BACKGROUND: A novel supported liquid extraction approach using small polymeric nanofibrous discs was demonstrated and applied to the analysis of real river water. Nanofibrous discs were tested to extract model mixture of 9 common water contaminants 4-nitrophenol, various chlorophenols, bisphenol A, permethrin, and fenoxycarb featuring a wide range of log P values (1.9-6.5). Polyacrylonitrile, polyhydroxybutyrate, and polylactic acid nanofibers were selected as adsorptive materials. One-step desorption was performed directly in HPLC vials, to avoid time-consuming evaporation and reconstitution steps. The discs were allowed to sediment to the bottom of the vial before injection into the chromatographic system. RESULTS: Various parameters affecting the extraction efficiency including 1-octanol volume, extraction time, ionic strength, and sample volume were investigated and optimized. Wetting the nanofiber discs with 1-octanol resulted in up to 20-fold increase in enrichment factor when compared to non-wetted polymer counterparts. The highest enrichment factors were observed for analytes with a log P range of 3.3-4.5. Our developed method showed good linearity in the range 20-200 μg/L for all analytes tested. Satisfactory repeatability with RSD <13 % were achieved covering all steps including disc preparation, wetting, extraction/elution, and chromatography analysis, and recoveries ranged from 58.93 to 121.43 %. SIGNIFICANCE: This work represents novel simple supported liquid extraction approach using impregnated polymer nanofiber discs. Using only 50 μL 1-octanol, we reduced the organic solvent compared to other extraction methods. There was no need for any plastic cartridge to hold the sorbent and direct in-vial desorption reduced the unnecessary, time-consuming steps and simplified the sample preparation protocol.
- Publication type
- Journal Article MeSH
The adsorption process efficiently removes per- and polyfluoroalkyl substances (PFAS) from water, but managing exhausted adsorbents presents notable environmental and economic challenges. Conventional disposal methods, such as incineration, may reintroduce PFAS into the environment. Therefore, advanced regeneration techniques are imperative to prevent leaching during disposal and enhance sustainability and cost-effectiveness. This review critically evaluates thermal and chemical regeneration approaches for PFAS-laden adsorbents, elucidating their operational mechanisms, the influence of water quality parameters, and their inherent advantages and limitations. Thermal regeneration achieves notable desorption efficiencies, reaching up to 99% for activated carbon. However, it requires significant energy input and risks compromising the adsorbent's structural integrity, resulting in considerable mass loss (10-20%). In contrast, chemical regeneration presents a diverse efficiency landscape across different regenerants, including water, acidic/basic, salt, solvent, and multi-component solutions. Multi-component solutions demonstrate superior efficiency (>90%) compared to solvent-based solutions (12.50%), which, in turn, outperform salt (2.34%), acidic/basic (1.17%), and water (0.40%) regenerants. This hierarchical effectiveness underscores the nuanced nature of chemical regeneration, significantly influenced by factors such as regenerant composition, the molecular structure of PFAS, and the presence of organic co-contaminants. Exploring the conditional efficacy of thermal and chemical regeneration methods underscores the imperative of strategic selection based on specific types of PFAS and material properties. By emphasizing the limitations and potential of particular regeneration schemes and advocating for future research directions, such as exploring persulfate activation treatments, this review aims to catalyze the development of more effective regeneration processes. The ultimate goal is to ensure water quality and public health protection through environmentally sound solutions for PFAS remediation efforts.
