Preparation of Hydrolyzed Electrospun Polyacrylonitrile Fiber Mats as Chelating Substrates: A Case Study on Copper(II) Ions

Abstract

Ultrafine polyacrylonitrile (PAN) fiber mats were prepared by electrospinning and subsequently hydrolytically treated with a sodium hydroxide ethanolic/aqueous solution to impart the ability to chelate metal ions. This was achieved through the conversion of the nitrile functional groups on the surface of the PAN fibers into imine conjugated sequences, which was confirmed by Fourier-transform infrared spectroscopy. The chelating property of the hydrolyzed electrospun PAN fiber mats (i.e., H-ePAN fiber mats) was evaluated against Cu(II) ions. The amounts of the Cu(II) ions adsorbed onto the H-ePAN fiber mats were influenced by the initial pH and the initial concentration of the metal ion solutions. At the optimal pH of 5.0, the amounts of the Cu(II) ions adsorbed onto the H-ePAN fiber mats increased with an initial increase in the time the materials were in contact with the metal ion solution to finally reach the maximal, plateau values after about 5 h of immersion. The maximal adsorption capacity of the H-ePAN fiber mats for the Cu(II) ions was determined to be 31.3 mg g À1 , and the fully adsorbed materials could be regenerated upon submersion in 0.1 M hydrochloric acid aqueous solution for 30 min. Finally, X-ray photoelectron spectroscopy indicated specific interactions between the adsorbed Cu(II) ions and the N-and/or the O-atoms associated with the imine groups on the surface of the H-ePAN fibers.

Poly(dimethylsiloxane) and Poly[vinyltrimethoxysilane-co-2-(dimethylamino) ethyl methacrylate] Based Cross-Linked Organic-Inorganic Hybrid Adsorbent for Copper(II) Removal from Aqueous Solutions

“…For example, a high concentration of copper in the human body can damage the liver and kidneys. 4,5 Therefore, it has become necessary to exploit practical techniques employed for efficiently removing copper from aqueous solutions.…”

Electrospun fibrous membranes for efficient heavy metal removal

“…Among the various fibrous materials, those made of PAN can be easily modified into chelating fibers owing to the presence of nitrile groups (CN) which can be readily converted to other chelating groups . For instance, nonwoven PAN nanofibrous membrane was first fabricated by electrospinning, followed by reaction with NaOH ethanolic/aqueous solution to introduce carboxylate groups that is capable of chelating metal ions . The chelating ability of functionalized PAN fibrous membrane was tested using Cu(II) ions as the model hazardous metal ions, with the adsorption of Cu(II) well fitted with Langmuir isotherm model and the maximum capacity being 31.3 mg/g.…”

Functionalization of polyacrylonitrile nanofiber mat via surface-initiated atom transfer radical polymerization for copper ions removal from aqueous solution

“…It was observed that amine-functionalized adsorbents present high adsorption capacity for Cu 2+ ions. However, this kind of adsorbents needs a long time (usually several hours) to reach the adsorption equilibrium [17][18][19][20][21]23]. Although the adsorption capacity of carboxylic acid-functionalized adsorbents was a little lower than amine groups-functionalized adsorbents, the adsorption rate was much fast.…”

“…Electrospun PAN nanofiber mats were most commonly used in the adsorption of heavy metal ions for its easy preparation and modification. Aminated electrospun PAN nanofiber mat was used as adsorbent for heavy metal ions [21][22][23]. Amino groups are highly active in the formation of strong complexes with metal ions because they contain nitrogen atoms.…”