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Solid-phase extraction of palladium, platinum, and gold from water samples: comparison between a chelating resin and a chelating fiber with ethylenediamine groups

Solid-phase extraction of palladium, platinum, and gold from water samples: comparison between a... Dissolved palladium (Pd), platinum (Pt), and gold (Au) form inert chloride complexes at low concentrations of pmol/kg in environmental water, thus rendering difficulty in the development of a precise analytical method for these metals. Herein, we report the preconcentration of Pd, Pt, and Au with a chelating fiber Vonnel-en and a chelating resin TYP-en with ethyl- enediamine (en) groups. Batch adsorption experiments reveal the adsorption capacity of Vonnel-en for Pd(II), Pt(IV), and Au(III) in 0.10 M HCl as 0.53, 0.22, and 0.27 mmol/g, respectively. The adsorption capacity of TYP-en for Pd(II), Pt(IV), and Au(III) in 0.10 M HCl is 0.31, 0.17, and 0.52 mmol/g, respectively. In column extraction experiments using small-volume samples containing Pd(II), Pt(II), Pt(IV), Au(I), or Au(III) at concentrations of μmol/kg, TYP-en is able to quantitatively recover Pd, Pt, and Au from 0.01 to 0.2 M HCl irrespective of their oxidation states. In contrast, Vonnel-en is unable to quantitatively recover Au(I). In column extraction experiments using large-volume samples containing Pd(II), Pt(IV), and Au(III) at concentrations of pmol/kg, the recovery of Pd(II), Pt(IV), and Au(III) by TYP-en from 0.07 M HCl is 100–105%. However, the recovery of Pd(II), Pt(IV), and Au(III) by Vonnel-en from 0.03 to 0.3 M HCl is 102–110, 7–15, and 20–52%, respectively. Thus, the chelating resin TYP-en has a high potential for the multielemental determination of Pd, Pt, and Au in environmental water. Keywords Palladium · Platinum · Gold · Solid-phase extraction · Chelating resin · Chelating fiber Introduction Pd, Pt, and Au are siderophile elements, and their abun- dance in the earth’s crust is extremely low, at 0.4, 0.4, and Pd, Pt, and Au are precious metals with special properties, 2.5  ng/g, respectively [4]. The Pd and Pt cycles on the such as high electrical conductivity, resistance to corrosion, Earth’s surface are affected by anthropogenic activities [5 ]. high melting point, and catalytic ability. Pd is used in chemi- Pd and Pt concentrations in Greenland snow has increased cal catalysts, dental applications, electronic appliances, and by approximately 60–100-fold compared with that in ice jewelry [1, 2]. Pt is used in electronic appliances, chemical cores of 7000 years ago [6]. In addition, Pd and Pt concen- catalysts, jewelry, and medical applications [2]. Moreover, trations in airborne particulate matter and in soil of urban Pd and Pt are used predominantly in the three-way catalysts areas are higher than those of rural areas [7, 8]. High con- of gasoline vehicles [1, 2], whereas Au is used primarily in centrations of Pt are observed in hospital sewage owing to industrial fields, such as electronic and mechanical, and is Pt-based anticancer drugs for anticancer chemotherapy [9]. also used in dental applications and jewelry [3]. High concentrations of Au are found in urban sewage sludge, which suggests anthropogenic sources [10]. These precious metals are transported to the aquatic environment and bioac- cumulated to aquatic organisms via the food chain [1, 11]. * Misato Iwase In addition, it was reported that certain Pt compounds are iwase.misato.6v@kyoto-u.ac.jp cytotoxic and have mutagenic and carcinogenic effects [11]. Institute for Chemical Research, Kyoto University, Uji, Gold nanoparticles of 1–2 nm in size are highly cytotoxic Kyoto 611-0011, Japan Vol.:(0123456789) 1 3 M. Iwase et al. [12]. Although little is known about Pd toxicity, increased TOSOH (Japan). Standard solutions of Pd(II), Pt(IV), and emission of the precious metals may become a threat to the Au(III) were prepared from 1000  mg/ml standard solu- sustainability of aquatic ecosystems. Therefore, the distribu- tions (Wako Pure Chemicals). Wako 1st grade K [PtCl ] 2 4 tion of Pd, Pt, and Au in the aquatic environment must be and practical grade K[Au(CN) ] were obtained from Wako observed to achieve SDGs. Pure Chemical to prepare the standard solutions of Pt(II) These precious metals are present at very low concen- and Au(I), respectively. Deionized water (MQW) purified trations (pmol/kg) in environmental waters. The oxida- using a Milli-Q IQ 7005 system (Merck) was used through- tion states are as Pd(II), Pt(II), Pt(IV), Au(I), and Au(III) out the experiments. We paid special attention for eluents [13, 14]. These ions form inert complexes with chloride of NH –KCN and HCl–H O during preparation and usage. 3 2 2 2− 2− 2− 2− − ions: PdCl , PtCl , PtCl , PtCl (OH) , AuCl , and We did not acidify NH –KCN solution to avoid emission 5 3 4 4 6 2 AuCl (OH) [13, 15]. Thus, the determination of Pd, Pt, of HCN. We treated HCl–H O solution in a fume hood to 3 2 2 and Au in environmental waters is a challenge in analytical avoid inhalation of Cl . chemistry [2]. Conventionally, ion exchange methods have Nalgene low-density polyethylene (LDPE) bottles been used for the preconcentration of these metals [16–19]. (Thermo Fisher Scientific) were used to store the solutions. Anion exchange resins, AG1-X8 [20, 21] or Do wex 1-X8 Polypropylene tubes (SARSTEDT, Germany) were used [22], have been used to determine the concentrations of Pd for batch adsorption experiments. Nalgene perfluoroalkoxy and Pt in river water and seawater. In addition, some chelat- alkane (PFA) bottles (Thermo Fisher Scientific, USA) were ing resins have been used for the preconcentration of Pd, used for evaporation on a hot plate (AS ONE, Japan). The Pt, and Au; these include the Nobias Chelate-PA1 [23], bottles and tubes were soaked overnight in an alkaline deter- Presep PolyChelate [24], and MetaSEP AnaLig PM-05 gent (5% Scat 20-X, Nacalai Tesque, Japan), rinsed with tap [25]. However, these methods have drawbacks, such as a water, soaked overnight in 4 M HCl, and subsequently rinsed low recovery percentage. In addition, the simultaneous pre- with MQW. Finally, they were soaked overnight in 0.3 M concentration of Pd, Pt, and Au at concentrations of pmol/kg NH –0.03 M KCN and rinsed with MQW. has not been extensively examined. It has been reported that column extraction using a chelating fiber, poly(N -aminoe- thyl)acrylamide with ethylenediamine (en) groups, has the Apparatus potential to quantitatively recover Au(III), Pt(IV), Pd(IV), Ir(IV), Ru(III), and Rh(III) at concentrations of nmol/kg The elemental concentrations in the range of μmol/kg were [26]. It was also reported that chelating fiber synthesized determined by a calibration curve method using SPEC- by amination of acrylic fiber acts as an effective adsorbent TROBLUE ICP-AES (SPECTRO, Germany). Elemental for Cr(III), Cr(VI), Cu(II), and As(V) [27, 28]. The ultimate concentrations ranging from nmol/kg to pmol/kg were deter- goal of the present study is to develop a novel analytical mined by a calibration curve method using a NexION 350D method that can simultaneously determine Pd, Pt, and Au quadrupole ICP-MS (Perkin Elmer, USA). Sample solutions at a concentration of pmol/kg. As the first step, we prepared were introduced into the NexION using a desolvating nebu- a chelating fiber and a chelating resin with en groups using lizer Apex Q (Elemental Scientific, USA). The measured the synthetic method of poly(N-aminoethyl)acrylamide [26]. mass numbers were 105 and 108 for Pd, 194 and 195 for Pt, Herein, we report the results of both the batch and