Nanofiber Adsorbent Research Articles

MOF-5 anchored polymer@carbon core–shell nanofibers for efficient removal of chlortetracycline from aqueous solution

Antibiotics excreted by human or animal may contain un-degradable residues, which form high concentration accumulation in water, leading to seriously harmful effects on the environment. Herein, MOF-5 anchored polymer@carbon core–shell nanofibers (MAPC) are fabricated via the electrospinning-hydrothermal synthesis and used for high efficiency removing chlortetracycline (CTC) from water. The anchored MOF-5 enhances the adsorption ability of hydrothermal carbon core–shell nanofibers. The MAPC nanofibers exhibit 395.87 mg/g of adsorption capacity for CTC removal process, which well fitted with Freundlich isotherm model and pseudo-second-order kinetic model. After nanofiber membrane filtering, the removal efficiency of CTC is nearly 100 % at the concentration of 5 mg/L. And the chemical oxygen demand (COD) concentration of CTC is reduced from 156.72 mg/L to 50.39 mg/L, that is below the pharmaceutical wastewater discharge standard. In addition, MAPC exhibits high flux and good regeneration performance. This work gives a typical strategy of feasible preparation of high efficiency MOFs anchored carbon-based nanofiber adsorbent towards the pharmaceutical wastewater treatment.

Theory-Driven Tailoring of the Microenvironment of Quaternary Ammonium Binding Sites on Electrospun Nanofibers for Efficient Bilirubin Removal in Hemoperfusion.

Efficient adsorbents for excess bilirubin removal are extremely important for the treatment of hyperbilirubinemia. However, traditional adsorbents, such as activated carbons and ion-exchange resins, still suffer from dissatisfactory adsorption performance and poor blood compatibility. Herein, we adopted a rational design strategy guided by density functional theory (DFT) calculations to prepare blood-compatible quaternary ammonium group grafted electrospun polyacrylonitrile nanofiber adsorbents. The calculation analysis and adsorption experiments were used to investigate the structure-function relationship between group types and bilirubin adsorption, both indicating that quaternary ammonium groups with suitable configurations played a crucial role in bilirubin binding. The obtained nanofiber adsorbents showed the bilirubin removal efficiency above 90% even at a coexisting BSA concentration of 50 g L-1. The maximum adsorption capacities were 818.9 mg g-1 in free bilirubin solution and 163.7 mg g-1 in albumin bound bilirubin solution. The nanofiber adsorbents also showed considerable bilirubin removal in dynamic adsorption to reduce the bilirubin concentration to a normal level, which was better than commercial activated carbons. Our study demonstrates the high feasibility of a theory-driven design method for the development of grafted electrospun nanofibers, which have good potential as bilirubin adsorbents in hemoperfusion applications.

Improved mRNA affinity chromatography binding capacity and throughput using an oligo-dT immobilized electrospun polymer nanofiber adsorbent

Increased demand for mRNA-based therapeutics and improved in vitro transcription (IVT) yields have challenged the mRNA purification platform. Hybridization-affinity chromatography with an immobilized oligo-deoxythymidilic acid (oligodT) ligand is often used to capture mRNA through base pairing with the polyadenylated tail. Commercially available oligodT matrices include perfusive cross-linked poly(styrene-divinylbenzene) 50 µm POROS™ chromatography resin beads and convective polymethacrylate CIMmultus® monolithic columns consisting of 2 µm interconnected channels. POROS™ columns may be limited by poor mass transfer for larger mRNAs and slow flowrates, while monoliths can operate at higher flowrates but are limited by modest binding capacity. To enable both high flowrates and binding capacity for mRNA of all lengths, prototype chromatography media was developed by Cytiva using oligodT immobilized electrospun cellulose nanofibers (Fibro™) with a 0.3–0.4 µm pore size. In this work, four polyadenylated mRNAs ranging from ∼1900–4300 nucleotides were used to compare the dynamic binding capacity (DBC) of Fibro™, POROS® and CIMmultus® columns as a function of residence time and binding buffer compositions. Fibro™ improved the DBC ∼2–4-fold higher than CIMmultus® and ∼2–13-fold higher than POROS™ across all residence times, mRNA length, and binding matrix compositions tested. CIMmultus® DBC was least dependent on residence time and mRNA size, while both Fibro™ and POROS™ DBC increased at slower flowrates and with shorter mRNA. Surprisingly, inverse size exclusion (ISE) experiments showed that POROS™ was not limited by diffusion and POROS™ along with CIMmultus® demonstrate higher mRNA permeation however the Fibro™ prototype is not in the final configuration. Lastly, IVT reaction products were subjected to purification and oligodT elution product yield, quality, and purity were consistent across the three matrices investigated. These results highlight the benefits of high DBC and equivalent product profiles offered by the oligodT Fibro™ prototype compared to commercially available oligodT media.