- Publication type
- Journal Article MeSH
- Review MeSH
Spruce wood and Typha (wetland plant) derived biochars pyrolyzed at 350 °C and 600 °C were tested for their sorption affinity for organic pollutants (diclofenac, methylparaben, benzotriazole and sodium 1-decanesulfonate) and nutrients (nitrate, ammonium, phosphate and boron) commonly found in greywater. Batch and column studies combined with molecular dynamics modelling determined the sorption capacity, kinetics, and described the underlying mechanisms. The spruce biochar (600 °C) exhibited the highest sorption capacity mainly for the tested organics. The dynamic test performed for spruce biochar (600 °C) showed that the magnitude of desorption was low, and the desorbed amount ranged between 3 and 11 %. Molecular dynamics modelling (a computational tool for elucidating molecular-level interactions) indicated that the increased sorption of nitrate and boron on spruce biochar (600 °C) could be attributed to hydrophobic interactions. The molecular dynamics shows that predominant adsorption of organic pollutants was governed by π-π stacking, with a minor role of hydrogen-bonding on the biochar surface. In summary, higher pyrolysis temperature biochar yielded greater adsorption capacity greywater borne contaminants and the reaction temperature (10-34 °C) and presence of anionic surfactant had a limited effect on the adsorption of organic pollutants, suggesting efficacious application of biochar in general for greywater treatment in nature-based systems.
This work reveals the growing potential of novel electrochemical methods that are applicable for polysaccharides. It was shown for the first time that the molecules of hyaluronic acid (HA) exhibit electrochemical response using phase-sensitive alternating current (AC) voltammetry in phase-out mode. Adsorption and desorption processes of HA fragments at a charged interface of mercury electrode were observed in buffered HA solutions. Electrostatic and hydrophobic manners of interactions were distinguished for native hyaluronan fragments in a wide electric potential range. The AC voltammetry response depended on the temperature, concentration, and length of HA chains. Results of this work open possibilities for further structural characterization of widely used HA fragments and understanding manners of interactions with charged hydrophobic surfaces that could be useful in the future for understanding HA interactions at biological levels.
- Publication type
- Journal Article MeSH
Mesoporous material SBA-15 was functionalized with different polar and nonpolar groups: 3-aminopropyl, (SBA-15-NH2), 3-isocyanatopropyl (SBA-15-NCO), 3-mercaptopropyl (SBA-15-SH), methyl (SBA-15-CH3) and phenyl (SBA-15-Ph). The resulting surface grafted materials were investigated as matrices for controlled drug delivery. Anticancer agent, pemetrexed (disodium pemetrexed heptahydrate) was selected as a model drug and loaded in the unmodified and functionalized SBA-15 materials. Materials were characterized by elemental analysis, infrared spectroscopy, transmission electron microscopy, nitrogen adsorption/desorption analysis, small angle X-ray scattering, powder X-ray diffraction, solid state NMR spectroscopy and thermogravimetry. It was shown that surface modification has an impact on both encapsulated drug amount and release properties. Release experiments were performed into two media with different pH: simulated body fluid (pH = 7.4) and simulated gastric fluid (pH = 2). In general, the effect of pH was reflected by the lower release of pemetrexed under acidic conditions (pH = 2) compared to slightly alkaline saline environment (pH = 7.4). The release rate of pemetrexed from propylamine-, propylisocyanate- and phenyl-modified SBA-15 was found to be effectively controlled by intermolecular interactions as compared to that from pure SBA-15, SBA-15-SH, and SBA-15-CH3, that evidenced a steady and similar release. The highest release was observed for methyl-functionalized material whose hydrophobic surface accelerates the pemetrexed release. The data obtained from release studies were fitted using various kinetic models to determine the pemetrexed release mechanism and its release rate. The best correlations were found for Korsmeyer-Peppas and Higuchi models. Moreover, the theoretical three-parameter model for drug release kinetic was applied to calculate the strength of drug-support interactions. The in vitro cell study was performed on SKBR3 cancer cells and obtained results demonstrated that the modification of the mesoporous silica material by grafted polar/nonpolar groups may significantly affect the compatibility of this material with cells, drug release from this material and subsequent biological activity of PEM.
