Polypropylene nanofiber sheets prepared by CO2 laser supersonic multi-drawing

TiO2–Based Nanofibrous Membranes for Environmental Protection

Electrospinning is a unique technique that can be used to synthesize polymer and metal oxide nanofibers. In materials science, a very active field is represented by research on electrospun nanofibers. Fibrous membranes present fascinating features, such as a large surface area to volume ratio, excellent mechanical behavior, and a large surface area, which have many applications. Numerous techniques are available for the nanofiber’s synthesis, but electrospinning is presented as a simple process that allows one to obtain porous membranes containing smooth non-woven nanofibers. Titanium dioxide (TiO2) is the most widely used catalyst in photocatalytic degradation processes, it has advantages such as good photocatalytic activity, excellent chemical stability, low cost and non-toxicity. Thus, titanium dioxide (TiO2) is used in the synthesis of nanofibrous membranes that benefit experimental research by easy recyclability, excellent photocatalytic activity, high specific surface areas, and exhibiting stable hierarchical nanostructures. This article presents the synthesis of fiber membranes through the processes of electrospinning, coaxial electrospinning, electrospinning and electrospraying or electrospinning and precipitation. In addition to the synthesis of membranes, the recent progress of researchers emphasizing the efficiency of nanofiber photocatalytic membranes in removing pollutants from wastewater is also presented.

Nanofiber Systems as Herbal Bioactive Compounds Carriers: Current Applications in Healthcare

Nanofibers have emerged as a potential novel platform due to their physicochemical properties for healthcare applications. Nanofibers’ advantages rely on their high specific surface-area-to-volume and highly porous mesh. Their peculiar assembly allows cell accommodation, nutrient infiltration, gas exchange, waste excretion, high drug release rate, and stable structure. This review provided comprehensive information on the design and development of natural-based polymer nanofibers with the incorporation of herbal medicines for the treatment of common diseases and their in vivo studies. Natural and synthetic polymers have been widely used for the fabrication of nanofibers capable of mimicking extracellular matrix structure. Among them, natural polymers are preferred because of their biocompatibility, biodegradability, and similarity with extracellular matrix proteins. Herbal bioactive compounds from natural extracts have raised special interest due to their prominent beneficial properties in healthcare. Nanofiber properties allow these systems to serve as bioactive compound carriers to generate functional matrices with antimicrobial, anti-inflammatory, antioxidant, antiseptic, anti-viral, and other properties which have been studied in vitro and in vivo, mostly to prove their wound healing capacity and anti-inflammation properties.

Multifunctional Membranes-A Versatile Approach for Emerging Pollutants Removal

This paper presents a comprehensive literature review surveying the most important polymer materials used for electrospinning processes and applied as membranes for the removal of emerging pollutants. Two types of processes integrate these membrane types: separation processes, where electrospun polymers act as a support for thin film composites (TFC), and adsorption as single or coupled processes (photo-catalysis, advanced oxidation, electrochemical), where a functionalization step is essential for the electrospun polymer to improve its properties. Emerging pollutants (EPs) released in the environment can be efficiently removed from water systems using electrospun membranes. The relevant results regarding removal efficiency, adsorption capacity, and the size and porosity of the membranes and fibers used for different EPs are described in detail.

Electrospun Nanofiber Mats for Filtering Applications-Technology, Structure and Materials

Air pollution is one of the biggest health and environmental problems in the world and a huge threat to human health on a global scale. Due to the great impact of respiratory viral infections, chronic obstructive pulmonary disease, lung cancer, asthma, bronchitis, emphysema, lung disease, and heart disease, respiratory allergies are increasing significantly every year. Because of the special properties of electrospun nanofiber mats, e.g., large surface-to-volume ratio and low basis weight, uniform size, and nanoporous structure, nanofiber mats are the preferred choice for use in large-scale air filtration applications. In this review, we summarize the significant studies on electrospun nanofiber mats for filtration applications, present the electrospinning technology, show the structure and mechanism of air filtration. In addition, an overview of current air filtration materials derived from bio- and synthetic polymers and blends is provided. Apart from this, the use of biopolymers in filtration applications is still relatively new and this field is still under-researched. The application areas of air filtration materials are discussed here and future prospects are summarized in conclusion. In order to develop new effective filtration materials, it is necessary to understand the interaction between technology, materials, and filtration mechanisms, and this study was intended to contribute to this effort.

Flexible and transparent composite nanofibre membrane that was fabricated via a "green" electrospinning method for efficient particulate matter 2.5 capture

Air particulate pollution from ever-increasing industrialization poses an enormous threat to public health. Thus, the development of a green air filter with high efficiency and performance is of urgent necessity. In this study, we introduce a new effective air filtration membrane that can be used for outdoor protection. The air filter's composite nanofibre materials were prepared from polyvinyl alcohol (PVA)-sodium lignosulfonate (LS) via a "green" electrospinning method and thermal crosslinking. The addition of LS helped increase the PM_2.5 removal efficiency compared to that of a pure PVA nanofibre membrane. The pressure drops of the electrospun PVA-LS membranes exceeded those of the pristine PVA air filter. The remarkable air filtration performance was maintained even after 10 cycles of circulation filtration. In addition, the PVA-LS composite nanofibre membrane exhibited excellent mechanical properties and transparency due to the introduction of LS. This study provides new insight into the design and development of high-performance and high-visibility green filter media, which include personal protection and building screens.

Polyethylene Terephthalate Nanofiber Sheet as the Novel Extraction Medium for the Determination of Phthalates in Water Samples

A novel extraction medium was developed by packing polyethylene terephthalate (PET) nanofiber sheet having a diameter of 500 nm into a stainless-steel capillary of 0.8 mm inner diameter. The nanofiber was prepared by a carbon dioxide (CO₂) laser supersonic multi-drawing method, which has a significantly higher surface area than the original PET fiber. A nanofiber sheet was prepared by winding the nanofibers. Extraction of phthalates in water samples by a PET nanofiber-packed extraction capillary was investigated using a conventional high-performance liquid chromatography (HPLC). Water samples were introduced into the extraction capillary with a low pressure. After extracting the water sample, the extraction capillary was directly connected to a six-port valve of HPLC with a PEEK nut, and the extracted analytes were desorbed, followed by injection to an HPLC system using a small amount of organic solvent. In this manuscript, the fundamental performance of the nanofiber sheet-packed extraction capillary for the extraction of organic compounds in water samples is quantitatively evaluated using a conventional HPLC system.