Synthesis of micron and nanoscale carbon spheres and structures using hydrothemal carbonization

Patent metadata

Field	Value
Publication number	US-2021107796-A1
Application number	US-201916970265-A
Country	US
Kind code	A1
Filing date	Feb 15, 2019
Priority date	Feb 15, 2018
Publication date	Apr 15, 2021
Grant date	—

Abstract

Provided are methods for preparing carbon powders and activated carbon powders from cellulose-containing liquids. In some embodiments, the methods include exposing a cellulose-containing liquid to a hydrothermal carbonization process to convert the carbonaceous material present therein into a carbon powder. Also provided are methods for activating carbon powders, methods for producing carbon powder-containing polymer matrices, and carbon powders, activated carbon powders, and polymer matrices that that include the disclosed carbon powders and/or activated carbon powders that are produced by the presently disclosed methods.

First claim

What is claimed is:

1 . A method for preparing a carbon powder from a cellulose-containing liquid, the method comprising exposing the cellulose-containing liquid to a hydrothermal carbonization process to convert carbonaceous material present therein into a carbon powder.

2 . The method of claim 1 , wherein the cellulose-containing liquid comprises about 5% micro- and/or nanofibrillated cellulose by weight in water or wherein the cellulose-containing liquid comprises agricultural waste residue.

3 . The method of claim 2 , wherein agricultural waste residue has been refined.

4 . The method of claim 1 , wherein the cellulose present in the cellulose-containing liquid comprises cellulose nanocrystals (CNCs), optionally wherein the CNCs have been generated from plant cellulose pulp by acid hydrolysis.

5 . The method of any of the previous claims, wherein the hydrothermal carbonization process is performed under conditions sufficient to carbonize at least 60%, at least 65%, at least 70% but less than 95%, less than 90%, less than 85%, less than 80%, or less than 75% of the carbonaceous material present in the cellulose-containing liquid.

6 . The method of any of the previous claims, wherein hydrothermal carbonization process comprises exposing the cellulose-containing liquid to the hydrothermal carbonization process at temperatures from about 170° C. to 350° C.

7 . The method of any of the previous claims, wherein the cellulose-containing liquid is subjected to a hydrothermal carbonization at temperatures in the range from about 180° C. to about 250° C., optionally 250° C. or optionally 225° C.

8 . The method of any of the previous claims, wherein the hydrothermal carbonization process comprises exposing the cellulose-containing liquid to the hydrothermal carbonization process in a closed reactor at a temperature of about 250° C. for about 25 minutes before allowing the processed material to cool to room temperature.

9 . The method of any of the previous claims, wherein performing the hydrothermal carbonization process in the closed reactor results in an autogenous pressure of about 10 to about 50 bars within the closed reactor.

10 . The process of any of the previous claims, wherein the carbon powder has an average grain size of about 100 nm or less, about 250 nm or less, about 500 nm or less, about 750 nm or less, about 1000 nm or less, about 1.25 μm or less, about 1.5 m or less, about 2.0 μm or less, or about 5.0 μm or less.

11 . The method of any of the previous claims, wherein the carbon powder is appropriate for use in a metal-carbon composite, an activated carbon such as but not limited to for CO 2 capture, an active surface, a structural composite, an absorbent, in an electronics application, and/or for energy storage.

12 . The method of any of the previous claims, wherein the hydrothermal carbonization process is a batch hydrothermal carbonization process.

13 . The method of any of the previous claims, wherein the hydrothermal carbonization process is a continuous hydrothermal carbonization process.

14 . The method of any of the previous claims, further comprising separating the carbon powder from liquid containing the carbon powder after the hydrothermal carbonization process is performed.

15 . The method of claim 14 , wherein the liquid containing the carbon powder comprises one or more chemicals of interest such as but not limited to furfurals and small organic acids after the hydrothermal carbonization process is performed.

16 . The method of claim 15 , further comprising isolating at least one of the one or more chemicals of interest from the liquid after the hydrothermal carbonization process is performed.

17 . A carbon powder produced by the method of any one of claims 1 - 14 .

18 . A method for producing a carbon powder-containing polymer matrix, the method comprising adding the carbon powder of claim 17 to a polymer matrix.

19 . The method of claim 18 , wherein the polymer matrix is selected from the group consisting of a polysiloxane, a polysulfonate, a poly(caprolactone), a styrene, a butyl acrylate latex, a poly(oxyethylene), a poly(styrene-co-butyl acrylate) (poly(S-co-BuA)), a cellulose acetatebutyrate, a carboxymethyl cellulose, a poly(vinyl alcohol), a poly(vinyl acetate), a poly(ethylene-vinyl acetate)(EVA), an epoxide, a polyethylene, a polypropylene, or any combination thereof.

20 . A method for producing an activated carbon powder, the method comprising exposing the carbon powder of claim 17 to an activation process, optionally wherein the activation process is selected from the group consisting of exposure to steam at a temperature of at least 800° C. and chemical activation, optionally chemical activation with phosphoric acid and zinc trichloride treated with sodium hydroxide.

21 . A composition comprising a carbon powder derived from nanofibrillated cellulose (NFC) and/or microfibrillated cellulose (MFC) or derived from agricultural waste residue, wherein the carbon powder comprises, consists essentially of, or consists of substantially spherical carbonized species with an average diameter of less than about 5 μm and/or aggregates thereof, and further wherein:
(i) the carbon content of the carbon powder is at least about 60% by weight of the carbon powder;
(ii) the hydrogen content of the carbon powder is about 4% to about 6% by weight of the carbon powder, and
(iii) the nitrogen content of the carbon powder is less than about 0.05% by weight of the carbon powder, optionally less than 0.02% by weight of the carbon powder.

22 . The composition of claim 21 , wherein the carbon content of the carbon powder is selected from the group consisting of about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, and about 95% by weight of the carbon powder.

23 . The composition of any one of claims 21 and 22 , wherein the carbon content of the carbon powder is within a range selected from the group consisting of about 60% to about 95% by weight of the carbon powder, about 60% to about 85% by weight of the carbon powder, about 65% to about 85% by weight of the carbon powder, and about 65% to about 70% by weight of the carbon powder.

24 . An activated carbon product comprising an activated form of the carbon powder present in the composition of any one of claims 21 - 23 .

25 . A method for preparing a carbon powder from a cellulose-containing liquid, the method comprising exposing the cellulose-containing liquid to a hydrothermal carbonization process to convert carbonaceous material present therein into a carbon powder; and exposing the carbon powder to an activation process, optionally wherein the activation process is selected from the group consisting of exposure to steam at a temperature of at least 800° C. and chemical activation, optionally chemical activation with phosphoric acid and zinc trichloride treated with sodium hydroxide.

26 . The method of claim 25 , wherein the cellulose-containing liquid comprises about 5% micro- and/or nanofibrillated cellulose by weight in water or wherein the cellulose-containing liquid comprises agricultural waste residue.

27 . The method of claim 26 , wherein agricultural waste residue has been refined.

28 . The method of claim 25 , wherein the cellulose present in the cellulose-containing liquid comprises cellulose nanocrystals (CNCs), optionally whe

Assignees

• Univ North Carolina State

Inventors

• Hakovirta Marko
• Saloni Daniel
• Venditti Richard

Classifications

• C01B32/336

  characterised by gaseous activating agents · CPC title

• C01B32/05

  Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30 · CPC title

• C01B32/342

  characterised by non-gaseous activating agents · CPC title

• C09C1/48

  Carbon black · CPC title

• C09C1/44

  Carbon · CPC title