Facile construction of ZIF-94/PAN nanofiber by electrospinning for the removal of Co(II) from wastewater

This study aimed to synthesize a novel nanofiber adsorbent based on metal–organic frameworks (MOFs), ZIF-94-PAN, by incorporating ZIF-94 into polyacrylonitrile (PAN) through electrospinning. The investigation of the adsorption characteristics of ZIF-94-PAN for cobalt ions was undertaken, yielding findings that suggest an optimum ZIF-94 loading content within the ZIF-94-PAN composite of 8%. The adsorption experiments revealed that, under pH 8.3 and 298 K, ZIF-94-PAN-8% attained cobalt ion equilibrium adsorption (139.08 mg/g). Additionally, the adsorption kinetics of cobalt ions exhibited conformity with the pseudo-second-order model, whereas adherence to the Freundlich isotherm model indicated a non-homogeneous, endothermic process. XPS analysis unveiled that the adsorption mechanism was characterized by the coordination of nitrogen and oxygen atoms within ZIF-94-PAN with cobalt ions. This study effectively addressed the challenges of separating and recovering MOFs adsorbents by fabricating them as nanofibers. The remarkable adsorption performance and stability of the ZIF-94-PAN nanofibers highlight their potential for removing cobalt-contaminated wastewater.

Removal of short- and long-chain PFAS from aquatic systems using electrostatic attraction of polyethylenimine-polyvinyl chloride electrospun nanofiber adsorbent

The presence of per- and polyfluoroalkyl substances (PFAS) in the water environment raises serious concerns due to their persistence and toxicity that links to adverse health consequences. Short-chain PFAS are more challenging to remove from water by adsorption than long-chain PFAS due to the weaker hydrophobic interaction, and conventional adsorbents usually demonstrated poor PFAS adsorption capacities near neutral pH. We have examined a novel polyethylenimine-polyvinyl chloride electrospun nanofiber (PEI-PVC NF) adsorbent to improve the adsorption capacity of both short- [perfluorobutanoic acid (PFBA) and perfluorobutanesulfonic acid (PFBS)] and long-chain [perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)] PFAS by maximizing electrostatic attraction using a PEI functional group with nanopore structure. At pH 7, PEI-PVC NF demonstrated adsorption capacities of 84.26 mg/g for PFBA and 214.37 mg/g for PFBS (short-chain PFAS), and 213.76 mg/g for PFOA and 326.39 mg/g for PFOS (long-chain PFAS). These adsorption capacities were only 20.1–61.3% lower than those obtained under acidic conditions. Excellent adsorption capacities by PEI-PVC NF are likely due to the strong electrostatic attraction with PEI under acidic to neutral pHs as well as pore-mediated adsorption driven by nanopore structure. The isotherm adsorption data were well fitted with the Langmuir model, which supports dominant monolayer adsorption driven by electrostatic attraction. Maximum adsorption capacities (qmax, 98.70 mg/g for PFBA, 222.36 mg/g for PFBS, 234.85 mg/g for PFOA, and 319.82 mg/g for PFOS) were superior to adsorbents that were previously reported at pH 7. Adsorption kinetic tests demonstrated remarkable PFAS adsorption rates (reached equilibrium in 300 min) by PEI-PVC NF likely driven by electrostatic and intraparticle diffusion into nanopores.

Efficient adeno-associated virus serotype 5 capture with affinity functionalized nanofiber adsorbents.

