Detailed Action
This is a Non-Final Office action based on application 17/270852 filed on February 23, 2021. The application is a 371 of PCT/US2019/047922 with priority to US provisional application 62/721,647 filed August 23, 2018.
Claims 1-6, 8-20, and 22-31 are pending and have been fully considered.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Rejection
The §103 rejection of record is withdrawn
New §103 grounds are established in view of Tax et al (US 2019/0292075 A1)
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-4, 6, 8-10, 12-13, 15-18, 20, 22-23, and 31 are rejected under 35 U.S.C. 103 as being unpatentable over Huang et al (US 2019/0185351 A1) in view of Branchick et al (US 4,399,020 A) and Tax et al (US 2019/0292075 A1).
Regarding claim 1, Huang teaches a method of treating water containing per- and polyfluoroalkyl substances (PFASs) (para [0059], "treating a composition, such as an aqueous composition (e.g., contaminated wastewater) containing one or more types of PFAS contaminants"), comprising:
introducing the water containing PFASs to an electrochemical cell comprising a cathode and a Magnéli phase titanium oxide anode (para [0059], "contacting the contaminated composition with a Magnéli phase titanium suboxide (TSO) ceramic electrode ... in an electrochemical cell (e.g., three electrode cell), with the Magnéli phase TSO ceramic electrode as the working electrode (e.g., anode)"; para [0066], " the system further includes a cathode/counter electrode"); and
applying a voltage to the anode in an amount sufficient to promote oxidation of the PFASs in order to produce treated water (para [0059], "supplying an electric current (e.g., via a power source) to the Magnéli phase titanium oxide ceramic electrode, such that the electrode electrochemically oxidizes the PFASs to oxidatively degrade the PFASs into mineral components"; para [0083]-[0085]).
Huang further teaches that the Magnéli phase titanium oxide anode has a porosity in the range of from 5 to 75% (para [0063]) which overlaps the claimed range of at least 25%. Huang teaches that the porosity of the Magnéli phase titanium oxide anode can be controlled and tailored to the application (para [0063]).
Huang does not specify that the porosity is necessarily at least 25%. However, it would have been obvious to a person having ordinary skill in the art at the time of the invention, given the teachings of Huang regarding a porosity range of 5 to 75% for the anode to select and utilize a porosity within the disclosed range, including those amounts that overlap within the claimed range of at least 25%, in order to attain a suitably high electrochemically active area. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
In an embodiment, Huang teaches the anode takes the form of a microporous filter or membrane disc with a pore size of from about 0.1 μm (100 nm) to 10 μm (para [0062]). In another embodiment, Huang teaches the anode is formed by a polyurethane foam scaffold coated with the Magnéli phase material (para [0081]), but Huang does not disclose the pore size of the foam anode.
Huang does not teach an anode with a mean pore size of from 100 μm to 2 mm.
Branchick teaches an electrochemical cell (figure 1) comprising foam electrodes formed of electrochemically active material coated on a scaffold of polyurethane foam (col 7 ln 55 - 64; col 8 ln 10-37), and the use of the cell to remove contaminants from wastewater (see examples described in col 10 ln 48 - col 14 ln 50). In one embodiment, Branchick's electrode is an anode having as its electrochemically active material an oxide of titanium or other valve metal (col 47-54). Branchik teaches that the foam electrode has a mean pore size of from 0.020 to 0.040 inches (col 7 ln 54 - col 8 ln 6) i.e. 510 to 1020 µm, which falls within the claimed range of from about 100 µm to about 2 mm. Branchick teaches that the electrode with a pore size in the claimed range is effective for removing contaminants from wastewater (col 3 ln 33 - col 4 ln 3; in the six examples described in col 10 ln 48 - col 14 ln 50, Branchick employs electrodes with pore size of 33 mils = 840 µm and demonstrates they are effective to remove metal and cyanide ions from wastewater).
It would have been obvious to a person having ordinary skill in the art at the time of the invention, when implementing the foam anode comprising polyurethane foam coated with Magneli phase titanium oxide as contemplated in Huang (para [0081]), to use a foam anode with a pore size within the claimed range of from about 100 µm to about 2 mm, because Branchick teaches that a foam electrode formed of electrochemically active material coated on a polyurethane foam substrate typically has a pore size within the claimed range (col 7 ln 54 - col 8 ln 6) and such pore size is suitable for a flow through electrode that is used to remove contaminants from wastewater (col 3 ln 33 - col 4 ln 3; col 10 ln 48 - col 14 ln 50).