column and 197 for Au. methods of solid-phase extraction for Pd, Pt, and Au using chelating adsorbents with en groups in order to make the difference between fiber and resin clear. Synthesis of Vonnel‑en A sample of acrylic staple fiber V onnel was cut into approximately 5 mm-long pieces and soaked in acetone Experimental overnight. Subsequently, the fiber was soaked in methanol overnight, rinsed with MQW, and dried at 50 °C in a drying Reagents and materials oven (Yamato Scientic fi , Japan). A 2.5 g portion of the dried fiber and 125 g of 9 M en solution were mixed at pH 12.5 in Reagent-grade HCl, HNO, NH, H O , methanol, acetone, 3 3 2 2 en, and NaOH were obtained from FUJIFILM Wako Pure an LDPE bottle and shaken at 260 rpm and 70 °C for 15 h using a constant-temperature incubator shaker (TAITEC, Chemical (Japan). EMSURE -grade KCN was obtained from Merck (Germany). A sample of acrylic staple fiber, Japan). The reaction is shown in Fig.  1a. The Vonnel-en fiber was washed with MQW until the wash solution attained Vonnel , was obtained from Mitsubishi Chemical (Japan). TOYOPEARL AF-Epoxy-650 M (particle size, 40–90 μm; a neutral pH. Subsequently, it was dried at 50 °C in a drying oven and stored in an LDPE bottle in a desiccator. amount of epoxy group, 0.8 mmol/g) was obtained from 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… Fig. 1 Synthetic reactions of a Vonnel-en and b TYP-en where C and C represent the concentrations of the metal Synthesis of TYP‑en s f ions in the sample solution and filtrate, respectively; and W and W represent the weights of the sample solution and the A 2.4 g portion of TOYOPEARL AF-Epoxy-650 M and dried adsorbent, respectively. 144 g of 200 mM en solution were mixed in an LDPE bottle and the pH was adjusted to pH 11 by adding 1 M HCl. The Column extraction experiments mixture was shaken at 260 rpm and 70 °C for 36 h in a con- stant-temperature incubator shaker. The reaction is shown in The Vonnel-en fiber (approximately 100 mg dry weight) or Fig. 1b. The TYP-en resin was sieved using a Teflon screen the TYP-en resin (approximately 200 mg dry weight) was with 170 mesh to remove fine particles. The TYP-en resin packed in a Type-M cartridge column (TOMOE, Japan), was washed with MQW until the wash solution became neu- with a polypropylene body and polyethylene frits, with an tral and stored in MQW in an LDPE bottle. inner diameter of 8.4 mm and a bed height of 8.5 mm. The column experiments were performed in a clean hood. Batch adsorption experiments Prior to use, the column was cleaned by passing successively 500 ml of 0.3 M NH –0.03 M KCN at a flow rate of 0.2 ml/min In a 50 ml polypropylene tube, 25 g of a sample solution and 100 ml of MQW at a flow rate of 2 ml/min. A preconcen- containing 40–500 μmol/kg of a metal ion was mixed with tration system was constructed with the column, LDPE bottles, 20 mg of Vonnel-en or TYP-en and agitated at 200 rpm PFA tubes with an internal diameter of 3 mm, Tygon tubes and 25 °C for 2 h using a constant-temperature incubator (SAINT-GOBAIN, France) with that of 3.18 mm, PharMed shaker. Subsequently, the adsorbent was collected on a tubes (TOKYO RIKAKIKAI, Japan) with that of 2.15 mm, 0.2 μm Nuclepore membrane and dried at 50 °C in a dry- and a cassette tube pump SMP-23 (TOKYO RIKAKIKAI) ing oven. The dry weight of the adsorbent was determined (Fig. 2a). A column of Vonnel-en or TYP-en was conditioned using a balance (SHIMADZU, Japan). The concentration by successively passing 20 ml of 0.1 M NH , 20 ml of MQW, of the metal ions in the filtrate was determined using ICP- and 20 ml of HCl solution with the same HCl concentration AES. The amount of metal ions adsorbed on the adsorbent as the sample solution at a flow rate of 2 ml/min just before was assumed to be the difference between the metal ion column extraction. For column extraction experiments using a amounts in the sample solution and the filtrate. The adsorp- small-volume sample containing a metal ion at a high concen- tion capacity of the metal ions is calculated using the fol- tration, the samples used were: 25 g of 0.01–0.2 M HCl solu- lowing equation: tions containing 50 μmol/kg of Pd(II) or 25 μmol/kg of Pt(II), (C − C ) × W s f s Pt(IV), Au(I) or Au(III). For column extraction experiments Adsorption capacity (mmol/g) = using a large-volume sample containing metal ions at low con- centrations, the samples used were: 500 g of 0.03–0.3 M HCl solutions containing 35 pmol/kg of Pd(II), Pt(IV), and Au(III) 1 3 M. Iwase et al. Fig. 2 Diagrams of a precon- (a) (b) centration system and b elution system Columns Air Columns Drain Cleaning, Pump Pump Eluent conditioning, and sample solutions or 600 g of 0.03–0.3 M HCl solutions containing 50 pmol/kg where C , C , and C represent the concentration of metal s p e of Pd(II), Pt(IV), and Au(III). The sample solution was loaded ions in the sample solution, the solution passing through the into the column at a flow rate of 1 ml/min. The solution that column during sample loading, and the eluate, respectively; passed through the column during the sample loading was col- and W and W represent the weights of the sample solution s e lected in an LDPE bottle. After sample loading, 20 ml of HCl and the eluate, respectively. When evaporation–redissolu- solution with the same HCl concentration as the sample solu- tion was applied, the concentration and weight of the re- tion was passed through the column at a flow rate of 2 ml/min dissolved solution were used instead of C and W . e e to remove remaining salts from sample solution. Subsequently, the column was detached from the precon- centration system and attached to an elution system, which Results and discussion was constructed with the column, LDPE bottles, PFA tubes with an internal diameter of 2 mm, Tygon tubes with that Adsorption and elution conditions of 3.18 mm, PharMed tubes with that of 1.15 mm, and a cassette tube pump SMP-23 (Fig. 2b). The elution system Pd, Pt, and Au form negatively charged chloride complexes flowed through the column in the direction opposite to that in HCl solution [13–15]. TYP-en and Vonnel-en have posi- of the preconcentration system. Pd, Pt, and Au adsorbed on tive charges in HCl solution owing to protonation of the en Vonnel-en or TYP-en were eluted with 0.3 M NH –0.003 M groups. Therefore, the negatively charged Pd, Pt, and Au KCN or 8 M HCl–10 mM H O at a flow rate of 0.6 ml/min. chloride complexes are attracted and adsorbed in the adsor- 2 2 When the metal ions remained in the column after elution bent through electrostatic forces, thereby forming chelates with 8 M HCl–10 mM H O , they were further eluted with (Fig. 3a). 