Mixed Cellulose Ester Research Articles

Preparation of cellulose-based optical brightening agent by a two-step one-pot reaction and its application in fiber treatment

AbstractA simple and efficient two-step one-pot procedure for the manufacturing of a cellulose-based polymeric optical brightening agent is demonstrated. The method employs a consecutive in situ activation of two carboxylic acids in a cellulose solution prepared in N,N-dimethylacetamide and LiCl. As an activating agent, 4-toluenesulfonyl chloride was employed. The optical brightening properties were introduced by a 4-hydroxythiazole moiety. These compounds show strong fluorescence over a large range of the visible electromagnetic spectrum. The properties can be largely tuned by reactions at the 2- and 5-position of the thiazole ring. The water solubility of the cellulose derivative is introduced in the second step, by attaching betaine to the cellulose backbone. This cationic moiety allows not only a fast dissolution of the cellulose mixed ester in water, but also an efficient adsorption onto cellulose fibers via electrostatic interactions. After adsorption onto the fibers, the resulting material appears bright white in daylight and shows a strong blue fluorescence when probed under ultraviolet light. The coating process is fast and almost quantitative as absorption and fluorescence measurements reveal, showing no leaching effect. The cellulose mixed ester synthesized is characterized by means of 1D and 2D 1H- and 13C nuclear magnetic resonance, infrared-, UV–Vis-, and fluorescence spectroscopy. In addition, elemental analysis and size-exclusion chromatography were performed. The polymeric optical brightening agents presented consists of environmentally benign compounds only and can be considered as a green alternative for traditional low molecular optical brightening agents employed today.

Using syringe filtration after lab-scale adsorption processes potentially overestimates PFAS adsorption removal efficiency from non-conventional irrigation water.

The adsorption process, known for its cost-effectiveness and high efficiency, has been extensively investigated at the laboratory scale for removing per- and polyfluoroalkyl substances (PFAS) from non-conventional irrigation water. However, a syringe filtration step is commonly used when quantifying PFAS removal during this adsorption process, potentially leading to PFAS retention onto the filters and an overestimate of adsorption removal efficiency. Here, we assessed the retention of three prevalent PFAS (i.e., perfluorooctanoic acid [PFOA], perfluorooctane sulfonic acid [PFOS], and perfluorobutanoic acid [PFBA]) on six syringe filters. When filtering distilled deionized water spiked with 1µg/L and 100µg/L of each PFAS, we observed the highest and lowest PFAS recovery percentages by mixed cellulose ester (MCE) (0.20µm, 25mm; 97±11%, 101±4.8%) and polytetrafluoroethylene (0.45µm, 13mm; 61±37%, 80±28%), respectively. Under the initial concentration of 1µg/L and 100µg/L, PFOS had recovery percentages of 55±25% and 68±24%, significantly lower than 96±12% and 99±5% for PFOA and 95±8% and 97±4% for PFBA, highlighting the importance of PFAS functional groups. PFAS recovery percentage increased with filtration volume in the order of 80±28% (1mL)<85±21% (5mL)<90±18% (10mL). Using MCE to filter treated municipal wastewater spiked with 1µg/L and 100µg/L of each PFAS, we found recovery percentages>90% for all three PFAS. Our study underscores the significance of syringe filter selection and potential overestimate of PFAS removal efficacy by the lab-scale adsorption processes.

Synthetic membrane selection for in vitro release testing (IVRT): A case study of topical mometasone furoate semi-solid dosage forms