Huang discloses monitoring the pH level of the water and the voltage of the electrochemical cell (pg 15 Table 6). Huang further teaches systematically varying the voltage, flow rate, and pH and studying how these parameters effect the efficiency of water treatment (para [0162], [0165]). However, Huang and Branchick do not disclose that the control of the applied voltage is in response to a monitored parameter selected from flow rate or voltage.
Tax is similarly directed to a method of treating a wastewater containing organic contaminants (para [0006], “a process for removing pesticides from wastewater”), the method comprising:
introducing the contaminated water to an electrochemical cell comprising a cathode and a Magnéli phase titanium oxide anode (para [0006], “The process includes feeding a wastewater stream (A) to an electrolysis cell, oxidizing the wastewater stream (A)”; para [0012], “the electrolysis cell electrodes comprise ... a Magneli phase material of the formula (Tin O2n−1)”; para [0043]);
applying a voltage to the anode in an amount sufficient to promote oxidation of the contaminants in order to produce treated water (para [0006], “oxidizing the wastewater stream (A)”; para [0053]-[0060] discuss mechanisms of electrochemical oxidation of the contaminant);
monitoring flow rate upstream of the electrochemical cell, and controlling the applied voltage in response to the monitored parameter (para [0014]-[0015], “monitoring a parameter of the flow ... voltage supplied to the electrolysis cell by the power supply may be increased or decreased based on the monitored parameter; para [0064], “a flow meter upstream of the electrolytic cell may provide a signal to a controller corresponding to the volumetric flow rate and/or the mass flow rate. The controller may process the signal according to pre-programmed algorithms and send an appropriate power signal to the electrolytic cell”); and
monitoring a voltage downstream of the electrochemical cell, and controlling the applied voltage in response to the monitored parameter (para [0015], “monitoring the oxidation-reduction potential, ... in the product stream. At least one parameter within the process may be changed if a monitored concentration is above a preset limit. The parameter being changed may include ... the amount of voltage supplied to the electrolysis cell”).
Tax teaches that when the electrolysis cell power is controlled in such a manner, the electrolysis reaction may adapt to flow fluctuations in the influent wastewater and maintain peak performance (para [0064]).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Huang by incorporating the features, taught in Tax, of monitoring flow rate upstream of the electrochemical cell and controlling the applied voltage in response to the measured flow rate, because Tax teaches that when the electrolysis cell power is controlled in such a manner, the electrolysis reaction may adapt to flow fluctuations in the influent wastewater and maintain peak performance (para [0064]). The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Regarding claim 2, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches wherein the PFASs comprise perfluorooctane sulfonic acid (PFOS) or perfluorooctanoic acid (PFOA) (para [0083]-[0085]).
Regarding claim 3, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches the anode comprises TinO2n-1, where n is 4 or 5 (para [0065], "comprising Ti4O7, Ti5O9, or a combination of both"), which fits within the claimed range of wherein n ranges from 3 to 9 inclusive.
Regarding claim 4, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches the anode comprises Ti4O7 (para [0065], "comprising Ti4O7, Ti5O9, or a combination of both"; para [0083]-[0085], "Ti4O7").
Regarding claim 6, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches the anode comprises a foam structure (para [0081], "In yet another embodiment, polyurethane foam can be used as a template to produce Magnéli phase Ti4O7 or Ti4O7/Ti5O9 foam electrodes ... the Ti4O7 nano powder slurry is coated to a polyurethane foam template before sintering").
Regarding claim 8, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches the cathode is made of a stainless steel material (para [0066]; para [0085], "cathodes (304 stainless steel sheets)").
Regarding claim 9, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches the water is circulated between the cathode and the anode (in the embodiment of figures 23-24, anode and cathode are disposed as concentric cylinders, and water is circulated through the annular space between the two electrodes; para [0160]).
Regarding claim 10, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches the water is circulated through the anode and cathode in series (the embodiment of figure 21A, showing that water is circulated through the anode and cathode in series; para [0133]-[0134]).
Regarding claim 12, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches introducing the treated water to a downstream unit operation for further treatment (para [0166]-[0167] and figure 25, water treated by the PFAS oxidation method is subsequently introduced to a downstream cell for an electrochemical chlorate reduction treatment).
