DETAILED ACTION
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 .
Election/Restriction
This application contains claims directed to the following patentably distinct species:
Species A, wherein the metal, metal oxide, or combination thereof is bismuth and bismuth oxide and the metal phosphate is a bismuth phosphate, corresponding to claims 3, 10, and 15;
Species B, wherein the metal, metal oxide or combination thereof is zinc and zinc oxide and the metal phosphate is a zinc phosphate, corresponding to claims 6 and 7;
Species C, wherein the metal, metal oxide, or combination thereof is copper and copper oxide, and the metal phosphate is a copper phosphate, corresponding to claim 4; and
Species D, wherein the metal, metal oxide, or combination thereof is iron and iron oxide, and the metal phosphate is an iron phosphate, corresponding to claim 5.
The species are independent or distinct because they require mutually exclusive electrode compositions. In addition, these species are not obvious variants of each other based on the current record.
Applicant is required under 35 U.S.C. 121 to elect a single disclosed species, or a single grouping of patentably indistinct species, for prosecution on the merits to which the claims shall be restricted if no generic claim is finally held to be allowable. Currently, claims 1-2, 8-9, 11-14, and 16-20 are generic to Species A-D.
There is a serious search and/or examination burden for the patentably distinct species as set forth above because at least the following reason(s) apply:
the inventions have acquired separate statuses in the art due to their recognized divergent subject matter;
the inventions require a different field of search (e.g., searching different classes/subclasses or electronic resources, or employing different search strategies or search queries); and/or
the prior art applicable to one invention would likely not be applicable to another invention.
Furthermore, this application contains claims directed to the following patentably distinct species:
Species E, wherein the step of at least partially converting the metal, metal oxide, or combination thereof is carried out electrochemically, corresponding to claims 2-5, 7, 10-15, 17, and 19-20;
Species F, wherein the step of at least partially converting the metal, metal oxide, or combination thereof is carried out non-electrochemically, corresponding to claim 6.
The species are independent or distinct because they require mutually exclusive methods of forming the metal phosphate. In addition, these species are not obvious variants of each other based on the current record.
Applicant is required under 35 U.S.C. 121 to elect a single disclosed species, or a single grouping of patentably indistinct species, for prosecution on the merits to which the claims shall be restricted if no generic claim is finally held to be allowable. Currently, claims 1, 8-9, 16, and 18 are generic to Species E-F.
There is a serious search and/or examination burden for the patentably distinct species as set forth above because at least the following reason(s) apply:
the inventions have acquired separate statuses in the art in view of their different statutory categories;
the inventions have acquired separate statuses in the art due to their recognized divergent subject matter;
the inventions require a different field of search (e.g., searching different classes/subclasses or electronic resources, or employing different search strategies or search queries);
the prior art applicable to one invention would likely not be applicable to another invention; and/or
the inventions are likely to raise different non-prior art issues (i.e., under 35 U.S.C. § 101 and/or 112).
Applicant is advised that the reply to this requirement to be complete must include (i) an election of a species to be examined even though the requirement may be traversed (37 CFR 1.143) and (ii) identification of the claims encompassing the elected species or grouping of patentably indistinct species, including any claims subsequently added. An argument that a claim is allowable or that all claims are generic is considered nonresponsive unless accompanied by an election.
The election may be made with or without traverse. To preserve a right to petition, the election must be made with traverse. If the reply does not distinctly and specifically point out supposed errors in the election of species requirement, the election shall be treated as an election without traverse. Traversal must be presented at the time of election in order to be considered timely. Failure to timely traverse the requirement will result in the loss of right to petition under 37 CFR 1.144. If claims are added after the election, applicant must indicate which of these claims are readable on the elected species or grouping of patentably indistinct species.
Should applicant traverse on the ground that the species, or groupings of patentably indistinct species from which election is required, are not patentably distinct, applicant should submit evidence or identify such evidence now of record showing them to be obvious variants or clearly admit on the record that this is the case. In either instance, if the examiner finds one of the species unpatentable over the prior art, the evidence or admission may be used in a rejection under 35 U.S.C. 103 or pre-AIA 35 U.S.C. 103(a) of the other species.
Upon the allowance of a generic claim, applicant will be entitled to consideration of claims to additional species which depend from or otherwise require all the limitations of an allowable generic claim as provided by 37 CFR 1.141.
During a telephone conversation with Atty. Michelle Manning on 10/21/2025 a provisional election was made without traverse to prosecute the inventions of groups A and E, claims 1, 3, and 8-20. Affirmation of this election must be made by applicant in replying to this Office action. Claims 2 and 4-7 are withdrawn from further consideration by the examiner, 37 CFR 1.142(b), as being drawn to a non-elected invention.