2 2 0.3 M NH –0.003 M KCN. Subsequently, the eluates were The preliminary experiments revealed that the good elu- collected in PFA bottles. The column was again mounted ents for Pd, Pt, and Au were 0.3 M NH –0.003 M KCN and on the preconcentration system and cleaned with 30 ml of 8 M HCl–10 mM H O (Supplementary Figs. S1–S3). In 2 2 MQW at a flow rate of 2 ml/min.0.3 M NH –0.003 M KCN, Pd, Pt, and Au formed negatively The eluate of 0.3 M NH –0.003 M KCN was directly charged cyanide complexes (Fig. 3b). As the en groups were introduced to ICP-AES or ICP-MS to measure Pd, Pt, and neutral in this solution, the cyanide complexes were eas- Au. The eluate of 8 M HCl–10 mM H O , collected in a ily removed. Although this eluent was strong, some defects 2 2 PFA bottle, was evaporated to dryness for 8 h at 180 °C on a were observed: (1) cyanide ions are highly toxic; (2) potas- hot plate. After evaporation, the residue was re-dissolved in sium ions interfere with the determination of Pd, Pt, and Au 3 ml of 1 M HCl–1 M HNO at 270 rpm and 70 °C for 8 h by ICP-MS; and (3) when this eluent was applied to natural in a constant-temperature incubator. The re-dissolved solu- samples, some ferric ions that were adsorbed on the adsor- tion was used for measurement. The adsorption and recovery bent from the sample solution formed iron hydroxide during percentages are calculated using the following equations: elution, which adsorbed Pd, Pt, and Au, thereby resulting in a low recovery in the eluate (Supplementary Table S1). C − C s p In 8 M HCl–10 mM H O , reverse adsorption reaction Percentage of adsorption (%) = × 100 2 2 s occurred owing to the high concentration of chloride ions (Fig. 3c). This eluent was not very strong owing to the elec- C × W trostatic forces between the chloride complex ions and the e e Percentage of recovery (%) = × 100 adsorbent, and a large volume of the eluent was necessary C × W s s for quantitative recovery. However, the defects of 0.3 M 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… Fig. 3 a Adsorption reaction of metal ions on TYP-en from HCl solution. Elution reaction of metal ions in b NH –KCN solution and c HCl– O solution 2 2 NH –0.003 M KCN were overcome. When 8 M HCl was used as the eluent, Au recovery was not quantitative. We assumed that this was caused by the formation of Au(0) on the adsorbent due to the following disproportionation reaction: − − − 3AuCl ⇌ AuCl + 2Au(0) + 2Cl 2 4 We added H O to 8 M HCl to oxidize Au(0) using the 2 2 following reaction: − + 2Au(0) + 3H O + 8HCl → 2AuCl + 2H + 6H O 2 2 2 Evidently, Au recovery was higher in the 8  M HCl–10 mM H O solution. Therefore, it was considered as 2 2 Fig. 4 Effect of HCl concentration on the adsorption capacity of the most promising eluent. TYP-en for Pd(II), Pt(IV), and Au(III). Metal ion concentration in sample solution: 100–500  μmol/kg Pd(II), 40–200  μmol/kg Pt(IV), or 40–400  μmol/kg Au(III). Error bars show the standard deviation Adsorption capacity (n = 2) First, using TYP-en, the HCl concentration dependency of the adsorption capacities of Pd(II), Pt(IV), and Au(III) were Table 1 Adsorption capacities of Vonnel-en and TYP-en examined (Fig. 4). We repeated the experiments for each Element HCl (M) Adsorption capacity (mmol/g) condition and obtained highly reproducible data. Evidently, Vonnel-en TYP-en the adsorption capacities of Pd(II), Pt(IV), and Au(III) decreased when the HCl concentration increased from 0.1 M n ave ± sd n ave ± sd to 0.5 M. Subsequently, the adsorption capacities of Pd(II), Pd(II) 0.10 3 0.526 ± 0.006 2 0.310 ± 0.007 Pt(IV), and Au(III) in 0.10 M HCl between Vonnel-en and Pt(IV) 0.10 3 0.217 ± 0.004 2 0.166 ± 0.005 TYP-en were compared (Table 1). The adsorption capacities Au(III) 0.10 3 0.27 ± 0.02 2 0.52 ± 0.03 of Pd(II) and Pt(IV) for Vonnel-en were 1.7 and 1.3 times higher than those for TYP-en, respectively. In contrast, the adsorption capacity of TYP-en for Au(III) was 1.9 times higher than that for Vonnel-en. The reason of these opposite the adsorption behavior of Vonnel-en. As approximately results is not clear now. Vonnel is copolymer of acrylamide 100 mg dry weight of the Vonnel-en fiber or approximately and other constituents, of which detail is not open to the 200 mg dry weight of the TYP-en resin was packed in a col- public. It is possible that the other constituents influence umn, the adsorption capacity of the column was higher than 1 3 M. Iwase et al. Fig. 5 Effect of HCl concentration on the adsorption percentage of or 25  μmol/kg Pt(II), Pt(IV), Au(I), or Au(III). Error bars show the Pd(II), Pt(II), Pt(IV), Au(I), and Au(III) for a Vonnel-en and b TYP- standard deviation (n = 3) en. Metal ion concentration in sample solution: 50  μmol/kg Pd(II) 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… Fig. 6 Effect of HCl concentration on the recovery percentage of NH –0.003  M KCN (triangles), 90  g of 8  M HCl–10  mM H O 3 2 2 Pd(II), Pt(II), Pt(IV), Au(I), and Au(III) for a Vonnel-en and b TYP- (diamonds), or 90  g of 8  M HCl–10  mM H O and 30  g of 0.3  M 2 2 en. Metal ion concentration in sample solution: 50 μmol/kg Pd(II) or NH –0.003 M KCN (squares). Error bars show the standard deviation 25  μmol/kg Pt(II), Pt(IV), Au(I), or Au(III). Eluent: 90  g of 0.3  M (n = 3) 1 3 M. Iwase et al. 0.022 mmol for Pd(II), Pt(IV), and Au(III), which was > 35 of 0.3 M NH –0.003 M KCN or 8 M HCl–10 mM H O . 3 2 2 times higher than the metal ion amount in the subsequent Thus, TYP-en is expected to have the potential to deter- column extraction experiments. mine the total dissolved concentrations of Pd, Pt, and Au irrespective of their oxidation states. Column extraction experiments using small‑volume samples containing a metal ion at a high Column extraction experiments using concentration large‑volume samples containing metal ions at low concentrations The effect of HCl concentration on the percentage of adsorption for Vonnel-en and TYP-en in column extraction Column extraction experiments were performed using large- experiments was investigated using small-volume samples volume samples (500–600 g) containing Pd(II), Pt(IV), and of 25 g containing a metal ion at a high concentration of Au(III) at a low concentration of 35–50 pmol/kg (Fig. 7). 25–50  μmol/kg (Fig.  5). For Vonnel-en, Au(I) was not Pd(II) was quantitatively recovered from 0.03 to 0.3  M quantitatively collected from > 0.15 M HCl solution. In HCl solution by Vonnel-en and from 0.03 to 0.1 M HCl contrast, TYP-en was able to quantitatively recover Pd(II), solution by TYP-en. Pt(IV) was quantitatively recovered Pt(II), Pt(IV), Au(I), and Au(III) from 0.01 to 0.2 M HCl from 0.07 M HCl solution and Au(III) was quantitatively solution. recovered from 0.03 to 0.3 M HCl solution by TYP-en. The In addition, the effect of the HCl concentration on recovery of Pt(IV) and Au(III) from 0.03 to 0.3 M HCl solu- the recovery of Vonnel-en and TYP-en was investigated tion by Vonnel-en was 7–15% and 20–52%, respectively, (Fig.  6). Pd(II), Pt(IV), and Au(III) were quantitatively when the eluent was 8 M HCl–10 mM H O . Additional 2 2 recovered from a 0.07–0.2 M HCl solution by both Von- elution with 0.3 M NH –0.003 M KCN slightly increased nel-en and TYP-en. Pt(II) recovery by Vonnel-en was the recovery of Pt(IV) and Au(III) to 15–30% and 22–55%, 70–100% when the eluent was 8 M HCl–10 mM H O . respectively. These results indicate that Pt(IV) and Au(III) 2 2 However, a quantitative recovery was obtained by addi- were not quantitatively retained by Vonnel-en, although the tional elution with 0.3  M NH –0.003  M KCN. Au(I) total amount of metal ions was only 53 pmol in these exper- recovery by Vonnel-en decreased with increasing HCl iments. Thus, the recovery of Pt(IV) and Au(III) by Von- concentration, and the obtained recoveries from 0.07 to nel-en may depend on the sample volume and on the ana- 0.2 M HCl solution were lower than the percentages of lyte concentration. These results are inconsistent with our adsorption. This was because a portion of Au(I) adsorbed previous experience of the solid-phase extraction of metal on the Vonnel-en was desorbed when 20 ml of HCl solu- ions, wherein chelating adsorbents that have groups, such tion with the same concentration as the sample solution as 8-hydroxyquinoline [29] and ethylenediaminetriacetic was passed through the column after sample loading. In acids, were used [30]. In these studies, metal ions were contrast, Pt(II) and Au(I) were quantitatively recovered quantitatively recovered, independent of sample volume from 0.01 to 0.2 M HCl solution by