Regarding claim 13, Huang, Branchick, and Tax render obvious the method of claim 1, and Huang further teaches monitoring a PFAS concentration upstream of the electrochemical cell (para [0165], “The concentrations of PFAAs will be monitored in the influent, effluent and retentate to measure the efficiency of anodic oxidation”).
Regarding claim 15, Huang, Branchick, and Tax render the method of claim 1 obvious, and Huang further teaches monitoring a PFAS concentration downstream of the electrochemical cell (per figure 13-14, PFAS concentration downstream of the electrochemical cell is monitored; and para [0097], [0119]-[0122], said monitoring is carried out via liquid chromatography-coupled-mass spectrometry (LCMS)).
Regarding claim 16, Huang teaches a water treatment system (para [0053], "methods and systems for electrochemically oxidizing PFASs ... to oxidatively mineralize the PFASs for decontamination of compositions containing PFASs"; para [0068], "to decontaminate wastewater"), comprising:
an electrochemical cell comprising a Magneli phase titanium oxide anode (para [0059], " an electrochemical cell (e.g., three electrode cell), with the Magnéli phase TSO ceramic electrode as the working electrode (e.g., anode)"); and
a source of water comprising perfluoroalyl and polyfluoroalkyl substances (PFASs) fluidly connected to an inlet of the electrochemical cell (para [0066]-[0068], " a reservoir for containing an aqueous solution or other substance contaminated with PFASs ... pump for moving the aqueous composition into and out of the reservoir through the system"); and
an outlet of the electrochemical cell configured to discharge treated water (in para [0139] and figure 21A, and also in para [0166]-[0167] and figure 25, treated water is discharged as effluent via an outlet).
Huang further teaches that the Magneli phase titanium oxide anode has a porosity in the range of from 5 to 75% (para [0063]) which overlaps the claimed range of at least 25%. Huang teaches that the porosity of the Magneli phase titanium oxide anode can be controlled and tailored to the application (para [0063]). However, Huang does not specify that the porosity is necessarily at least 25%.
It would have been obvious to a person having ordinary skill in the art at the time of the invention, given the teachings of Huang regarding a porosity range of 5 to 75% for the anode to select and utilize a porosity within the disclosed range, including those amounts that overlap within the claimed range of at least 25%, in order to attain a suitably high electrochemically active area. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
In an embodiment, Huang teaches the anode takes the form of a microporous filter or membrane disc with a pore size of from about 0.1 μm (100 nm) to 10 μm (para [0062]). In another embodiment, Huang teaches the anode is formed by a polyurethane foam scaffold coated with the Magneli phase material (para [0081]), but Huang does not disclose the pore size of the foam anode.
However, Huang does not teach an anode with a mean pore size of from 100 μm to 2 mm.
Branchick teaches an electrochemical cell (figure 1) comprising foam electrodes formed of electrochemically active material coated on a scaffold of polyurethane foam (col 7 ln 55 - 64; col 8 ln 10-37), and the use of the cell to remove contaminants from wastewater (see examples described in col 10 ln 48 - col 14 ln 50). In one embodiment, Branchick's electrode is an anode having as its electrochemically active material an oxide of titanium or other valve metal (col 47-54). Branchick teaches that the foam electrode has a mean pore size of from 0.020 to 0.040 inches (col 7 ln 54 - col 8 ln 6) i.e. 510 to 1020 µm, which falls within the claimed range of from about 100 µm to about 2 mm. Branchick teaches that the electrode with a pore size in the claimed range is effective for removing contaminants from wastewater (col 3 ln 33 - col 4 ln 3; in the six examples described in col 10 ln 48 - col 14 ln 50, Branchick employs electrodes with pore size of 33 mils = 840 µm and demonstrates they are effective to remove metal and cyanide ions from wastewater).
It would have been obvious to a person having ordinary skill in the art at the time of the invention, when implementing the foam anode comprising polyurethane foam coated with Magneli phase titanium oxide as contemplated in Huang (para [0081]), to use a foam anode with a pore size within the claimed range of from about 100 µm to about 2 mm, because Branchick teaches that a foam electrode formed of electrochemically active material coated on a polyurethane foam substrate typically has a pore size within the claimed range (col 7 ln 54 - col 8 ln 6) and such pore size is suitable for a flow through electrode that is used to remove contaminants from wastewater (col 3 ln 33 - col 4 ln 3; col 10 ln 48 - col 14 ln 50).