During examination, generic claims 16 and 17 were determined to be allowable over the prior art when only species A (wherein the electrode comprises bismuth, bismuth oxide, and bismuth phosphate) was considered (see below). A partial search of species D (wherein the electrode comprises iron, iron oxide, and iron phosphate) was therefore conducted, upon which the remaining generic claims, as currently drafted, were determined to be unpatentable over the prior art (MPEP § 803.02(III)(C)(2)). No search has been conducted on species B or C.
Applicant is reminded that upon the cancelation of claims to a non-elected invention, the inventorship must be corrected in compliance with 37 CFR 1.48(a) if one or more of the currently named inventors is no longer an inventor of at least one claim remaining in the application. A request to correct inventorship under 37 CFR 1.48(a) must be accompanied by an application data sheet in accordance with 37 CFR 1.76 that identifies each inventor by his or her legal name and by the processing fee required under 37 CFR 1.17(i).
Claim Objections
Claims 3 and 15 are objected to because of the following informalities:
Claims 3 and 15 line 1 recite “the bismuth”, but should recite “bismuth” to be grammatically correct.
Appropriate correction is required.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-3, and 8-9 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Jang and Choi (“Enabling electrochemical N2 reduction to NH3 in the low overpotential region using non-noble metal Bi electrodes via surface composition modification.” J. Mater. Chem. A, 2020, 8, 13842) as evidenced by Lan et al. (“Synthesis of ammonia directly from air and water at ambient temperature and pressure.” SCIENTIFIC REPORTS 3 1145 (2013)).
Regarding claim 1, Jang teaches a method for removing phosphorus from a phosphate ion-containing aqueous solution using an electrochemical cell (“during the potential sweep in the positive direction in the phosphate buffer, the surface of the p-Bi electrode was oxidized to BiPO4” p. 13845 para. bridging cols. 1-2) comprising:
a first electrode in the aqueous solution (“Porous Bi electrodes (p-Bi)” § 2.1. and “A p-Bi electrode was used as a working electrode” § 2.3.), the first electrode comprising bismuth and bismuth oxide (“A p-Bi electrode was used as a working electrode” § 2.3 and “a thin Bi2O3 layer on the surface” § 3.1. para. 2) the method comprising:
at least partially converting bismuth and bismuth oxide in the first electrode into a bismuth phosphate phase in the first electrode (“incorporation of BiPO4 in the Bi surface by the CV process” p. 13845 para. bridging cols. 1-2);
replacing the phosphate ion-containing solution with a second aqueous solution (Fig. 2c and see below);
providing an anode for phosphate recovery in the electrochemical cell (“a graphite rod as the counter electrode” § 2.4 para. 1); and
applying a voltage across the phosphatated first electrode and the anode for phosphate recovery (“ENRR at constant potentials” § 2.4 para. 1), wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into the second aqueous solution (“The Bi 4f XPS spectra of the ap-Bi electrode after the repeated use for the ENRR at -0.3 V further confirmed the presence of BiPO4 during the ENRR; the intensity of the Bi3+ peaks from BiPO4 gradually decreases” p. 13845 col. 2 para. 1, indicating phosphate is released from the ap-Bi electrode due to electrochemical reduction), and drives an oxidation reaction at the anode for phosphate recovery (as the ap-Bi electrode is operated as a cathode, the anode necessarily results in an oxidation reaction, see e.g., Lan Fig. 2 and p. 6 col. 1 para. starting “When N2 …” through para. ending “… oxyfuel combustion”).
Regarding the limitation “replacing the phosphate ion-containing solution with a second aqueous solution”, Fig. 2c shows the Bi electrodes comprising the bismuth phosphate (ap-Bi electrodes) were, in one embodiment, transferred into a solution comprising potassium sulfate, rather than phosphate, for use as cathodes in the electrochemical nitrogen reduction.
Regarding claim 2, Jang further teaches the electrochemical cell comprises a cathode for phosphate removal (“a graphite rod … as a counter … electrode” § 2.3), and the step of at least partially converting the metal, metal oxide, or combination thereof in the first electrode into a metal phosphate phase is carried out electrochemically by applying a voltage across the first electrode and the cathode for phosphate removal (“during the potential sweep in the positive direction in the phosphate buffer, the surface of the p-Bi electrode was oxidized to BiPO4” p. 13845 para. bridging cols. 1-2).
Regarding claim 3, Jang further teaches the first electrode comprises bismuth (“Porous Bi electrodes (p-Bi)” § 2.1. and “A p-Bi electrode was used as a working electrode” § 2.3.) and the metal phosphate is bismuth phosphate (“during the potential sweep in the positive direction in the phosphate buffer, the surface of the p-Bi electrode was oxidized to BiPO4” p. 13845 para. bridging cols. 1-2).
Regarding claim 8, Jang anticipates the limitations of claim 1, as described above. Jang further teaches the phosphate ion-containing aqueous solution has an initial phosphate ion concentration of 0.5 M, a value within the claimed range (“cyclic voltammetry in a 0.5 M phosphate buffer (pH 7.5)” § 2.3).