In vitro release testing (IVRT) is extensively used to develop the formulation of topical semi-solid products, to evaluate the quality and consistency of the product after scale-up and post-approval changes, and more recently to aid the evaluation of topical generic products’ equivalency. The selection of synthetic membrane is one of the most critical parameters of the method development part of IVRT. It is well known that the membrane features namely its polymer matrices, porosity, pore size, thickness can have a substantial effect on the IVRT data. However, there is no detailed information available in the literature regarding the membrane selection for different types of topical dosage forms. Therefore, we aimed to investigate whether difference topical semi-solid dosage forms of the same drug molecule would cause to variation in the membrane selection. Within this framework, rheological behaviour of commercially available three different types of topical semi-solid dosage forms (ointment, cream, and lotion) of mometasone furoate (0.1%) were primarily characterized. Then, the membrane inertness test was conducted using a series of synthetic hydrophilic membranes (regenerated cellulose, cellulose acetate, cellulose nitrate, mixed cellulose ester membranes) and hydrophobic membranes (polyether sulfone, polypropylene, polytetrafluoroethylene membranes) after identifying of an appropriate receptor medium that ensures sink condition for mometasone furoate. Lastly, IVRT studies from the topical semi-solid products were performed utilizing Franz-type diffusion cells. The membrane inertness and in vitro release data demonstrated that the cellulose acetate membrane showed superior diffusion properties in general while the other synthetic membranes exhibited varying outcomes for different semi-solid dosage forms of mometasone furoate. Overall, the results indicated that the release rate and the cumulative drug released amount of drug after 6 h through the different synthetic membranes might vary depending on the semi-solid dosage form. In order to select the synthetic membrane for IVRT, it should also be considered potential interactions between the polymer matrices and the chemical structure of drug molecule as well as formulation components prior to conducting membrane inertness test and IVRT studies.

Surface treatment optimization of mixed cellulose ester membrane by cold plasma treatment to improve apple juice clarification

This study aimed to determine the optimal conditions for the surface modification of mixed cellulose ester (MCE) microfiltration membrane by cold plasma (CP) for apple juice clarification. Response surface method using central cubic design (CCD) was employed for the optimization of the membrane surface modification process. Plasma gas type (oxygen, carbon dioxide, and air), power (10, 15, and 20 W), and exposure time (120, 180, and 240 s) were used as the factors for cold plasma surface modification. The results revealed the surface modification of the MCE membrane using air as plasma gas with plasma power and exposure time equal to 10 W and 180 s resulted in the maximum permeate flux in apple juice clarification. The results of scanning electron microscope, and atomic force microscope confirm the effect of CP treatment on the membrane surface roughness. Fourier transform infrared spectroscopy showed the incorporation of the hydroxyl group into the membrane surface due to CP treatment which affected the surface contact angle and hydrophilicity. The CP treatment of the membrane significantly affects the membrane resistances. Also, the surface modification of the MCE membrane using the CP treatment process in optimal conditions is an effective method for clarifying apple juice.

Design of ternary GO@AgNPs@g-C3N4 membranes for efficient dye removals in integrated photocatalysis-filtration reactors

Photocatalytic composite membranes (PCMs), which integrate the high degradation efficiency of photocatalysts and the physical separation properties of membranes, have emerged as a promising technology for wastewater treatment. Herein, the ternary GO@AgNPs@g-C3N4 PCM was fabricated through a facile vacuum-filtration assembly of graphene oxide (GO), graphitic phase carbon nitride (g-C3N4), and silver nanoparticles (AgNPs) onto commercial mixed cellulose ester (MCE) substrates. The effects of g-C3N4 synthesized from different precursors and various metal nanoparticles on the performance of PCM were systematically investigated. Interestingly, results show the addition of AgNPs not only significantly improves the photocatalytic performance of PCMs but also enhances the mechanical adhesion between the active layer and the MCE substrate. The resultant PCMs exhibit outstanding photocatalytic performance, maintaining dye removal above 89% even after 25 consecutive cycles. Moreover, dye degradation pathways over the PCMs were investigated through free radical scavenging experiments and electron spin resonance characterizations. This simple assembly method results in a 3–12 times increase in flux compared to the layer-by-layer assembly method. Accordingly, our designed PCMs exhibit significant potential for wastewater treatment and water purification applications.