Huang discloses monitoring the pH level of the water and the voltage of the electrochemical cell (pg 15 Table 6). Huang further teaches systematically varying the voltage, flow rate, and pH and studying how these parameters effect the efficiency of water treatment (para [0162], [0165]).
However, Huang and Branchick do not disclose that the a controller is in communication with at least one sensor and configured to control the applied voltage in response to a monitored parameter selected from pH, flow rate, voltage or temperature.
Tax is similarly directed to a water treatment system (para [0006], “a process for removing pesticides from wastewater”; para [0018], “a system configured to execute the process”, comprising:
an electrochemical cell comprising a cathode and a Magnéli phase titanium oxide anode (para [0006], “The process includes feeding a wastewater stream (A) to an electrolysis cell, oxidizing the wastewater stream (A)”; para [0012], “the electrolysis cell electrodes comprise ... a Magneli phase material of the formula (Tin O2n−1)”; para [0043]) having a mean pore size of from about 100 m to about 2mm and a porosity of at least about 25%, an inlet of the electrochemical cell being fluidly connected to a source of contaminated water (figure 1-2, wastewater inlet 101; para [0069]-[0074]) and an outlet of the electrochemical cell configured to discharge treated water (figure 1-2, outlet 117 discharges water treated by the electrochemical cell 108;
at least one flow rate or voltage sensor positioned upstream and/or downstream of the electrochemical cell, and a controller in communication with the at least one sensor configured to control a voltage applied to the electrochemical cell in response to the sensor (para [0064], “a flow meter upstream of the electrolytic cell may provide a signal to a controller corresponding to the volumetric flow rate and/or the mass flow rate. The controller may process the signal according to pre-programmed algorithms and send an appropriate power signal to the electrolytic cell”).
Tax teaches that when the electrolysis cell power is controlled in such a manner, the electrolysis reaction may adapt to flow fluctuations in the influent wastewater and maintain peak performance (para [0064]).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Huang by incorporating the features, taught in Tax, of a sensor that monitors the flow rate upstream of the electrochemical cell and a controller that controls the applied voltage in response to the measured flow rate, because Tax teaches that when the electrolysis cell power is controlled in such a manner, the electrolysis reaction may adapt to flow fluctuations in the influent wastewater and maintain peak performance (para [0064]). The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Regarding claim 17, Huang, Branchick, and Tax render the system of claim 16 obvious, and Huang further teaches wherein the PFASs comprise perfluorooctane sulfonic acid (PFOS) or perfluorooctanoic acid (PFOA) (para [0083]-[0085]).
Regarding claim 18, Huang, Branchick, and Tax render the system of claim 16 obvious, and Huang further teaches the anode comprises Ti4O7 (para [0065], "comprising Ti4O7, Ti5O9, or a combination of both"; para [0083]-[0085], "Ti4O7").
Regarding claim 20, Huang, Branchick, and Tax render the system of claim 16 obvious, and Huang further teaches the anode comprises a foam structure (para [0081], "In yet another embodiment, polyurethane foam can be used as a template to produce Magnéli phase Ti4O7 or Ti4O7/Ti5O9 foam electrodes ... the Ti4O7 nano powder slurry is coated to a polyurethane foam template before sintering").
Regarding claim 22, Huang, Branchick, and Tax render the system of claim 16 obvious, and Huang further teaches the electrochemical cell is constructed and arranged to circulate the water between the cathode and the anode (in the embodiment of figures 23-24, anode and cathode are disposed as concentric cylinders, and water is circulated through the annular space between the two electrodes; para [0160]).
Regarding claim 23, Huang, Branchick, and Tax render the system of claim 16 obvious, and Huang further teaches the electrochemical cell is constructed and arranged to circulate the water through the cathode and the anode in series (the embodiment of figure 21A, showing that water is circulated through the anode and cathode in series; para [0133]-[0134]).
Regarding claim 31, Huang, Branchick, and Tax render obvious the system of claim 16 and Huang further teaches a downstream unit operation configured for further treatment of the treated water fluidly connected to the outlet of the electrochemical cell (figure 25 and para [0075], [0166]-[0169], figure 25, water flowing out the outlet of the PFAS anodic oxidation cell is fluidly connected to one or more other downstream units for further treatment).