Adeno-associated viruses (AAVs) are one of the most promising tools for gene therapy applications. These vectors are purified using affinity and ion exchange chromatography, typically using packed beds of resin adsorbents. This leads to diffusion and pressure drop limitations that affect process productivity. Due to their high surface area and porosity, electrospun nanofiber adsorbents offer mass transfer and flow rate advantages over conventional chromatographic media. The present work investigated the use of affinity cellulose-based nanofiber adsorbents for adeno-associated virus serotype 5 (AAV5) capture, evaluating dynamic binding capacity, pressure drop, and AAV5 recovery at residence times (RT) less than 5s. The dynamic binding capacity was found to be residence time-dependent, but nevertheless higher than 1.0 × 1014TP mL-1 (RT = 1.6s), with a pressure drop variation of 0.14MPa obtained after loading more than 2,000 column volumes of clarified AAV5 feedstock. The single affinity chromatography purification step using these new affinity adsorbents resulted in 80% virus recovery, with the removal of impurities comparable to that of bead-based affinity adsorbents. The high binding capacity, virus recovery and reduced pressure drop observed at residence times in the sub-minute range can potentially eliminate the need for prior concentration steps, thereby reducing the overall number of unit operations, process time and costs.

Bio-inspired functionalization of electrospun nanofibers with anti-biofouling property for efficient uranium extraction from seawater

The development of efficient adsorbents with anti-biofouling properties for uranium extraction from seawater is highly attractive to meet the growing demands for energy. However, traditional fiber adsorbents still suffer from the challenge of weak binding energy, low functional group density, and inefficient antifouling ability. Herein, inspired by the structures of phospholipid, the bio-inspired zwitterionic phosphate groups were created onto the electrospun nanofibers to manipulate the affinity with uranium and the anti-biofouling property. Additionally, hyperbranched grafting reaction together with thin diameters of the fibers were applied to significantly improve the available density of functional groups. The constructed hyperbranched zwitterionic phosphate groups functionalized nanofiber adsorbents (ZP-PAN fibers) exhibited high distribution coefficient kd (7.38 × 106 mL/g) and large adsorption capacity (1294.0 mg g−1) in the uranium-spiked seawater, surpassing most of reported polymeric adsorbents. ZP-PAN fibers also showed good selectivity against competitive cations and stable reusability. Owing to their zwitterionic structures, ZP-PAN fibers had satisfactory anti-adhesive ability toward bacteria and protein. Consequently, the uranium could be effectively extracted by ZP-PAN fibers from natural seawater with the extraction capacity of 8.1 mg g−1 after contacting with seawater for 15 days. This work demonstrates a new functionalization selection for nanofiber materials and provides a promising adsorbent in the practical uranium extraction from seawater.

Polystyrene electrospun nanofibers as effective sorbents for the removal of atypical antipsychotics: Kinetic and thermodynamic studies

In this study, polystyrene nanofibers were prepared by electrospinning for the adsorption of olanzapine, risperidone, and clozapine from aqueous solution. The properties of polystyrene nanofibers were characterized via FTIR, SEM, TEM, TG, and XRD analyses. In addition, the impact of contact time, initial ion concentration, adsorbent dosage, temperature, and pH on the adsorption was studied. The adsorption kinetics and thermodynamic evaluation of three analytes on PS nanofibers were performed. The adsorption of the three analytes by polystyrene nanofibers followed the first-order kinetics with constant rates of 0.02348, 0.02683, and 0.03024 mg/g min for olanzapine, risperidone, and clozapine, respectively. Further, the adsorption conformed to Redlich-Peterson isotherm model and the maximum adsorption capacities for olanzapine, risperidone, and clozapine were 12.33, 8.36, and 12.96 mg/g, respectively. The adsorption process was characterized by spontaneous, exothermic, and physical reaction. The regeneration of nanofiber adsorbent showed that the adsorption capacity did not significantly change after 5 cycles of desorption. The selectivity of different analytes followed the order of clozapine > risperidone > olanzapine. Thus, the polystyrene electrospun nanofibers exhibit good potential as novel adsorbents for the isolation and purification of antipsychotic drugs from biological samples.

Anti-biofouling multi-modified chitosan/polyvinylalcohol air-blown nanofibers for selective radionuclide capture in wastewater

Significant amounts of radioactive wastewater including uranium are discharged into the environment as a result of the expansion of large-scale nuclear power. Due to uranium's toxicity and bioaccumulation, it is crucial to develop efficient and long-lasting adsorbents with functional groups for improving the selective removal of U(VI). By successfully introducing amidoxime and phosphate groups into quaternary ammonium chitosan (QCS-AO/P, i.e., QAP), an antimicrobial composite nanofiber adsorbent (PQAP) composed of polyvinyl alcohol (PVA) and the as-prepared QAP was synthesized via the solution blow spinning technology (SBS) technique for the highly efficient recovery of uranium from wastewater. The influence of initial pH, contact time, and sorbent composition on the uranyl ion absorption and the antibacterial assay was studied. The PQAP composite fiber mat had the highest adsorption capacity of uranyl ions at pH 8 (559.26 mg/g), and showed excellent antibacterial activities. After six adsorption–desorption cycles, PQAP still retained a high uranium adsorption capacity of 420 mg/g and elimination efficiency (84%). The novel integrated sorption and antibacterial strategy provides new insights for highly efficient treatment of radioactive wastewater.