Optimization of iron flocculation for enrichment of CyHV-2 in aquaculture water

Cyprinid herpesvirus 2 (CyHV-2) is an important infectious virus endangering the farmed Carassius species industry. The enrichment and identification of CyHV-2 in the water is a vital means of early warning diagnostics, which is helpful to aquatic diseases prevention and control. In this study, we employed and optimized iron flocculation to enrich the concentrations of CyHV-2 in aquaculture water. Different Fe3+ concentrations (0.5, 1.0, and 10.0 mg/L), various membrane filters (mixed cellulose ester, glass fiber, nylon microporous filter membrane), different elution buffers containing reductants (ascorbate, citrate, DL-malate, and their combinations with EDTA or TE buffer) were compared to check the recovery yield of CyHV-2. Viral genome quantitation was determined using quantitative real-time PCR. The results showed that Fe3+ concentration of 1.0 mg/L, the glass fiber and citrate-TE were determined to have high efficiency and stable recovery yield. To evaluate infectious CyHV-2 viral titres, crucian carps (Carassius auratus) were intraperitoneally injected with CyHV-2. The mortality rate was 100 % at 9 days postinoculation (dpi) with the 96.7 % detection of CyHV-2 in the pooled tissues. The histopathological phenotype showed necrotic cell death in the liver, spleen and kidney. The CyHV-2 genome was ranging from 101.1 to 107.5 copies/μl in the deceased fish, and 101.4 to 103.0 copies/μl in the feeding water at various stages from latent infection to onset of disease. The field samples from Huzhou, Zhejiang Province on June 4th and 7th had higher detection rates, 87.5 % and 100 % respectively, corresponding to higher CyHV-2 detected in the aquaculture water. CyHV-2 viral load in cultured waters tends to increase prior to fish death, which provides a new indicator for the prediction of fish diseases. In summary, we have established a unified operational standard for enrichment of CyHV-2 in the aqueous environment by iron flocculation.

Methodology Approach for Microplastics Isolation from Samples Containing Sucrose.

The growing production and use of plastics significantly contribute to microplastics (MPs) contamination in the environment. Humans are exposed to MPs primarily through the gastrointestinal route, as these particles are present in beverages and food, e.g., sugar. Effective isolation and identification of MPs from food is essential for their elimination. This study aimed to evaluate factors influencing the isolation of MPs from sucrose solutions to determine optimal conditions for the process. Polyethylene particles were used to test separation methods involving chemical digestion with acids and filtration through membrane filters made of nylon, mixed cellulose ester, and cellulose acetate with pore sizes of 0.8 and 10 µm. The effects of temperature and acid type and its concentration on plastic particles were examined using scanning electron microscopy and µ-Raman spectroscopy. The results indicate that increased temperature reduces solution viscosity and sucrose adherence to MPs' particles, while higher acid concentrations accelerate sucrose hydrolysis. The optimal conditions for MPs' isolation were found to be 5% HCl at 70 °C for 5 min, followed by filtration using an efficient membrane system. These conditions ensure a high recovery and fast filtration without altering MPs' surface properties, providing a reliable basis for further analysis of MPs in food.

Band gap engineering of g-C3N4/CuS and its application in Solar Still

Interfacial solar steam generation is considered as economical and more effective implementation of Solar steam generation (SSG) where solar energy is concentrated at the liquid surface via the utilization of heat localization materials (HLM). Herein we report the fabrication of an HLM constituted of a nanocomposite absorber of graphitic carbon nitride (g-C3N4) and covellite copper sulfide (CuS) supported on a mixed cellulose ester membrane, with a substrate of air laid paper-wrapped polystyrene foam. This structure allowed for strong broad-spectrum absorbance, increased hydrophilic character and minimal thermal losses. The HLM system absorbed 98% of the material and had an evaporation rate of 2.58 kgs per square meter per hour. This is twice the evaporation rate of water tested under the same conditions. Moreover, as fabricated HLM was also incorporated in a solar still in order to assess its practical performance in solar distillation. Initial studies proved that HLM modified solar still was more effective than conventional solar stills.