Claims 5, 14, 19, and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Huang, Branchick, and Tax as applied to claims 1 and 16 above, and further in view of Fath (US 2012/0055807 A1).
Regarding claims 5 and 19, Huang, Branchick, and Tax render obvious the method of claim 1 and the system of claim 16, but do not teach the anode comprises a mesh structure.
Fath is directed to a water treatment method and apparatus for decomposing perfluorinated alkylsulfonates (PFASs) by anodic oxidation (abstract, para [0037]). Fath's system comprises an electrolysis cell comprising an anode with a mesh structure (para [0047], [0056]; figure 3, mesh anodes 3). Fath teaches that the mesh structure is advantageous because the PFAS-contaminated water is able to flow through the mesh anode and access a large electrochemically-active surface area, which facilitates the thorough decomposition of the contaminant (para [0078]).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to implement the system of Huang using an anode with a mesh structure, because Fath, similarly directed to anodic oxidation of perfluoroalkyl surfactant pollutants in water, teaches that structuring the anode as a mesh allows the contaminated water to flow through the anode and imparts a large active surface area to the anode, thereby facilitating the complete destruction of the contaminant (para [0078]).
Regarding claims 14 and 26, Huang, Branchick, and Tax render the method of claim 1 and the system of claim 16 obvious. Tax teaches that the voltage can be varied to optimize the cell performance responsive to fluid parameters (para [0064]). However, Huang, Branchick, and Tax do not specify that the operating voltage is about 6 volts.
Fath is similarly directed to a water treatment method and apparatus for decomposing perfluorinated alkylsulfonates (PFASs) by anodic oxidation (abstract, para [0037]). Fath's system comprises an electrolysis cell comprising an anode with a mesh structure (para [0047], [0056]; figure 3, mesh anodes 3). Fath teaches that the voltages ranging from 4 V to 15 V are effective for the degradation of PFAS in wastewater (pg 4, Table 1; para [0020] and [0057]-[0060]).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention, when setting the anode voltage in Huang’s device and method, to select and utilize an optimal voltage from within the range that the prior art teaches is suitable for the intended purpose of PFAS degradation (from 4 V to 15 V as taught in Fath [0057]-[0060]), including those amounts that overlap within the claimed range of about 6 V. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art; see MPEP 2144.05 (I).
Claims 11 and 24 are rejected under 35 U.S.C. 103 as being unpatentable over Huang, Branchick, and Tax as applied to claims 1 and 16 above, and further in view of Farhat et al ("Removal of Persistent Organic Contaminants by Electrochemically Activated Sulfate", Environmental Science & Technology, 49, 14326-14333 (2015)).
Regarding claim 11, Huang, Branchick, and Tax render obvious the method of claim 1 and Huang further teaches the electrochemical cell comprises a sodium sulfate electrolyte at a concentration of 10 mM (para [0071], "a supporting electrolyte (e.g. 10 mM Na2SO4)"; para [0139]). Huang does not teach the concentration of sodium sulfate is about 5 mM.
Farhat studies the effect of sulfate electrolyte on the degradation of persistent organic contaminants by anodic oxidation in wastewater (abstract, pg 14327 left column para 2), and finds that sulfate oxidizes to persulfate and radical sulfate species at the anode, which in turn mediate the oxidation of the organic contaminant (pg 14328 right column para 2 - pg 14329 right column para 1). Farhat studies the effect of sodium sulfate over a concentration range of from 1.6 mM to 40 mM, and finds that the oxidation of the organic contaminant is effective over this entire concentration range (pg 14330 right column para 2 - pg 14331 left column para 4; pg 14330 Table 2), including at a concentration of 5 mM (pg 14330, Table 2, row 2).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the concentration of the sodium sulfate electrolyte of Huang to a concentration within the disclosed range of Farhat (i.e 1.6 - 40 mM), including those amounts that are within the claimed range (i.e., about 5 mM), in order to provide a concentration of sodium sulfate that supports anodic oxidation of the pollutant without introducing excessive salt concentrations to the water that is to be purified. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I). Furthermore, differences in concentration will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical (MPEP § 2144.05(II)(A)). In this case, the teachings of Farhat provide evidence that anodic oxidation proceeds predictably as sodium sulfate concentration is varied over the range in question (pg 14330 right column para 2 - pg 14331 left column para 4; pg 14330 Table 2), suggesting that the concentration is not critical.