Regarding claim 9, Jang anticipates the limitations of claim 1, as described above. Jang further teaches the phosphate ion-containing aqueous solution has an initial phosphate ion concentration of 0.5 M, a value within the claimed range (“cyclic voltammetry in a 0.5 M phosphate buffer (pH 7.5)” § 2.3).
Claims 1 and 2 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Groterud and Smoczynski (“Phosphorous Removal from Water by Means of Electrolysis” Wat. Res. 20 (1986) 667-669) as evidenced by Ingelsson et al. (“Electrode passivation, faradaic efficiency, and performance enhancement strategies in electrocoagulation—a review” Water Research 187 (2020) 116433).
Regarding claim 1, Groterud teaches a method for removing phosphorus from a phosphate ion-containing aqueous solution using an electrochemical cell (title) comprising:
a first electrode in the aqueous solution the first electrode comprising iron (“Two electrodes (Al, Fe)” Material and Methods § para. 1 and see Fig. 1) the method comprising:
at least partially converting iron in the first electrode into an iron phosphate phase in the first electrode (“Phosphate is removed by precipitation (AlPO4 or FePO4)” Introduction § para. 1, “P removal and pH as a function of current frequency” Result and Discussion § para 1 and see below);
replacing the phosphate ion-containing solution with a second aqueous solution (“water containing 20 mg Pl-1 [mg P/L] … flows continuously to the electrolyzer” Material and Methods § para. 1, see also para. 2, indicating the solution is continually replaced during the method);
providing an anode for phosphate recovery in the electrochemical cell (“Two electrodes (Al, Fe)” Material and Methods § para. 1);
applying a voltage across the phosphatated first electrode and the anode for phosphate recovery (“changing of the current direction” Material and Methods § para. 1), wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into the second aqueous solution (see below), and drives an oxidation reaction at the anode for phosphate recovery (see below).
Regarding the limitation “at least partially converting the metal, metal oxide, or combination thereof in the first electrode into a metal phosphate phase in the first electrode, the metal phosphate phase comprising iron phosphate”, the method of Groterud teaches that phosphate is removed from the solution by application of an anodic potential to an iron electrode (Material and Methods § para. 1) to form iron phosphate (Introduction § para. 1) and that during this process fouling occurs at the surface of the anode (p. 669 para. bridging cols. 1-2). As evidenced by Ingelsson, when an iron anode is used to form iron phosphate, a portion of the iron phosphate is formed as a layer on the anode (see e.g., Fig. 3) causing fouling. It is therefore considered that the fouling layer at the surface of the anode in the method of Groterud at least partially comprises iron phosphate. The method of Groterud therefore inherently anticipates the limitation “at least partially converting the metal, metal oxide, or combination thereof in the first electrode into a metal phosphate phase in the first electrode, the metal phosphate phase comprising iron phosphate” (MPEP § 2112).
Regarding the limitation “wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into the second aqueous solution”, Groterud teaches that a cathodic potential is applied to the phosphatated iron i.e., first, electrode for 256 s (Result and Discussion § para. 2) to clean the electrodes (abstract) i.e., to remove the fouling layer which, as evidenced by Ingelsson, comprises iron phosphate (see e.g. Fig. 3). The instant specification indicates that application of a cathodic potential to a phosphatated iron electrode results in a reduction of the iron phosphate phase, with a concurrent release of phosphate ions (para. 70). It is therefore considered that the cathodic voltage applied to the phosphatated iron electrode in the method of Groterud necessarily results in at least a partial reduction of the metal phosphate phase, thereby releasing phosphate ions into the second aqueous solution. Groterud therefore inherently anticipates the limitation “wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into the second aqueous solution” (MPEP § 2112).
Regarding the limitation “and drives an oxidation reaction at the anode for phosphate recovery”, the method of Groterud results in a chemical reduction at the phosphatated first electrode i.e., the potential applied to the first electrode is reversed every 256 s (Result and Discussion § para. 2). As evidenced by e.g., the instant specification, an electrochemical reduction reaction at a cathode necessarily results in an oxidation reaction at the anode (see e.g., paras. 31-39). Therefore, the voltage applied in the method of Groterud necessarily drives an oxidation reaction at the anode for phosphate recovery. Groterud therefore inherently anticipates the limitation “and drives an oxidation reaction at the anode for phosphate recovery”.
Claim Rejections - 35 USC § 102/103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 11 and 18 are rejected under 35 U.S.C. 102(a)(1) as anticipated by or, in the alternative, under 35 U.S.C. 103 as obvious over Jang and Choi (“Enabling electrochemical N2 reduction to NH3 in the low overpotential region using non-noble metal Bi electrodes via surface composition modification.” J. Mater. Chem. A, 2020, 8, 13842) and as evidenced by Lan et al. (“Synthesis of ammonia directly from air and water at ambient temperature and pressure.” SCIENTIFIC REPORTS 3 1145 (2013).
