Enhancing Solid-Phase Extraction of Tamoxifen and Its Metabolites from Human Plasma Using MOF-Integrated Polyacrylonitrile Composites: A Study on CuBTC and ZIF-8 Efficacy

This study investigates electrospun fibers of metal-organic frameworks (MOFs), particularly CuBTC and ZIF-8, in polyacrylonitrile (PAN) for the solid-phase extraction (SPE) of Tamoxifen (TAM) and its metabolites (NDTAM, ENDO, and 4OHT) from human blood plasma. The focus is on the isolation, pre-concentration, and extraction of the analytes, aiming to provide a more accessible and affordable breast cancer patient-monitoring technology. The unique physicochemical properties of MOFs, such as high porosity and surface area, combined with PAN's stability and low density, are leveraged to improve SPE efficiency. The study meticulously examines the interactions of these MOFs with the analytes under various conditions, including elution solvents and protein precipitators. Results reveal that ZIF-8/PAN composites outperform CuBTC/PAN and PAN alone, especially when methanol is used as the protein precipitator. This superior performance is attributed to the physicochemical compatibility between the analytes' properties, like solubility and polarity, and the MOFs' structural features, including pore flexibility, active site availability, surface polarity, and surface area. The findings underscore MOFs' potential in SPE applications and provide valuable insights into the selectivity and sensitivity of different MOFs towards specific analytes, advancing more efficient targeted extraction methods in biomedical analysis.

Polyacrylonitrile support impregnated with amine-functionalized graphitic carbon nitride/magnetite composite nanofibers towards enhanced arsenic remediation: A mechanistic approach

Recently, novel composite materials are rapidly being explored for water treatment applications. However, their physicochemical behavior and mechanistic investigations are still a mystery. Therefore, our key prospect is to develop a highly stable mixed-matrix adsorbent system using polyacrylonitrile (PAN) support impregnated with amine-functionalized graphitic carbon nitride/magnetite (gCN-NH₂/Fe₃O₄) composite nanofibers (PAN/gCN-NH₂/Fe₃O₄: PCNFe) by simple electrospinning techniques. Various instrumental techniques were used to explore the structural, physicochemical, and mechanical behavior of the synthesized nanofiber. The developed PCNFe with a specific surface area of 39.0 m²/g was found to be non-aggregated and to have outstanding water dispersibility, abundant surface functionality, greater hydrophilicity, superior magnetic property, and higher thermal & mechanical characteristics making it favorable for rapid As removal. Based on the experimental findings from the batch study, 97.0 and 99.0 % of arsenite (As(III)) and arsenate (As(V)), respectively, could be adsorbed by utilizing0.02 g of adsorbent dosage within 60 min of contact time at pH 7 and 4, with an initial concentration of 10 mg/L. Adsorption of As(III) and As(V) followed the pseudo-second-order kinetic and Langmuir isotherm models with an sorption capacities of 32.26 and 33.22 mg/g, respectively, at ambient temperature. The adsorption was endothermic and spontaneous, in accordance with the thermodynamic study. Furthermore, the addition of co-anions in a competitive environment did not affect As adsorption except for PO₄^3-. Moreover, PCNFe preserves its adsorption efficiency above 80 % after five regeneration cycles. The combined results of FTIR and XPS after adsorption further support the adsorption mechanism. Also, the composite nanostructures retain their morphological and structural integrity after the adsorption process. The facile synthesis protocol, high As adsorption capacity, and enhanced mechanical integrity of PCNFe foreshadow its huge prospects for real wastewater treatment.

Dielectric Properties and Flexibility of Polyacrylonitrile/Graphene Oxide Composite Nanofibers

Energy storage and modern electronics industries are in essential need of high dielectric and highly flexible materials. In this study, polyacrylonitrile and reduced graphene oxide (PAN/GO) were prepared by electrospinning. The composite morphology produced a homogeneous, smooth, and flexible surface with high tensile strength and durability. The diameter of the fibers in the composite mats ranged from 232 to 592 nm. The X-ray diffraction pattern recording displayed a sharp peak characteristic centered between 20 and 30° angles with a maximum degree of crystallinity of 86.23%. The evaluation of the Fourier-transform infrared spectrum indicated the interaction between GO and PAN through hydrogen bonds. The differential scanning calorimetry measurements confirmed that GO acted as a nucleating agent that improves the thermal stability of the composite. The dielectric properties exhibited the relative permittivity of the composite of 86.4 with a dielectric loss (tan δ) of 4.97 at 10² Hz, and the maximum conductivity was achieved at 34.9 × 10^-6 Sm^-1 at high frequencies.