- MeSH
- Hydrogen-Ion Concentration MeSH
- Delayed-Action Preparations chemistry pharmacokinetics pharmacology MeSH
- Humans MeSH
- Cell Line, Tumor MeSH
- Neoplasms drug therapy metabolism pathology MeSH
- Silicon Dioxide * chemistry pharmacokinetics pharmacology MeSH
- Pemetrexed * chemistry pharmacokinetics pharmacology MeSH
- Surface Properties MeSH
- Antineoplastic Agents * chemistry pharmacokinetics pharmacology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
In this study, we report for the first time a novel type of sorbent that can be used for mercury adsorption from the air-based off-gasses-vermiculite impregnated with alkali polysulfides and thiosulfates. In contrast to other sorbents, vermiculite exhibits superior thermal stability in air and low adsorption capacity for organic vapors. This allows for a more favorable design of the soil remediation unit-direct coupling of thermal desorber with catalytic oxidizer using air as a carrier gas. In the bench-scale test at 180 °C, the sulfur/vermiculite sorbent exhibited significantly higher efficiency for the adsorption of mercury vapor from the off-gasses than the commercial sulfur/activated carbon sorbent at its highest operating temperature (120 °C). The average mercury concentration in the adsorber off-gas decreased from 1.634 mg/m3 for the sulfur/activated carbon to 0.008 mg/m3 achieved with impregnated vermiculite. The total concentration of organic compounds in the soil after thermal desorption was below the detection limit of the employed analytical method.
- MeSH
- Adsorption MeSH
- Gases MeSH
- Mercury * MeSH
- Aluminum Silicates MeSH
- Sulfur * MeSH
- Publication type
- Journal Article MeSH
Cellulose-based preparative isoelectric focusing was used for preseparation and concentration of uropathogens Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Staphylococcus epidermidis, Candida albicans, and Candida parapsilosis in a urine sample containing a high concentration of human serum albumin. For the visibility of the colorless microbial zones in the separation medium, the microbial cells were labeled with red nonionogenic tenside (1-[[4-(phenylazo)phenyl]azo]-2-hydroxy-3-naphthoic acid polyethylene glycol ester, PAPAN). A very short incubation time, about 2 min, was sufficient for the adsorption of 0.001% (w/v) PAPAN onto the cell surface at the optimized conditions. As low as 103 cells of E. coli (pI 4.6) resuspended in 100 μL of urine sample and spiked with 0.1 mg mL-1 of human serum albumin (pI 4.8) were successfully preseparated and concentrated using this method. Because the pI values of the labeled microorganisms remained unchanged, the focused red zones of microbial cells were collected from the separation media and further analyzed by either capillary isoelectric focusing or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The viability of the cells extracted from the collected zones was also confirmed. The proposed method provides reliable, relatively fast, and cost-effective identification of uropathogens in urine specimens with a high level of albumin.
- MeSH
- Bacteria classification isolation & purification MeSH
- Staining and Labeling methods MeSH
- Fungi classification isolation & purification MeSH
- Urinary Tract Infections microbiology MeSH
- Isoelectric Focusing MeSH
- Humans MeSH
- Serum Albumin, Human analysis MeSH
- Surface-Active Agents chemistry MeSH
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Zwitterionic chiral ion-exchange selectors (ZWIX) obtained by conjugation of quinine and 2-aminocyclohexanesulfonic acid via a carbamate bond were immobilized on three different silica particle types, viz. 120 Å 3 μm fully porous particles (FPP), 200 Å 3 μm FPP and 160 Å 2.7 μm superficially porous particles (SPP). Selector densities were determined by elemental analysis and the porosities of packed columns measured by inverse size exclusion chromatography with polystyrene standards. Liquid chromatographic tests with a set of chiral zwitterionic, acidic and basic analytes showed that the surface chemistry was successfully transferred to the distinct particle morphologies. The chromatographic performance of the three columns was evaluated by acquiring van Deemter curves. The results showed that the column packed with the SPP particles gives the best performance and kinetic plots further demonstrated that they represent the most favorable compromise in terms of speed, efficiency and pressure drop. Sub-minute separations could be accomplished at much lower pressure drop on the core-shell column, e.g. 2-amino-2-phenylbutyric acid was baseline separated in less than 15 s on a 5 cm long column. The Maxwell effective medium theory with second order approximation was applied to calculate effective diffusion in the mesoporous zones of SPP and FPP, which allowed eventually to deconvolute the individual peak dispersion contributions (ha, hb, hc,m, hc,s, hc,ads). The efficiency gain of the 160 Å SPP column compared to the 120 Å FPP (benchmark) column was mainly due to lower eddies (ha), smaller c-term accounting for slow adsorption-desorption kinetics in enantioselective chromatography (hc,ads), and also due to lower stationary mass transfer resistance (hc,s). Enhanced effective diffusion (Deff) in the SPP column contributed to a lower longitudinal diffusion (hb). In contrast, the mobile phase mass transfer coefficient was similar in the two columns leading to comparable hc,m contributions. This study discloses some options for improvement of the efficiency of ZWIX-type chiral columns such as replacing narrow pore (120 Å) by wide pore (200 Å) particles, substituting FPP by SPP and reducing the selector density on the surface.