Regarding claim 11, Jang anticipates the limitations of claim 2, as described above.
Jang does not explicitly teach a water reduction reaction is carried out at the cathode for phosphate removal, but is silent as to the reaction at the cathode during phosphate removal. However, the system of Jang comprises water (§ 2.3), and the instant specification teaches that a water reduction reaction is carried out at the cathode during removal of phosphate at a Bi anode (paras. 32-34 and Fig. 1). It is therefore considered that the method of Jang necessarily carries out at least some reduction of water at the cathode for phosphate removal. Jang therefore inherently anticipates the limitation “a water reduction reaction is carried out at the cathode for phosphate removal” (MPEP § 2112).
Alternatively, because the system of Jang comprises water (§ 2.3), and the instant specification teaches that a water reduction is carried out at the cathode during removal of phosphate at a Bi anode (paras. 32-34 and Fig. 1), a person having ordinary skill in the art would have found it obvious that the method of Jang carries out at least some reduction of water at the cathode for phosphate removal. Jang therefore renders the limitation “a water reduction reaction is carried out at the cathode for phosphate removal” obvious.
Regarding claim 18, Jang anticipates the limitations of claim 1, as described above.
Jang does not explicitly teach a water oxidation reaction is carried out at the anode for phosphate recovery, but is rather silent as to the reaction carried out at the anode for phosphate recovery. However, the system of Jang comprises only nitrogen, phosphate and water (§ 2.4), and, as evidenced by Lan, the electrochemical reduction of nitrogen must be accompanied by a corresponding oxidation of water at the anode in the absence of a sacrificial reductant (see e.g., Fig. 2 and p. 6 col. 1 para. starting “When N2 …” through para. ending “… oxyfuel combustion”). It is therefore considered that the method of Jang necessarily at least partially carries out a water oxidation reaction at the anode for phosphate recovery. Jang therefore inherently anticipates the limitation “a water oxidation reaction is carried out at the anode for phosphate recovery” (MPEP § 2112).
Alternatively, because the system of Jang comprises only nitrogen, phosphate and water (§ 2.4), and, as evidenced by Lan, the electrochemical reduction of nitrogen must be accompanied by a corresponding oxidation of water at the anode in the absence of a sacrificial reductant (see e.g., Fig. 2 and p. 6 col. 1 para. starting “When N2 …” through para. ending “… oxyfuel combustion”), a person having ordinary skill in the art would have found it obvious that the method of Jang at least partially carries out a water oxidation reaction at the anode for phosphate recovery. Jang therefore renders the limitation “a water oxidation reaction is carried out at the anode for phosphate recovery” obvious.
Claim Rejections - 35 USC § 103
Claims 1-3, 8, 12-13, and 18-20 are rejected under 35 U.S.C. 103 as being unpatentable over Mindler (US Pat. No. 4632737) in view of Lei et al. (“Electrochemical recovery of phosphorus from wastewater using tubular stainless-steel cathode for a scalable long-term operation” Water Research 199 (2021) 117199), and as evidenced by, in the case of claim 12, Vanysek (“The Electrochemical Series” in CRC Handbook of Chemistry and Physics, 104th Ed. (Internet Version 2023), John R. Rumble, ed., CRC Press/Taylor & Francis, Boca Raton, FL).
Regarding claim 1, Mindler teaches a method for removing phosphorus from a phosphate ion-containing aqueous solution using an electrochemical cell (see below) comprising:
a first electrode in the aqueous solution, the first electrode comprising bismuth and bismuth oxide (“a purple/-brown bismuth pentoxide is formed on the anode” col. 1 line 66 – col. 2 line 15) the method comprising:
at least partially converting the bismuth and bismuth oxide in the first electrode into a bismuth phosphate phase in the first electrode (see below);
providing an anode for phosphate recovery in the electrochemical cell (“a black metallic coating of bismuth is formed on the cathode” and “During current reversal the bismuth is sloughed off from the cathode and some is converted to bismuth pentoxide on the new anode surface” col. 1 line 66 – col. 2 line 15); and
applying a voltage across the phosphatated first electrode and the anode for phosphate recovery (“a purple/-brown bismuth pentoxide is formed on the anode” and “the bismuth pentoxide which was on the anode is solubilized to sodium bismuthate and the remainder reduced to metallic bismuth on the new cathode” col. 1 line 66 – col. 2 line 23), wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into an aqueous solution (see below) and drives an oxidation reaction at the anode for phosphate recovery (“During current reversal the bismuth is sloughed off from the cathode and some is converted to bismuth pentoxide on the new anode surface” col. 1 line 66 – col. 2 line 15).