Fabrication of a porous polyacrylonitrile nanofiber adsorbent for removing radioactive 60Co

A Co2+ adsorbent was prepared using electrospun porous polyacrylonitrile (PAN) nanofibers, featuring easy recovery for reuse compared with a nanoparticle-based adsorbent. As an efficient ligand for Co2+, ethylenediaminetetraacetic acid (EDTA) was introduced on the surface of porous PAN nanofibers with the aid of a branched polyethyleneimine (PEI) linker to obtain an adsorbent with carboxylic acid groups. On the adsorbent surface, the carboxylic acid and amine groups from EDTA could adsorb Co2+ via ion exchange and chelation, and amine groups from PEI that remained after EDTA functionalization played a role in coordinating Co2+. The amine and carboxylic acid groups were simultaneously involved in the adsorption on the surface, making it possible to remove Co2+ over a wide pH range. An investigation of the adsorption isotherms and kinetics of the nanofibrous adsorbent indicated that monolayer chemisorption was achieved with a maximum Co2+ adsorption capacity of 8.32 mg/g. In addition, radioactive 60Co was efficiently removed by the adsorbent with a removal extent of more than 98%. Considering the easy separation from Co2+ solution and regeneration of the nanofibrous adsorbent and its availability in a wide pH range, the adsorbent has great advantages in practical applications.

Electrospun carbon nanofibre-assisted patterning of metal oxide nanostructures

This work establishes carbon nanofibre-mediated patterning of metal oxide nanostructures, through the combination of electrospinning and vapor-phase transport growth. Electrospinning of a suitable precursor with subsequent carbonization results in the patterning of catalyst gold nanoparticles embedded within carbon nanofibres. During vapor-phase transport growth, these nanofibres allow preferential growth of one-dimensional metal oxide nanostructures, which grow radially outward from the nanofibril axis, yielding a hairy caterpillar-like morphology. The synthesis of metal oxide caterpillars is demonstrated using zinc oxide, indium oxide, and tin oxide. Source and substrate temperatures play the most crucial role in determining the morphology of the metal oxide caterpillars, whereas the distribution of the nanofibres also has a significant impact on the overall morphology. Introducing the current methodology with near-field electrospinning further facilitates user-defined custom patterning of metal oxide caterpillar-like structures.

Changes in adsorption mechanisms of radioactive barium, cobalt, and strontium ions using spent coffee waste biochars via alkaline chemical activation: Enrichment effects of O-containing functional groups

The single adsorption of radioactive barium (Ba(II)), cobalt (Co(II)), and strontium (Sr(II)) ions using pristine (SCWB-P) and chemically activated spent coffee waste biochars with NaOH (SCWB-A) were thoroughly explored in order to provide deeper insights into the changes in their adsorption mechanisms through alkaline chemical activation. The greater removal efficiencies of SCWB-A (76.6-97.3%) than SCWB-P (45.6-75.2%) and the consistency between the adsorptive removal patterns (Ba(II) > Sr(II) > Co(II)) and oxygen bond dissociation enthalpies (BaO (562 kJ/mol) > SrO (426 kJ/mol) > CoO (397 kJ/mol)) of radioactive species supported the assumption that the adsorption removal of radioactive species with spent coffee waste biochars highly depended on the abundances of O-containing functional groups. The calculated R² values of the pseudo-first-order (SCWB-P = 0.998-0.999; SCWB-A = 0.850-0.921) and pseudo-second-order kinetic models (SCWB-P = 0.988-0.998; SCWB-A = 0.935-0.966) are evident that the physisorption mainly controlled the adsorption of radioactive species toward SCWB-P and the chemisorption played a crucial role in their adsorptive removal with SCWB-A. From the calculated intra-particle diffusion, isotherm, thermodynamic parameters, it can be concluded that the intra-particle diffusion and monolayer adsorption primarily governed the adsorption of radioactive species using SCWB-P and SCWB-A, and their adsorption processes occurred spontaneously and endothermically. The dominant adsorption mechanism of spent coffee waste biochars was changed from physisorption (ΔH° of SCWB-P = 21.6-29.8 kJ/mol) to chemisorption (ΔH° of SCWB-A = 42.4-81.3 kJ/mol) through alkaline chemical activation. The distinctive M-OH peak in the O1s XPS spectra of SCWB-A directly corresponding to the decrease in the abundances of O-containing functional groups confirms again that the enrichment of O-containing functional groups markedly facilitated the adsorption removal of radioactive species by chemisorption occurred at the inner and outer surfaces of spent coffee waste biochars.

