Ultraviolet light activated oxidation process for the reduction of organic carbon in semiconductor process water
View Patent ↗In a system for decomposing organic compounds in water for use in semiconductor manufacturing, a chemical reactor vessel having a fluid inlet and a fluid outlet, a persulfate anion addition system upstream of the reactor vessel, and a light emitting device contained within the reactor vessel. The light emitting device provides light capable of decomposing persulfate anions.
1. A method of treating semiconductor manufacturing water to reduce total organic carbon (TOC), the method comprising:
providing a source of semiconductor manufacturing water;
adding a solution of aqueous persulfate to the semiconductor manufacturing water to provide a mixture;
exposing the mixture to ultraviolet light in a chemical reactor vessel for a predetermined residence time to provide a treated water comprising a TOC concentration of less than about 5 ppb;
measuring the TOC concentration of at least one of the semiconductor manufacturing water and the treated water; and
adjusting a rate of aqueous persulfate addition to the semiconductor manufacturing water based on a TOC measurement of the at least one of the semiconductor manufacturing water and the treated water.
2. The method of claim 1 , wherein the treated water comprises a TOC concentration of less than about 1 ppb.
3. The method of claim 2 , wherein adjusting the rate of aqueous persulfate addition is based on a TOC measurement of the semiconductor manufacturing water.
4. The method of claim 2 , further comprising removing dissolved solids and dissolved gases.
5. The method of claim 2 , wherein adjusting the rate of aqueous persulfate addition is based on a TOC measurement of the treated water.
6. The method of claim 1 , wherein exposing the mixture to ultraviolet light in a chemical reactor vessel comprises exposing the mixture to ultraviolet light in a plug-flow reactor.
7. The method of claim 1 , wherein exposing the mixture to ultraviolet light in a chemical reactor vessel comprises exposing the mixture to ultraviolet light in a continuous-stirred tank reactor.
8. The method of claim 7 , wherein exposing the mixture to ultraviolet light in a chemical reactor vessel comprises exposing the mixture to ultraviolet light in a plug-flow reactor downstream of the continuous-stirred tank reactor.
9. The method of claim 1 , further comprising passing the semiconductor manufacturing water through a reverse osmosis unit prior to adding a solution of persulfate to the semiconductor manufacturing water.
10. The method of claim 1 , wherein the method is performed at ambient temperature.