Metal adsorption acrylic fiber, non-woven fabric, sheet-like product, and uses thereof as metal adsorbent

Patent metadata

Field	Value
Publication number	US-9802177-B2
Application number	US-201314374050-A
Country	US
Kind code	B2
Filing date	Jan 25, 2013
Priority date	Jan 27, 2012
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A metal adsorption acrylic fiber wherein the strontium adsorption rate is 85% or more when the strontium adsorption rate is measured using the following measurement method. A strontium adsorption rate measurement method (strontium 0.1 ppm measurement method) involves immersing a metal adsorption acrylic fiber into an immersion fluid, collecting the immersion fluid as a testing solution 24 hours after beginning the immersion, analyzing the quantity of strontium in the testing solution, obtaining the concentration (C 1 ) (ppm) of strontium in the testing solution, creating a contrast solution, analyzing the quantity of strontium in the contrast solution as in the case with the testing solution, obtaining the concentration (C 2 ) (ppm) of strontium in the contrast solution, and calculating the strontium adsorption rate of the metal adsorption acrylic fiber by using the following equation: strontium adsorption rate (%)={(C 2 −C 1 )/C 2 }×100.

First claim

The invention claimed is:

1. A metal adsorption acrylic fiber, wherein:
said fiber consists of an acrylonitrile-based copolymer comprising at least 85 mass % of a component unit derived from acrylonitrile and component units derived from vinyl acetate and sodium methallylsulfonate and 30-300 mass % of water relative to the mass of the acrylonitrile-based copolymer; and
said fiber has a BET specific surface area of 50 to 500 m 2 /g, a SAG value of 2 to 20, and a strontium adsorption rate of 85% or more;
wherein the SAG value represents an amount of acidic terminal groups in said copolymer and is determined by a measurement method comprising:
X g of the metal adsorption acrylic fiber is dissolved in 50 ml of dimethylformamide, and passed through an ion exchange resin to give a free acid after which neutralization titration is performed with A ml of a 0.01 N potassium hydroxide/methanol solution until pH 7 is reached;
separately, 50 ml of dimethylformamide which does not contain the metal adsorption acrylic fiber is taken as a blank and passed through the ion exchange resin after which neutralization titration is performed with B ml of a 0.01 N potassium hydroxide/methanol solution until pH 7 is reached; and
the SAG value is calculated using the following equation:
SAG value (equivalent g/g )=( A−B )/ X×f× 10 −5

where f=a titer of the 0.01 N potassium hydroxide/methanol solution;
and wherein the strontium adsorption rate is measured by a measurement method comprising:
adding 5 g of the metal adsorption acrylic fiber, which has been vacuum dried, to a 1000 mL capacity fluorine resin container, then adding 500 mL of an immersion liquid at 20° C. to the container to start immersion of the metal adsorption acrylic fiber, wherein the immersion liquid comprises an aqueous solution of strontium carbonate with a concentration of 0.1 ppm;
agitating the container for 24 hours after the start of immersion, while maintaining a temperature of the immersion liquid at 20° C., and then collecting the immersion liquid as a test liquid;
introducing the test liquid into an inductively-coupled plasma mass spectrometer, and quantitatively measuring a concentration of strontium C 1 (ppm) in the test liquid; and
adding 500 mL of the immersion liquid at 20° C., without the metal adsorption acrylic fiber, to another container to give a reference liquid, and quantitatively measuring a concentration of strontium C 2 (ppm) in the reference liquid;
wherein the strontium adsorption rate of the metal adsorption acrylic fiber is given by:
strontium adsorption rate (%)={(C 2 −C 1 )/C 2 }×100.

2. The metal adsorption acrylic fiber according to claim 1 , wherein said fiber has a cesium adsorption rate that is 70% or more, wherein the cesium adsorption rate is measured by a measurement method comprising:
adding 5 g of the metal adsorption acrylic fiber, which has been vacuum dried, to a 1000 mL capacity fluorine resin container, then adding 500 mL of an immersion liquid at 20° C. to the container to start immersion of the metal adsorption acrylic fiber, wherein the immersion liquid comprises an aqueous solution of cesium chloride with a concentration of 0.1 ppm;
agitating the container for 24 hours after the start of immersion, while maintaining a temperature of the immersion liquid at 20° C., and then collecting the immersion liquid as a test liquid;
introducing the test liquid into an inductively-coupled plasma mass spectrometer, and quantitatively measuring a concentration of cesium C 3 (ppm) in the test liquid; and
adding 500 mL of the immersion liquid at 20° C., without the metal adsorption acrylic fiber, to another container to give a reference liquid, and quantitatively measuring a concentration of cesium C 4 (ppm) in the reference liquid;
wherein the cesium adsorption rate of the metal adsorption acrylic fiber is given by:
cesium adsorption rate (%)={(C 4 −C 3 )/C 4 }×100.