Regarding claim 24, modified Huang renders obvious the method of claim 16 and Huang further teaches the electrochemical cell comprises a sodium sulfate electrolyte at a concentration of 10 mM (para [0071], "a supporting electrolyte (e.g. 10 mM Na2SO4)"; para [0139]). Huang does not teach the concentration of sodium sulfate is about 5 mM.
Farhat studies the effect of sulfate electrolyte on the degradation of persistent organic contaminants by anodic oxidation in wastewater (abstract, pg 14327 left column para 2), and finds that sulfate oxidizes to persulfate and radical sulfate species at the anode, which in turn mediate the oxidation of the organic contaminant (pg 14328 right column para 2 - pg 14329 right column para 1). Farhat studies the effect of sodium sulfate over a concentration range of from 1.6 mM to 40 mM, and finds that the oxidation of the organic contaminant is effective over this entire concentration range (pg 14330 right column para 2 - pg 14331 left column para 4; pg 14330 Table 2), including at a concentration of 5 mM (pg 14330, Table 2, row 2).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the concentration of the sodium sulfate electrolyte of Huang to a concentration within the disclosed range of Farhat (i.e 1.6 - 40 mM), including those amounts that are within the claimed range (i.e., about 5 mM), in order to provide a concentration of sodium sulfate that supports anodic oxidation of the pollutant without introducing excessive salt concentrations to the water that is to be purified. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I). Furthermore, differences in concentration will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical (MPEP § 2144.05(II)(A)). In this case, the teachings of Farhat provide evidence that anodic oxidation proceeds predictably as sodium sulfate concentration is varied over the range in question (pg 14330 right column para 2 - pg 14331 left column para 4; pg 14330 Table 2), suggesting that the concentration is not critical.
Claim 25 is rejected under 35 U.S.C. 103 as being unpatentable over Huang, Branchick, and Tax as applied to claim 16 above, in further view of Weres et al (US 5,439,577 A).
Regarding claim 25, Huang, Branchick, and Tax render obvious the system of claim 16. Huang further teaches monitoring a PFAS concentration both upstream and downstream of the electrochemical cell (per figure 13-14, PFAS concentration downstream of the electrochemical cell is monitored; and para [0097], [0119]-[0122], said monitoring is carried out via liquid chromatography-coupled-mass spectrometry (LCMS); para [0165], “The concentrations of PFAAs will be monitored in the influent, effluent and retentate to measure the efficiency of anodic oxidation”). Huang further discloses monitoring the pH level of the water and the voltage of the electrochemical cell (pg 15 Table 6). However, Huang does not explicitly disclose that the system uses a PFAS concentration sensor, pH sensor, or temperature sensor to carry out the sensing of PFAS concentration, pH, or temperature.
Weres is similarly directed to an electrochemical oxidation system for treating water contaminated with fluoroalkyl substances (abstract, “electrochemical water treatment device for producing hydroxyl free radicals and decomposing by oxidation chemical substances dissolved in water”; col 4 ln 46-51, “We have demonstrated the electrolytic destruction of several organic compounds, including ... a fluoroalkyl foaming agent”), comprising:
an electrochemical cell comprising an inlet for contaminated water, an outlet for treated water, a cathode, and a titanium oxide anode (figure 4, influent water 78 is admitted to a cell inlet, water is discharged from the cell to treated water outlet 90, and the cell comprises a stack of titanium oxide electrodes 80; col 20 ln 63 - col 21 ln 5); and
at least one pH, PFAS concentration, or temperature sensor positioned upstream and/or downstream of the electrochemical cell (col 29 ln 39-48, “Control module 68 monitors the temperature and pH of the water in the device”; figure 4, pH probe 100 is located upstream of the cell; col 17 ln 35 – col 18 ln 20; col 29 ln 39-56, a chemical concentration sensor is located downstream of the cell to monitor a concentration of target contaminant species in water leaving the electrochemical cell); and
a controller in communication with the at least one sensor configured to control a voltage applied to the electrochemical cell in response to the sensor (figure 1 and 9, controller 68; col 29 ln 38-60, “Control module 68 monitors the temperature and pH of the water ... It controls ... power supply module 58 to achieve the level of treatment desired ... by adjusting its output voltage as necessary”).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Huang by incorporating the features, taught in Weres, of using sensors to monitor pH and/or temperature of the water upstream of the electrochemical cell, and contaminant concentration downstream of the cell, and controlling the applied voltage in response to the measured parameter(s), because Huang is directed to monitoring the recited temperature, pH, and PFAS concentration (figure 13-14, para [0097], [0119]-[0122], [0165]), and Weres teaches that sensors are an appropriate way of implementing the monitoring of these parameters for the sake of process control (col 12 ln 30-47, col 29 ln 38-60). The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Claims 27-30 are rejected under 35 U.S.C. 103 as being unpatentable over Huang, Branchick, and Tax as applied to claims 1 and 16 above, and further in view of Duan et al ("Fabrication of a hydrophobic SDBS-PbO2 anode for electrochemical degradation of nitrobenzene in aqueous solution", Electrochimica Acta, 282, 662-671 (2018)).