Regarding the limitation “a method for removing phosphorus from a phosphate ion-containing aqueous solution using an electrochemical cell”, Mindler teaches the application of a potential of 3-4 V (Table 5) to convert bismuth to bismuth oxide (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1). As evidenced by the instant specification, application of a potential sufficient to produce bismuth oxide is sufficient to form bismuth phosphate (see e.g., paras. 42-43 and Fig. 3). It is therefore considered that the method of Mindler necessarily results in at least a partial removal of phosphorous from the phosphate ion-containing aqueous solution used, due to the formation of bismuth phosphates. Mindler therefore reads on the limitation “a method for removing phosphorus from a phosphate ion-containing aqueous solution using an electrochemical cell”.
Alternatively, because Mindler teaches the application of a potential of 3-4 V (Table 5) to convert bismuth to bismuth oxide (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1), and the instant specification indicates application of a potential sufficient to produce bismuth oxide is sufficient to form bismuth phosphate (see e.g., paras. 42-43 and Fig. 3), a person having ordinary skill in the art would have found it obvious that the method of Mindler results in at least a partial removal of phosphorous from the phosphate ion-containing aqueous solution used, due to the formation of bismuth phosphates. Mindler therefore renders the limitation “a method for removing phosphorus from a phosphate ion-containing aqueous solution using an electrochemical cell” obvious.
Regarding the limitation “at least partially converting the metal, metal oxide, or combination thereof in the first electrode into a metal phosphate phase in the first electrode, the metal phosphate phase comprising bismuth phosphate”, Mindler teaches the application of a potential of 3-4 V (Table 5) to convert bismuth to bismuth oxide (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1). As evidenced by the instant specification, application of a potential sufficient to produce bismuth oxide is sufficient to form bismuth phosphate (see e.g., paras. 42-43 and Fig. 3). It is therefore considered that the method of Mindler necessarily results in at least a partial conversion of the bismuth on the first electrode to a bismuth phosphate phase. Mindler therefore reads on the limitation “at least partially converting the metal, metal oxide, or combination thereof in the first electrode into a metal phosphate phase in the first electrode, the metal phosphate phase comprising bismuth phosphate”.
Alternatively, because Mindler teaches the application of a potential of 3-4 V (Table 5) to convert bismuth to bismuth oxide (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1) and, as evidenced by the instant specification, application of a potential sufficient to produce bismuth oxide is sufficient to form bismuth phosphate (see e.g., paras. 42-43 and Fig. 3), a person having ordinary skill in the art would have found it obvious that the method of Mindler results in at least a partial conversion of the bismuth on the first electrode to a bismuth phosphate phase. Mindler therefore render the limitation “at least partially converting the metal, metal oxide, or combination thereof in the first electrode into a metal phosphate phase in the first electrode, the metal phosphate phase comprising bismuth phosphate” obvious.
Mindler does not explicitly teach replacing the phosphate ion-containing solution with a second aqueous solution.
However, Lei teaches a method of purifying water using a continuous process (abstract), i.e., wherein the phosphate ion-containing solution is continually replaced with a fresh (i.e., second) solution, which provides the predictable benefit of allowing the system to operate with reduced maintenance relative to a batch system (abstract).
As Mindler teaches a method for purifying water using electrodes comprising bismuth, Mindler is analogous art to the instant invention. As Lei teaches a method of removing phosphorous from wastewater, Lei is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mindler, such that the method is a continuous method, as taught by Lei. I.e., such that the phosphate ion-containing solution is continuously replaced with a second aqueous solution. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefit of reducing the required maintenance, as taught by Lei. Furthermore, simple substitution of one known element for another (i.e., using a continuous rather than batch process) to achieve predictable results (purification of a water stream) establishes a prima facie case of obviousness (MPEP § 2143(I)(B)).
Regarding the limitation “wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into the second aqueous solution”, Mindler teaches the application of a potential of -3-4 V (Table 5) to convert bismuth oxide to bismuth (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1). As evidenced by the instant specification, application of a potential of -3 V is substantially greater than that required to reduce bismuth phosphate to bismuth, and thereby release phosphate into an aqueous solution (see e.g., para. 41). It is therefore considered that the method of Mindler necessarily results in at least a partial reduction of the metal phosphate phase in the phosphatated first electrode, releasing phosphate ions into the aqueous solution i.e., the second aqueous solution in modified Mindler. Modified Mindler therefore reads on the limitation “wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into the second aqueous solution”.
Alternatively, because Mindler teaches the application of a potential of -3-4 V (Table 5) to convert bismuth oxide to bismuth (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1) and, as evidenced by the instant specification, application of a potential of -3 V is substantially greater than that required to reduce bismuth phosphate to bismuth, and thereby release phosphate into an aqueous solution (see e.g., para. 41), a person having ordinary skill in the art would have found it obvious that the method of Mindler results in at least a partial reduction of the metal phosphate phase in the phosphatated first electrode, releasing phosphate ions into the aqueous solution i.e., the second aqueous solution in modified Mindler. Modified Mindler therefore renders the limitation “wherein the voltage drives a reduction of the metal phosphate phase in the first electrode, releasing phosphate ions into the second aqueous solution” obvious.