Performance and Relative Humidity Impact of Cellulose‐Derivative Networks in All‐Day Passive Radiative Cooling

AbstractAll‐day passive daytime radiative coolers (PDRC) offer a promising solution for energy‐free cooling of buildings and devices. This study investigates the use of various cellulose‐derivative networks to achieve optimal and stable cooling performance. These results showed that the mixed cellulose ester network has a maximum solar reflectance of 97%. While cellulose acetate network has a maximum infrared emissivity of 96% in the atmospheric transparency window band, which is a near‐perfect infrared emitter, the nitrocellulose network shows the highest cooling temperature, with a significant reduction of 14 °C from the ambient temperature and a power of 124 W·m−2 during the daytime and at night of 7.7 °C and 72.8 W·m−2. This study also analyzes the dampness's effect on the cooling performance of cellulose‐derivative networks. The cooling performance of the nitrocellulose network drops ≈ 3 °C (from 14 to 11.3 °C) when the relative humidity of the day exceeds ≈ 30% is observed. These findings indicate that the capacity of a material to absorb water from the surrounding air significantly influences its performance as a passive cooler, primarily due to changes in its optical properties. This is an important insight, as it highlights the need to consider environmental factors like relative humidity and sample hydrophobicity for PDRC systems.

Method for lysis and paper-based elution-free DNA extraction with colourimetric isothermal amplification

Nucleic acid amplification testing has great potential for point-of-need diagnostic testing with high detection sensitivity and specificity. Current sample preparation is limited by a tedious workflow requiring multiple steps, reagents and instrumentation, hampering nucleic acid testing at point of need. In this study, we present the use of mixed cellulose ester (MCE) paper for DNA binding by ionic interaction under molecular crowding conditions and fluid transport by wicking. The poly(ethylene) glycol-based (PEG) reagent simultaneously provides the high pH for alkaline lysis and crowding effects for ionic binding of the DNA under high salt conditions. In this study, we introduce Paper-based Abridged Solid-Phase Extraction with Alkaline Poly(ethylene) Glycol Lysis (PASAP). The anionic mixed cellulose ester (MCE) paper is used as solid phase and allows for fluid transport by wicking, eliminating the need for pipetting skills and the use of a magnet to retain beads. Following the release of DNA from the cells due to the lytic activity of the PASAP solution, the DNA binds to the anionic surface of the MCE paper, concentrating at the bottom while the sample matrix is transported towards the top by wicking. The paper was washed by dipping it in 40% isopropanol for 10 s. After air-drying for 30 s, the bottom section of the paper (3 mm × 4 mm) was snapped off using the cap of a PCR tube and immersed in the colourimetric loop-mediated isothermal amplification (cLAMP) solution for direct amplification and colourimetric detection. The total sample processing was completed in 15 min and ready for amplification. cLAMP enabled the detection of 102 CFU/mL of Escherichia coli (E. coli) from culture media and the detection of E. coli in milk < 103 CFU/mL (10 CFU) after incubation at 68 °C for 60 min, demonstrating applicability of the method to complex biological samples.

Ionic liquid pretreatment of lignocellulose for complete hemicellulose removal to produce high-purity cellulose mixed esters

Strategic valorization of agricultural waste can serve as waste management and promote sustainable biorefineries. Sugarcane bagasse is a readily available lignocellulosic biomass and can be converted into valuable cellulose-based thermoplastics. However, the cellulose purity significantly influences the material properties of the resulting thermoplastics, potentially limiting their applications. Therefore, conventional production necessitates harsh pretreatment of lignocellulose to isolate high-purity cellulose, followed by chemical modification. Here, we demonstrate a facile and green pretreatment method for complete removal of hemicellulose by incubating bagasse in a mixed system of an ionic liquid, 1-ethyl-3-methylimidazolium acetate (EmimOAc), and dimethyl sulfoxide (DMSO) at 140 °C, followed by precipitation in water, achieving >99 % hemicellulose removal. The pretreated bagasse, containing 71 % cellulose and 28 % lignin, underwent homogeneous transesterification with vinyl decanoate and isopropenyl acetate, using EmimOAc as both the solvent and catalyst, assisted by a co-solvent of DMSO. The polysaccharide derivative in the resulting acylated bagasse was separated from the lignin derivative by precipitation in methanol. The obtained polysaccharide derivative with high cellulose purity displayed a high weight-average molar mass of 1.5×106 g mol−1 and a polydispersity of 4. It also exhibited superior thermal stability (thermal degradation temperature, Td−5 %: 359 °C; glass transition temperature, Tg: 144 °C) compared to pulp-derived cellulose acetate decanoate (Td−5 %: 349 °C; Tg: 129 °C).