TYP-en with an eluent and metal ion concentrations, as long as the total amount Fig. 7 Effect of HCl concentration on the recovery percentage of containing 50  pmol/kg Pd(II), Pt(IV), and Au(III) (gray triangles). Pd(II), Pt(IV), and Au(III) for Vonnel-en (white symbols) and TYP- Eluent: 60 g of 0.3 M NH –0.003 M KCN (triangles), 180 g of 8 M en (gray symbols). Sample solution: 500  g of 0.03–0.3  M HCl con-HCl–10 mM H O (diamonds), or 180  g of 8  M HCl–10  mM H O 2 2 2 2 taining 35  pmol/kg Pd(II), Pt(IV), and Au(III) (white diamonds, and 30 g of 0.3 M NH –0.003 M KCN (squares). Error bars show the white squares, and gray diamonds) or 600  g of 0.03–0.3  M HCl standard deviation (n = 3) 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… KAKENHI grants to YS (15H01727 and 19H01148). We would like to of metal ions was sufficiently lower than the adsorption thank Editage (www. edita ge. com) for English language editing. capacity of the chelating column. A possible explanation is that en is a neutral ligand and forms less stable chelate Data availability All data generated or analyzed during this study are with metal ions compared with negatively charged ligands. included in this published article. The reason of difference between TYP-en and Vonnel-en is Declarations not clear now. It is possible that the nature of copolymer of Vonnel-en causes the difference. Conflict of interest On behalf of all the authors, the corresponding au- thor states that there is no conflict of interest. Open Access This article is licensed under a Creative Commons Attri- Conclusions bution 4.0 International License, which permits use, sharing, adapta- tion, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, In this study, a chelating fiber Vonnel-en and a chelating provide a link to the Creative Commons licence, and indicate if changes resin TYP-en, which have en groups, were synthesized to were made. The images or other third party material in this article are evaluate their performance in a solid-phase extraction of Pd, included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in Pt, and Au. In batch adsorption experiments, the adsorption the article's Creative Commons licence and your intended use is not capacity of Vonnel-en was 1.7 and 1.3 times higher than permitted by statutory regulation or exceeds the permitted use, you will that of TYP-en for Pd(II) and Pt(IV), respectively, whereas need to obtain permission directly from the copyright holder. To view a the adsorption capacity of Vonnel-en was half that of TYP- copy of this licence, visit http://cr eativ ecommons. or g/licen ses/ b y/4.0/ . en for Au(III). Column extraction experiments revealed that TYP-en is superior to Vonnel-en. In experiments using small-volume samples containing a metal ion at a µmol/kg References concentration, Vonnel-en could not quantitatively recover 1. J. Kielhorn, C. Melber, D. Keller, I. Mangelsdorf, Int. J. Hyg. Au(I) from 0.07 to 0.2  M HCl solution. However, TYP- Environ. Health 205, 417 (2002) en was able to quantitatively recover Pd(II), Pt(II), Pt(IV), 2. A. Dubiella-Jackowska, Ż Polkowska, J. Namieśnik, Pol. J. Envi- Au(I), and Au(III) from 0.01 to 0.2  M HCl solution. In ron. Stud. 16, 329 (2007) experiments using large-volume samples containing metal 3. C.W. Corti, R.J. Holliday, Appl. Earth Sci. 114, 115 (2005) 4. K.H. Wedepohl, Geochim. Cosmochim. Acta 59, 1217 (1995) ions at pmol/kg concentrations, Vonnel-en was unable to 5. A. Mitra, I.S. Sen, Geochim. Cosmochim. Acta 216, 417 (2017) quantitatively recover Pt(IV) and Au(III). However, TYP- 6. C. Barbante, A. Veysseyre, C. Ferrari, K.V.D. Velde, C. Morel, en could quantitatively recover Pd(II), Pt(IV), and Au(III) G. Capodaglio, P. Cescon, G. Scarponi, C. Boutron, Environ. Sci. simultaneously. Based on these results, TYP-en was con- Technol. 35, 835 (2001) 7. H. Wichmann, G.A.K. Anquandah, C. Schmidt, D. Zachmann, cluded as a more promising adsorbent than Vonnel-en for the M.A. Bahadir, Sci. Total Environ. 388, 121 (2007) preconcentration of Pd, Pt, and Au. As the en groups both 8. F. Zereini, H. Alsenz, C.L. Wiseman, W. Puttmann, E. Reimer, participate in anion exchange and chelate formation, TYP-en R. Schleyer, E. Bieber, M. Wallasch, Sci. Total Environ. 416, 261 is effective for the solid-phase extraction of Pd, Pt, and Au (2012) 9. E. Abdulbur-Alfakhoury, G. Trommetter, N. Brion, D. Dumou- chloride complexes. Future investigations will include the lin, M. Reichstadter, G. Billon, M. Leermakers, W. Baeyens, Sci. development of an analytical method for the determination Total Environ. 784, 147075 (2021) of Pd, Pt, and Au in environmental water samples, such as 10. A. Yessoufou, B.E. Ifon, F. Suanon, B. Dimon, Q. Sun, C.A. Ded- river water and seawater. jiho, D. Mama, C.P. Yu, Environ. Monit. Assess. 189, 625 (2017) 11. K. Ravindra, L. Bencs, R. Van Grieken, Sci. Total Environ. 318, Supplementary Information The online version contains supplemen- 1 (2004) tary material available at https://doi. or g/10. 1007/ s44211- 023- 00270-3 . 12. Y. Pan, S. Neuss, A. Leifert, M. Fischler, F. Wen, U. Simon, G. Schmid, W. Brandau, W. Jahnen-Dechent, Small 2007, 3 (1941) Acknowledgements The authors thank Prof. Shigeru Yamago (Kyoto 13. C.H. Gammons, Geochim. Cosmochim. Acta 60, 1683 (1996) Univ.) for introducing us to Mitsubishi Chemical. The authors are 14. D.R. Turner, M. Whitfield, A.G. Dickson, Geochim. Cosmochim. profoundly grateful to Mitsubishi Chemical for providing a sample Acta 45, 855 (1981) TM of the acrylic staple fiber Vonnel . We express our appreciation to 15. A. Usher, D.C. McPhail, J. Brugger, Geochim. Cosmochim. Acta Emeritus Prof. Kazumasa Ueda (Kanazawa Univ.) and the graduates: 73, 3359 (2009) Shiori Goto, Junya Tanaka (Kanazawa Univ.); Taishi Sato, Keiko Inada, 16. D.S. Lee, Nature 305, 47 (1983) Kengo Sato, Jun Yamamoto, and Masanobu Sasaki (Kyoto Univ.) for 17. E.D. Goldberg, V. Hodge, P. Kay, M. Stallard, M. Koide, Appl. their assistance with the preliminary experiments of this study. This Geochem. 1, 227 (1986) research was supported by a Mitsumasa Ito Memorial Research Grant 18. M. Koide, V. Hodge, E.D. Goldberg, K. Bertine, Appl. Geochem. from the Research Institute for Oceanochemistry Foundation to MI 3, 237 (1988) (R3-R2) and by the Japan Society for the Promotion of Science (JSPS) 1 3 M. Iwase et al. 19. K.K. Falkner, J.M. Edmond, Earth Planet. Sci. Lett. 98, 208 25. H. Hasegawa, S. Barua, T. Wakabayashi, A. Mashio, T. Maki, Y. (1990) Furusho, I.M.M. Rahman, Microchem. J. 139, 174 (2018) 20. A. Suzuki, H. Obata, A. Okubo, T. Gamo, Mar. Chem. 166, 114 26. X. Chang, Y. Li, G. Zhan, X. Luo, W. Gao, Talanta 43, 407 (1996) (2014) 27. P. Tahaei, M. Abdouss, M. Edrissi, A.M. Shoushtari, M. Zargaran, 21. A.S. Mashio, A. Ichimura, H. Yamagishi, K.H. Wong, H. Obata, Materialwiss. Werkstofftech. 39, 839 (2008) H. Hasegawa, Mar. Chem. 243, 104124 (2022) 28. L. Niu, S. Deng, G. Yu, J. Huang, Chem. Eng. J. 165, 751 (2010) 22. L. Fischer, G. Smith, S. Hann, K.W. Bruland, Mar. Chem. 199, 44 29. Y. Sohrin, S. Iwamoto, S. Akiyama, T. Fujita, T. Kugii, H. Obata, (2018) E. Nakayama, S. Goda, Y. Fujishima, H. Hasegawa, K. Ueda, M. 23. K. Liu, X. Gao, L. Li, C.-T.A. Chen, Q. Xing, Chemosphere 212, Matsui, Anal. Chim. Acta 363, 11 (1998) 429 (2018) 30. Y. Sohrin, S. Urushihara, S. Nakatsuka, T. Kono, E. Higo, T. 24. A. Cobelo-Garcia, M.E. Mulyani, J. Schafer, Talanta 232, 122289 Minami, K. Norisuye, S. Umetani, Anal. Chem. 80, 6267 (2008) (2021) 1 3 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Analytical Sciences Springer Journals

