Carbon-modified titanium dioxide nanoparticles and the photocatalytic remediation of aqueous sources systems and methods thereof

Patent metadata

Field	Value
Publication number	US-10471289-B2
Application number	US-201715729904-A
Country	US
Kind code	B2
Filing date	Oct 11, 2017
Priority date	Jan 4, 2017
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

A closed-loop system and methods for the remediation of an aqueous solution comprising a polychlorinated biphenyl employing carbon modified titanium dioxide nanoparticles having a Ti:C atomic ratio of 3:1 to 6:1 and a bandgap energy of 1.4-2.0 eV as photocatalysts.

First claim

The invention claimed is:

1. A closed-loop system for remediation of an aqueous solution comprising a polychlorinated biphenyl, the system comprising:
a vessel comprising an aqueous solution comprising a first amount of at least one polychlorinated biphenyl and carbon modified titanium dioxide nanoparticles having a Ti:C atomic ratio in the range of 3:1 to 6:1 and a bandgap in the range of 1.4-1.8 eV dispersed in the aqueous solution;
a pump;
a tray oriented at a tilt angle from the horizontal comprising a distributor end and an opposing collector end located at a lower vertical height than the distributor end; and
wherein the vessel is configured to deliver the aqueous solution through the pump to the distributor end of the tray;
wherein the tray is configured to flow the aqueous solution along the tray via entirely gravity from the distributor end to the collector end while exposing the aqueous solution to a light source thereby forming a remediated aqueous solution comprising a second amount of the at least one polychlorinated biphenyl;
wherein the collector end is configured to return the remediated aqueous solution to the vessel; and
wherein the first amount of the at least one polychlorinated biphenyl is greater than the second amount of the at least one polychlorinated biphenyl.

2. The system of claim 1 , wherein the carbon modified titanium dioxide nanoparticles have a 5-10% atomic percentage of carbon relative to the total atomic percentage of the carbon modified titanium dioxide nanoparticles.

3. The system of claim 1 , wherein the carbon modified titanium dioxide nanoparticles have an average crystal size of 25-35 nm.

4. The system of claim 1 , wherein the tray is oriented at a tilt angle of 5-40° from the horizontal.

5. The system of claim 1 , wherein the light source is the sun.

6. The system of claim 1 , wherein the carbon modified titanium dioxide nanoparticles have a bandgap in the range of 1.78-1.8 eV.

7. The system of claim 1 , wherein the carbon modified titanium dioxide nanoparticles contain predominantly titanium dioxide in an anatase phase.

8. The system of claim 1 , wherein the carbon modified titanium dioxide nanoparticles comprise carbon in the form of a carbide.

9. A method for remediating an aqueous solution comprising at least one polychlorinated biphenyl employing the system of claim 1 , the method comprising:
flowing the aqueous solution from the vessel to the distributor end of the tray;
flowing the aqueous solution from the distributor end of the tray to the collector end of the tray via gravity while exposing the aqueous solution to the light source thereby photocatalytically degrading or mineralizing the at least one polychlorinated biphenyl to obtain the remediated aqueous solution; and
returning the remediated aqueous solution to the vessel.

10. The method of claim 9 , wherein greater than 70% by weight of the polychlorinated biphenyl relative to the first amount of the at least one polychlorinated biphenyl is photocatalytically degraded or mineralized after the exposing is carried out for a time period of 10-60 minutes.

11. The method of claim 9 , wherein the aqueous solution, the remediated aqueous solution, or both continuously circulates in a closed-loop circuit.

12. The method of claim 9 , wherein greater than 90% by weight of the polychlorinated biphenyl relative to the first amount of the at least one polychlorinated biphenyl is phototcatalytically degraded or mineralized after the exposing is carried out for a time period of less than 60 minutes.

13. A photocatalyst, comprising:
carbon modified titanium dioxide nanoparticles which have a Ti:C atomic ratio in the range of 3:1 to 6:1;
wherein the photocatalyst has a bandgap in the range of 1.4-1.8 eV.

14. The photocatalyst of claim 13 , which has a 5-10% atomic percentage of carbon relative to the total atomic percentage of the photocatalyst.

15. The photocatalyst of claim 13 , wherein the carbon modified titanium dioxide nanoparticles have an average crystal size of 25-35 nm.

16. The photocatalyst of claim 13 , wherein the carbon modified titanium dioxide nanoparticles have a bandgap in the range of 1.78-1.8 eV.

17. The photocatalyst of claim 13 , wherein the carbon modified titanium dioxide nanoparticles contain predominantly titanium dioxide in an anatase phase.

18. The photocatalyst of claim 13 , wherein the carbon modified titanium dioxide nanoparticles comprise carbon in the form of a carbide.

Assignees

• Univ King Abdulaziz

Inventors

• Shaban Yasser A
• El Sayed Mohamed A
• El Maradny Amr A
• Al Farawati Radwan Kh
• Al Zobidi Mosa I
• Khan Shahed U M

Classifications

• B01J37/086

  Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid · CPC title

• C01P2002/77

  by unit-cell parameters, atom positions or structure diagrams · CPC title

• A62D2101/28

  containing oxygen, sulfur, selenium or tellurium, i.e. chalcogen · CPC title

• C02F2305/10

  Photocatalysts · CPC title

• C01G23/053

  Producing by wet processes, e.g. hydrolysing titanium salts · CPC title