Efficacy Assessment of Biosynthesized Copper Oxide Nanoparticles (CuO-NPs) on Stored Grain Insects and Their Impacts on Morphological and Physiological Traits of Wheat (Triticum aestivum L.) Plant

Herein, CuO-NPs were fabricated by harnessing metabolites of Aspergillus niger strain (G3-1) and characterized using UV-vis spectroscopy, XRD, TEM, SEM-EDX, FT-IR, and XPS. Spherical, crystallographic CuO-NPs were synthesized in sizes ranging from 14.0 to 47.4 nm, as indicated by TEM and XRD. EDX and XPS confirmed the presence of Cu and O with weight percentages of 62.96% and 22.93%, respectively, at varied bending energies. FT-IR spectra identified functional groups of metabolites that could act as reducing, capping, and stabilizing agents to the CuO-NPs. The insecticidal activity of CuO-NPs against wheat grain insects Sitophilus granarius and Rhyzopertha dominica was dose- and time-dependent. The mortality percentages due to NP treatment were 55-94.4% (S. granarius) and 70-90% (R. dominica). A botanical experiment was done in a randomized block design. Low CuO-NP concentration (50 ppm) caused significant increases in growth characteristics (shoot and root length, fresh and dry weight of shoot and root, and leaves number), photosynthetic pigments (total chlorophylls and carotenoids), and antioxidant enzymes of wheat plants. There was no significant change in carbohydrate or protein content. The use of CuO-NPs is a promising tool to control grain insects and enhance wheat growth performance.

Physicochemical properties and performance of graphene oxide/polyacrylonitrile composite fibers as supercapacitor electrode materials

Graphene oxide derived from palm kernel shells (rGOPKS) and polyacrylonitrile (PAN) were electrospun into composite fiber mats and evaluated as supercapacitor electrode materials. Their morphologies and crystalline properties were examined, and chemical interactions between rGOPKS and PAN were investigated. The diameters of individual fibers in the rGOPKS/PAN composite mats ranged from 1.351 to 1506 μm and increased with increasing rGOPKS content. A broad peak centered near 23° in the X-ray diffraction (XRD) pattern of rGOPKS corresponded to the (002) planes in graphitic carbon. Characteristic rGOPKS and PAN peaks were observed in the XRD patterns of all the composite fibers, and their Fourier-transform infrared (FTIR) spectra indicated hydrogen bond formation between rGOPKS and PAN. The composite fiber mats had smooth and homogeneous surfaces, and they exhibited excellent flexibility and durability. Their electrochemical performance as electrodes was assessed, and a maximum specific capacitance of 203 F g-1 was achieved. The cycling stability of this electrode was excellent, and it retained over 90% of its capacitance after 5000 cycles. The electrode had an energy density of 17 W h kg-1 at a power density of 3000 W kg-1. Dielectric results showed a nanofiber composite dielectric constant of 72.3 with minor leakage current (tan δ) i.e., 0.33 at 51 Hz. These results indicate that the rGOPKS/PAN composite fibers have great promise as supercapacitor electrode materials.

Zwitterion Co-Polymer PEI-SBMA Nanofiltration Membrane Modified by Fast Second Interfacial Polymerization

Nanofiltration membranes have evolved as a promising solution to tackle the clean water scarcity and wastewater treatment processes with their low energy requirement and environment friendly operating conditions. Thin film composite nanofiltration membranes with high permeability, and excellent antifouling and antibacterial properties are important component for wastewater treatment and clean drinking water production units. In the scope of this study, thin film composite nanofiltration membranes were fabricated using polyacrylonitrile (PAN) support and fast second interfacial polymerization modification methods by grafting polyethylene amine and zwitterionic sulfobutane methacrylate moieties. Chemical and physical alteration in structure of the membranes were characterized using methods like ATR-FTIR spectroscopy, XPS analysis, FESEM and AFM imaging. The effects of second interfacial polymerization to incorporate polyamide layer and ‘ion pair’ characteristics, in terms of water contact angle and surface charge analysis was investigated in correlation with nanofiltration performance. Furthermore, the membrane characteristics in terms of antifouling properties were evaluated using model protein foulants like bovine serum albumin and lysozyme. Antibacterial properties of the modified membranes were investigated using E. coli as model biofoulant. Overall, the effect of second interfacial polymerization without affecting the selectivity layer of nanofiltration membrane for their potential large-scale application was investigated in detail.