3. The metal adsorption acrylic fiber according to claim 1 , wherein said fiber has a cerium adsorption rate that is 85% or more, wherein the cerium adsorption rate is measured by a measurement method comprising:
adding 5 g of the metal adsorption acrylic fiber, which has been vacuum dried, to a 1000 mL capacity fluorine resin container, then adding 500 mL of an immersion liquid at 20° C. to the container to start immersion of the metal adsorption acrylic fiber, wherein the immersion liquid comprises an aqueous solution of cerium chloride (III) heptahydrate with a concentration of 0.1 ppm;
agitating the container for 24 hours after the start of immersion, while maintaining a temperature of the immersion liquid at 20° C., and then collecting the immersion liquid as a test liquid;
introducing the test liquid into an inductively-coupled plasma mass spectrometer, and quantitatively measuring a concentration of cerium C 5 (ppm) in the test liquid; and
adding 500 mL of the immersion liquid at 20° C., without the metal adsorption acrylic fiber, to another container to give a reference liquid, and quantitatively measuring a concentration of cerium C 6 (ppm) in the reference liquid;
wherein the cerium adsorption rate of the metal adsorption acrylic fiber is given by:
cerium adsorption rate (%)={(C 6 −C 5 )/C 6 }×100.

4. The metal adsorption acrylic fiber according to claim 1 , wherein the fiber has a second strontium adsorption rate that is 70% or more, wherein the second strontium adsorption rate is measured by a measurement method comprising:
adding 5 g of the metal adsorption acrylic fiber, which has been vacuum dried, to a 1000 mL capacity fluorine resin container, then adding 500 mL of an immersion liquid at 20° C. to the container to start immersion of the metal adsorption acrylic fiber, wherein the immersion liquid comprises an aqueous solution of strontium carbonate with a concentration of 1.0 ppm;
agitating the container for 24 hours after the start of immersion, while maintaining a temperature of the immersion liquid at 20° C., and then collecting the immersion liquid as a test liquid;
introducing the test liquid into an inductively-coupled plasma mass spectrometer, and quantitatively measuring a concentration of strontium C 7 (ppm) in the test liquid; and
adding 500 mL of the immersion liquid at 20° C., without the metal adsorption acrylic fiber, to another container to give a reference liquid, and quantitatively measuring a concentration of strontium C 8 (ppm) in the reference liquid;
wherein the second strontium adsorption rate of the metal adsorption acrylic fiber is given by:
second strontium adsorption rate (%)={(C 8 −C 7 )/C 8 }×100.

5. The metal adsorption acrylic fiber according to claim 1 , wherein said fiber has a second cesium adsorption rate that is 70% or more, wherein the second cesium adsorption rate is measured by a measurement method comprising:
adding 5 g of the metal adsorption acrylic fiber, which has been vacuum dried, to a 1000 mL capacity fluorine resin container, then adding 500 mL of an immersion liquid at 20°C. to the container to start immersion of the metal adsorption acrylic fiber, wherein the immersion liquid comprises an aqueous solution of cesium chloride with a concentration of 1.0 ppm;
agitating the container for 24 hours after the start of immersion, while maintaining a temperature of the immersion liquid at 20° C., and then collecting the immersion liquid as a test liquid;
introducing the test liquid into an inductively-coupled plasma mass spectrometer, and quantitatively measuring a concentration of cesium C 9 (ppm) in the test liquid; and
adding 500 mL of the immersion liquid at 20° C., without the metal adsorption acrylic fiber, to another container to give a reference liquid, and quantitatively measuring a concentration of cesium C 10 (ppm) in the reference

Assignees

• Mitsubishi Chem Corp

Inventors

• Onohara Yukio
• Inagaki Tatsuhiko
• Fujii Yasuyuki
• Ootsubo Masahiro
• Kobayashi Hideaki

Classifications

• D04H1/43

  Acrylonitrile series · CPC title

• D01F6/18

  from polymers of unsaturated nitriles, e.g. polyacrylonitrile, polyvinylidene cyanide · CPC title

• B01J20/28061

  being in the range 100-500 m2/g · CPC title

• B01J20/28059

  being less than 100 m2/g · CPC title

• B01J20/28023

  Fibres or filaments (fibres or filaments in the form of membranes B01J20/28038; B01J20/28007 takes precedence) · CPC title