Synthesis, Characterization and Sorption Ability of Epoxy Resin-Based Sorbents with Amine Groups

Water pollution by toxic substances, such as azo dyes, is a serious environmental problem that needs to be addressed. This study presents the synthesis and characterization of new polymeric sorbents, based on the epoxy resin Epidian® 5 (Ep5), as a potential adsorbent for the removal of the toxic azo dye C.I. Acid Violet 1 (AV1). Triethylenetetramine (TETA) was applied as a cross-linking agent in the amounts of 1 g (6.67 wt %), 1.5 g (10 wt %), and 2 g (13.33 wt %). The use of a compound with amino groups allows for the simultaneous functionalization of the obtained material. The reaction was carried out in an environment of ethylene glycol, with the addition of a porophore solvent (toluene) and bis(2-ethylhexyl)sulfosuccinate sodium salt (S). The attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) revealed the existence of a strong band in the 828–826 cm−1 range corresponding to the second-order amine group, which indicates their incorporation into the epoxy structure. The glass transition and decomposition temperatures of the resins decreased with the increasing amounts of amine in the material. The thermogravimetry (TGA) analysis demonstrated that all products are thermally stable up to 340 °C. The surface morphology and microstructural properties of the obtained sorbents were determined using scanning electron microscopy (SEM) images and showed an irregular star shape, with dimensions ranging from 400 to 1000 µm. The adsorption capacities of Ep5-TETA1, Ep5-TETA1.5, Ep5-TETA2 and Ep5-TETA1.5 + S for AV1 evaluated during batch experiments were found to be 2.92, 3.76, 7.90 and 3.30 mg/g, respectively.

Tailored Polymer-Based Selective Extraction of Lipid Mediators from Biological Samples

Lipid mediators, small molecules involved in regulating inflammation and its resolution, are a class of lipids of wide interest as their levels in blood and tissues may be used to monitor health and disease states or the effect of new treatments. These molecules are present at low levels in biological samples, and an enrichment step is often needed for their detection. We describe a rapid and selective method that uses new low-cost molecularly imprinted (MIP) and non-imprinted (NIP) polymeric sorbents for the extraction of lipid mediators from plasma and tissue samples. The extraction process was carried out in solid-phase extraction (SPE) cartridges, manually packed with the sorbents. After extraction, lipid mediators were quantified by liquid chromatography–tandem mass spectrometry (LC–MSMS). Various parameters affecting the extraction efficiency were evaluated to achieve optimal recovery and to reduce non-specific interactions. Preliminary tests showed that MIPs, designed using the prostaglandin biosynthetic precursor arachidonic acid, could effectively enrich prostaglandins and structurally related molecules. However, for other lipid mediators, MIP and NIP displayed comparable recoveries. Under optimized conditions, the recoveries of synthetic standards ranged from 62% to 100%. This new extraction method was applied to the determination of the lipid mediators concentration in human plasma and mouse tissues and compared to other methods based on commercially available cartridges. In general, the methods showed comparable performances. In terms of structural specificity, our newly synthesized materials accomplished better retention of prostaglandins (PGs), hydroxydocosahexaenoic acid (HDoHE), HEPE, hydroxyeicosatetraenoic acids (HETE), hydroxyeicosatrienoic acid (HETrE), and PUFA compounds, while the commercially available Strata-X showed a higher recovery for dihydroxyeicosatetraenoic acid (diHETrEs). In summary, our results suggest that this new material can be successfully implemented for the extraction of lipid mediators from biological samples.

THE USE OF OIL-CAKE (SUNFLOWER) IN THE DEPOLLUTION OF PETROLEUM INFESTED WATER

"Oil pollution of surface and groundwater is an undesirable phenomenon but it is possible to happen. The pollutant can appear as a result of leaks from the transport pipelines, the damage of the oil extraction and processing installations, and the distribution states of the petroleum products. In the vast majority of interventions to combat pollution, polymeric sorbents are used which are spread over the pollutant and then washed with warm water. This technology does not completely clean the pollutants, and the polymeric sorbents are difficult to remove. Oil-cake (sunflower) is a grated residue after oil extraction and contains the amino acid lysine and high content of fiber and methionine. At a quantity of 100 kg of sunflower seeds, a processor obtains a quantity of 35 kg of residual mass consisting of a sunflower meal. This product can be used as a sorbent for petroleum products, being then used to produce green energy. The physical properties of two sorbent substances (sunflower oil and peat) are presented. Also, their adsorption capacities for four pollutants specific to the oil industry (gasoline, diesel, paraffin oil and sulfur oil) are analyzed, as well as the adsorption kinetics. The adsorption equations of the pollutants are also described."

