Electrospun nanofibers for efficient adsorption of heavy metals from water and wastewater

Abstract

<abstract> <p>Heavy metals (HMs) are persistent and toxic environmental pollutants that pose critical risks toward human health and environmental safety. Their efficient elimination from water and wastewater is essential to protect public health, ensure environmental safety, and enhance sustainability. In the recent decade, nanomaterials have been developed extensively for rapid and effective removal of HMs from water and wastewater and to address the certain economical and operational challenges associated with conventional treatment practices, including chemical precipitation, ion exchange, adsorption, and membrane separation. However, the complicated and expensive manufacturing process of nanoparticles and nanotubes, their reduced adsorption capacity due to the aggregation, and challenging recovery from aqueous solutions limited their widespread applications for HM removal practices. Thus, the nanofibers have emerged as promising adsorbents due to their flexible and facile production process, large surface area, and simple recovery. A growing number of chemical modification methods have been devised to promote the nanofibers' adsorption capacity and stability within the aqueous systems. This paper briefly discusses the challenges regarding the effective and economical application of conventional treatment practices for HM removal. It also identifies the practical challenges for widespread applications of nanomaterials such as nanoparticles and nanotubes as HMs adsorbents. This paper focuses on nanofibers as promising HMs adsorbents and reviews the most recent advances in terms of chemical grafting of nanofibers, using the polymers blend, and producing the composite nanofibers to create highly effective and stable HMs adsorbent materials. Furthermore, the parameters that influence the HM removal by electrospun nanofibers and the reusability of adsorbent nanofibers were discussed. Future research needs to address the gap between laboratory investigations and commercial applications of adsorbent nanofibers for water and wastewater treatment practices are also presented.</p> </abstract>

Removal of Ionic Dyes by Nanofiber Membrane Functionalized with Chitosan and Egg White Proteins: Membrane Preparation and Adsorption Efficiency

“…Furthermore, the nanofibers' limited mechanical stability and reusability hinder their capability to be used in the large-scale water and wastewater treatment. Hence, there is a need for developing advanced technological solutions to improve the physical and chemical performances of nanofibers [53][54][55]. The suggestions for future works are as follows: (1) Further improvement of the stability, mechanical strength, and reusability of nanofiber membranes by means such as adjustment of the compositions of polymer solutions or water-insoluble polymer solutions; (2) Design and application of nanofiber membrane reactor in dynamic adsorption membrane chromatography.…”

Sustainable Applications of Nanofibers in Agriculture and Water Treatment: A Review

“…Thus, there is a great need for researchers to develop effective technology in wastewater purification [35]. The main strategies in wastewater treatment may include filtration, adsorption, catalysis, centrifugation, biological treatment, and electro-coalescence [87]. More than 200 natural and synthetic polymers were successfully electrospun into nanofiber membranes, such as polyimide (PI), polyacrylonitrile (PAN), poly/vinyl alcohol (PVA), poly/vinylidene-fluoride (PVDF), polylactic acid (PLA), cellulose acetate (CA), polyurethane (PU), polyethylene oxide (PEO), and polycaprolactone (PCL) [35].…”

Colloidal Stabilization of Submicron-Sized Zeolite NaA in Ethanol–Water Mixtures for Nanostructuring into Thin Films and Nanofibers

“…Finally, electrospinning is an advanced shaping technique, which has been used to structure microporous framework materials either into 1D fiber structures or their more complex 3D variations for a broad range of applications, such as biomedical applications, air filtration, catalytic applications, water treatment and gas separation processes. − As an example, in gas adsorption processes hierarchical porous zeolite nanofiber structures can reduce pressure drop and improve the diffusion of molecules. , However, the zeolite particles are usually embedded in the nanofiber polymer matrix after electrospinning. It has been shown that the coverage of the zeolite surfaces with the polymer often leads to a significantly reduced surface area and accessible pore volume, resulting in significantly lower gas uptake.…”