Nanofibrous materials for heavy metal adsorption

Patent metadata

Field	Value
Publication number	US-2016263554-A1
Application number	US-201615065972-A
Country	US
Kind code	A1
Filing date	Mar 10, 2016
Priority date	Mar 10, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

Water filtration membranes are provided. Such membranes include polysaccharide fibers that have been modified to possess thiol groups thereon, resulting in materials that effectively bind heavy metal ions. The resulting fibers may be used by themselves or applied to a scaffold to form a membrane suitable for removing heavy metals from water, including groundwater.

First claim

What is claimed is:

1 . A membrane comprising:
ultra-fine polysaccharide nanofibers functionalized with at least one thiol group, the nanofibers having a diameter from about 3 nm to about 50 nm and a length from about 100 nm to about 5000 nm.

2 . The membrane of claim 1 , wherein the ultra-fine polysaccharide nanofibers include a polysaccharide selected from the group consisting of cellulose, chitin, collagen, gelatin, chitosan, microcrystalline cellulose, bacterial cellulose, starch, alginic acid, and combinations thereof.

3 . The membrane of claim 1 , further comprising a nanofibrous scaffold layer.

4 . The membrane of claim 3 , wherein the scaffold layer comprises nanofibers having diameters from about 50 nm to about 500 nm.

5 . The membrane of claim 3 , wherein the scaffold layer possesses pores with average pore sizes from about 10 nm to about 200 μm.

6 . The membrane of claim 3 , wherein the scaffold layer comprises nanofibers selected from the group consisting of polyolefins, polysulfones, polyethersulfones, fluoropolymers, poly(vinylidene fluoride)s, polyesters, polyamides, polycarbonates, polystyrenes, polyacrylonitriles, poly(meth)acrylates, poly(vinyl acetate)s, poly(vinyl alcohol)s, polysaccharides, cellulose, chitosan, chitin, hyaluronic acid, proteins, poly(alkylene oxides), polyurethanes, polyureas, poly(vinyl chlorides), polyimines, poly(vinylpyrrolidones), poly(acrylic acid)s, poly(methacrylic acid)s, polysiloxanes, poly (ester-co-glycol) polymers, poly(ether-co-amide) polymers, cross-linked forms thereof, derivatives thereof, and copolymers thereof.

7 . The membrane of claim 3 , wherein the scaffold layer has a thickness of from about 10 μm to about 300 μm.

8 . The membrane of claim 1 , further comprising a substrate layer comprising non-woven fibers of a material selected from the group consisting of poly(ethylene terephthalate), polypropylene, glass and cellulose, the scaffold layer being on at least a portion of the substrate layer.

9 . A method comprising:
passing a fluid through a membrane of claim 1 ; and recovering the fluid that has passed through the membrane.

10 . A method comprising:
contacting ultra-fine polysaccharide nanofibers with an oxidation agent, an optional acid, and an optional base, to form an activated polysaccharide nanofiber possessing functional groups selected from the group consisting of carboxylates, aldehydes, amines, and combinations thereof; contacting the activated polysaccharide nanofiber with at least one reactant selected from the group consisting of cysteine, cystamine, 3-amino-1-propanethiol, 6-amino-1-hexanethiol, 8-amino-1-octanethiol, 11-amino-1-undecanethiol, 16-amino-1-hexadecanethiol. 3-mercaptopropionic acid, 6-mercaptohexanoic acid, 8-mercaptooctanoic acid, 11-mercaptoundecanoic acid, 12-mercaptododecanoic acid, 16-mercaptohexadecanoic acid, and combinations thereof to form thiol-functional polysaccharide nanofibers; and recovering the thiol-functional polysaccharide nanofibers possessing thiol groups.

11 . The method of claim 10 , further comprising contacting the ultra-fine polysaccharide nanofibers, the at least one reactant, or both, with a catalyst.

12 . The method of claim 11 , wherein the catalyst is selected from the group consisting of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and combinations thereof.

13 . The method of claim 10 , wherein the ultra-fine polysaccharide nanofibers include a polysaccharide selected from the group consisting of cellulose, chitin, collagen, gelatin, chitosan, microcrystalline cellulose, bacterial cellulose, starch, alginic acid, and combinations thereof.

14 . The method of claim 10 , wherein the oxidation agent is selected from the group consisting of sodium hypochlorite, sodium chlorite, concentrated nitric acid/sodium nitrite, and combinations thereof.

15 . The method of claim 10 , wherein the optional acid is selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, trifluoroacetic acid, formic acid, and combinations thereof.

16 . The method of claim 10 , wherein the optional base is selected from the group consisting of sodium hydroxide, lithium hydroxide, potassium hydroxide, and combinations thereof.

17 . The method of claim 10 , further comprising forming a membrane with the thiol-functional polysaccharide nanofibers.

18 . The method of claim 17 , further comprising contacting a nanofibrous scaffold layer with a solution possessing the thiol-functional polysaccharide nanofibers.

19 . The method of claim 18 , wherein the scaffold layer comprises nanofibers having diameters from about 50 nm to about 500 nm.

20 . The method of claim 18 , wherein the scaffold layer possesses pores with average pore sizes from about 10 nm to about 200 μm.

21 . The method of claim 18 , wherein the scaffold layer has a thickness of from about 10 μm to about 300 μm.

22 . The method of claim 18 , further comprising applying the nanofibrous scaffold to a substrate layer comprising non-woven fibers of a material selected from the group consisting of poly(ethylene terephthalate), polypropylene, glass and cellulose.

Assignees

• Univ New York State Res Found

Inventors

• Grubbs Robert B
• Hsiao Benjamin S
• Chu Benjamin
• Yang Rui

Classifications

• B01D2325/12

  Adsorbents being present on the surface of the membranes or in the pores · CPC title

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title

• B01J20/28038

  Membranes or mats made from fibers or filaments · CPC title

• C02F1/444

  by ultrafiltration or microfiltration · CPC title

• B01J20/265 Primary

  modified or post-treated polymers (polymer carriers or substrates subjected to further impregnating or coating B01J20/3208) · CPC title