Millimeter-sized Bi2S3@polyacrylonitrile hybrid beads for highly efficient iodine capture

Chemisorption of iodine by forming BiI₃was the main capturing mechanism of Bi₂S₃@PAN for iodine.

Amidoxime Functionalization of Algal/Polyethyleneimine Beads for the Sorption of Sr(II) from Aqueous Solutions

There is a need for developing new sorbents that incorporate renewable resources for the treatment of metal-containing solutions. Algal-polyethyleneimine beads (APEI) (reinforced with alginate) are functionalized by grafting amidoxime groups (AO-APEI). Physicochemical characteristics of the new material are characterized using FTIR, XPS, TGA, SEM, SEM-EDX, and BET. AO-APEI beads are tested for the recovery of Sr(II) from synthetic solutions after pH optimization (≈ pH 6). Uptake kinetics is fast (equilibrium ≈ 60-90 min). Sorption isotherm (fitted by the Langmuir equation) shows remarkable sorption capacity (≈ 189 mg Sr g-1). Sr(II) is desorbed using 0.2 M HCl/0.5 M CaCl2 solution; sorbent recycling over five cycles shows high stability in terms of sorption/desorption performances. The presence of competitor cations is studied in relation to the pH; the selectivity for Sr(II) is correlated to the softness parameter. Finally, the recovery of Sr(II) is carried out in complex solutions (seawater samples): AO-APEI is remarkably selective over highly concentrated metal cations such as Na(I), K(I), Mg(II), and Ca(II), with weaker selectivity over B(I) and As(V). AO-APEI appears to be a promising material for selective recovery of strontium from complex solutions (including seawater).

Aerosol Cross-Linked Crown Ether Diols Melded with Poly(vinyl alcohol) as Specialized Microfibrous Li+ Adsorbents

Crown ether (CE)-based Li⁺ adsorbent microfibers (MFs) were successfully fabricated through a combined use of CE diols, electrospinning, and aerosol cross-linking. The 14- to 16-membered CEs, with varied ring subunits and cavity dimensions, have two hydroxyl groups for covalent attachments to poly(vinyl alcohol) (PVA) as the chosen matrix. The CE diols were blended with PVA and transformed into microfibers via electrospinning, a highly effective technique in minimizing CE loss during MF fabrication. Subsequent aerosol glutaraldehyde (GA) cross-linking of the electrospun CE/PVA MFs stabilized the adsorbents in water. The aerosol technique is highly effective in cross-linking the MFs at short time (5 h) with minimal volume requirement of GA solution (2.4 mL g^-1 MF). GA cross-linking alleviated CE leakage from the fibers as the CEs were securely attached with PVA through covalent CE-GA-PVA linkages. Three types of CE/PVA MFs were fabricated and characterized through Fourier transform infrared-attenuated total reflection, ¹³C cross-polarization magic angle spinning NMR, field emission scanning electron microscope, N₂ adsorption/desorption, and universal testing machine. The MFs exhibited pseudo-second-order rate and Langmuir-type Li⁺ adsorption. At their saturated states, the MFs were able to use 90-99% CEs for 1:1 Li⁺ complexation, suggesting favorability of their microfibrous structures for CE accessibility to Li⁺. The MFs were highly Li⁺-selective in seawater. Neopentyl-bearing CE was most effective in blocking larger monovalents Na⁺ and K⁺, whereas the dibenzo CE was best in discriminating divalents Mg²⁺ and Ca²⁺. Experimental selectivity trends concur with the reaction enthalpies from density functional theory calculations, confirming the influence of CE structures and cavity dimensions in their "size-match" Li⁺ selectivity.

Effective removal of cesium by pristine graphene oxide: performance, characterizations and mechanisms

Cs is effectively removed by graphene oxide (GO). Characterization reveals the Cs capture mechanism by oxygen functional groups and hole defects.

Polystyrene/poly(dibenzo-18-crown-6) composite nanofibers for the selective adsorption of plasma catecholamines

This convenient and selective packed fiber SPE method might be promising in analysis of human plasma CAs.

Functionalized and reusable polyethylene fibres for Au(iii) extraction from aqueous solution with high adsorption capacity and selectivity

Functional UHMWPE fibres, used for efficient and selective Au(iii) adsorption from aqueous solutions, were successfully synthesized by a radiation grafting method.