Method and Apparatus to Separate Per-and Polyfluoroalkyl Substances (PFAS) from Water Using Colloidal Gas Aphrons (CGAs)
A method for the decontamination of water containing one or more PFAS, having the steps of generating colloidal gas aphrons (CGAs) by mixing a gas, water, and one or more surfactants together with high shear forces, introducing the CGAs and a PFAS-containing water in an enclosed space where the CGAs move upwards through the water allowing the plurality of CGAs to extract PFAS from the water, and separating the PFAS-containing CGAs from the water in the enclosed space for further treatment or disposal, leaving the water with lower PFAS concentrations in the vessel. The aphrons may be anionic or cationic and created by mixing speeds or surfactant concentration, and treatment may be with gas bubbles to remove PFAS from water gas bubbles or destruction of PFAS without ultrasonic cavitation.
1 - 33 . (canceled)
34 . A method for the removal of-per- and polyfluoroalkyl substances (PFAS) from water, comprising:
(a) mechanically generating colloidal gas aphrons (CGAs) by shear mixing of a gas, water, and at least one surfactant using a device selected from a spinning disc, rotor-stator mixer, impeller, or gas-liquid mixer thereby forming surfactant-stabilizing gas microstructure;
(b) contacting the CGAs with PFAS-containing water under conditions to allow that PFAS sorb onto the CGAs by at least one of electrostatic attraction or hydrophobic partitioning; and
(c) separating PFAS-laden CGAs from the water by physical collection at a surface of the water in a vessel wherein removal occurs without ultrasonic cavitation, plasma formation, or radical-driven degradation.
35 . The method as claimed in claim 34 , wherein the surfactant is cationic, anionic, or zwitterionic.
36 . The method as claimed in claim 34 , wherein at least two surfactants having different charges are used.
37 . The method as claimed in claim 34 , wherein properties of the CGAs are controlled by mechanical shear rate; rotational speed of the mixing devices; or surfactant properties and concentration.
38 . The method as claimed in claim 34 , wherein the CGAs are formed with high shear forces.
39 . The method as claimed in claim 38 , wherein the system is continuous.
40 . The method as claimed in claim 34 , wherein the CGAs are removed by gravitational overflow or skimming from the upper region of the vessel.
41 . The method as claimed in claim 34 , wherein the shear mixing is produced by a spinning disc rotating at a speed sufficient to generate CGAs having diameters greater than 25 micrometers.
42 . The method as claimed in claim 34 , wherein the water contains a single PFAS.
43 . The method as claimed in claim 34 , wherein one or more of the PFAS are from a group comprising anionic, cationic, zwitterionic or long-chain PFAS.
44 . The method as claimed in claim 34 , wherein one or more of the PFAS are short-chain PFAS.
45 . The method as claimed in claim 34 , wherein one or more of the PFAS are Perfluoroalkyl acids.
46 . The method as claimed in claim 34 , wherein one or more of the PFAS are precursor compounds.
47 . The method as claimed in claim 34 , wherein PFAS extraction occurs through combined electrostatic attraction and hydrophobic partitioning.
48 . The method as claimed in claim 34 , wherein the CGAs are transported from the vessel by pumping after buoyant separation.
49 . The method as claimed in claim 34 , wherein the CGAs are removed from the vessel by decanting after buoyant separation.
50 . The method as claimed in claim 34 , wherein the CGAs are directly treated or disposed.
51 . The method as claimed in claim 34 , further comprising allowing the CGAs to collapse into a liquid phase after separation by cessation of mechanical shear.
52 . The method as claimed in claim 34 , further comprising facilitating collapse of the CGAs by salt addition, pressure reduction, or mechanical agitation.
53 . The method as claimed in claim 34 , wherein baffles are placed in the vessel to facilitate separation.
54 . A method for the decontamination of water containing one or more PFAS, comprising the steps of:
(a) generating colloidal gas aphrons (CGAs) by mixing under shear forces in the absence of ultrasonic cavitation using a spinning disc gas, water, and one or more surfactants together;
(b) introducing the CGAs into a vessel containing the PFAS-containing water, wherein the CGAs maintain a diameter of approximately 10-100 micrometers and remain non-collapsing during operation; and
(c) sorbing the PFAS to the CGAs to extract PFAS from the water without inducing ultrasonic bubble collapse, whereby PFAS molecules are electrostatically sorbed to the CGA surfactant shells; and separating the PFAS-containing CGAs from the water for further treatment or disposal.
55 . The method as claimed in claim 54 , wherein the shear mixing is produced by a spinning disc rotating at a speed sufficient to generate CGAs having diameters greater than 25 micrometers.
56 . The method as claimed in claim 54 , wherein the water contains a single PFAS.
57 . The method as claimed in claim 54 , wherein one or more of the PFAS are from a group comprising anionic, cationic, zwitterionic or long-chain PFAS.
58 . A method for decontamination of bulk liquid containing one of more PFAS contaminants, comprising the steps of:
(a) generating colloidal gas aphrons (CGAs) using a gas, a PFAS-containing water, and electrostatically charged surfactant;
(b) sorbing the PFAS to the CGAs from electrostatic and hydrophobic partitioning to remove PFAS from the bulk liquid; and
(c) disposing of the PFAS-containing CGAs.
59 . The method as claimed in claim 58 , wherein the shear mixing is produced by a spinning disc rotating at a speed sufficient to generate CGAs having diameters greater than 25 micrometers.
60 . The method as claimed in claim 58 , wherein the water contains a single PFAS.
61 . The method as claimed in claim 58 , wherein one or more of the PFAS are from a group comprising anionic, cationic, zwitterionic or long-chain PFAS.
62 . A method for the decontamination of water containing one or more PFAS contaminants, comprising the steps of:
(a) generating colloidal gas aphrons (CGAs) using a gas, water and electrostatically charged surfactant where the water contains PFAS;
(b) sorbing the PFAS to the CGAs from electrostatic and hydrophobic partitioning to remove the PFAS from the bulk liquid; and
(c) disposing of the PFAS-containing CGAs.
63 . The method as claimed in claim 62 , wherein the shear mixing is produced by a spinning disc rotating at a speed sufficient to generate CGAs having diameters greater than 25 micrometers.
64 . The method as claimed in claim 62 , wherein the water contains a single PFAS.
65 . The method as claimed in claim 62 , wherein one or more of the PFAS are from a group comprising anionic, cationic, zwitterionic, or long-chain PFAS.
66 . The method as claimed in claim 62 , wherein properties of the CGAs are controlled by mechanical shear rate; rotational speed of the mixing devices; or surfactant properties and concentration.