A fast and effective way to measure the inner pore size distributions of wetted cotton fibers and their pretreatment performance using time-domain nuclear magnetic resonance

This study reports the findings from using time-domain nuclear magnetic resonance (TD-NMR) to analyze the pore structures of cotton fibers. Cotton fibers, which swell and soften in water, present challenges for conventional pore measurement techniques. TD-NMR overcomes these by measuring the transverse relaxation time (T2) of water protons within the fibers, indicative of internal pore sizes. We established a T2-to-pore size conversion equation using mixed cellulose ester membranes. This enabled differentiation between strongly bound, loosely bound, and free water within the fibers, and detailed the water distribution. A method for measuring the pore size distribution of wet cotton fiber was developed using TD-NMR. We then examined how various pretreatments affect the fibers' internal pores by comparing their pore size distribution and porosity. Specifically, caustic mercerization primarily enlarges the porosity and size of larger pores, while liquid ammonia treatment increases porosity but reduces the size of smaller pores. This research confirms TD-NMR's utility in assessing cotton fabrics' wet processing performance.

Pondering performance of hybrid microfiltration and membrane distillation (MF-MD) process for purifying chromium-contaminated groundwater: Optimization, fouling control, and long-term operation

Nowadays, a hazardous compound such as Chromium (Cr) in groundwater is an emerging issue worldwide due to its environmental and health impacts. Membrane distillation (MD) is a promising technique to purify Chromium-contaminated groundwater (CCG). Assisted microfiltration (MF) is lodged to overcome a major problem in MD, specifically membrane fouling. In this work, a hybrid MF-MD process is proposed with fouling control incorporated into long-term operation. Derived from the results, mixed cellulose ester with 0.1 μm of pore size (MCE0.1) at 3-min ultrasonication cleaning is chosen as the optimal parameter in the MF process, because of superior flux recovery ratio (FRR) with negligible flux deficiency of approximately 10 %. Permeate flux and total suspended solids (TSS) rejection of MCE0.1 was achieved around 440 Lm−2h−1bar−1 and > 90 %, respectively. The optimized parameters in MD were selected accordingly: feed temperature of 80 °C, and feed and coolant flow rates at 4 L/min. Eventually, the long-term batch operation was executed by obtaining average flux and permeate conductivity was 7.5 LMH and around 10 μs/cm, respectively. The Cr concentration in permeate was relatively stable around 0.05 mg/L, which meets the wastewater discharge limit of 0.5 mg/L.

Composite ultrathin membranes for clarification and primary recovery of biobased itaconic acid from fermentation broths

Itaconic acid is a biobased organic acid with clear potential to become a relevant renewable building-block chemical. However, to compete with petrochemical processes, the production cost of biobased processes, particularly the downstream processing contribution, needs to be reduced. In this work, composite membranes comprising ultrathin films of crosslinked poly[(o-cresyl glycidyl ether)-co-formaldehyde] and branched polyethyleneimine on mixed cellulose ester supports were developed for application in the primary recovery of itaconic acid from fermentation broths. In contrast to commercial and literature-reported counterparts, these membranes exhibit low itaconic acid rejections over a wide range of pH, ionic strength, organic acid concentration and operating pressure. Moreover, these membranes can efficiently recover itaconic acid from clarified fermentation broth as well as unclarified fermentation broth of Pichia pastoris cultivations, with average rejections below 15 % recorded over 8 h of operation. Lastly, the performance of these membranes was compared to literature-reported strategies for primary recovery of biobased organic acids. The efficient recovery of itaconic acid from unclarified fermentation broth opens the possibility to perform clarification and primary recovery simultaneously, thus simplifying the downstream processing of biobased itaconic acid considerably.

