New Carvone-Based Deep Eutectic Solvents for Siloxanes Capture from Biogas

Magnetic superhydrophobic melamine sponges for crude oil removal from water

This paper proposes the preparation of a new sorbent material based on melamine sponges (MS) with superhydrophobic, superoleophilic, and magnetic properties. This study involved impregnating the surface of commercially available MS with eco-friendly deep eutectic solvents (DES) and Fe3O4 nanoparticles. The DES selection was based on the screening of 105 eutectic mixtures using COSMO-RS modeling. Other parameters affecting the efficiency and selectivity of oil removal from water were optimized using the Box-Bhenken model. Menthol:Thymol (1:1)@Fe3O4-MS exhibited the highest sorption capacity for real crude oils (101.7-127.3 g/g). This new sponge demonstrated paramagnetic behavior (31.06 emu/g), superhydrophobicity (151°), superoleophobicity (0°), low density (15.6 mg/cm3), high porosity (99 %), and excellent mechanical stability. Furthermore, it allows multiple regeneration processes without losing its sorption capacity. Based on these benefits, Menthol:Thymol (1:1)@Fe3O4-MS shows promise as an efficient, cost-effective, and eco-friendly substitute for the existing sorbents.

VOCs absorption from gas streams using deep eutectic solvents - A review

Volatile organic compounds (VOCs) are one of the most severe atmospheric pollutants. They are mainly emitted into the atmosphere from anthropogenic sources such as automobile exhaust, incomplete fuel combustion, and various industrial processes. VOCs not only cause hazards to human health or the environment but also adversely affect industrial installation components due to their specific properties, i.e., corrosive and reactivity. Therefore, much attention is being paid to developing new methods for capturing VOCs from gaseous streams, i.e., air, process streams, waste streams, or gaseous fuels. Among the available technologies, absorption based on deep eutectic solvents (DES) is widely studied as a green alternative to other commercial processes. This literature review presents a critical summary of the achievements in capturing individual VOCs using DES. The types of used DES and their physicochemical properties affecting absorption efficiency, available methods for evaluating the effectiveness of new technologies, and the possibility of regeneration of DES are described. In addition, critical comments on the new gas purification methods and future perspectives are included.

Superhydrophobic sponges based on green deep eutectic solvents for spill oil removal from water

The paper described a new method for crude oil-water separation by means of superhydrophobic melamine sponges impregnated by deep eutectic solvents (MS-DES). Due to the numerous potential of two-component DES formation, simple and quick screening of 156 non-ionic deep eutectic solvents using COSMO-RS (Conductor-like Screening Model for Real Solvents) computational model was used. DES which were characterized by high solubility of hydrocarbons and the lowest water solubility were synthesized and embedded on melamine sponges. The new sponges were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and goniometer. Several parameters affecting the crude oil-water separation (i.e. type and amount of DES, density and porosity of sponges, water contact eagle) were thoroughly studied. In order to studies of MS-DES affinity to the selected groups of crude oil i.e. Saturated, Aromatic, Resins, Asphaltenes (SARA) the thin layer liquid chromatography-flame ionization detection (TLC-FID) was used. The obtained results indicate that the melamine sponges impregnated by DES composed of eucalyptol and menthol in 1:5 molar ratio have high real crude oil absorption capacity in the range of 96.1 - 132.2 g/g and slightly depends on crude oil compositions, superhydrophobic properties (water contact angle 152°), low density of 9.23 mg/cm³, high porosity of 99.39%, and excellent reusability which was almost not changing even after 80 cycles. The outcomes indicate that new MS-DES materials could be excellent alternatives as absorbents for the cleanup of crude oil-polluted water.

Efficient Extraction of Fermentation Inhibitors by Means of Green Hydrophobic Deep Eutectic Solvents

The methods for hydrogen yield efficiency improvements, the gaseous stream purification in gaseous biofuels generation, and the biomass pretreatment are considered as the main trends in research devoted to gaseous biofuel production. The environmental aspect related to the liquid stream purification arises. Moreover, the management of post-fermentation broth with the application of various biorefining techniques gains importance. Chemical compounds occurring in the exhausted liquid phase after biomass pretreatment and subsequent dark and photo fermentation processes are considered as value-added by products. The most valuable are furfural (FF), 5-hydroxymethylfurfural (HMF), and levulinic acid (LA). Enriching their solutions can be carried with the application of liquid–liquid extraction with the use of a suitable solvent. In these studies, hydrophobic deep eutectic solvents (DESs) were tested as extractants. The screening of 56 DESs was carried out using the Conductor-like Screening Model for Real Solvents (COSMO-RS). DESs which exposed the highest inhibitory effect on fermentation and negligible water solubility were prepared. The LA, FF, and HMF were analyzed using FT-IR and NMR spectroscopy. In addition, the basic physicochemical properties of DES were carefully studied. In the second part of the paper, deep eutectic solvents were used for the extraction of FF, LA, and HMF from post-fermentation broth (PFB). The main extraction parameters, i.e., temperature, pH, and DES: PFB volume ratio (V_DES:V_PFB), were optimized by means of a Box–Behnken design model. Two approaches have been proposed for extraction process. In the first approach, DES was used as a solvent. In the second, one of the DES components was added to the sample, and DES was generated in situ. To enhance the post-fermentation broth management, optimization of the parameters promoting HMF, FF, and LA extraction was carried under real conditions. Moreover, the antimicrobial effect of the extraction of FF, HMF, and LA was investigated to define the possibility of simultaneous separation of microbial parts and denatured peptides via precipitation.