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 .
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 03/07/2023 and 03/14/2024 have been considered by the examiner.
Claim Rejections - 35 USC § 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
Claims 1-21 are rejected under 35 U.S.C. 103 as being unpatentable over Custelcean et al., (US 2019/0010118 A1, hereinafter as “Custelcean”) in view of Seipp et al., (Journal of Visualized Experiments, 2016, hereinafter as “Seipp”).
Regarding claim 1, Custelcean teaches a method for removing oxyanions from water containing sulfate and said oxyanions (Abstract; ¶ [0007]), the method comprising:
(i) dissolving an oxyanion precipitating compound into the aqueous source to result in precipitation of an oxyanion salt of the oxyanion precipitating compound into the aqueous source to precipitate an oxyanion-containing salt followed by removing the precipitated salt from solution (¶ [0008]), wherein the oxyanions is selected from the group consisting of sulfate, nitrate , chromate , selenate , phosphate , arsenate , carbonate , or bicarbonate (¶ [0007]), wherein the oxyanion precipitating compound is added to the aqueous source in an amount corresponding to at least , and generally above , the molar amount of oxyanion expected to be contained within a sample of aqueous source to be processed (¶ [0038]); and
(ii) removing the precipitated salt, where the anionic species being removed is the sulfate oxyanion from the aqueous source to result in a supernatant exceeding 90% sulfate removal compared to the initial sulfate concentration of the aqueous source (Table 3, ¶¶ [0039, 0080-0081]);
wherein the oxyanion precipitating compound has the following structure:
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wherein:
In the above Formula (la), A is a ring-containing moiety (i.e., a ring linker can contain 3-12 carbon atoms) (¶ [0029]);
R1 and R2 are independently selected from H atoms and one or more of the hydrogen atoms in Formula (la), whether the hydrogen atoms are shown or not shown, may be replaced with one or more methyl groups (¶ [0033]);
Xm- is an anionic species with a magnitude of charge m, where m is an integer of at least 1 , provided that Xm- is an anionic species exchangeable with the oxyanion (i.e., sulfate, chromate, arsenate, selenate) in the aqueous source before the oxyanion precipitating compound contacts the oxyanion in step (i) (¶ [0009]), and Xm- is the oxyanion in the resulting oxyanion salt formed in step (i) and as separated from the water in step (ii) (¶ [0009]); and
the subscript n is an integer of at least 1;
provided that n x m = 2. Moreover, one or more of the hydrogen atoms in Formula (la), whether the hydrogen atoms are shown or not shown, may be replaced with one or more methyl groups, respectively (¶ [0009]).
But, Custelcean does not explicitly disclose sulfate in the aqueous source is in a molar concentration equal to or greater than the total molar concentration of the toxic oxyanion.
However, Seipp teaches a simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG) (Abstract).
Seipp discloses sulfate-selective crystallization using BBIG in a sulfate-rich (30 mM) aqueous systems with other oxyanions (i.e., chromate, phosphate) to form extremely insoluble salt that can be easily removed from solution by simple filtration (p. 1, introduction, second paragraph, lines 7-9; Table 1, Representative results from sulfate separation from seawater, The initial sulfate concentration was 30 mM) and sulfate molar concentration was optimized to improve % sulfate removal rate (Table 1, page 4). This disclosure of Seipp implies that the sulfate concentration having a molar concentration equal to or greater than the total molar concentration of the toxic oxyanion (i.e., chromate, phosphate) in aqueous source is a routine optimization as shown in Table 1 where sulfate molar concentration is adjusted to enhance sulfate removal in aqueous solution (Table 1, page 4, sulfate removed (%)) and as evidenced by Einkauf (JACS, 2023, p. 886, right column, second paragraph, lines 20-23) that the large excess of sulfate present in the wastewater enhance removal of trace amounts of oxyanions.
Custelcean and Seipp are analogous because both references are directed to aqueous sulfate/oxyanion removal using bis-iminoguanidinium crystallization chemistry.
Therefore, before the effective filing date of the claimed invention, it would have been prima facie obvious to one of ordinary skill in the art to use the bis-iminoguanidinium (BIG) oxyanion precipitation process by Custelcean under sulfate-rich crystallization condition taught by Seipp because such modification would predictably enhance precipitation and removal of oxyanions from sulfate-containing aqueous systems by forming low-solubility co-crystalline salts removable by solid-liquid separation (Seipp: p. 1, introduction, second paragraph, lines 7-9; p. 5, Discussion, fourth paragraph, lines 4-5), and further evidenced by Einkauf (JACS, 2023, p. 886, right column, second paragraph, lines 20-23) that the large excess of sulfate present in the wastewater help remove trace amounts of oxyanions (i.e., selenate) by co-crystallization with 1,4-benzene-bis (iminoguanidine) (BBIG) or (2, 6 -pyridine-bis(iminoguanidine) (PyBIG), down to sub-ppb levels of Se.