Optimal filter materials for protist quantification via droplet digital PCR

The use of droplet digital polymerase chain reaction (ddPCR) has greatly improved the quantification of harmful protists, outperforming traditional methods like quantitative PCR. Notably, ddPCR provides enhanced consistency and reproducibility at it resists PCR inhibitors commonly found in environmental DNA samples. This study aimed to determine the most effective filter material for ddPCR protocols by assessing the reproducibility of species-specific gene copy numbers and filtration time across six filter types: cellulose acetate (CA), mixed cellulose ester (MCE), nylon (NY), polycarbonate (PC), polyethersulfone (PES), and polyvinylidene fluoride (PVDF). The study used two species of Chattonella marina complexes as a case study. Filtration rates were slower for NY, PC, and PVDF filters. Moreover, MCE, NY, PES, and PVDF yielded lower DNA amounts than other filters. Importantly, the CA filter exhibited the lowest variance (38–39%) and the highest determination coefficients (R2 = 0.92–0.96), indicating superior performance. These findings suggest that the CA filter is the most suitable for ddPCR quantification of marine protists, offering quick filtration and reliable reproducibility.

Wax screen-based fabrication of paper devices for the determination of iron in particulates of selected welding fumes in Addis Ababa, Ethiopia

In this study a paper-based analytical device was developed using screen printing technique for the determination of particulate iron from welding fumes. The operational parameters such as volume and concentration of 1,10-phenanthroline, volume and concentration of hydroxylamine were optimized by the Box Behnken Design (BBD) using Minitab. Additionally, the µ-PAD's sample solution holding capacity and reaction time were also optimized. Under the optimized condition, particulate metal concentrations were colorimetrically quantified usinga handheld mobile phone and image processing software, ImageJ. Very good analytical performance such as good linearity of the calibration curve and better selectivity was observed by the developed method. The limit of detection for Fe3+ assay was 4.6 mg/L; which is adequate to determine the threshold concentration limit of particulate iron set by the regulatory bodies (6 mg/L). The µ-PAD revealed 95-99% recovery compared with the UV-Vis spectrophotometry (98-100%). Furthermore, welding fume samples were collected in Addis Ababa over five days, using mixed cellulose ester filters and the findings show a high concentration that exceeds the standard levels. Analyzing particulate iron with µ-PADs yielded results consistent with UV-Vis spectrophotometry, suggesting µ-PADs' potential application for occupational particulate iron exposure measurement, eliminating the need for expensive analytical devices.&#x0D; KEY WORDS: µ-PADs, Particulate iron, Response surface methodology, Wax screen-printing, Welding fume, Colorimetric detection&#x0D; Bull. Chem. Soc. Ethiop. 2024, 38(3), 563-576. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v38i3.2 &#x0D;

Plasmonic group 4 transition metal carbide interfaces for solar‐driven desalination

AbstractTo combat the dwindling supply of freshwater, solar‐driven desalination using plasmonic nanomaterials has emerged as a promising and renewable solution. Refractory plasmonic carbide nanomaterials are exciting candidates that are inexpensive and chemically robust but have not been widely explored. Herein, plasmonic carbide interfaces made of TiC, ZrC, and HfC nanoparticle aggregates loaded onto to a mixed cellulose ester (MCE) membrane were explored to gain insight into their solar‐vapor generation and desalination potential. Desalination using Atlantic Ocean water under 1 sun intensity yielded rates of 1.26 ± 0.01, 1.18 ± 0.02, and 1.40 ± 0.01 kg m−2 h−1, with efficiencies of 86%, 80%, and 96% for TiC, ZrC, and HfC, respectively. Carbide interfaces showed good stability and effectively removed heavy metal ions and salt from solutions with concentrations up to 35%. PVA hydrogel based TMC evaporators afforded rates of 3.31 ± 0.03 and 3.22 ± 0.03 kg m−2 h−1 for TiC and ZrC, respectively. The HfC‐PVA interface afforded a high solar desalination rate of 3.69 ± 0.04 kg m−2 h−1, corresponding to an efficiency of 97% under 1‐sun illumination. The hydrogel evaporators also retained their strong salt rejection action over time.