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 8.32mg/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.

Excellent fluoride removal performance by electrospun La–Mn bimetal oxide nanofibers

A novel La–Mn bimetal oxide nanofiber adsorbent was fabricated by the combination of an electrospinning approach and heat treatment in a simple strategy to remove fluoride ions from water.

Determination of three urinary catecholamines and serotonin by on-line packed-fiber solid-phase extraction

生物单胺包括儿茶酚胺类以及5-羟色胺等,在中枢神经系统中扮演着非常关键的角色,也是临床上诊断神经内分泌肿瘤疾病的重要生物标志物。由于这类单胺类物质的强化学极性导致传统吸附材料对其吸附效果不佳,从复杂生物样本中同时检测更多的生物单胺存在挑战性。该文建立了一种基于聚冠醚纳米纤维在线固相萃取检测尿液中3种儿茶酚胺(多巴胺、肾上腺素、去甲肾上腺素)和5-羟色胺的方法。采用静电纺丝法制备聚二苯并-18-冠-6醚-聚苯乙烯复合纳米纤维(PCE-PS),制成装填纤维的固相萃取(PFSPE)柱,再将PFSPE柱与HPLC进行在线联用。该在线PFSPE-HPLC方法采用双三元泵进行样品富集净化和分析,左泵连接PFSPE柱,进行样品富集净化;右泵连接分析柱进行样品分离检测。控制切换阀的切换,实现样品富集后洗脱至分析柱中分离检测。结果表明,在线PFSPE-HPLC检测尿液儿茶酚胺(多巴胺、肾上腺素、去甲肾上腺素)和5-羟色胺在1~200 ng/mL范围内有良好的线性关系,线性相关系数达0.996以上。3种儿茶酚胺和5-羟色胺的检出限(S/N=3)分别为1和2.5 ng/mL,定量限(S/N=10)分别为2.5和5 ng/mL。空白尿液和实际尿液加标回收率在83.5%~117.7%之间,日内精密度<10%。PCE-PS复合纳米纤维在多次使用后无明显变化,具有良好的稳定性,可重复使用达95次以上。在线PFSPE-HPLC方法能够集样品在线前处理与分析检测于一体,省时省力,实现分析过程的高度自动化。该方法成功应用于尿液中3种儿茶酚胺和5-羟色胺的检测,可以为临床上相关疾病检测诊断和研究提供有力的技术支持。

Production of red mud based nanofibers and their potential in arsenate removal from waste water

In this study, it was aimed to utilize red mud (RM, an industrial waste material) as a nanofiber adsorbent in arsenate removal from waste water. RM, obtained from Seydişehir Aluminum Plant (Konya, Turkey), was leached using nitric acid in order to recover metallic elements such as Fe, Al, and Ti. Oxides and hydroxides of these elements are known to have a high affinity toward arsenic. Metallic salt solution, obtained after leaching treatment, was used to produce nanofibers via electrospinning method to get an adsorbent material with high surface area. Compositional, phase structural, microstructural, and thermal analyses were conducted using AAS, XRF, XRD, SEM, and DT/TGA. Organic removal from nanofibers were conducted at 600 °C for 5 h, based on the DT/TGA results. After heat treatment, nanofibers with diameters ranging from 45 to 58 nm were obtained. Performance of nanofibers in As(V) (arsenate) removal from waste water was also evaluated with different amount of nanofibers (1-3 mg/L), arsenate concentration (5-100 ppm), and contact time (10-120 min). Experimental results showed that the fastest and highest removal efficiency (∼80.2%) was obtained for 3 mg/L nanofiber and 10 ppm arsenate concentration at 90 min. Kinetic studies revealed that the pseudo-second-order kinetic model was dominantly active in the adsorption process.