Regarding claim 2, Modified Mindler, via Mindler, further teaches the electrochemical cell comprises a cathode for phosphate removal (“a black metallic coating of bismuth is formed on the cathode” col. 1 line 66 – col. 2 line 15), and
the step of at least partially converting the metal, metal oxide, or combination thereof in the first electrode into a metal phosphate phase is carried out electrochemically by applying a voltage across the first electrode and the cathode for phosphate removal (“In the operation of the process, a black metallic coating of bismuth is formed on the cathode and a purple/-brown bismuth pentoxide is formed on the anode” col. 1 line 66 – col. 2 line 15).
Regarding claim 3, Modified Mindler, via Mindler, further teaches the first electrode comprises bismuth (“a purple/-brown bismuth pentoxide is formed on the anode” col. 1 line 66 – col. 2 line 15) and the metal phosphate is a bismuth phosphate (see below).
Regarding the limitation “the metal phosphate is a bismuth phosphate”, Mindler teaches the application of a potential of 3-4 V (Table 5) to convert bismuth to bismuth oxide (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1). As evidenced by the instant specification, application of a potential sufficient to produce bismuth oxide is sufficient to form bismuth phosphate (see e.g., paras. 42-43 and Fig. 3). It is therefore considered that the method of Mindler necessarily results in at least a partial conversion of the bismuth on the first electrode to a bismuth phosphate phase. Modified Mindler therefore reads on the limitation “the metal phosphate is a bismuth phosphate”.
Alternatively, because Mindler teaches the application of a potential of 3-4 V (Table 5) to convert bismuth to bismuth oxide (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1) and, as evidenced by the instant specification, application of a potential sufficient to produce bismuth oxide is sufficient to form bismuth phosphate (see e.g., paras. 42-43 and Fig. 3), a person having ordinary skill in the art would have found it obvious that the method of Mindler results in at least a partial conversion of the bismuth on the first electrode to a bismuth phosphate phase. Modified Mindler therefore renders the limitation “the metal phosphate is a bismuth phosphate” obvious.
Regarding claim 8, modified Mindler teaches the limitations of claim 1, as described above.
Mindler further teaches the phosphate ion-containing aqueous solution has an initial phosphate ion concentration of about 8*10-3 M, a value within the claimed range (Table 1, see calculations below).
Calculations: The concentration of phosphate in the solution was calculated using the weight percent of Na3PO4 reported in table 1 (0.13%), dividing by the molar mass of trisodium phosphate (about 164 g/mol) and presuming the aqueous solution has a density of about 1 kg/L, giving a value of 7.9*10-3 M.
Regarding claim 12, modified Mindler teaches the limitations of claim 2, as described above.
Mindler further teaches the system contains oxygen gas (col. 2 line 62 – col. 3 line 8), and the applied potential is between 2 and 4 volts (col. 3 line 52 – col. 4 line 6), a potential significantly greater than that to reduce oxygen gas (see e.g., Vanysek p. 3 col. 1 near bottom of page).
It is therefore considered that the method of Mindler necessarily carries out at least some oxygen reduction reaction at the cathode for phosphate removal. Mindler (and modified Mindler) therefore render the limitation “an oxygen reduction reaction is carried out at the cathode for phosphate removal” obvious.
Regarding claim 13, modified Mindler teaches the limitations of claim 1, as described above.
Mindler further teaches a metal ion reduction reaction is carried out at the cathode for phosphate removal (“a black metallic coating of bismuth is formed on the cathode” col. 1 line 66 – col. 2 line 15).
Regarding claim 18, modified Mindler teaches the limitations of claim 1, as described above.
Mindler further teaches a water oxidation reaction is carried out at the anode for phosphate recovery (“The outlet gases from the cell contain a mixture of ammonia, nitrogen, and oxygen.” col. 2 line 62 through col. 3 line 8, “The substrate solutions comprise water” col. 3 lines 14-51, and “thereby producing oxygen gases at said anodes” claim 1).
Regarding claim 19, modified Mindler teaches the limitations of claim 2, as described above.
Mindler further teaches the cathode for phosphate removal and the anode for phosphate recovery are the different electrodes (“a black metallic coating of bismuth is formed on the cathode” and “During current reversal the bismuth is sloughed off from the cathode and some is converted to bismuth pentoxide on the new anode surface” col. 1 line 66 – col. 2 line 15, and Fig. 1 shows the electrolysis cell comprises two groups of three and four electrodes. Therefore, during the current reversal step, both the same electrode that served as the “cathode for phosphate removal” and at least two additional electrodes each serve as “anodes for phosphate recovery”).
Regarding claim 20, modified Mindler teaches the limitations of claim 2, as described above.
Mindler further teaches the cathode for phosphate removal and the anode for phosphate recovery are the same electrode (“a black metallic coating of bismuth is formed on the cathode” and “During current reversal the bismuth is sloughed off from the cathode and some is converted to bismuth pentoxide on the new anode surface” col. 1 line 66 – col. 2 line 15).