Solid-phase extraction of palladium, platinum, and gold from water samples: comparison between a chelating resin and a chelating fiber with ethylenediamine groups

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Abstract

Dissolved palladium (Pd), platinum (Pt), and gold (Au) form inert chloride complexes at low concentrations of pmol/kg in environmental water, thus rendering difficulty in the development of a precise analytical method for these metals. Herein, we report the preconcentration of Pd, Pt, and Au with a chelating fiber Vonnel-en and a chelating resin TYP-en with ethyl- enediamine (en) groups. Batch adsorption experiments reveal the adsorption capacity of Vonnel-en for Pd(II), Pt(IV), and Au(III) in 0.10 M HCl as 0.53, 0.22, and 0.27 mmol/g, respectively. The adsorption capacity of TYP-en for Pd(II), Pt(IV), and Au(III) in 0.10 M HCl is 0.31, 0.17, and 0.52 mmol/g, respectively. In column extraction experiments using small-volume samples containing Pd(II), Pt(II), Pt(IV), Au(I), or Au(III) at concentrations of μmol/kg, TYP-en is able to quantitatively recover Pd, Pt, and Au from 0.01 to 0.2 M HCl irrespective of their oxidation states. In contrast, Vonnel-en is unable to quantitatively recover Au(I). In column extraction experiments using large-volume samples containing Pd(II), Pt(IV), and Au(III) at concentrations of pmol/kg, the recovery of Pd(II), Pt(IV), and Au(III) by TYP-en from 0.07 M HCl is 100–105%. However, the recovery of Pd(II), Pt(IV), and Au(III) by Vonnel-en from 0.03 to 0.3 M HCl is 102–110, 7–15, and 20–52%, respectively. Thus, the chelating resin TYP-en has a high potential for the multielemental determination of Pd, Pt, and Au in environmental water. Keywords Palladium · Platinum · Gold · Solid-phase extraction · Chelating resin · Chelating fiber Introduction Pd, Pt, and Au are siderophile elements, and their abun- dance in the earth’s crust is extremely low, at 0.4, 0.4, and Pd, Pt, and Au are precious metals with special properties, 2.5  ng/g, respectively [4]. The Pd and Pt cycles on the such as high electrical conductivity, resistance to corrosion, Earth’s surface are affected by anthropogenic activities [5 ]. high melting point, and catalytic ability. Pd is used in chemi- Pd and Pt concentrations in Greenland snow has increased cal catalysts, dental applications, electronic appliances, and by approximately 60–100-fold compared with that in ice jewelry [1, 2]. Pt is used in electronic appliances, chemical cores of 7000 years ago [6]. In addition, Pd and Pt concen- catalysts, jewelry, and medical applications [2]. Moreover, trations in airborne particulate matter and in soil of urban Pd and Pt are used predominantly in the three-way catalysts areas are higher than those of rural areas [7, 8]. High con- of gasoline vehicles [1, 2], whereas Au is used primarily in centrations of Pt are observed in hospital sewage owing to industrial fields, such as electronic and mechanical, and is Pt-based anticancer drugs for anticancer chemotherapy [9]. also used in dental applications and jewelry [3]. High concentrations of Au are found in urban sewage sludge, which suggests anthropogenic sources [10]. These precious metals are transported to the aquatic environment and bioac- cumulated to aquatic organisms via the food chain [1, 11]. * Misato Iwase In addition, it was reported that certain Pt compounds are iwase.misato.6v@kyoto-u.ac.jp cytotoxic and have mutagenic and carcinogenic effects [11]. Institute for Chemical Research, Kyoto University, Uji, Gold nanoparticles of 1–2 nm in size are highly cytotoxic Kyoto 611-0011, Japan Vol.:(0123456789) 1 3 M. Iwase et al. [12]. Although little is known about Pd toxicity, increased TOSOH (Japan). Standard solutions of Pd(II), Pt(IV), and emission of the precious metals may become a threat to the Au(III) were prepared from 1000  mg/ml standard solu- sustainability of aquatic ecosystems. Therefore, the distribu- tions (Wako Pure Chemicals). Wako 1st grade K [PtCl ] 2 4 tion of Pd, Pt, and Au in the aquatic environment must be and practical grade K[Au(CN) ] were obtained from Wako observed to achieve SDGs. Pure Chemical to prepare the standard solutions of Pt(II) These precious metals are present at very low concen- and Au(I), respectively. Deionized water (MQW) purified trations (pmol/kg) in environmental waters. The oxida- using a Milli-Q IQ 7005 system (Merck) was used through- tion states are as Pd(II), Pt(II), Pt(IV), Au(I), and Au(III) out the experiments. We paid special attention for eluents [13, 14]. These ions form inert complexes with chloride of NH –KCN and HCl–H O during preparation and usage. 3 2 2 2− 2− 2− 2− − ions: PdCl , PtCl , PtCl , PtCl (OH) , AuCl , and We did not acidify NH –KCN solution to avoid emission 5 3 4 4 6 2 AuCl (OH) [13, 15]. Thus, the determination of Pd, Pt, of HCN. We treated HCl–H O solution in a fume hood to 3 2 2 and Au in environmental waters is a challenge in analytical avoid inhalation of Cl . chemistry [2]. Conventionally, ion exchange methods have Nalgene low-density polyethylene (LDPE) bottles been used for the preconcentration of these metals [16–19]. (Thermo Fisher Scientific) were used to store the solutions. Anion exchange resins, AG1-X8 [20, 21] or Do wex 1-X8 Polypropylene tubes (SARSTEDT, Germany) were used [22], have been used to determine the concentrations of Pd for batch adsorption experiments. Nalgene perfluoroalkoxy and Pt in river water and seawater. In addition, some chelat- alkane (PFA) bottles (Thermo Fisher Scientific, USA) were ing resins have been used for the preconcentration of Pd, used for evaporation on a hot plate (AS ONE, Japan). The Pt, and Au; these include the Nobias Chelate-PA1 [23], bottles and tubes were soaked overnight in an alkaline deter- Presep PolyChelate [24], and MetaSEP AnaLig PM-05 gent (5% Scat 20-X, Nacalai Tesque, Japan), rinsed with tap [25]. However, these methods have drawbacks, such as a water, soaked overnight in 4 M HCl, and subsequently rinsed low recovery percentage. In addition, the simultaneous pre- with MQW. Finally, they were soaked overnight in 0.3 M concentration of Pd, Pt, and Au at concentrations of pmol/kg NH –0.03 M KCN and rinsed with MQW. has not been extensively examined. It has been reported that column extraction using a chelating fiber, poly(N -aminoe- thyl)acrylamide with ethylenediamine (en) groups, has the Apparatus potential to quantitatively recover Au(III), Pt(IV), Pd(IV), Ir(IV), Ru(III), and Rh(III) at concentrations of nmol/kg The elemental concentrations in the range of μmol/kg were [26]. It was also reported that chelating fiber synthesized determined by a calibration curve method using SPEC- by amination of acrylic fiber acts as an effective adsorbent TROBLUE ICP-AES (SPECTRO, Germany). Elemental for Cr(III), Cr(VI), Cu(II), and As(V) [27, 28]. The ultimate concentrations ranging from nmol/kg to pmol/kg were deter- goal of the present study is to develop a novel analytical mined by a calibration curve method using a NexION 350D method that can simultaneously determine Pd, Pt, and Au quadrupole ICP-MS (Perkin Elmer, USA). Sample solutions at a concentration of pmol/kg. As the first step, we prepared were introduced into the NexION using a desolvating nebu- a chelating fiber and a chelating resin with en groups using lizer Apex Q (Elemental Scientific, USA). The measured the synthetic method of poly(N-aminoethyl)acrylamide [26]. mass numbers were 105 and 108 for Pd, 194 and 195 for Pt, Herein, we report the results of both the batch and column and 197 for Au. methods of solid-phase extraction for Pd, Pt, and Au using chelating adsorbents with en groups in order to make