Regarding claims 27 and 29, Huang, Branchick, and Tax render obvious the system of claim 16 and method of claim 1 respectively. Huang teaches that PFAS, being hydrophobic, can be removed from water by coagulation onto hydrophobic flocs (para [0138]-[0140]). Huang also teaches that adsorption of PFAS on the anode is poor because the anode has a hydrophilic surface (para [0114]), suggesting that interaction between PFAS and the anode would be improved if the anode were made hydrophobic. In this regard, Huang's system is a base invention ready for improvement. Huang does not teach that their anode surface is hydrophobic.
Duan studies the destruction of a hydrophobic organic pollutant (nitrobenzene) from wastewater by anodic oxidation on a lead oxide (PbO2) anode (abstract, pg 667 left column para 4 - right column), and compares an unmodified PbO2 anode to an anode that has been modified with the surfactant SDBS to present a more hydrophobic surface (abstract; figure 4, the "PbO2" anode is more hydrophilic and the "SDBS-PbO2" anodes are more hydrophobic). Duan finds that the hydrophobic anode is more effective than the hydrophilic anode for destruction of the hydrophobic target (pg 667 left column para 4 - pg 668 left column para 1; pg 669 figure 7, showing that nitrobenzene (NB) removal and total organic carbon (TOC) removal were both faster with the SDBS-modified anode than the unmodified anode). Duan additionally finds that the working lifetime of the hydrophobic anode is greater than that of the hydrophilic anode (pg 669 right column para 3 - pg 670 left column para 1).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to modify Huang by making the anode hydrophobic, e.g. by surface functionalization with a surfactant as disclosed in Duan, because Huang is directed to anodic oxidation of a hydrophobic pollutant in wastewater using a metal oxide (Ti4O7) electrode, Duan applies the similar hydrophobic surface modification to a similar device based a metal oxide (PbO2) anode, and Duan teaches that modifying the surface of a metal oxide anode to make it more hydrophobic improves the performance of the anode for oxidation of a hydrophobic contaminant in wastewater. All the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results. The incorporation of a predictable improvement into a known base invention, based on a finding that the prior art contained a comparable device that has been improved in the same way, is prima facie obvious as being part of the ordinary capabilities of one skilled in the art (MPEP 2143(C)).
Regarding claims 28 and 30, these claims further recite that the anode is formed by a process that uses whatever amount of binder is effective to produce a hydrophobic surface. Note that a claim is only limited by positively recited elements, and the patentability of a product does not depend on its method of production. However, claims 28 and 30 do not positively recite any further structural feature of the anode. There is no apparent structural difference between the anode formed according to the process of claims 28 and 30, and the prior art anode of Huang, Branchick, Tax. and Duan. See MPEP 2113 for case law pertaining to product-by-process claims.
Furthermore, since Duan teaches the surface of the anode is hydrophobic (abstract; figure 4, the "PbO2" anode is more hydrophilic and the "SDBS-PbO2" anodes are more hydrophobic; per pg 667 left column para 4 - pg 668 left column para 1 and pg 669 figure 7, removal of the hydrophobic contaminant is faster using the hydrophobic anode than the hydrophilic anode), it follows that, no matter what amount of polymer binder Duan used in the formation of their anode, that amount is enough to achieve the effect of producing a hydrophobic surface. Note that Duan used no polymer binder.
Claims 28 and 30 were rejected above on product-by-process grounds, based on the understanding that the claim language does not actually require the anode to contain a polymer binder. In the interest of compact prosecution, the following alternative ground of rejection is presented.