In regard to claims 2, 3, 4, 5, 6, and 7, Custelcean discloses structurally related bis-iminoguanidinium oxyanion precipitating compounds useful for removing oxyanions from aqueous sources (¶ [0032]),
For claim 2, Custelcean discloses formula (1a) bis-iminoguanidinium compounds having the claimed cationic guanidinium/hydrazone framework with exchangeable (Xm-) (Fig. 1a, ¶ [0007-0009]), and further discloses glyoxal- bis-iminoguanidinium/GBIG type compounds in which the two imine carbon atoms are directly connected without the intervening hydrocarbon linker (¶ [0073])
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1a. Modified the structure from Custercean by adding the R1 and R2 for emphasis: R1 and R2 = contain H atoms
For claim 3, Custelcean discloses methyl-substituted embodiments wherein one of more of the hydrogen atoms in formula (1a) may be replaced with one or more methyl groups (¶ [0113]), making selection of at least one methyl group for R1 or R2 an obvious structural variant.
For claim 4, Custelcean discloses that the central linking moiety may include a ring-containing portion (¶ [0113]).
For claim 5, Custelcean specifically discloses benzene/aromatic ring-containing bis-iminoguanidinium compounds (Fig. 1a-1; (¶ [0030]).
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1a-1. Modified the structure from Custelcean by adding the R1 and R2 for emphasis: R1 and R2 = contain H atoms
For claim 6, Custelcean specifically discloses pyridine ring-containing bis-iminoguanidinium compounds [Fig. 1a-4, (¶ [0031]).
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1a-4. Modified the structure from Custelcean by adding the R1 and R2 for emphasis: R1 and R2 = contain H atoms.
For claim 7, Custelcean discloses BIG species including 1,4-benzene-bis (iminoguanidine (BBIG)/ (2, 6 -pyridine-bis(iminoguanidine) PyBIG-type for precipitating oxyanions from aqueous sources (¶¶ [0032). Seipp further confirms that a bis-iminoguanidinium such as BBIG crystallizes sulfate from aqueous solution (p. 1, introduction, second paragraph, lines 7-9; Table 1, Representative results from sulfate separation from seawater, The initial sulfate concentration was 30 mM). Therefore, selecting the claimed bond, methyl, aromatic, pyridyl, and named BIG species would have been obvious because they are known structurally related oxyanion-precipitating compounds used for the same aqueous oxyanion-removal purpose (Custelcean: ¶¶ [0028-0032, 0039]).
In regard to claims 8 and 11, Custelcean discloses that Xm-, before contact with the aqueous source, maybe a halide, such as fluoride, chloride, bromide, or, iodide (¶ [0028]).
For claim 8, this teaches the claimed halide species Xm- before the oxyanions precipitating compounds contacts the aqueous sources (¶¶ [0028, 0037]).
For claim 11, this discloses the claimed acid-forming anion (X) selected from chloride, bromide, or iodide for reforming oxyanions precipitating compound (¶¶ [0028, 0037). Custelcean further discloses that the initial halide or pseudohalide is exchangeable with target oxyanions such as sulfate, chromate, selenate, arsenate, carbonate, bicarbonate and perchlorate during precipitation (¶¶ [0036-0037]). Seipp likewise uses BBIG as a chloride salt before sulfate crystallization (p. 1, introduction, second paragraph, lines 7-9; Table 1, Representative results from sulfate separation from seawater, The initial sulfate concentration was 30 mM).
In regard to claim 9, Custelcean discloses removal of oxyanions including selenate, chromate, arsenate, sulfate, nitrate, phosphate, carbonate, bicarbonate and perchlorate from aqueous sources (¶ [0037). Thus, the claimed toxic oxyanions comprising selenate would have been expressly taught, and use for selenite would have been obvious closely related selenium oxyanion selection for the same water-treatment purpose because the process is directed broadly to oxyanion removal from aqueous media, and the claim merely selects selenium oxyanions from the broader toxic anion group and Se exist in a variety of forms in industrial wastewater, it is present largely as selenate and selenite oxyanions as evidenced by Einkauf et al., (ACS Environ. Au, 2026, p. 116, Introduction, left column, first paragraph, lines 15-18).
In regard to claim 10 and 13, Custelcean discloses regeneration and reuse of the bis-iminoguanidinium precipitating compound after oxyanion removal (¶¶ [0040, 0092, 0111]).
For claim 10, Custelcean discloses reacting the precipitated oxyanion salt with a base to convert the cationic precipitating compound to its neutral form while releasing the bound oxyanion as a byproduct salt, followed by regeneration of the starting oxyanion precipitating compound (¶ [0040).
For claim 13, the additional step of combining precipitated salts before regeneration would have been an obvious process-handling step because such recovery and regeneration of the precipitated oxyanion salt to reduce reagent cost and environmental impact (Custelcean: ¶ [0040).