Claims 14-15 are rejected under 35 U.S.C. 103 as being unpatentable over Mindler in view of Lei, as applied to claim 2, and further in view of Bradbury (US Pat. No. 5306400).
Regarding claim 14, modified Mindler teaches the limitations of claim 2, as described above.
Modified Mindler does not teach the metal ion is an iron ion, a zinc ion, or a copper ion.
However, Bradbury teaches that copper and stainless steel are suitable alternatives to nickel as electrode materials (“The cathode may be any material which is a good cathode material for the reduction of nitrogen, such as copper, stainless steel or nickel” col. 4 lines 17-24) in a water purification cell configured to remove nitrate (title).
As Bradbury teaches a method of electrochemical water purification, Bradbury is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mindler, such that the electrodes comprise copper or iron (i.e., stainless steel), and therefore such that the metal ion comprises iron or copper in addition to bismuth, as taught by Bradbury. A person having ordinary skill in the art would have been motivated to make this modification because Bradbury teaches copper and stainless steel are good cathode materials for the reduction of nitrogen. Use of a material known in the art as suitable for a purpose establishes a prima facie case of obviousness (MPEP § 2144.07).
Regarding claim 15, Mindler further teaches the first electrode comprises bismuth (“a purple/-brown bismuth pentoxide is formed on the anode” col. 1 line 66 – col. 2 line 15) and the metal phosphate is a bismuth phosphate (see below).
Regarding the limitation “the metal phosphate is a bismuth phosphate”, Mindler teaches the application of a potential of 3-4 V (Table 5) to convert bismuth to bismuth oxide (col. 1 line 66 – col. 2 line 15) in a solution containing sodium phosphate (Table 1). As evidenced by the instant specification, application of a potential sufficient to produce bismuth oxide is sufficient to form bismuth phosphate (see e.g., paras. 42-43 and Fig. 3). It is therefore considered that the method of Mindler necessarily results in at least a partial conversion of the bismuth on the first electrode to a bismuth phosphate phase. Mindler therefore reads on the limitation “the metal phosphate is a bismuth phosphate”.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Groterud and Smoczynski (“Phosphorous Removal from Water by Means of Electrolysis” Wat. Res. 20 (1986) 667-669) in view of Sakakibara and Nakajima (“Phosphate removal and recovery by a novel electrolytic process” Water Science and Technology 46 (2002) 147-152).
Regarding claim 13, Groterud anticipates the limitations of claim 2, as described in the rejection under 35 U.S.C. § 102(a)(1) above, incorporated herein by reference.
Goterud does not teach a metal ion reduction reaction is carried out at the cathode for phosphate removal. However, Sakakibara teaches that during electrochemical phosphate removal using an iron anode (“ion [sic] electrodes are immersed in synthetic wastewater …” abstract), metal ions present in the wastewater feed i.e., Cu2+, can be reduced and deposited on the cathode to balance the reaction (abstract).
As Goterud and Sakakibara each teach electrochemical methods for removing phosphate from water, Goterud and Sakakibara are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to apply the method of Goterud to wastewaters comprising metal ions i.e., Cu2+, thereby resulting in a metal ion reduction reaction is carried out at the cathode for phosphate removal, as taught by Sakakibara. A person having ordinary skill in the art would have been motivated to make this modification because Goterud suggests applying their method to wastewater (Introduction § para. 1), and Sakakibara teaches application of this method to wastewater containing metal ions results in the benefit of additionally removing those metal ions from the wastewater. Furthermore, simple substitution of one known element for another (i.e., using wastewater comprising metal ions rather than simulated wastewater in the method of Goterud) to achieve predictable results (reducing metal ions at the cathode) establishes a prima facie case of obviousness (MPEP § 2143(I)(B)).
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Groterud and Smoczynski (“Phosphorous Removal from Water by Means of Electrolysis” Wat. Res. 20 (1986) 667-669) in view of Ben Salah (US Pat. Pub. 2022/0289599 A1).
Regarding claim 16, Groterud anticipates the limitations of claim 1, as described in the rejection under 35 U.S.C. § 102(a)(1) above, incorporated herein by reference.
Groterud does not teach the phosphate ion-containing aqueous solution comprises metal phosphates obtained from a chemical or electrochemical coagulation process or from a biological phosphate removal process.
However, Ben Salah teaches a method for purifying water in a plurality of electrochemical systems (abstract and Fig. 13) comprising iron anodes and cathodes (paras. 112-113), wherein the output of a first electrochemical system is used as the feed in a subsequent electrochemical system (para. 59 and Fig. 13), which provides the predictable benefit of removing additional impurities not removed in the first electrochemical system (e.g., para. 134).