Phosphorus reduction from wastewater is vital to mitigate eutrophication of receiving waters. In this study, discarded lignocellulose biochar loaded with lanthanum (defined as La-biochar) was applied for phosphate adsorption. Based on the design of response surface methodology, La-biochar displayed a high phosphate adsorption capacity of 36.06 mg P/g, strong pH-compatibility from 3 to 12, favorable selectivity for phosphate among foreign ions (Cl-, SO42-, CO32-, HCO3- and NO3-), excellent reusability with 92.3% desorption efficiency and retained 85% adsorption capacity after five recycles. The adsorption law of La-biochar perfectly matched with the pseudo-second-order model and the Langmuir model. Moreover, real wastewater adsorption experiments indicated the removal of total phosphorus within 20 min. Ligand exchange, electrostatic attraction, and complexation mechanisms contributed to phosphate adsorption on La-biochar. Overall, the La-biochar material could be applied as a potential sustainable building block for the preconcentration of phosphorus for practical pollutant purification.
- MeSH
- Adsorption MeSH
- Charcoal MeSH
- Phosphates * MeSH
- Kinetics MeSH
- Lanthanum * MeSH
- Lignin MeSH
- Regeneration MeSH
- Publication type
- Journal Article MeSH
Solid-phase microextraction (SPME) is an alternative method to dialysis and ultrafiltration for the determination of plasma protein binding (PPB) of drugs. It is particularly advantageous for complicated analytes where standard methods are not applicable. Di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) is a lead compound of novel thiosemicarbazone anti-cancer drugs, which entered clinical trials in 2016. However, this agent exhibited non-specific binding on filtration membranes and had intrinsic chelation activity, which precluded standard PPB methods. In this study, using a simple and fast procedure, we prepared novel SPME fibers for extraction of DpC based on a metal-free, silicon string support, covered with C18 sorbent. Reproducibility of the preparation process was demonstrated by the percent relative standard deviation (RSD) of ≤ 9.2% of the amount of DpC extracted from PBS by several independently prepared fibers. The SPME procedure was optimized by evaluating extraction and desorption time profiles. Suitability of the optimized protocol was verified by examining reproducibility, linearity, and recovery of DpC extracted from PBS or plasma. All samples extracted by SPME were analyzed using an optimized and validated UHPLC-MS/MS method. The developed procedure was applied to the in vitro determination of PPB of DpC at two clinically relevant concentrations (500 and 1000 ng/mL). These studies showed that DpC is highly bound to plasma proteins (PPB ≥ 88%) and this did not differ significantly between both concentrations tested. This investigation provides novel data in the applicability of SPME for the determination of PPB of chelators, as well as useful information for the clinical development of DpC. Graphical abstract.
- MeSH
- Adsorption MeSH
- Equipment Design MeSH
- Silicon chemistry MeSH
- Blood Proteins metabolism MeSH
- Rats MeSH
- Solid Phase Microextraction instrumentation methods MeSH
- Antineoplastic Agents metabolism MeSH
- Pyridines metabolism MeSH
- Cattle MeSH
- Tandem Mass Spectrometry methods MeSH
- Thiosemicarbazones metabolism MeSH
- Protein Binding MeSH
- Chromatography, High Pressure Liquid methods MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Cattle MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