An Evaluation of the Relationship between Membrane Properties and the Fouling Mechanism Based on a Blocking Filtration Model

Microfiltration plays an increasingly important role in various fields. Consequently, elucidating the mechanism of membrane fouling has emerged as a pivotal issue that needs to be resolved. In this study, a blocking filtration model was employed to evaluate the effects of membrane properties on the fouling mechanism during the microfiltration of representative polysaccharides, namely sodium alginate, pectin, and xanthan gum. Microfiltration membranes composed of hydrophilic and hydrophobic PVDF, mixed cellulose ester, as well as hydrophilic and hydrophobic PTFE were used as filter media. The flux decline behavior was significantly affected by the membrane properties, with hydrophilic membranes exhibiting a slower decrease in filtration rate. The model analysis revealed a correlation between the blocking characteristic values and the membrane properties. Although the blocking index n showed membrane material dependence, the values of this parameter remained consistent across various filtration conditions, including the wettability of the membrane surface, solute concentration, and pressure (pectin: n = 1.86, 1.85, 1.50, and 1.50 for hydrophilic PVDF, hydrophobic PVDF, hydrophilic PTFE, and hydrophobic PTFE, respectively). The resistance coefficient k was influenced by the characteristics of the membrane surface; the k values of the hydrophobic membranes were higher than those of the hydrophilic ones (pectin: k = 0.00084, 0.00725, 0.00714, and 0.0384 s1−n/cm2−n for hydrophilic PVDF, hydrophobic PVDF, hydrophilic PTFE, and hydrophobic PTFE, respectively). The model calculations, based on the values of n and k, demonstrated a relatively good agreement with the experimental data.

UIO-66-NH2 encapsulated polyoxometalate loaded on graphene oxide accommodated on mixed cellulose esters (MCE) paper for thin film microextraction of pesticides besides their quantification via high-performance liquid chromatography-ultraviolet detection

A POM@UIO-66-NH2/GO composite was designed and prepared via a facile in-situ synthesis method for microextraction purposes. The proper sizes (window size and pore size) of UIO-66-NH2 can effectively seal POM as a monomolecular active component and prevent POM leaching during the extraction. After that, a membrane containing POM@UIO-66-NH2/GO nanocomposite was synthesized and utilized in thin film microextraction (TFME) of various pesticides such as imidacloprid, tebuconazole, and propiconazole as the model analytes in different real samples such as cucumber, tomato, potato, head lettuce, and strawberry. It is worth mentioning that the introduction of GO can improve the electron transfer of the sorbent. The extracted model analytes were desorbed by a suitable organic solvent. The extracted analytes were quantified via high-performance liquid chromatography-ultraviolet detection (HPLC-UV). Under the optimized condition, the method's linear dynamic range (LDR) was obtained in the range of 1.0–200.0 μg L−1 for testing analytes. The obtained correlation coefficients (r2) were higher than 0.9918. The limits of detection (LODs) were also calculated to be between 0.31 and 0.34 μg L−1. The relative standard deviations (%RSDs) were obtained in the range of 2.06 to 4.11. The enrichment factor (EF) values for the studied analytes were also obtained in the range of 89–102. The obtained recoveries indicated that the presented method is useful for analyzing pesticides in various real samples.

Quorum Quenching Nanofibers for Anti-Biofouling Applications

Biofilms, complex microbial communities, adept at forming on diverse surfaces within environments, such as membrane technologies, ship hulls, medical devices, and clinical infections, pose persistent challenges. While various biofilm prevention methods, including antimicrobial coatings, physical barriers, and bacteriophage utilization, have been devised for engineered systems, their efficacy fluctuates based on application type and microbial species. Consequently, there remains a pressing need for the development of highly targeted and efficient biofilm control strategies tailored to specific applications remains a pressing need. In our investigation, we disrupt microbial cell-to-cell communication in Pseudomonas aeruginosa through the application of anti-quorum sensing (anti-QS) furanone C-30 molecules. The incorporation of these molecules onto electrospun surfaces yielded substantial reductions of 69% in petri dish assays and 58% on mixed cellulose ester (MCE) membranes in a dead-end nanofiltration system, showcasing the potent anti-biofouling impact. Notably, the functionalization of MCE surfaces with anti-QS molecules resulted in a remarkable 16.7% improvement in filtration output. These findings underscore the potential of this targeted approach to mitigate biofilm formation, offering a technical foundation for advancing tailored strategies in the ongoing pursuit of effective and application-specific biofilm control measures.