Particulate crystalline nanocomposite and adsorbent

Patent metadata

Field	Value
Publication number	US-12486180-B1
Application number	US-202519250482-A
Country	US
Kind code	B1
Filing date	Jun 26, 2025
Priority date	Jun 26, 2025
Publication date	Dec 2, 2025
Grant date	Dec 2, 2025

Abstract

A method of immobilizing contaminants disposed in an aqueous medium, the method including contacting the aqueous medium with a CaHPO 4 /Ca 6 Si 6 O 17 (OH) 2 /g-C 3 N 4 particulate crystalline nanocomposite for a sufficient contact time to permit adsorption of the contaminants. The particulate crystalline nanocomposite includes: a calcium hydrogen phosphate (CaHPO 4 ) crystalline phase; a calcium silicate hydroxide (Ca 6 Si 6 O 17 (OH) 2 ) crystalline phase; a silicon dioxide (SiO 2 ) crystalline phase; and, a graphitic carbon nitride (g-C 3 N 4 ) crystalline phase, wherein at least a fraction of the g-C 3 N 4 is in the form of mesoporous nanosheets.

First claim

The invention claimed is:

1 . A method of immobilizing contaminants disposed in an aqueous medium, the method comprising contacting the aqueous medium with a particulate crystalline nanocomposite for a sufficient contact time to permit adsorption of the contaminants, the particulate crystalline nanocomposite comprising:
a calcium hydrogen phosphate (CaHPO 4 ) crystalline phase; a calcium silicate hydroxide (Ca 6 Si 6 O 17 (OH) 2 ) crystalline phase; a silicon dioxide (SiO 2 ) crystalline phase; and, a graphitic carbon nitride (g-C 3 N 4 ) crystalline phase,
wherein at least a fraction of the graphitic-C 3 N 4 is in the form of mesoporous nanosheets.

2 . The method according to claim 1 , wherein the contaminants comprise organic contaminants selected from the group consisting of: a polyaromatic hydrocarbon, a halogenated polyaromatic hydrocarbon; a phenol, a halogenated phenol; a furan, a halogenated furan; a dioxine, a halogenated dioxine; a biphenyl, a halogenated phenyl; and, an organic dye.

3 . The method according to claim 1 , wherein the contaminants comprise inorganic contaminants selected from the group consisting of: a radioactive nuclide; a heavy metal; and, a metalloid.

4 . The method according to claim 1 , wherein based on the weight of the particulate crystalline nanocomposite:
CaHPO 4 is present in an total amount of from about 20 to about 40 weight percent (wt. %); Ca 6 Si 6 O 17 (OH) 2 is present in an amount of about 20 to about 30 wt. %; SiO 2 is present in an amount of from about 1 to about 10 wt. %; and, g-C 3 N 4 is present in an amount of about 20 to about 30 wt. %.

5 . The method according to claim 1 , wherein the particulate crystalline nanocomposite comprises acicular particles of Ca 6 Si 6 O 17 (OH) 2 having a median length of from about 20 to about 80 nanometers (nm), as determined by Transmission Electron Microscopy.

6 . The method according to claim 1 , wherein the particulate crystalline nanocomposite comprises aggregates of the mesoporous nanosheets of g-C 3 N 4 with substantially spherical particles of SiO 2 and CaHPO 4 .

7 . The method according to claim 1 , wherein the particulate crystalline nanocomposite comprises aggregates of:
the mesoporous nanosheets of g-C 3 N 4 ; and, substantially spherical particles of SiO 2 and CaHPO 4 having a median particle size of from about 5 to about 30 nm, as determined by Transmission Electron Microscopy.

8 . The method according to claim 1 , wherein at least about 50 wt. % of the g-C 3 N 4 is in the form of mesoporous nanosheets.

9 . The method according to claim 1 , wherein at least about 80 wt. % of the g-C 3 N 4 is in the form of mesoporous nanosheets.

10 . The method according to claim 1 , wherein the particulate crystalline nanocomposite has an average pore diameter of from about 10 to about 25 nm, as determined by Barrett-Joyner-Halenda (BJH) desorption analysis.

11 . The method according to claim 1 , wherein the particulate crystalline nanocomposite has an average pore diameter of from about 15 to about 25 nm, as determined by BJH desorption analysis.

12 . The method according to claim 1 , wherein the particulate crystalline nanocomposite has a pore volume of from about 0.1 to about 0.4 cm 3 /g, as determined by BJH desorption analysis.

13 . The method according to claim 1 , wherein the particulate crystalline nanocomposite has a pore volume of from about 0.2 to about 0.3 cm 3 /g, as determined by BJH desorption analysis.

14 . The method according to claim 1 , wherein the particulate crystalline nanocomposite has a hysteresis loop of Type H3 (IUPAC Classification), as determined by nitrogen (N 2 ) adsorption-desorption analysis at 77 kelvin (K).

15 . The method according to claim 1 further comprising preparing the particulate crystalline nanocomposite by:
forming a solution of a calcium salt and an alkali metal silicate in a solvent comprising water and a C 1 -C 4 alkanol;
heating the solution at a temperature of from about 150 to about 250 degrees Celsius (° C.) to form a dry product of CaSiO 3 ;
forming g-C 3 N 4 by heating urea in a closed vessel at a temperature of from about 500 to about 700° C.;
dispersing the CaSiO 3 , graphitic-C 3 N 4 , and P 2 O 5 in a polar protic solvent and heating the dispersion at a temperature of from about 150 to about 250° C. at a pressure of from about 2 to about 8 Bar; and,
separating the particulate crystalline nanocomposite from the heated dispersion.

16 . The method according to claim 1 , wherein the contact time of the aqueous medium with the particulate crystalline nanocomposite is from about 1 to about 120 minutes (min).

17 . The method according to claim 1 , wherein the contact time of the aqueous medium with the particulate crystalline nanocomposite is from about 5 to about 30 min.

18 . The method according to claim 1 , wherein a fixed volume of the aqueous medium is provided in which the particulate crystalline nanocomposite is dispersed.

19 . The method according to claim 1 , wherein a flow of the aqueous medium contacts a membrane in which the particulate crystalline nanocomposite is disposed.

20 . The method according to claim 1 , wherein the particulate crystalline nanocomposite is provided in an amount of from about 0.1 to about 5 grams per liter (g/L) of the aqueous medium.

Assignees

• Imam Mohammad Ibn Saud Islamic Univ

Inventors

• Abdulkhair Babiker Yagoub Elhadi
• Omran Mohamed Khairy Abdel Fattah

Classifications

• B01J20/28007

  with size in the range 1-100 nanometers, e.g. nanosized particles, nanofibers, nanotubes, nanowires or the like (carbon nanostructures B01J20/205) · CPC title

• C02F2101/006

  Radioactive compounds · CPC title

• C02F2103/003

  Wastewater from hospitals, laboratories and the like, heavily contaminated by pathogenic microorganisms · CPC title

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title

• C02F2305/08

  Nanoparticles or nanotubes · CPC title