the difference between fiber and resin clear. Synthesis of Vonnel‑en A sample of acrylic staple fiber V onnel was cut into approximately 5 mm-long pieces and soaked in acetone Experimental overnight. Subsequently, the fiber was soaked in methanol overnight, rinsed with MQW, and dried at 50 °C in a drying Reagents and materials oven (Yamato Scientic fi , Japan). A 2.5 g portion of the dried fiber and 125 g of 9 M en solution were mixed at pH 12.5 in Reagent-grade HCl, HNO, NH, H O , methanol, acetone, 3 3 2 2 en, and NaOH were obtained from FUJIFILM Wako Pure an LDPE bottle and shaken at 260 rpm and 70 °C for 15 h using a constant-temperature incubator shaker (TAITEC, Chemical (Japan). EMSURE -grade KCN was obtained from Merck (Germany). A sample of acrylic staple fiber, Japan). The reaction is shown in Fig.  1a. The Vonnel-en fiber was washed with MQW until the wash solution attained Vonnel , was obtained from Mitsubishi Chemical (Japan). TOYOPEARL AF-Epoxy-650 M (particle size, 40–90 μm; a neutral pH. Subsequently, it was dried at 50 °C in a drying oven and stored in an LDPE bottle in a desiccator. amount of epoxy group, 0.8 mmol/g) was obtained from 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… Fig. 1 Synthetic reactions of a Vonnel-en and b TYP-en where C and C represent the concentrations of the metal Synthesis of TYP‑en s f ions in the sample solution and filtrate, respectively; and W and W represent the weights of the sample solution and the A 2.4 g portion of TOYOPEARL AF-Epoxy-650 M and dried adsorbent, respectively. 144 g of 200 mM en solution were mixed in an LDPE bottle and the pH was adjusted to pH 11 by adding 1 M HCl. The Column extraction experiments mixture was shaken at 260 rpm and 70 °C for 36 h in a con- stant-temperature incubator shaker. The reaction is shown in The Vonnel-en fiber (approximately 100 mg dry weight) or Fig. 1b. The TYP-en resin was sieved using a Teflon screen the TYP-en resin (approximately 200 mg dry weight) was with 170 mesh to remove fine particles. The TYP-en resin packed in a Type-M cartridge column (TOMOE, Japan), was washed with MQW until the wash solution became neu- with a polypropylene body and polyethylene frits, with an tral and stored in MQW in an LDPE bottle. inner diameter of 8.4 mm and a bed height of 8.5 mm. The column experiments were performed in a clean hood. Batch adsorption experiments Prior to use, the column was cleaned by passing successively 500 ml of 0.3 M NH –0.03 M KCN at a flow rate of 0.2 ml/min In a 50 ml polypropylene tube, 25 g of a sample solution and 100 ml of MQW at a flow rate of 2 ml/min. A preconcen- containing 40–500 μmol/kg of a metal ion was mixed with tration system was constructed with the column, LDPE bottles, 20 mg of Vonnel-en or TYP-en and agitated at 200 rpm PFA tubes with an internal diameter of 3 mm, Tygon tubes and 25 °C for 2 h using a constant-temperature incubator (SAINT-GOBAIN, France) with that of 3.18 mm, PharMed shaker. Subsequently, the adsorbent was collected on a tubes (TOKYO RIKAKIKAI, Japan) with that of 2.15 mm, 0.2 μm Nuclepore membrane and dried at 50 °C in a dry- and a cassette tube pump SMP-23 (TOKYO RIKAKIKAI) ing oven. The dry weight of the adsorbent was determined (Fig. 2a). A column of Vonnel-en or TYP-en was conditioned using a balance (SHIMADZU, Japan). The concentration by successively passing 20 ml of 0.1 M NH , 20 ml of MQW, of the metal ions in the filtrate was determined using ICP- and 20 ml of HCl solution with the same HCl concentration AES. The amount of metal ions adsorbed on the adsorbent as the sample solution at a flow rate of 2 ml/min just before was assumed to be the difference between the metal ion column extraction. For column extraction experiments using a amounts in the sample solution and the filtrate. The adsorp- small-volume sample containing a metal ion at a high concen- tion capacity of the metal ions is calculated using the fol- tration, the samples used were: 25 g of 0.01–0.2 M HCl solu- lowing equation: tions containing 50 μmol/kg of Pd(II) or 25 μmol/kg of Pt(II), (C − C ) × W s f s Pt(IV), Au(I) or Au(III). For column extraction experiments Adsorption capacity (mmol/g) = using a large-volume sample containing metal ions at low con- centrations, the samples used were: 500 g of 0.03–0.3 M HCl solutions containing 35 pmol/kg of Pd(II), Pt(IV), and Au(III) 1 3 M. Iwase et al. Fig. 2 Diagrams of a precon- (a) (b) centration system and b elution system Columns Air Columns Drain Cleaning, Pump Pump Eluent conditioning, and sample solutions or 600 g of 0.03–0.3 M HCl solutions containing 50 pmol/kg where C , C , and C represent the concentration of metal s p e of Pd(II), Pt(IV), and Au(III). The sample solution was loaded ions in the sample solution, the solution passing through the into the column at a flow rate of 1 ml/min. The solution that column during sample loading, and the eluate, respectively; passed through the column during the sample loading was col- and W and W represent the weights of the sample solution s e lected in an LDPE bottle. After sample loading, 20 ml of HCl and the eluate, respectively. When evaporation–redissolu- solution with the same HCl concentration as the sample solu- tion was applied, the concentration and weight of the re- tion was passed through the column at a flow rate of 2 ml/min dissolved solution were used instead of C and W . e e to remove remaining salts from sample solution. Subsequently, the column was detached from the precon- centration system and attached to an elution system, which Results and discussion was constructed with the column, LDPE bottles, PFA tubes with an internal diameter of 2 mm, Tygon tubes with that Adsorption and elution conditions of 3.18 mm, PharMed tubes with that of 1.15 mm, and a cassette tube pump SMP-23 (Fig. 2b). The elution system Pd, Pt, and Au form negatively charged chloride complexes flowed through the column in the direction opposite to that in HCl solution [13–15]. TYP-en and Vonnel-en have posi- of the preconcentration system. Pd, Pt, and Au adsorbed on tive charges in HCl solution owing to protonation of the en Vonnel-en or TYP-en were eluted with 0.3 M NH –0.003 M groups. Therefore, the negatively charged Pd, Pt, and Au KCN or 8 M HCl–10 mM H O at a flow rate of 0.6 ml/min. chloride complexes are attracted and adsorbed in the adsor- 2 2 When the metal ions remained in the column after elution bent through electrostatic forces, thereby forming chelates with 8 M HCl–10 mM H O , they were further eluted with (Fig. 3a). 