Synthesis and characterisation of diglycolic acid functionalised polyethylene terephthalate nanofibers for rare earth elements recovery

The big advantage of functionalised nanofibers is their fast adsorption kinetics and considerable interest is currently devoted to developing nanofiber adsorbents for rapid sorption of metal ions. Polyethylene terephthalate nanofibers (PET-nf) functionalised with diglycolic anhydride ligand (PET-DGAnf) were prepared using a simple one-step reaction route. The surface characterisation of the synthesised PET-DGAnf adsorbents was performed using HR-SEM, XRD, TGA, BET, WCA and ATR-FTIR. The electrospinning optimisation was described by response surface methodology (RSM) and the collector distance was statistically significant to describe the production of nanofibers at optimum conditions. The average fiber diameter and the RSM analysis predicted values (113.6 nm) were in good agreement. Experiments in batch mode investigated factors such as the role of pH, solution concentration and contact time to evaluate their application for neodymium (Nd3+) and cerium (Ce3+) adsorption. The maximum PET-DGAnf adsorption capacity using the Langmuir model equation was 135.9 and 123.7 mg/g for Ce3+ and Nd3+ respectively and the equilibrium adsorption was attained within 5 min. The PET-DGAnf demonstrated good selectivity for Ce3+ in the presence of contending ions like Sr2+, Ni2+ and Co2+ ions after four successive adsorption and desorption assessments, and the desorption rate of Ce3+ and Nd3+ was maintained at more than 90% of their adsorption abilities. The PET-DGAnf nanofibers may provide a promising adsorbent for metal adsorption based on their fast binding kinetics and the high selectivity in recovering REE ions from aqueous solution.

A Novel Hollow Carbon@MnO2 Electrospun Nanofiber Adsorbent for Efficient Removal of Pb2+ in Wastewater

A Novel Hollow Carbon@MnO2 Electrospun Nanofiber Adsorbent for Efficient Removal of Pb2+ in Wastewater

Magnetic carbon nanofiber composite adsorbent through green in-situ conversion of bacterial cellulose for highly efficient removal of bisphenol A

A magnetic carbon nanofiber sorbent was facilely synthesized from bio-based bacterial cellulose and FeCl3via impregnation, freeze-drying, followed by pyrolysis at 700 °C, without additional activation or nanofiber fabrication. The obtained material possessed intrinsic 3D naturally fibrous and porous structure with good magnetization. The adsorption results showed that the adsorption capacity of the prepared adsorbent towards bisphenol A (BPA) was as high as 618 mg/g, outperforming other adsorbents. Moreover, recycling the adsorbent for 10 consecutive cycles retained 96% of initial adsorption efficiency. The magnetic sorbent can maintain good magnetic properties even with recycling. Hence, the use of bacterial cellulose as a renewable carbon nanofiber precursor and FeCl3 as a source of magnetic particles, and a green pore generating agent in the present protocol, lead to a superior magnetic carbon nanofiber adsorbent with sustainable characteristics.

Blow spinning of pre–acid-activated polyamidoxime nanofibers for efficient uranium adsorption from seawater

Polyamidoxime (PAO)-based adsorbents have been extensively studied for uranium (U) extraction from seawater for decades. ‘Hot alkali activation’ treatments are found to significantly improve the U adsorption capacity while inevitably decreasing the strength of PAO-based adsorbents, especially nanofiber (NF) adsorbents. Herein, for the first time, we report that, with proper modification, PAO can be dissolved in acid solution with high solubility, and the pre–acid-activated PAO (PA-PAO) exhibits high uranium capture ability (>1800 mg/g). For better use and collection in large-scale application, PA-PAO is mixed with chitosan (CS) and fabricated to PA-PAO/CS NFs via acidic aqueous solution blow spinning and glutaraldehyde vapor cross-linking. The covalently cross-linked PA-PAO/CS NFs are ready to use without postactivation treatment and achieve highly efficient U capturing performance in U-spiked seawater (913.13 mg/g) and natural seawater (4.91 mg/g, in 10 days), as well as enhanced mechanical stability and antibiofouling (antibacterial) activity. This strategy shows great potential for extraction of U from seawater and contaminated water in a cost-effective, industrial-scale manner.

The fabrication of a novel polyacrylonitrile/reduced graphene oxide-amino-halloysite/bimetallic metal-organic framework electrospun nanofiber adsorbent for the ultrasonic-assisted thin-film microextraction of fatty acid methyl esters in dairy products with gas chromatography-flame ionization detection.

