The Director of the United States 

Patent and Trademark Office 

Has received an application for a patent for 

a new and useful invention. The title and 

description of the invention are enclosed. 

The requirements of law have been complied with, and it has been determined that 

a patent on the invention shall be granted 

under the law. 

Therefore, this 

United States Patent 

Grants to the person(s) having title to this 

patent the right to exclude others from making, using, offering for sale, or selling the 

invention throughout the United States of 

America or importing the invention into the 

United States of America, and if the invention is a process, of the right to exclude others from using, offering for sale or selling 

throughout the United States of America, or 

importing into the United States of 

America, products made by that process, 

for the term set forth in 35 US. C. 154(a)(2) 

or (c)(l), subject to the payment of maintenance fees as provided by 3 5 US. C. 41 (b). 

See the Maintenance Fee Notice on the 

inside of the cover. 

Deputy Director of rite United Stares Parent and Trademark Office 
c•2> United States Patent 

Sawyer et al. 

(54) METHOD FOR CONTAMINANT REMOVAL 

FROM AQUEOUS SOLUTION 

(75) lnvemors: John Sawyer, Charleston, WV (US); 

Geofl'rey PapeUer. Dunbar, WV (US); 

Marty L. Weirick. South Charleston, 

WV (US) 

(73) Assignee: Liberty Hydro, Inc.. South Charleston, 

WV (US) 

( • ) Notice: Subject to any disclaimer. the term of this 

patent is extended or adjusted under 35 

U.S.C. 154(b) by 670 days. 

(21) Appl. No.: 12/762,501 

(22) Filed: Apr. 19, 2010 

(65) Prior Publication Data 

US 201010307978 AI Dec. 9. 2010 

Related U.S. AppUcation Data 

(60) Provisional application No. 611214,566, filed on Apr. 

25, 2009. provisional application No. 61/236.424. 

liled on Aug. 24, 2009. 

(51) Int. Cl. 

BOlD 15/00 (2006.01 ) 

(52) U.S. Cl. 

USPC ...... 21CW679; 2101694; 2101747.1:2101502.1 

(58) Field or Classification Search 

USPC ............................ 2101679.694.747.1.502.1 

See application file for complete search history. 

100 

\. 

I IIII IIII ~ llllllllllll lllllllllllll lllllllllllllllll 

US00866883 1 82 

( 1 O) Patent No.: US 8,668,831 B2 

(45) Date of Patent: Mar. 11, 2014 

(56) References Cited 

U.S. PATENT DOCUMENTS 

4.800.190 A • .1/1989 Smolik ......................... 5021416 

5.869.32 1 A • 211999 Franklin .................. _ 4351253.6 

5,87 1,569 A • 2/1999 OehiCf"etal .....•..••...•...... 961153 

• cited by examiner 

Primary Examiner- Chester Barry 

(74) Auomey, Agent, or Finn - Mendelsohn, Ducker & 

Dunleavy, P.C. 

(57) ABSTRACT 

l ne prescm invention provides for a permeable reactive barrier and an effective method of removing contaminants from 

water using adsorbent powders. such as 1..ero valent iron particles. adhered throughout a reticulated foam structure. This 

structure provid<!S improved mass transfer. higher reaction 

rates and reduced residence times. The barrier includes a 

reticulated foam substrate with high permeability, an adherent coating and a reactive adsorbent arranged in a reticulated 

foam structure. The substrate can be selected from various 

materials including polyurethane and polyester. The adherent 

may be selected from a wide range of materials including 

polyurethanes. acrylics. silicones. siliconized acrylics, latex 

ernul ions. and Olher inherently tacky materials that cure to a 

wa1er resistant coating. 1be reactive adsorbent can be 

selected from various adsorbents including a powdered zero-

'-alent iron (ZVI). 

8 C1aiJm, 1 Drawing Sheet 

Coating reticulated foam substrate with an 

adherent coating on the substrate. - 110 

Coating foam substrate with an excess of a 

reactive adsorbent. - 120 

Subjecting the substrate to movement, such 

as vibration. shaking or spinning, to force ,_ 130 

th~ adsorbent to migrate therethrough 

coating the entire substrate 

,. 
U.S. Patent Mar.ll,2014 US 8,668,831 B2 

100 

"'-

Coating reticulated foam substrate with an 

adherent coating f- on the substrate. 110 

Coating foam substrate with an excess of a I-- 120 

reactive adsorbent. 