Claims 27-30 are rejected under 35 U.S.C. 103 as being unpatentable over Huang, Branchick, and Tax as applied to claims 1 and 16 above, and further in view of Zhou et al ("Electrochemical oxidation of PFOA in aqueous solution using highly hydrophobic modified PbO2 electrodes", Journal of Electroanalytical Chemistry, 801, 235-243 (2017)).
Regarding claims 27-30, modified Huang renders obvious the method of claim 1 and the system of claim 16. Huang teaches that PFAS, being hydrophobic, can be removed from water by coagulation onto hydrophobic flocs (para [0138]-[0140]). Huang also teaches that adsorption of PFAS on the anode is poor because the anode has a hydrophilic surface (para [0114]), suggesting that interaction between PFAS and the anode would be improved if the anode were made hydrophobic. In this regard, Huang's system is a base invention ready for improvement.
However, Huang does not teach that their anode surface is hydrophobic, or that the anode is formed with an amount of polymer binder that is effective to make it hydrophobic.
Zhou is directed to decomposing perfluorooctanoic acid (PFOA) in water by electrochemical oxidation at a metal oxide anode (pg 235 abstract; pg 236 left column para 2; pg 242 left column para 2 - right column para 1). Zhou prepares a tin-antimony-lead oxide anode, both with and without a hydrophobic polymer binder of PVDF (pg 236 left column para 236 left column para 4 - right column para 4, "2.2. Fabrication of Ti/PbO2, Ti/SnO2-Sb2O5/PbO2, and Ti/SnO2-Sb2O5/ PbO2-PVDF ... "). Zhou teaches that the addition of PVDF binder is effective to render the anode surface hydrophobic (pg 240 figure 8; pg 239 right column para 1, "As depicted in the Fig. 8, the contact angles of the modified electrodes increased with the introduction of PVDF ... from 73.4 ° to 119.8°"). Zhou also teaches that the anode that is made hydrophobic by addition of polymer binder is more effective for decomposition of PFOA as compared to the anode that does not include the binder (pg 239 left column para 2 and figure 6, the electrodes with PVDF binder display longer lifespans than the electrodes without; pg 240 left column para 1 - pg 242 right column para 1; pg 241 figure 9, PFOA is degraded faster by the anodes that include PVDF binder than by the anodes without the binder).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to modify the anode of Huang by adding a polymer binder that is effective to make the anode surface hydrophobic, because Huang is directed to using the anode to decompose PFAS in wastewater, and Zhou teaches that a metal oxide anode becomes more effective for degrading PFAS in wastewater when the anode is modified by addition of a polymer binder that is effective to make the anode hydrophobic (Zhou pg 235 abstract).
Response to Arguments
Applicant’s arguments, see pg 6-8 of Remarks filed November 6, 2025, with respect to the rejections of claims 1 and 16 under §103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, new grounds of rejection are made in view of Tax.
Claim 1 previously recited:
monitoring at least one parameter selected from pH level, flow rate, voltage, or temperature upstream and/or downstream of the electrochemical cell; and controlling the applied voltage in response to the monitored parameter.
This portion of claim 1 was previously rejected based on teachings from Weres, who discloses monitoring pH and temperature upstream from the electrochemical cell, and controlling the applied voltage in response. Applicant has now amended claim 1 to read:
monitoring at least one parameter selected from or voltage, upstream and/or downstream of the electrochemical cell; and controlling the applied voltage in response to the monitored parameter.
(emphasis added). Claim 16 is amended similarly. Applicant’s argument is, that the §103 rejection should be withdrawn because neither Weres nor the other applied references disclose controlling the applied voltage responsive to flow rate or voltage.
Examiner agrees, the previous §103 rejection has been overcome, and is withdrawn. However, upon further search we find that Tax discloses a related electrochemical water treatment system and method, in which the water flow rate is monitored upstream of the cell, and the oxidation-reduction potential (a voltage) is monitored downstream of the cell, and the applied voltage is controlled responsive to each of these measured parameters. New §103 grounds are therefore established in view of Tax.
Conclusion
Applicant's amendment necessitated the new grounds of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ANDREW KOLTONOW/Examiner, Art Unit 1795
/LUAN V VAN/Supervisory Patent Examiner, Art Unit 1795