Rapid removal of nitrate from liquid dairy manure by cationic poly (vinyl alcohol-co-ethylene) nanofiber membrane

A label-free electrochemical immunosensor based on decorated cellulose nanofibrous membrane for point-of-care diagnosis of amanitin poisoning via human urine

α-Amanitin (AMN) is one of the deadliest toxins from mushrooms, present in the deadly mushroom species Amanita phalloides. It is a bicyclic octapeptide and represents up to 40% of the amatoxins in mushrooms, damaging the liver and kidneys. Current methods of detecting amatoxins are time-consuming and require the use of expensive equipment. A novel label-free electrochemical immunosensor was successfully developed for rapid detection of α-amanitin, which was fabricated by immobilization of anti-α-amanitin antibodies onto a functionalized cellulose nanofibrous membrane-modified carbon screen-printed electrode. An oxidation peak of the captured amanitin on the tethered antibodies was observed at 0.45 V. The performance of the nanofibrous membrane on the electrode and necessary fabrication steps were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Due to its unique structural features and properties such as high specific surface area and microporous structure, the nanofibrous membrane as an immunosensor matrix for antibody tethering improved the electrochemical performance of the immunosensor by more than 3 times compared with cast membranes. Under the optimal conditions, the assembled immunosensor exhibited high sensitivity toward α-amanitin detection in the range of 0.009-2 ng mL-1 with a limit of detection of 8.3 pg mL-1. The results clearly indicate that the fabricated nanofiber-based-immunosensor is suitable for point-of-care detection of lethal α-amanitin in human urine without any pretreatment within 30 min.

A comprehensive review on preparation, functionalization and recent applications of nanofiber membranes in wastewater treatment

The direct discharge of significant amounts of polluted water into water bodies causes adverse ecological and human health effects. This severe deterioration in water quality creates significant challenges to meet the growing demand for clean water. Therefore, the world urgently needs environmentally friendly advanced technology to overcome this global crisis. In this regard, nanofiber-based membrane filtration is a promising technique in wastewater remediation because of their huge surface area, extremely porous structure, amenable pore size/pore size distribution, variety of material choices, and flexibility to modification with other functional materials. However, despite their unique properties, fouling, poor mechanical properties, shrinkage, and deformation are major drawbacks of nanofiber membranes for treating wastewater. This review presents a comprehensive overview of nanofiber membranes' fabrication and function in water purification applications as well as providing novel approaches to overcoming/alleviating the mentioned disadvantages. The review first presents nanofiber membrane preparation methods, focusing on electrospinning as a versatile and viable technique alongside discussing the parameters controlling nanofiber morphology. Afterward, the functionalization of nanofiber membranes by combining them with other nanomaterials, such as metal and metal-oxide nanoparticles, carbon nanotubes, metal-organic frameworks, and biomolecules, were demonstrated and discussed. In addition, nanofiber membranes functionalized with microorganisms were highlighted. Finally, we introduced and discussed in detail the most relevant and recent advances in nanofiber applications in wastewater treatment in the context of removing different pollutants (e.g., heavy metals, nutrients, radioactive elements, pharmaceuticals, and personal care products, dyes, and pesticides). Moreover, the promising antimicrobial ability of nanofiber membranes in removing microorganisms from wastewater has been fully underscored. We believe this comprehensive review could provide researchers with preliminary data and guide both researchers and producers engaged in the nanofiber membrane industry, letting them focus on the research gaps in wastewater treatment.