' 

Subjecting the substrate to movement, such 

as vibration, shaking or pinnin~ to for~e 

,__ 130 

the adsorbent to migrate therethrough 

coating the entire substrate 
US 8,668,831 B2 

1 

METHOD FOR CONTAMINANT REMOVAL 

FROM AQUEOUS SOLUTION 

REFERENCE TO PENDlNG APPLICATIONS 

This application claims the benefit of U.S. Provisional 

Patent Application Ser. No. 611214,566 filed on Apr. 25,2009 

and entitled Contaminant Removal form Aqueous Solutions 

and of U.S. Provisional Patent Application Ser. No. 611236, 

424 111ed on Aug. 24, 2009 entitled Permeable Reactive Barrier. 

REFERENCE TO MlCROACHE APPENDIX 

2 

Various aspectS of the substrate include any known or 

foreseeably known substrate material such as polyurethane 

and polyester. The adherent may be selected from a wide 

range of materials including polyurethanes. acrylics. sili5 cones, siliconized acrylics. latex emulsions. and other inherently tacky materials tbat cure to a water resistant coating. 

The reactive adsorbent can be selected from various adsorbents including, but not limited to, powdered ze~valent iron 

(ZVl), activated carbon, carbon, copper, zinc. or zeolites. or 

10 any combinations thereof. 

This application is not referenced in any microfiche appen- IS 

dix. 

Upon reading the above description •. various alternative 

embodiments will become obvious to those sltilled in the art. 

These embodiments are to be considered within the scope and 

spirit of the subject invention, which is only to be limited by 

the claims which follow and their equivalents. 

BACKGROUND OF THE INVENTION 

I. Field of the Invention 

The present invention is generally directed toward a foam 

and method to remove contaminants from aqueous solutions, 

more specifically toward a method utilizing reticulated foam 

BRfEF DESCRIPTION OF THE DRAWINGS 

FIG. 1 is a flow chart showing an embodiment 100 of the 

20 method of the present invention. 

DESCRIPTION OF THE INVENTION 

used in fluid treatment and the method to make same. The present invention is generally directed toward a foam 

2. Background 25 and method to remove contaminants from aqueous solutions. 

There are several contaminants in surface waters that are of more specifically toward a reticulated foam used in flui d 

considerable concern due to their effects on wildlife as well as treatment and the method to make same. 

humans. These contaminants can include, but are not limited It is to be understood that the invention is not limited in its 

to: selenium. perchlorate. chromates, halogenated organic application to the details of the construction and arrangement 

compounds, aluminum, lead, copper, technetium and arsenic. 30 of pans illustrated in the accompanying drawings. The invenThe prior an discloses that these contaminants can be Lion is capable of other cmbod.iments and of being practiced 

removed or neutralized by reaction with cenain adsorbents or carried out in a variety of ways. It is to be understood that 

such as; but not limited to, activated carbon, diatomaceous the phraseology and terminology employed herein are for the 

earth, alumina, or zero valent iron (Fe 0 , or ZVI). purpose of description and not of Jimitation. 

However, the prior art usc of these adsorbents have been 35 The present invention provides the effective removal of 

shown to have economic and physical constraints with their contaminants in ground water. By using a reticulated foam 

use. For instance, while ZVI is well known as an adsorbent, structure with the active species on the surface of the foam, 

drawbacks in actual application have been identified. To many of the shoncomings of prior art permeable reactive 

maximize surface area. ZV1 has been used as a powder. barriers can be overcome. Examples of applications include 

Unfonunately. the powder quickJy agglomerates, reducing 40 removal of chlorinated organic compounds from groundwaboth the available surface area and the ability of water to flow ter or reducing hexavalent chromium species to the less toxic 

through the ZVI particles. Ribbons of ZVI have been used, trivalent chromium species using zero valent iron (ZVI) parsuch as iron wool, but the surface area is not maximi1.ed, and tides. By incorporating the zero valent iron particles into a 

the flow path is quickly diminished. Thus, there is a need for reticulated foam structure, the high permeability can be mainan improvement to the removal or neutralization of contami- 45 tained over the course of the lifetime of the ZVI as it reacts 

nants in surface water. with impurities and decontaminates the water. This structure 

BRIEF SUMMARY OF THE INVENTION 

The present invention satisfies tbe needs discussed above. 

