Highly selective and sensitive colorimetric chemosensor using PVA/chitosan ion-imprinted nanofibers for copper ion detection and removal

Herein, a highly efficient colorimetric chemosensor incorporating ion-imprinted electrospun nanofiber was developed for the removal and detection of Cu2+ ions. In this regard, PVA/chitosan composites were used as the polymeric matrix, and 1-(2-pyridylazo)-2-naphthol was employed for complex formation. The prepared naked-eye sensor was characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction analysis, revealing the morphological, structural, and molecular properties of the sensor. The results showed that the colorimetric chemosensor based on copper-imprinted nanofiber (Cu-INF) possesses higher selectivity for Cu2+ compared to interference ions. The selectivity coefficient (k) and relative selectivity coefficient (K') indicated the selective behavior of Cu-INF in the adsorption of Cu2+ in binary systems including Cu2+/Co2+, Cu2+/Ni2+, and Cu2+/Zn2+. Furthermore, the ion-imprinted nanofiber was used for the preconcentration of copper ions, demonstrating a high adsorption capacity of 128.205 mg g-1 for Cu2+. The equilibrium adsorption isotherm and adsorption kinetics of Cu2+ on Cu-INF followed the Freundlich adsorption isotherm and a pseudo-second-order model, respectively. The developed sensor exhibited a linear detection range of 5 × 10-8 - 2 × 10-7 M with a limit of detection (LOD) of 1.07 × 10-8 M for copper ions. The results indicated satisfactory adsorption and successful detection of Cu2+ at trace concentrations.

Semisolid extrusion 3D printing of Dolutegravir-Chitosan nanoparticles laden polymeric buccal films: personalized solution for pediatric treatment

In this work, the semi solid extrusion 3D printing process was utilized to incorporate anti-HIV drug Dolutegravir and its nanoparticles into the buccal film (BF) that was fabricated using the developed polymer ink. The composite made of polyvinyl alcohol (PVA) and sodium alginate was processed into a 3D printing polymer ink with optimum viscosity (9587 ± 219 cP) needed for the seamless extrusion through the nozzle of the 3D printer. The formulated BFs were assessed for its physical properties like weight (0.414 ± 0.3 g), thickness (1.54 ± 0.02 mm), swelling index (18.5 ± 0.91%), and mucoadhesiveness strength (0.165 ± 0.09 N) etc, The structural integrity and the surface morphology of the developed BFs were investigated by scanning electron microscopy analysis. The chemical stability and the solid-state nature of the drug in the BFs were assessed by Fourier transform infrared and x-ray diffraction analysis respectively. Further the BFs were assessed for drug dissolutionin-vitroandex-vivo, to study the effect of polymer composition and printing condition on the dissolution profile of the drug in the simulated salivary fluid. The results demonstrated that the developed PVA based polymer ink for 3D printing utilizing pressure is a versatile approach in the context of manufacturing mucoadhesive BFs customized in terms of shape and the amount of drug loaded.

Chitosan-based hollow nanofiber membranes with polyvinylpyrrolidone and polyvinyl alcohol for efficient removal and filtration of organic dyes and heavy metals

Due to their large specific surface area and numerous diffusion channels, hollow fibers are widely used in wastewater treatment. In this study, we successfully synthesized a chitosan (CS)/polyvinylpyrrolidone (PVP)/polyvinyl alcohol (PVA) hollow nanofiber membrane (CS/PVP/PVA-HNM) via coaxial electrospinning. This membrane demonstrated remarkable permeability and adsorption separation. Specifically, the CS/PVP/PVA-HNM had a pure water permeability of 4367.02 L·m^-2·h^-1·bar^-1. The hollow electrospun nanofibrous membrane exhibited a continuous interlaced nanofibrous framework structure with the extraordinary advantages of high porosity and high permeability. The rejection ratios of CS/PVP/PVA-HNM for Cu²⁺, Ni²⁺, Cd²⁺, Pb²⁺, malachite green (MG), methylene blue (MB) and crystal violet (CV) were 96.91 %, 95.29 %, 87.50 %, 85.13 %, 88.21 %, 83.91 % and 71.99 %, and the maximum adsorption capacities were 106.72, 97.46, 88.10, 87.81, 53.45, 41.43, and 30.97 mg·g^-1, respectively. This work demonstrates a strategy for the synthesis of hollow nanofibers, which provides a novel concept for the design and fabrication of highly efficient adsorption separation membranes.

Solution blow spinning polysulfone-Aliquat 336 nanofibers: synthesis, characterization, and application for the extraction and preconcentration of losartan from aqueous solutions

Nanofibers are materials used in a wide range of applications due to their unique physicochemical properties. As an alternative to the most common method of its manufacturing (electrospinning) blow spinning has been used since it has greater production efficiency and simplicity. A wide variety of polymers is used for its preparation and can be modified to improve the interaction and selectivity toward specific analytes. Thereby nanofibers have been used for the extraction or removal of organic compounds such as drugs but there are still few reports of drug extractions like losartan. In this work polysulfone-Aliquat 336 nanofibers were prepared using the blow spinning method to extract and preconcentrate losartan. The studies showed that Aliquat 336 incorporation significantly improve the extraction of losartan with polysulfone fibers. Adsorption process was thermodynamically favorable with an adsorption capacity of 15.45 mg·g−1. Thus, it was possible to extract more than 92% of initial losartan using 10 mg of polysulfone-Aliquat 336 fibers (9 and 3.5% (w/v)), at pH 6 from deionized water and synthetic wastewater. Finally, losartan preconcentration was evaluated to facilitate its quantification using ultraviolet–visible spectrometry (UV-Vis), which allowed the determination of this drug at concentrations below the detection limit.

Hydrophilicity and flux properties improvement of high performance polysulfone membranes via sulfonation and blending with Poly(lactic acid)

To achieve increased flow and reduce fouling, polymeric membranes can be functionalized with hydrophilic groups such as sulfone, amines, and others. This research has aimed at the sulfonation of Polysulfone (PSU) with various agents and at varying substitution degrees to change its hydrophobic character. PSU was also blended with Poly(lactic acid) (PLA), which is a more hydrophilic polymer. The phase inversion method was used to make PSU, PLA, sulfonated PSU, and PSU/PLA blend-based membranes. Sulfonation degrees of sulfonated PSU membranes were assessed using FT-IR, mechanical characteristics of membranes were determined, and thermal properties of membranes were clarified using DSC and TGA techniques. Hydrophilic natures and membrane alterations were investigated, as well as contact angle and water uptake measures. Among three distinct sulfonation agents (trimethylsilyl chlorosulfonate (TMSCS), sulfuric acid, and chlorosulfonic acid) employed to produce a 20% sulfonation degree of polysulfone, TMSCS was chosen as having the highest sulfonation efficiency (91.5%). With increasing sulfonation degree, a drop in molecular weight was seen in all sulfonated polysulfone samples. The mechanical strength values of polysulfone after sulfonation with TMSCS rose from 35.23 MPa to 63.35 MPa, while the contact angle value decreased from 85.58° to 71°. The contact angle value reduced from 85.58° to 64.68° while the mechanical strength of the PSU and PSU/PLA (50:50) blend increased from 35.23 MPa to 39.3 MPa. Membranes were also tested for pure water flux, hydrostability, and biostability. In terms of application requirements, it was determined that sulfonated PSU-based membranes manufactured with TMSCS with a 20% sulfonation degree and PSU/PLA blend-based membranes with a 50:50 (w:w) ratio have the optimum compositions with high flux quantities.