Recovery of volatile organic compounds from emulsion of volatile organic compounds in water by pervaporation

• US 6,039,878 A
• Filed: 05/23/1997
• Issued: 03/21/2000
• Est. Priority Date: 05/23/1996
• Status: Expired due to Term

• Current Assignee: United States Environmental Protection Agency, United States Incorporated
• Original Assignee: United States Of America As Represented By The Administrator Of The United States Environmental Protection Agency
• Inventors: Sikdar, Subhas, Vane, Leland
• Primary Examiner(s): FORTUNA, ANA M
• Application Number:
  US08/862,308
• Time in Patent Office: 1,033 Days
• Field of Search: 210/640, 210/649, 95/43, 95/45, 95/46, 95/50, 95/502.1
• US Class Current: 210/640
• CPC Class Codes: B01D 61/362 Pervaporation
• CPC Class Codes: C02F 1/448 by pervaporation
• CPC Class Codes: C02F 2101/322 Volatile compounds, e.g. benzene
• CPC Class Codes: C02F 2101/325 Emulsions
• CPC Class Codes: C02F 2103/06 Contaminated groundwater or leachate

Abstract

Volatile organic compounds (VOCS) can be removed from surfactant solutions using pervaporation with hydrophobic pervaporation membranes. This process can be used to remove volatile non-laqueous phase liquids from surfactant-based soil washing and soil flushing solutions for recovery of the volatile compounds and reuse of the surfactant. The process of the present invention can also be used to separate VOCs from industrial process streams containing surfactants for in-process recycling and reclamation of the VOCs and/or surfactants. In addition, the process of the present invention can be used to separate VOCs from industrial waste streams containing surfactants for waste volume reduction or for recovery/recycle of the VOCs and/or surfactant.

Claims

1. A method for removing volatile organic compounds from an emulsion comprising volatile organic compounds, water, and a surfactant, wherein the continuous phase of said emulsion is water, comprising passing said emulsion through a hydrophobic pervaporation membrane.

2. The method according to claim 1 wherein the surfactant is selected from the group consisting of nonionic surfactants and anionic surfactants.

3. The method according to claim 1 wherein the volatile organic compounds are reused.

4. The method according to claim 1 wherein the water is groundwater.

5. The method according to claim 1 wherein the emulsion is obtained from surfactant flushing of vadosezone soils.

6. The method according to claim 1 wherein the membrane is made of silicone rubber.

7. The method according to claim 1, wherein the membrane is made of a material selected from the group consisting of polyethylene, polypropylene, polydimethyl siloxane, poly(1-trimethylsiliyl-1-propyne), polyurethanes, polybutadiene polyether imides, polyether block polymers, styrene-butadiene rubbers, nitrile butadiene rubbers, and ethene-propene terpolymers.

8. A method for removing volatile organic compounds from groundwater contaminated with volatile organic compounds comprising:

flushing soil containing said contaminated groundwater with a surfactant to form an emulsion of surfactant, water, and volatile organic compounds; and

passing said emulsion through a hydrophobic pervaporation membrane.

9. The method according to claim 8 wherein the surfactant is selected from the group consisting of nonionic surfactants and anionic surfactants.

10. The method according to claim 8 wherein the volatile organic compounds are reused.

11. The method according to claim 8 wherein the emulsion is obtained from surfactant flushing of vadosezone soils.

12. The method according to claim 8 wherein the membrane is made of silicone rubber.

13. The method according to claim 8 wherein the membrane is made of a material selected from the group consisting of polyethylene, polypropylene, polydimethyl siloxane, poly(1-trimethylsiliyl-1-propyne), polyurethane polybutadiene polyether imides, polyether block polymers, styrene-butadiene rubbers, nitrile butadiene rubbers, and ethene-propene terpolymers.