The present invention is generally directed toward a foam and 

a method to remove contaminants from aqueous solutions. 

more specifically toward a method utilizing reticulated foam 

used in flui d treatment and the method to make same. 

It is to be understood that the invention is not limited in its 

application to the details of the construction and arrangement 

of parts illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced 

or carried out in a variety of ways. It is to be understood that 

the phraseology and terminology employed herein are for the 

purpose of description and not of limitation. 

provides improved mass transfer. higher reaction rates, and 

reduced reactive adsorbent volume. 

One embodiment of the reticulated foam substrate of the 

so present invention is constructed from preferably polyurethane or polyether and having an appropriate size with 

approximately 4to 60 pores per inch. This substrate is coated 

and moistened with an adherent to give a uniform light coating over all of the surfaces of the foam. The moist co:ued 

55 substrate is then covered with powdered ze~valent iron 

(ZVI), which becomes stuck in the adherent on the surface of 

the substrate. An excess of the powder is applied to one or 

more surfaces of the substrate. Movement of the substrale. 

such as vibration, shaking or spinning. allows or forces the 

60 powder to migrate therethrough. As the iron powder strikes a 

wet surface. it adheres until the entire subslrale is coated with 

iron particles. The amount of iron adhered 10 the substrale i 

dependent on the particle size of tbe iron powder and the 

One aspect of the present invention provides for a permeable reactive barrier which is easily manufactured and its size 

easily controlled to remove contaminants in ground water. 

The barrier includes a reticulated foam substrate having a 65 

high permeability. an adherent coating and a reactive adsorbent arranged in a reticulated foam structure. 

available surface area of the substrale_ 

ZVI particle sizes from I 10 350 microns~ accepcable 

sizes. with the smaller particle sizes resulting in a lower total 

amount ofZVI in the resulting subsuale.llle larger pore sizes 
US 8,668,831 B2 

3 

of the substrate result in reduced surface area. and a lower 

amount ofZVI. The pore size and ZVI particle size are chosen 

depending on the requirements of a particular application, but 

smaller pore sizes generally require smaller particle si7-es. 

Further, when the substrate is placed in-ground, the pore size 5 

is chosen such that the reticulated foam substrate acts as a 

protective barrierto prevent migration oft he surrounding soil 

into the reticulated structure, and the resulting blockage and 

flow restriction. 

4 

residence time required to completely react the contaminants. 

the flow rate of the ground water. and the specific site conditions. 

There are several benefits from the present invention. One 

of the major benefits is the foam substrate has a greatly 

increased pore area. allowing for a longer life of the media. 

Iron undergoes an expansion as the oxidation process proceeds. opening up new surface area 10 the liquid and providing continued area for reactions to occur. As the natural 

It is not necessary that the adherent be able to withstand 

permanent water contact, as the ZVI powder will form a three 

dimensional interlinked structure in a short time, giving some 

structura.l integrity to the coating independent of the adherent 

The purpose of the adherent is to hold the ZVI in place until 

this bonding of the ZVI panicles occurs. The net result of the 

ZVI panicle bonding is a microporous reticulated ZVI foam. 

10 expansion of the iron closes ofT the flow path of the fluid, il 

prevents further flow through the remediation unit. 'The 

present invention provides a larger volume to absorb this 

expansion, and thus a longer useful life. with a greater proportion of the iron being used to remove contaminants, mainIS taining a low flu id fl ow pressure drop throughout the life of 

the media. 

The state of the surface of the ZVI is critical to the successful reaction with the oxidi:t.ed selenium, or other contaminants, in the water. As such, the surface oxides must be 20 

removed from the iron surface by dissolution. Said dissolution may be accomplished with an acid species where the 

anion is soluble as an iron salt or. in cases where the water has 

the proper chemistry. simply by contact with flowing water. 

Once a surface of truly 7-ero valent iron is established, the 25 

normal chemical reactions proceed. 

The reactive adsorbent may include more than just ZVI. 

For instance, an activated carbon may be included to assist in 

the removal of certain contaminants. either before or after 

reduction by ZVI. In some cases the activated carbon alone 30 

may be sufficient to completely remove the contaminants. 

One embodiment of the use of a permeable reactive barrier 

to act as a filter for ground water having contaminants therein 

is disclosed. This permeable reactive barrier is easily manufactured and its size easily controlled to remove contaminants 35 

in ground water. The barrier includes a reticulated foam substrate having a high permeability, an adherent coating and a 

reactive adsorbent arranged in a reticulated foam structure. 