As Groterud teaches an electrochemical method for removing phosphate from water, Groterud is analogous art to the instant invention. As Ben Salah teaches methods for removing contaminants from water using iron electrodes, Ben Salah is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the system of Groterud, such that it comprises multiple electrochemical systems arranged in series i.e., such that a second electrochemical system operates on a phosphate ion-containing aqueous solution comprising metal phosphates obtained from a chemical or electrochemical coagulation i.e., from a first electrochemical system, as taught by Ben Salah. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefit of improving the removal of contaminants, as taught by Ben Salah. Furthermore, combining prior art elements according to known methods to yield predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(A)).
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Groterud in view of Sakakibara, as applied to claim 13, and further in view of Ben Salah (US Pat. Pub. 2022/0289599 A1).
Regarding claim 17, modified Groterud teaches the limitations of claim 13, as described above.
Modified Groterud does not teach the phosphate ion-containing aqueous solution comprises metal phosphates obtained from a chemical or electrochemical coagulation process.
However, Ben Salah teaches a method for purifying water in a plurality of electrochemical systems (abstract and Fig. 13) comprising iron anodes and cathodes (paras. 112-113), wherein the output of a first electrochemical system is used as the feed in a subsequent electrochemical system (para. 59 and Fig. 13), which provides the predictable benefit of removing additional impurities not removed in the first electrochemical system (e.g., para. 134).
As Ben Salah teaches methods for removing contaminants from water using iron electrodes, Ben Salah is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the system of Groterud, such that it comprises multiple electrochemical systems arranged in series i.e., such that a second electrochemical system operates on a phosphate ion-containing aqueous solution comprising metal phosphates obtained from a chemical or electrochemical coagulation i.e., from a first electrochemical system, as taught by Ben Salah. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefit of improving the removal of contaminants, as taught by Ben Salah. Furthermore, combining prior art elements according to known methods to yield predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(A)).
Allowable Subject Matter
Claim 10 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Furthermore, claims 16-17 are rejected as currently drafted, but would be considered allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims and to require that the first electrode comprising a metal, metal oxide, or a combination therefore is bismuth and bismuth oxide and the metal phosphate phase comprising a metal phosphate is bismuth phosphate(s).
The following is a statement of reasons for the indication of allowable subject matter:
Regarding claim 10, the prior art of record, alone or in combination, does not disclose or render obvious the cumulative limitations of claim 10, with a particular emphasis on the limitations “the first electrode comprises the bismuth and the metal phosphate is a bismuth phosphate” and “the second aqueous solution is acidic and the phosphate ions released into the second aqueous solution form phosphoric acid”.
The closest prior art of record is considered to be Jang and Choi (“Enabling electrochemical N2 reduction to NH3 in the low overpotential region using non-noble metal Bi electrodes via surface composition modification.” J. Mater. Chem. A, 2020, 8, 13842), Mindler (US Pat. No. 4632737), Lei et al. (“Electrochemical recovery of phosphorus from wastewater using tubular stainless-steel cathode for a scalable long-term operation” Water Research 199 (2021) 117199), and Choi (US Pat. Pub. 2018/0201524 A1).
Jang is considered to anticipate the limitations of claim 3, as described above. However, Jang teaches the second aqueous solution has a neutral, rather than acidic, pH i.e., pH 7.5. Furthermore, the purpose of the method of Jang is reduction of nitrogen gas. As is understood in the art, under low pH conditions reduction of protons to hydrogen gas interferes with the reduction of nitrogen gas. It is therefore considered that any attempts to modify the method of Jang such that the second aqueous solution is acidic would render the method unsatisfactory for its intended purpose, and would therefore be non-obvious (MPEP § 2143.01(V)).
Mindler in view of Lei is considered to render the limitations of claim 3 prima facie obvious, as described above. However, Mindler teaches the aqueous solution (i.e., the second aqueous solution in modified Mindler) is strongly alkaline (4.2 % NaOH by weight, Table 1) rather than acidic, and further teaches the primary aim of the method is the removal of nitrate and nitrite, rather than phosphate (abstract), and teaches nickel is used as a substrate for the bismuth and bismuth oxide electrodes (col. 2 line 62 – col. 3 line 8).
Choi teaches that bismuth electrodes are capable of purifying highly acidic waste streams (“pH 1.15” para. 53). However, Choi is silent as to the effect of the pH on the removal of phosphate and/or nitrite. Given the highly alkaline environment and nickel base electrode material used in the method of Mindler, it is considered that a person having ordinary skill in the art would not have had a reasonable expectation of success modifying the method of Mindler to use an acidic feed based on the teachings of Choi.
The cumulative limitations of Claim 10 are therefore considered patentably distinguished over the prior art, and would be allowable if rewritten in independent form and incorporating all limitations of the base claim and any intervening claims.
Regarding claims 16-17, the prior art of record, alone or in combination, does not disclose or render obvious the cumulative limitations of claims 16 or 17, with a particular emphasis on the limitations “the first electrode comprising … bismuth, bismuth oxide,” and