2 2 0.3 M NH –0.003 M KCN. Subsequently, the eluates were The preliminary experiments revealed that the good elu- collected in PFA bottles. The column was again mounted ents for Pd, Pt, and Au were 0.3 M NH –0.003 M KCN and on the preconcentration system and cleaned with 30 ml of 8 M HCl–10 mM H O (Supplementary Figs. S1–S3). In 2 2 MQW at a flow rate of 2 ml/min.0.3 M NH –0.003 M KCN, Pd, Pt, and Au formed negatively The eluate of 0.3 M NH –0.003 M KCN was directly charged cyanide complexes (Fig. 3b). As the en groups were introduced to ICP-AES or ICP-MS to measure Pd, Pt, and neutral in this solution, the cyanide complexes were eas- Au. The eluate of 8 M HCl–10 mM H O , collected in a ily removed. Although this eluent was strong, some defects 2 2 PFA bottle, was evaporated to dryness for 8 h at 180 °C on a were observed: (1) cyanide ions are highly toxic; (2) potas- hot plate. After evaporation, the residue was re-dissolved in sium ions interfere with the determination of Pd, Pt, and Au 3 ml of 1 M HCl–1 M HNO at 270 rpm and 70 °C for 8 h by ICP-MS; and (3) when this eluent was applied to natural in a constant-temperature incubator. The re-dissolved solu- samples, some ferric ions that were adsorbed on the adsor- tion was used for measurement. The adsorption and recovery bent from the sample solution formed iron hydroxide during percentages are calculated using the following equations: elution, which adsorbed Pd, Pt, and Au, thereby resulting in a low recovery in the eluate (Supplementary Table S1). C − C s p In 8 M HCl–10 mM H O , reverse adsorption reaction Percentage of adsorption (%) = × 100 2 2 s occurred owing to the high concentration of chloride ions (Fig. 3c). This eluent was not very strong owing to the elec- C × W trostatic forces between the chloride complex ions and the e e Percentage of recovery (%) = × 100 adsorbent, and a large volume of the eluent was necessary C × W s s for quantitative recovery. However, the defects of 0.3 M 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… Fig. 3 a Adsorption reaction of metal ions on TYP-en from HCl solution. Elution reaction of metal ions in b NH –KCN solution and c HCl– O solution 2 2 NH –0.003 M KCN were overcome. When 8 M HCl was used as the eluent, Au recovery was not quantitative. We assumed that this was caused by the formation of Au(0) on the adsorbent due to the following disproportionation reaction: − − − 3AuCl ⇌ AuCl + 2Au(0) + 2Cl 2 4 We added H O to 8 M HCl to oxidize Au(0) using the 2 2 following reaction: − + 2Au(0) + 3H O + 8HCl → 2AuCl + 2H + 6H O 2 2 2 Evidently, Au recovery was higher in the 8  M HCl–10 mM H O solution. Therefore, it was considered as 2 2 Fig. 4 Effect of HCl concentration on the adsorption capacity of the most promising eluent. TYP-en for Pd(II), Pt(IV), and Au(III). Metal ion concentration in sample solution: 100–500  μmol/kg Pd(II), 40–200  μmol/kg Pt(IV), or 40–400  μmol/kg Au(III). Error bars show the standard deviation Adsorption capacity (n = 2) First, using TYP-en, the HCl concentration dependency of the adsorption capacities of Pd(II), Pt(IV), and Au(III) were Table 1 Adsorption capacities of Vonnel-en and TYP-en examined (Fig. 4). We repeated the experiments for each Element HCl (M) Adsorption capacity (mmol/g) condition and obtained highly reproducible data. Evidently, Vonnel-en TYP-en the adsorption capacities of Pd(II), Pt(IV), and Au(III) decreased when the HCl concentration increased from 0.1 M n ave ± sd n ave ± sd to 0.5 M. Subsequently, the adsorption capacities of Pd(II), Pd(II) 0.10 3 0.526 ± 0.006 2 0.310 ± 0.007 Pt(IV), and Au(III) in 0.10 M HCl between Vonnel-en and Pt(IV) 0.10 3 0.217 ± 0.004 2 0.166 ± 0.005 TYP-en were compared (Table 1). The adsorption capacities Au(III) 0.10 3 0.27 ± 0.02 2 0.52 ± 0.03 of Pd(II) and Pt(IV) for Vonnel-en were 1.7 and 1.3 times higher than those for TYP-en, respectively. In contrast, the adsorption capacity of TYP-en for Au(III) was 1.9 times higher than that for Vonnel-en. The reason of these opposite the adsorption behavior of Vonnel-en. As approximately results is not clear now. Vonnel is copolymer of acrylamide 100 mg dry weight of the Vonnel-en fiber or approximately and other constituents, of which detail is not open to the 200 mg dry weight of the TYP-en resin was packed in a col- public. It is possible that the other constituents influence umn, the adsorption capacity of the column was higher than 1 3 M. Iwase et al. Fig. 5 Effect of HCl concentration on the adsorption percentage of or 25  μmol/kg Pt(II), Pt(IV), Au(I), or Au(III). Error bars show the Pd(II), Pt(II), Pt(IV), Au(I), and Au(III) for a Vonnel-en and b TYP- standard deviation (n = 3) en. Metal ion concentration in sample solution: 50  μmol/kg Pd(II) 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… Fig. 6 Effect of HCl concentration on the recovery percentage of NH –0.003  M KCN (triangles), 90  g of 8  M HCl–10  mM H O 3 2 2 Pd(II), Pt(II), Pt(IV), Au(I), and Au(III) for a Vonnel-en and b TYP- (diamonds), or 90  g of 8  M HCl–10  mM H O and 30  g of 0.3  M 2 2 en. Metal ion concentration in sample solution: 50 μmol/kg Pd(II) or NH –0.003 M KCN (squares). Error bars show the standard deviation 25  μmol/kg Pt(II), Pt(IV), Au(I), or Au(III). Eluent: 90  g of 0.3  M (n = 3) 1 3 M. Iwase et al. 0.022 mmol for Pd(II), Pt(IV), and Au(III), which was > 35 of 0.3 M NH –0.003 M KCN or 8 M HCl–10 mM H O . 3 2 2 times higher than the metal ion amount in the subsequent Thus, TYP-en is expected to have the potential to deter- column extraction experiments. mine the total dissolved concentrations of Pd, Pt, and Au irrespective of their oxidation states. Column extraction experiments using small‑volume samples containing a metal ion at a high Column extraction experiments using concentration large‑volume samples containing metal ions at low concentrations The effect of HCl concentration on the percentage of adsorption for Vonnel-en and TYP-en in column extraction Column extraction experiments were performed using large- experiments was investigated using small-volume samples volume samples (500–600 g) containing Pd(II), Pt(IV), and of 25 g containing a metal ion at a high concentration of Au(III) at a low concentration of 35–50 pmol/kg (Fig. 7). 25–50  μmol/kg (Fig.  5). For Vonnel-en, Au(I) was not Pd(II) was quantitatively recovered from 0.03 to 0.3  M quantitatively collected from > 0.15 M HCl solution. In HCl solution by Vonnel-en and from 0.03 to 0.1 M HCl contrast, TYP-en was able to quantitatively recover Pd(II), solution by TYP-en. Pt(IV) was quantitatively recovered Pt(II), Pt(IV), Au(I), and Au(III) from 0.01 to 0.2 M HCl from 0.07 M HCl solution and Au(III) was quantitatively solution. recovered from 0.03 to 0.3 M HCl solution by TYP-en. The In addition, the effect of the HCl concentration on recovery of Pt(IV) and Au(III) from 0.03 to 0.3 M HCl solu- the recovery of Vonnel-en and TYP-en was investigated tion by Vonnel-en was 7–15% and 20–52%, respectively, (Fig.  6). Pd(II), Pt(IV), and Au(III) were quantitatively when the eluent was 8 M HCl–10 mM H O . Additional 2 2 recovered from a 0.07–0.2 M HCl solution by both Von- elution with 0.3 M NH –0.003 M KCN slightly increased nel-en and TYP-en. Pt(II) recovery by Vonnel-en was the recovery of Pt(IV) and Au(III) to 15–30% and 22–55%, 70–100% when the eluent was 8 M HCl–10 mM H O . respectively. These results indicate that Pt(IV) and Au(III) 2 2 However, a quantitative recovery was obtained by addi- were not quantitatively retained by Vonnel-en, although the tional elution with 0.3  M NH –0.003  M KCN. Au(I) total amount of metal ions was only 53 pmol in these exper- recovery by Vonnel-en decreased with increasing HCl iments. Thus, the recovery of Pt(IV) and Au(III) by Von- concentration, and the obtained recoveries from 0.07 to nel-en may depend on the sample volume and on the ana- 0.2 M HCl solution were lower than the percentages of lyte concentration. These results are inconsistent with our adsorption. This was because a portion of Au(I) adsorbed previous experience of the solid-phase extraction of metal on the Vonnel-en was desorbed when 20 ml of HCl solu- ions, wherein chelating adsorbents that have groups, such tion with the same concentration as the sample solution as 8-hydroxyquinoline [29] and ethylenediaminetriacetic was passed through the column after sample loading. In acids, were used [30]. In these studies, metal ions were contrast, Pt(II) and Au(I) were quantitatively recovered quantitatively recovered, independent of sample volume from 0.01 to 0.2 M HCl solution by TYP-en with an eluent and metal ion concentrations, as long as the total amount Fig. 7 Effect of HCl concentration on the recovery