Various aspects of the substrate include any known or 

foreseeably known substrate material such as polyurethane 40 

and polyester. The adherent may be selected from a wide 

range of materials including polyurethanes, acrylics, silicones, siliconized acrylics, latex emulsions, and other inherently tacky materials that cure to a water resistant coating. 

The reactive adsorbent can be selected from various adsor- 45 

bents including, but not limited to. powdered zero-valent iron 

(ZVI), activated carbon, carbon, copper. zinc, or zeolites. or 

any combinations thereof. 

The present invention provides the effective removal of 

contaminants in ground water. By using a reticulated foam so 

structure with the active species on the surface of the foam. 

many of the shortcomings of prior an permeable reactive 

barriers can be overcome. Examples of applications include 

removal of chlorinated organic compounds from groundwater or reducing hexavalent chromium species 10 the less toxic ss 

trivalent chromium species using zero valent iron (ZVI) particles. By incorporating the 1-ero valent iron particles into a 

reticulated foam structure, the high permeability can be maintained over the course of the lifetime of the ZVI as it reacts 

with impurities and decontaminates the water. This structure 60 

provides improved mass transfer. higher reaction rates. and 

reduced reactive adsorbent volume. 

In one use, the reactive reticulated foam is placed in the 

ground so as to intercept the groundwater containing contaminants. As the water fl ows through the reactive foam, the 65 

contaminants arc reduced, destroying them. or rendering 

them non-toxic. The amount of foam required depends on the 

Another benefit of the present invention is the surface area 

of the iron is greatly increased from other designs. resulting in 

a larger surface of solid contacting the liquid. leading to a 

higher reaction rate with the contaminants per unit volume. 

This higher reaction rate means a much smaller unit can be 

used. saving space and cost. 

'The amount of iron used in reducing contaminants is 

increased, resulting in a decreased volume of iron left at the 

end for disposal/recycle. resulting in a fu rther reduction in 

costs. 

A further benefit of the present invention is that low resistance to flow leads to a lowered pressure drop. and decreased 

bypass around the reactive foam. In most cases the flow rate 

through the reactive foam will be greater than through the 

surrounding soil, decreasing the amount of bypass over other 

designs. 

As illustrated in AG. I. an embodiment tOO of the method 

10 create the reticulated foam used in the present invention is 

disclosed. A reticulated foam substrate is coated with an 

adherent coating the adherent. as shown in step 110, and then 

with an excess of a reactive adsorbent, as shown in step 120. 

These adsorbents can be selected from various adsorbents 

including. but not limited to, powdered zero-valent iron 

(ZVl). activated carbon, carbon, copper, zinc, or 7-Colites, or 

any combinations thereof. The substrate is then subjected to 

movement, such as vibration, shaking or spinning. forces the 

adsorbent to migrate therethrough, coating the entire substrate. as shown in step 130. 

Examples of use include: 

Example I 

Ten disks of three inch diameter by one inch thick reticulated polyurethane foam with nominal I 0 pores per inch were 

coated with a urethane paint to give approximately 1.1 g/cubic inch of urethane coating. The disks were then placed one 

at a time in a plastic container and 60 g of Mallincrockt Baker 

zero valent iron powder was added. The container was sealed 

and tumbled to give a uniform coating of the ZVI over the 

entire volume of the foam disk. 'The disks were removed from 

the container and allowed to dry in air. After drying the disks 

contained 45-50 g of ZVI. or 6 glcubic inch. 

Example 2 

A six inch diameter by one inch thick disks of reticulated 

polyurethane foam with nominal I 0 pores per inch was coated 

with an aqueous silieonized acrylic slurry to give a coating of 

approximately 1.1 g/cubic inch of adherent. The disks were 

then placed one at a lime in a plastic container and 60 g of 

Mallincrockt Baker zero valent iron powder was added. The 

,. 

container" 

the ZVI ov 

were remo1 

The disk 

of seleniuo 

dence lime 

resuJts shm 

to first ordc 

halflifeof1 

give the des 

desired red! 

outlet. 