In regard to claims 12, 14, 15, 16, Custelcean teaches that the oxyanion precipitating compound is added in an amount at least, and generally above, the molar amount of oxyanion expected in the aqueous source (¶ [0038]).
For claim 12, Seipp discloses sulfate crystallization from aqueous solution using BIG chemistry (p. 1, introduction, second paragraph, lines 7-9; Table 1, Representative results from sulfate separation from seawater, The initial sulfate concentration was 30 mM), and Custelcean discloses sulfate as a removable oxyanion ((¶ [0037-0038]); therefore, sulfate-rich systems would have been within the predictable operating conditions for the combined process (Seipp: p. 1, introduction, second paragraph, lines 7-9; Table 1, Representative results from sulfate separation from seawater, The initial sulfate concentration was 30 mM; Custelcean: Table 3; ¶¶ [0075-0079, 0080-0081]).
For claim 14, Custelcean discloses that adding the precipitating compounds at least twice the total molar amount of sulfate and toxic oxyanion would have been obvious optimization because increasing precipitant amount improves sulfate removal (Custelcean: Fig. 4, [0016, 0038, 0067]).
For claim 15, adding sulfate to reach at least 100 times the toxic oxyanion concentration would have been an obvious adjustment where sulfate participates in the desired precipitated salt formation and the claimed concentrations are result-effective variables as evidenced by Einkauf eta l., (ACS Environ. Au, 2026, p. 120, Figure 4, left column starting from the first paragraph, lines 1-25).
For claim 16, adding sulfate to reach at least 500 times the toxic oxyanion concentration would have been likewise be an obvious optimization where sulfate participates in the desired precipitated salt formation and the claimed concentrations are result-effective variables (Einkauf eta l., (ACS Environ. Au, 2026, p. 120, Figure 4, left column starting from the first paragraph, lines 1-25).
In regard to claim 17, Custelcean discloses treating seawater or other aqueous sources and removing oxyanions from water without pressure, nanofiltration, preconcentration, or organic solvents (¶ [0007]). Applying the same aqueous oxyanions precipitation method to drinking water would have been an obvious use of the known water-treatment process for removing toxic oxyanion contaminants from aqueous source because drinking water is an aqueous source and the claimed toxic oxyanions are water contaminants removable by the same precipitating mechanism as evidenced by Einkauf et al., (ACS Environ. Au, 2026, p. 116, Introduction, left column, first paragraph, line 9 thru p. 117, left column, second paragraph, line 6).
In regard to claims 18, 19, 20, and 21, Custelcean teaches that the oxyanion concentration may be reduced by at least or above 98%, 99%, 99.5%, or 99.9% compared to the original concentration in the aqueous source (¶ [0039]).
For claim 18, reducing at least 500 ppb to no more than 50 ppb corresponds to at least 90% reduction. Since the claimed reduction of toxic oxyanion concentration by at least 90% overlaps the reduction of toxic oxyanion concentration by at least or above 98%, 99%, 99.5%, or 99.9% (¶ [0039]) taught by Custelcean, the range recited in claim 18 is considered prima facie obvious (see MPEP 2144.05).
For claim 19, reducing at least 200 ppb to no more than 20 ppb corresponds to at least 90% reduction. Since the claimed reduction of toxic oxyanion concentration by at least 90% overlaps the reduction of toxic oxyanion concentration by at least or above 98%, 99%, 99.5%, or 99.9% taught by Custelcean, the range recited in claim 18 is considered prima facie obvious (see MPEP 2144.05).
For claim 20, reducing at least 100 ppb to no more than 10 ppb corresponds to at least 90% reduction. Since the claimed reduction of toxic oxyanion concentration by at least 90% overlaps the reduction of toxic oxyanion concentration by at least or above 98%, 99%, 99.5%, or 99.9% (¶ [0039]) taught by Custelcean, the range recited in claim 18 is considered prima facie obvious (see MPEP 2144.05).
For claim 21, reducing at least 50 ppb to no more than 5 ppb corresponds to at least 90% reduction. Since the claimed reduction of toxic oxyanion concentration by at least 90% overlaps the reduction of toxic oxyanion concentration by at least or above 98%, 99%, 99.5%, or 99.9% taught (¶ [0039]) by Custelcean, the range recited in claim 18 is considered prima facie obvious (see MPEP 2144.05).
Conclusion
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, In Suk Bullock can be reached on 571-272-5954. The fax phone number for the organization where this application or processing is assigned is 571-273-8300.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, In Suk Bullock can be reached on 571-272-5954. The fax phone number for the organization where this application or processing is assigned is 571-273-8300.
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/WILSON GALLARDO MENDOZA/Examiner, Art Unit 1772
/YOUNGSUL JEONG/Primary Examiner, Art Unit 1772
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