percentage of containing 50  pmol/kg Pd(II), Pt(IV), and Au(III) (gray triangles). Pd(II), Pt(IV), and Au(III) for Vonnel-en (white symbols) and TYP- Eluent: 60 g of 0.3 M NH –0.003 M KCN (triangles), 180 g of 8 M en (gray symbols). Sample solution: 500  g of 0.03–0.3  M HCl con-HCl–10 mM H O (diamonds), or 180  g of 8  M HCl–10  mM H O 2 2 2 2 taining 35  pmol/kg Pd(II), Pt(IV), and Au(III) (white diamonds, and 30 g of 0.3 M NH –0.003 M KCN (squares). Error bars show the white squares, and gray diamonds) or 600  g of 0.03–0.3  M HCl standard deviation (n = 3) 1 3 Solid‑phase extraction of palladium, platinum, and gold from water samples: comparison between… KAKENHI grants to YS (15H01727 and 19H01148). We would like to of metal ions was sufficiently lower than the adsorption thank Editage (www. edita ge. com) for English language editing. capacity of the chelating column. A possible explanation is that en is a neutral ligand and forms less stable chelate Data availability All data generated or analyzed during this study are with metal ions compared with negatively charged ligands. included in this published article. The reason of difference between TYP-en and Vonnel-en is Declarations not clear now. It is possible that the nature of copolymer of Vonnel-en causes the difference. Conflict of interest On behalf of all the authors, the corresponding au- thor states that there is no conflict of interest. Open Access This article is licensed under a Creative Commons Attri- Conclusions bution 4.0 International License, which permits use, sharing, adapta- tion, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, In this study, a chelating fiber Vonnel-en and a chelating provide a link to the Creative Commons licence, and indicate if changes resin TYP-en, which have en groups, were synthesized to were made. The images or other third party material in this article are evaluate their performance in a solid-phase extraction of Pd, included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in Pt, and Au. In batch adsorption experiments, the adsorption the article's Creative Commons licence and your intended use is not capacity of Vonnel-en was 1.7 and 1.3 times higher than permitted by statutory regulation or exceeds the permitted use, you will that of TYP-en for Pd(II) and Pt(IV), respectively, whereas need to obtain permission directly from the copyright holder. To view a the adsorption capacity of Vonnel-en was half that of TYP- copy of this licence, visit http://cr eativ ecommons. or g/licen ses/ b y/4.0/ . en for Au(III). Column extraction experiments revealed that TYP-en is superior to Vonnel-en. In experiments using small-volume samples containing a metal ion at a µmol/kg References concentration, Vonnel-en could not quantitatively recover 1. J. Kielhorn, C. Melber, D. Keller, I. Mangelsdorf, Int. J. Hyg. Au(I) from 0.07 to 0.2  M HCl solution. However, TYP- Environ. Health 205, 417 (2002) en was able to quantitatively recover Pd(II), Pt(II), Pt(IV), 2. A. Dubiella-Jackowska, Ż Polkowska, J. Namieśnik, Pol. J. Envi- Au(I), and Au(III) from 0.01 to 0.2  M HCl solution. In ron. Stud. 16, 329 (2007) experiments using large-volume samples containing metal 3. C.W. Corti, R.J. Holliday, Appl. Earth Sci. 114, 115 (2005) 4. K.H. Wedepohl, Geochim. Cosmochim. Acta 59, 1217 (1995) ions at pmol/kg concentrations, Vonnel-en was unable to 5. A. Mitra, I.S. Sen, Geochim. Cosmochim. Acta 216, 417 (2017) quantitatively recover Pt(IV) and Au(III). However, TYP- 6. C. Barbante, A. Veysseyre, C. Ferrari, K.V.D. Velde, C. Morel, en could quantitatively recover Pd(II), Pt(IV), and Au(III) G. Capodaglio, P. Cescon, G. Scarponi, C. Boutron, Environ. Sci. simultaneously. Based on these results, TYP-en was con- Technol. 35, 835 (2001) 7. H. Wichmann, G.A.K. Anquandah, C. Schmidt, D. Zachmann, cluded as a more promising adsorbent than Vonnel-en for the M.A. Bahadir, Sci. Total Environ. 388, 121 (2007) preconcentration of Pd, Pt, and Au. As the en groups both 8. F. Zereini, H. Alsenz, C.L. Wiseman, W. Puttmann, E. Reimer, participate in anion exchange and chelate formation, TYP-en R. Schleyer, E. Bieber, M. Wallasch, Sci. Total Environ. 416, 261 is effective for the solid-phase extraction of Pd, Pt, and Au (2012) 9. E. Abdulbur-Alfakhoury, G. Trommetter, N. Brion, D. Dumou- chloride complexes. Future investigations will include the lin, M. Reichstadter, G. Billon, M. Leermakers, W. Baeyens, Sci. development of an analytical method for the determination Total Environ. 784, 147075 (2021) of Pd, Pt, and Au in environmental water samples, such as 10. A. Yessoufou, B.E. Ifon, F. Suanon, B. Dimon, Q. Sun, C.A. Ded- river water and seawater. jiho, D. Mama, C.P. Yu, Environ. Monit. Assess. 189, 625 (2017) 11. K. Ravindra, L. Bencs, R. Van Grieken, Sci. Total Environ. 318, Supplementary Information The online version contains supplemen- 1 (2004) tary material available at https://doi. or g/10. 1007/ s44211- 023- 00270-3 . 12. Y. Pan, S. Neuss, A. Leifert, M. Fischler, F. Wen, U. Simon, G. Schmid, W. Brandau, W. Jahnen-Dechent, Small 2007, 3 (1941) Acknowledgements The authors thank Prof. Shigeru Yamago (Kyoto 13. C.H. Gammons, Geochim. Cosmochim. Acta 60, 1683 (1996) Univ.) for introducing us to Mitsubishi Chemical. The authors are 14. D.R. Turner, M. Whitfield, A.G. Dickson, Geochim. Cosmochim. profoundly grateful to Mitsubishi Chemical for providing a sample Acta 45, 855 (1981) TM of the acrylic staple fiber Vonnel . We express our appreciation to 15. A. Usher, D.C. McPhail, J. Brugger, Geochim. Cosmochim. Acta Emeritus Prof. Kazumasa Ueda (Kanazawa Univ.) and the graduates: 73, 3359 (2009) Shiori Goto, Junya Tanaka (Kanazawa Univ.); Taishi Sato, Keiko Inada, 16. D.S. Lee, Nature 305, 47 (1983) Kengo Sato, Jun Yamamoto, and Masanobu Sasaki (Kyoto Univ.) for 17. E.D. Goldberg, V. Hodge, P. Kay, M. Stallard, M. Koide, Appl. their assistance with the preliminary experiments of this study. This Geochem. 1, 227 (1986) research was supported by a Mitsumasa Ito Memorial Research Grant 18. M. Koide, V. Hodge, E.D. Goldberg, K. Bertine, Appl. Geochem. from the Research Institute for Oceanochemistry Foundation to MI 3, 237 (1988) (R3-R2) and by the Japan Society for the Promotion of Science (JSPS) 1 3 M. Iwase et al. 19. K.K. Falkner, J.M. Edmond, Earth Planet. Sci. Lett. 98, 208 25. H. Hasegawa, S. Barua, T. Wakabayashi, A. Mashio, T. Maki, Y. (1990) Furusho, I.M.M. Rahman, Microchem. J. 139, 174 (2018) 20. A. Suzuki, H. Obata, A. Okubo, T. Gamo, Mar. Chem. 166, 114 26. X. Chang, Y. Li, G. Zhan, X. Luo, W. Gao, Talanta 43, 407 (1996) (2014) 27. P. Tahaei, M. Abdouss, M. Edrissi, A.M. Shoushtari, M. Zargaran, 21. A.S. Mashio, A. Ichimura, H. Yamagishi, K.H. Wong, H. Obata, Materialwiss. Werkstofftech. 39, 839 (2008) H. Hasegawa, Mar. Chem. 243, 104124 (2022) 28. L. Niu, S. Deng, G. Yu, J. Huang, Chem. Eng. J. 165, 751 (2010) 22. L. Fischer, G. Smith, S. Hann, K.W. Bruland, Mar. Chem. 199, 44 29. Y. Sohrin, S. Iwamoto, S. Akiyama, T. Fujita, T. Kugii, H. Obata, (2018) E. Nakayama, S. Goda, Y. Fujishima, H. Hasegawa, K. Ueda, M. 23. K. Liu, X. Gao, L. Li, C.-T.A. Chen, Q. Xing, Chemosphere 212, Matsui, Anal. Chim. Acta 363, 11 (1998) 429 (2018) 30. Y. Sohrin, S. Urushihara, S. Nakatsuka, T. Kono, E. Higo, T. 24. A. Cobelo-Garcia, M.E. Mulyani, J. Schafer, Talanta 232, 122289 Minami, K. Norisuye, S. Umetani, Anal. Chem. 80, 6267 (2008) (2021) 1 3

Journal

Analytical Sciences – Springer Journals

Published: May 1, 2023

Keywords: Palladium; Platinum; Gold; Solid-phase extraction; Chelating resin; Chelating fiber

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