test was conducted in order to detect the sensory differences of the intensity of aroma between the WCO treated with the two different bentonites. In addition, characterization of the bentonite by means of powder X-ray diffraction (XRD) and thermogravimetric measurements (TG) was performed.

The consideration towards waste cooking oils is changing from hazardous waste to valuable raw material for industrial application. During the last 5 years, some innovative processes based on the employment of recycled waste cooking oil have appeared in the literature. In this review article, the most recent and innovative applications of recycled waste cooking oil are reported and discussed. These include the production of bioplasticizers, the application of chemicals derived from waste cooking oils as energy vectors and the use of waste cooking oils as a solvent for pollutant agents.

International audience; Efficient renewable and nontoxic absorbents can now be designed to eliminate air pollutants such as volatile organic compounds (VOCs) from confined atmospheres. New hybrid materials result from the combination of deep eutectic systems (DESs) with well-known VOC capture agents like β-cyclodextrin (βCD). However, a question arises: does βCD retain its encapsulation ability in DESs? Multiple nuclear magnetic resonance (NMR) techniques are used here to demonstrate the formation of inclusion complexes of βCD with two VOCs, aniline and toluene, in the pure DES reline and in reline/water mixtures. Complexation-induced chemical shift changes and intermolecular host–guest nuclear Overhauser effects (NOEs) in the rotating frame give evidence of genuine encapsulation in the βCD cavity, and complementary information on the dynamics of the VOC is gathered via relaxation and diffusion experiments. This work shows how different NMR techniques can contribute to the design of task-specific sustainable materials for absorption/extraction processes.

Samples of sunflower Waste Cooking Oils (WCOs) subjected to several cycles of frying were treated with water under four different combinations of temperature and pH. Several aspects of the chemical composition of edible, non-treated and processed samples was determined by three different analytic techniques: headspace Solid-Phase Microextraction (HS-SPME) coupled with gas-chromatography (GC), 1H NMR spectroscopy and ESI-MS spectrometry. Thus, a characteristic chemical fingerprint of each sample was derived and proposed as useful set of tools for the optimization of recycling of WCOs. On the basis of the presented results, a mini-plant for the production of bio-lubricants and bio-solvents with a circular economy approach was designed and herein described.

Recycling of waste cooking oil represents a source of convenient raw materials for industry. Within the large number of products derived from the treatment of waste cooking oil, eco-friendly lubricants grown in importance during the last years. Recycling process for such application consists usually of acid or basic degumming followed by a filtration step. The effect of the specific type of acid degumming on the density and on the flash point of the recycled oil was evaluated employing full factorial design. Two mathematical equations were derived which allow to estimate respectively the density and the flash point of the recycled oil, depending on the: (a) pH of the washing solution, (b) oil/water ratio, (c) temperature of the system, and (d) the stirring time. Practical applications Recycle of waste cooking oil presents several advantages. Mainly it is beneficial for the environment and considered as mandatory by law in several countries, and could furnish a useful low price raw material for several kind of industries. Recently, a multitude of local small scale industries have based their business on this topic and the recycling process employed often consists in a degumming step followed by filtration. This article deals with the tuning of the main parameters of the degumming step related with the density and the flash point of the final product. These parameters are important especially for lubricant synthesis.