In this work, electrospun polyacrylonitrile/reduced graphene oxide-amino-halloysite/bimetallic metal–organic framework (PAN/rGO-amino-HNT/Co0.5Zn0.5(MeIm)2) nanofiber film was synthesized and investigated as a novel adsorbent for the ultrasonic-assisted thin-film microextraction (UA-TFME) of fatty acid methyl esters (FAMEs), including palmitic methyl ester (PAME), oleic methyl ester (OAME), stearic methyl ester (SAME), and linoleic methyl ester (LAME), from dairy products. The hybrid nanocomposite was obtained via bonding halloysite nanotubes to reduced graphene oxide, followed by loading with bimetallic metal–organic frameworks. The determination of FAMEs with nanofiber film was performed in two stages of desorption and absorption where, initially, the analytes were adsorbed onto the nanofiber film and then desorbed with organic solvent. In this study, ultrasound was used for both the adsorption and desorption stages. The advantages of ultrasonication are extensive, overcoming the shortcomings of conventional techniques in terms of energy consumption and solvent use, allowing a shorter treatment time with a low cost of implementation. Based on PAN/rGO-amino-HNT/Co0.5Zn0.5(MeIm)2 thin film, a microextraction-gas chromatography-flame ionization detection (TFME-GC-FID) method was developed. Experimental parameters affecting the extraction and desorption steps were optimized. The desorption parameters, including desorption time and the properties of the desorption solvent, were investigated one factor at a time. Then, effective parameters in the adsorption step were optimized using a Box–Behnken design and Design-Expert 7 software. Under the optimal conditions, the method detection limits (S/N = 3) were in the range of 0.03–0.06 μg L−1 and the limits of quantification (S/N = 10) were within 0.11–0.23 μg L−1. The relative standard deviations for intra-day and inter-day precision were 2.4–4.7% and 2.6–3.4%, respectively. In the present work, the UA-TFME method was successfully applied for the quantification of fatty acid methyl esters in dairy products (milk, yogurt, cheese, yogurt soda and butter samples) for the first time. The fatty acids were transesterified using standard procedures and were subjected to UA-TFME treatment prior to GC-FID determination. The developed method possesses the advantages of simplicity, rapidity, cost-effectiveness, sensitivity, and non-invasiveness.

Fabrication of Composite-Based Electrospun Nanofiber Adsorbent and Application in Dye Removal

The improvement of processes for maintaining our ecosystem amidst rapidly developing and sustaining pollution is the ever-growing demand. This current research work is aimed at developing useful nanomaterials, such as silica nanoparticles and graphene oxide nanoparticles from solid agro-waste, coconut husk. The nanoparticles obtained were then blended with two other polymers, namely polyhydroxyalkanotes, a microbial biopolymer and polyvinylpyrrolidone, a synthetic biodegradable polymer to form nanocomposites, which are used as the base for nanofiber fabrication through electrospinning. The nanocomposites were characterized through Fourier-transform infrared (FTIR) spectrometer and the nanofibers under scanning electron microscope. The nanofibers were subjected to analyze the ability to function as adsorbents. The composite nanofibers developed were able to remove 62% of methylene blue dye in the test solution in a span of 12 hours with additional benefits of easy removal of used adsorbents and adsorbates.

Aqueous Solution Blow Spinning of Seawater‐Stable Polyamidoxime Nanofibers from Water‐Soluble Precursor for Uranium Extraction from Seawater

AbstractPolyamidoxime (PAO)‐based fibers are recognized as one of the most promising adsorbents for industrial‐scale extraction of uranium from seawater. The spinning of PAO is usually processed in environmentally unfriendly organic solvents, which cause serious environmental and cost concerns in industrial‐scale manufacturing. In this work, an aqueous solution blow spinning (ASBS) strategy is developed for large‐scale fabrication of seawater‐stable polyamidoxime/alginate nanofibers (PAO/Alg NFs) from water‐soluble PAO precursor solution. The as‐spun PAO/Alg NFs are ready to be used for uranium adsorption after simple immersion in calcium chloride solution for crosslinking. The 3D porous architecture, flexibility, and strength of nanofibers are well maintained as the inevitable shrinkage and degeneration accompanied by traditional “alkaline‐heat activation” post treatment are completely avoided. A high adsorption capacity of 892.77 and 8.42 mg‐U g−1 NFs is achieved in uranium spiked seawater and 8 tons of nonspiked natural seawater, respectively. Taking advantage of the simplicity, low cost, and industrially scalable features, this novel ASBS approach shows great potential for industrial‐scale production of PAO‐based nanofiber adsorbent with high capacity and good mechanical strength for uranium recovery from natural seawater and industrial wastewater.