Method of making activated carbon sorbent from seagrass for organic pollutant removal from water

Patent metadata

Field	Value
Publication number	US-11517876-B1
Application number	US-202217742089-A
Country	US
Kind code	B1
Filing date	May 11, 2022
Priority date	Dec 21, 2021
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A method of forming an activated carbon sorbent from a seagrass. The method involves treating a seagrass with a base solution to form an intermediate solid, drying the intermediate solid to form a precursor, and pyrolyzing the precursor at 600 to 1000° C. to form the activated carbon sorbent. Preferably the seagrass is Halodule uninervis. The activated carbon sorbent is used in a method of removing an organic pollutant from a contaminated water. Preferred organic pollutants removed are phenols, specifically 2,4-dimethylphenol and 2,4-dichlorophenol.

First claim

The invention claimed is:

1. A method of forming an activated carbon sorbent, the method comprising:
treating a seagrass with a base solution to form an intermediate solid;
drying the intermediate solid to form a precursor; and
pyrolyzing the precursor at 600 to 1000° C. to form the activated carbon sorbent, wherein the activated carbon sorbent has a mean surface area of 1000 to 1250 m 2 /g, and wherein the activated carbon sorbent comprises,
70 to 92.5 wt % carbon;
15 to 23 wt % oxygen;
1 to 5 wt % calcium;
1 to 5 wt % magnesium; and
0.1 to 0.9 wt % potassium, each based on a total weight of activated carbon sorbent.

2. The method of claim 1 , wherein the seagrass is a member of the family Cymodoceaceae.

3. The method of claim 1 , wherein the seagrass is a member of the genus Halodule.

4. The method of claim 1 , wherein the seagrass is Halodule uninervis.

5. The method of claim 1 , wherein the pyrolyzing is performed under an inert atmosphere for 1 to 12 hours.

6. The method of claim 1 , wherein the base solution is an aqueous solution of a hydroxide base.

7. The method of claim 6 , wherein the base solution is used in an amount of 5 to 20 mmol hydroxide base per gram of seagrass.

8. The method of claim 1 , wherein the activated carbon sorbent has a mean pore volume of 0.400 to 0.525 cc g −1 .

9. The method of claim 1 , wherein the activated carbon sorbent has a point of zero charge pH (pH zpc ) of 8 to 11.5.

10. The method of claim 1 , wherein the activated carbon sorbent comprises 16 to 21 wt % oxygen based on a total weight of activated carbon sorbent.

11. The method of claim 1 , wherein the activated carbon sorbent comprises 17 to 19 wt % oxygen based on a total weight of activated carbon sorbent.

12. The method of claim 1 , wherein the activated carbon sorbent comprises 17.5 to 18 wt % oxygen based on a total weight of activated carbon sorbent.

13. The method of claim 1 , wherein the activated carbon sorbent consists of:
81.5 to 92.5 wt % carbon;
15 to 23 wt % oxygen;
1 to 5 wt % calcium;
1 to 5 wt % magnesium; and
0.5 to 0.9 wt % potassium, each based on a total weight of activated carbon sorbent.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Nazal Mazen Khaled
• Abuzaid Nabeel Saeed

Classifications

• B01J20/3475

  in the liquid phase · CPC title

• B01J20/3441

  Regeneration or reactivation by electric current, ultrasound or irradiation, e.g. electromagnetic radiation such as X-rays, UV, light, microwaves · CPC title

• B01J20/3416

  of sorbents or filter aids comprising free carbon, e.g. activated carbon · CPC title

• B01J20/3078

  Thermal treatment, e.g. calcining or pyrolizing · CPC title

• B01J20/28073

  being in the range 0.5-1.0 ml/g · CPC title