Ten disk 

reticulated 1 

wcrecoatcx 

g/cubic in 

one at a tim 

valent iron 

tumbled to 

volume of I 

container a 

contained a 

Ten disli 

reticulated] 

were coat~ 

mately I g 

were then p 

g of HCA-1 

tainerwass 
US 8,668,83 I B2 

5 container was sealed and tumbled to give a uniform coating of 

the ZVI over the entire volume of the foam disk. The disks 

were removed from the container and allowed to dry in air. 

Example 3 

The d!sks from example 2 were tested by passing a stream 

of selemum laden water through them with a variable residence time. The results are given in table I below. These 

results show the ZV1 foam disks remove selenium according 

to first order kinetics in the selenium concentration. with a 

half life of about 12 minutes. Thus, the flow rate is adjusted to 

give the desired residence time in the ZVI foam bed to give the 

desired reduction of the inlet concentration of selenium in the 

outlet. 

TABLE I 

selenium reduction by contact with the ZVI foam 

Residence TOUII 

Time in Selenium. 

minutes ppb 

Inlet (0.0) 24.6 

2.7 21.7 

14.2 10.8 

21.5 7.36 

Example4 

Ten disks of 67 millimeter diameter by one inch thick 

reticulated polyurethane foam with nominal I 0 pores per inch 

were coated with a silicone adhesive to give approximately 1 

glcubic inch of silicone coating. The disks were then placed 

one at a time in a plastic container and 100 gofHCA-150zcro 

valent iron powder was added. The container was sealed and 

tumbled to give a uniform coating of the ZVI over the entire 

volume of the foam disk. The disks were removed from the 

container and allowed to dry in air. After drying the disks 

contained an average of 7.3 g of ZVI, or 1.3 glcubic inch. 

Example 5 

6 

ZVI O\ er the enure \oiUJDe of lbe fa.u 111te -ce 

remo\ed from the craainer and slowed 10 dn - WiL A!:la 

drying the di oont.ained 3D~ d 1- 'f. dZ\1. :1 

g/cubic mch -

While the tmentioo bas beell described a cr:r. 

degree o~ pan.icul~ty. it is maoifestlha m:~~~y ~ • 

be made 1n the detail of constructioo and the ~mall d 

components without departing from the spmt liDd sccpe of 

this disclosure. It i understood thai !he im-=ooo i DOl • 

10 ited to the embodiments set forth herrin for purposes d 

exemplification. 

The invention claimed is: 

l . A method to remove contaminants from an aquc:ou.s 

solution comprising the steps of: 

15 (a) placing a permeable reactive barrier in an aqueous 

20 

stream containing contaminants. said permeable barrier 

comprising: 

a reticulated foam substrate; 

an adherent coating said reticulated foam substrate; and 

reactive adsorbent coating said adherent: and 

(b) running said aqueous stream through said permeable 

reactive barrier. 

2. The method of claim 1. wherein said reticulated foam 

substrate is constructed from a material selected from ceram25 ics. metals. polyethers. polyurethane and polyester. 

3. The method of claim I. wherein said adherent is selected 

from the group consisting of polyurethanes. acrylics, silicones. siliconizcd acrylics. latex emulsions. and other inherently tacky materials that cure to a water-resistant coating. 

30 4. The method of claim I. wherein said reactive adsorbent 

is selected from the group consisting of powdered zcrovalent 

iron, activated carbon, carbon. copper. zinc. 7£0iites. and any 

combinations thereof. 

5. The method of claim 1, wherein said reticulated foam 

35 substrate has 4 to 60 pores per inch. 

6. The method of claim 1. wherein said pemu:able reactive 

barrier is made by a method comprising the steps of: 

(a) coating a reticulated foam substrate with an adherent 

(1 10); 

40 (b) coating said adherent of step (a) with a reactive adsorbent (120): and 

Ten disks of 67 millimeter diameter by one inch thick 

reticulated polyurethane foam with nominal I 0 pores per inch 45 

were coated with a polyurethane adhesive to give approximately I glcubic inch of polyurethane coating. The disks 

were then placed one at a time in a plastic container and 100 

(c) moving said reliculated foam substrnlc to force said 

reactive adsorbent to migrate through said reticulated 

foam substmte effectively coating substantially all of 

said reticulated foam substrate (130). 

7. The method of claim 6, wherein the reticulated foam 

substrate is reticulated polyethylene foam. 

8. The method of claim 6. wherein said reticulated foam 

sub trate is reticulated polyether foam. g of IICA-15C zero valent iron powder was added. The container was scaled and tumbled to give a uniform coating of the • • ••• 

. .