DFO@EVOH and 3,4-HP@EVOH: Towards New Polymeric Sorbents for Iron(III)

The paper presents the synthesis and preliminary characterization of two novel solid-phase sorbents for iron(III), resulting from the functionalization of ethylene-vinyl alcohol copolymer (EVOH) with deferoxamine, DFO (DFO@EVOH), and a novel tripodal 3-hydroxy-4-pyridinone, named 3,4-HP (3,4-HP@EVOH). DFO and 3,4-HP have been covalently bonded to EVOH, using carbonyldiimidazole as a coupling agent. Before their use as Fe(III) sorbents, they were warm-pressed to obtain a thin film. Polymers have been characterized by conventional physico-chemical techniques; furthermore, the sorption properties towards Fe(III) were investigated. The physico-chemical characterization of the new solid-state devices demonstrates the effective linkage of the two receptors on the polymeric support. Despite a relatively low sorption capacity for both materials, the stoichiometry and the complexation constants of Fe(III)/DFO@EVOH and Fe(III)/3,4-HP@EVOH are in pretty good agreement with those obtained for the same ligands in aqueous solutions.

Application of selective polymeric sorbents for simple coumarins extraction from deodorant samples

Coumarins (2H-1-benzopyran-2-coumarin derivatives) are derivatives of cinnamic acid naturally occurring in many plants, fungi, and fruits. They are used as ingredients in cosmetics to enhance the aroma and other biological effects. In this work, cosmetic samples (deodorants) were treated by solid phase extraction prior to high performance liquid chromatography determination of coumarins. Traditional sorbent (C18) and selective polymer-based sorbents (laboratory prepared and commercial) were used for solid phase extraction. Recovery values were above 85 % (RSDs below 6 %) except for esculin, where the recovery was lower. Core-shell column of C18 type and gradient of mobile phase methanol—1 % acetic acid were used for high performance liquid chromatography analysis of extracts. Limits of quantitation were 0.5 µg mL−1 for coumarin (ultraviolet detection) and below 12 ng mL−1 for esculin, umbelliferonene, scoparone, 4-methylumbelliferone, herniarin (fluorescence detection). In the tested samples, no coumarins were detected.

STUDY OF THE IN VITRO LIPOPROTEIN PLASMASORPTION AND PHYSICOCHEMICAL PROPERTIES OF POLYMERIC SORBENTS WITH SUBSTITUTED AMINO GROUPS

Currently, the plasmasorption method is widely used in clinical practice to remove excessive amounts of metabolites that cause various pathologies. However, the plasmasorbents applied often can give a number of side effects for the patient, such as the blood clotting, the release of dust particles, and the sorption of useful components from the plasma. Besides that, they can be quite expensive. The aim of the work was to create available plasmasorbents with a good hemocompatibility for the lipoprotein adsorption from the plasma. A number of anion exchangers with groups of trimethylamine, monoethanolamine, and triethanolamine were synthesized. For the sorbents obtained, adsorption and physico-chemical properties were investigated. Bulk density, specific volume at swelling, the swelling coefficient in various solvents (water, ethanol, isopropanol, propylene glycol, acetone) were determined and the theoretical calculations of total exchange capacity and crosslinking mass and molar fractions were made. It was found that the best swelling is achieved in propylene glycol. For the sorbents LP27 and LP29, the capacities on triglyceride and lipoprotein fractions and the coefficient of distribution of lipid profile components between the solid and liquid phases were determined. It is shown that both sorbents have good sorption properties, the sample LP29 being quite promising for the lipid profile components extraction. The developed sorbents are assumed to be cheaper than currently used ones as they are synthesized on the basis of commercially available matrix. The results obtained are expected to be useful for further investigations aimed at the modern plasmasorption technology quality improvement.