Selective extraction of Pd(II) ions from automotive catalyst residue in Cl− media by O-thiocarbamoyl-functionalized thiacalix[n]arenes

Gandhi, Muniyappan Rajiv; Yamada, Manabu; Kondo, Yoshihiko; Shibayama, Atsushi; Hamada, Fumio

doi:10.1016/j.hydromet.2014.11.017

Cited by 31 publications

(10 citation statements)

References 33 publications

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“…All the studied diluents showed very high Pd(II) extractabilities with respect to extractant 1 . In our previous article, we reported that macrocyclic extractants 3 – 5 showed very good solubility in chloroform. , In order to compare extraction capabilities of extractant 1 with macrocyclic extractants 3 and 4 , all the subsequent experiments were performed using chloroform. However, the use of diluents, namely, nitrobenzene, o -dichlorobenzene, toluene, and chlorobenzene, was not suitable for commercial operations because of environmental and safety reasons.…”

Section: Resultsmentioning

confidence: 99%

“…2,2′-Thiobis(4- t -butyl)phenol, 2 , was first synthesized using the procedure described in the literature . Extractants 3 and 4 were synthesized according to literature methods. , Extractant 1 was then synthesized as follows. 2,2′-Thiobis(4- t -butyl)phenol, 2 (8.00 g, 24.2 mmol), N , N -dimethyl(thiocarbamoyl) chloride (7.93 g, 64.2 mmol), and K 2 CO 3 (10.31 g, 74.6 mmol) were stirred in acetone (400 mL) and refluxed for 5 days under a nitrogen atmosphere.…”

Section: Methodsmentioning

confidence: 99%

“…Thiacalix[ n ]arenes are composed of phenol units linked by elemental sulfurs and have been found to act as multidentate ligands. − We recently reported that thiacalix[ n ]arene derivatives were functionalized as the thiacalixarene “upper” and “lower” rims and exhibited enhanced metal extraction capabilities . Among them, the tetra- and hexa-kis[(dimethylthiocarbamoyl)oxy]thiacalix[4/6]arene derivatives ( 3 and 5 in Figure ) are excellent candidates for Pd extraction from acidic leach liquors of automotive catalysts. , …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparative Study on Palladium(II) Extraction Using Thioamide-Modified Acyclic and Cyclic Extractants

Yamada

Gandhi

Sato

et al. 2016

Ind. Eng. Chem. Res.

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For extraction from a single Pd(II) solution, 1,1′bis[(dimethylthiocarbamoyl)oxy]-2,2′-thiobis [4-t-butylbenzene] (1) in a CHCl 3 diluent was found to exhibit a higher extractability for Pd(II) ions (E% = 99.9%) in Cl − media (0.1 M) over 30 min as well as a higher extraction efficiency compared to 2,2′-thiobis[4-tbutylphenol] (2) as a starting material of 1 and macrocyclic compounds such as tetrakis[(dimethylthiocarbamoyl)oxy]thiacalix-[4]arene (3) and p-tert-butylthiacalix[4]arene (4). Also, various parameters, such as the shaking time, diluents used, concentrations of Pd(II) and 1, effects of HCl, and effects of H + and Cl − ions, were studied. Extractant 1 could also be used for the selective extraction of Pd(II) ions (E% > 99%) from the leach liquors of automotive catalysts that also contained the ions of Rh, Pd, Pt, Zr, Ce, Ba, Al, La, and Y in Cl − media and was found to be a more efficient extractant than 2 for Pd(II) recovery. In addition, the Pd(II) ions could be stripped from 1 using 0.1 M thiourea in 1.0 M HCl, thus enabling the reuse of 1. Extractant 1 was actually found to exhibit a high E% for Pd (>96%) after five extraction cycles, indicating good stability in acidic media and potential usefulness for the rapid and selective recovery of Pd(II) from catalyst solutions in platinum group metal refineries.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparative Study on Palladium(II) Extraction Using Thioamide-Modified Acyclic and Cyclic Extractants

Yamada

Gandhi

Sato

et al. 2016

Ind. Eng. Chem. Res.

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“…Saguru and Ndlovu (2017) developed a leaching process for catalytic converters using acidic chloride media, which attained recoveries of 15%, 78%, and 86% for Rh, Pt, and Pd respectively. Solvent extraction (Nguyen, Kumar, and Lee, 2016, Nguyen, Sonu, and Lee, 2016, Gandhi et al, 2015, ion exchange resin technology, classical precipitation (Crundwell et al, 2011) and more recently, cloud point extraction (CPE) (Suoranta et al, 2015) have been investigated for PGM recovery from chloride leach liquors. CPE has been used for the analytical determination of metals at low concentration, and due to the nature of the chemicals used, has been touted as a more environmentally friendly option.…”

Section: Introductionmentioning

confidence: 99%

PGM recovery from a pregnant leach solution using solvent extraction and cloud point extraction: a preliminary comparison

Makua

Langa

Saguru

et al. 2019

J. S. Afr. Inst. Min. Metall.

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Global demand for the three platinum group metals (PGMs) Pt, Pd, and Rh has been steadily growing due to their widespread use in emission control, industrial catalysis, and numerous other applications. The primary supply of PGMs is currently the mining industry. However, legislative, operational, and environmental challenges faced by many mining operations result in erratic supply patterns and deficits for these three metals. Naturally, recycling scrap material to recover Pt, Pd, and Rh has therefore aroused research interest in the scientific and engineering communities. Given that the majority of the global demand for these three metals is driven by emission control devices, autocatalytic converters are therefore a significant source of already processed and beneficiated PGMs for recycling. Although pyrometallurgical processes dominate the recycling industry, hydrometallurgical processes may offer certain advantages, chief among these being lower emissions and reduced energy consumption. In this investigation, scrap converter material was leached in acidic chloride media and the leach liquor subjected to solvent extraction and cloud point extraction (CPE) to recover the PGMs. The recoveries for Pt and Pd using Alamine 308 ® dissolved in kerosene with decanol as a modifier were 95% and 81%, respectively. The maximum recoveries using CPE after complexation with 2-mercaptobenzothiazole (2-MBT) in the presence of Triton X-100 and tin (II) chloride dihydrate as a reductant were 97% for Pd, 96% for Pt, and 91% for Rh. This demonstrates that CPE, although relatively new, may have some potential as a breakthrough PGM recovery technology.

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“…Thus, functionalized macrocyclic calix[4]arenes (basket-like molecules) can simplify the enrichment of PGMs and significantly decrease the use of excess extractants 20 . Our previous results showed that macrocyclic calixarene or thiacalixarene-based extractants and other new thiocarbamoyl-based extractants are more durable in acid media than commercial extractants and extract approximately 3–5-fold more metal ions than commercial extractants from secondary resource leach liquors 19 , 21 – 28 . Generally, calixarenes and their derivatives are highly soluble only in aromatic/chlorinated diluents such as chloroform, dichloromethane, dichloroethane, and toluene 29 .…”

Section: Introductionmentioning

confidence: 99%

Rapid and selective recovery of palladium from platinum group metals and base metals using a thioamide-modified calix[4]arene extractant in environmentally friendly hydrocarbon fluids

Yamada

Gandhi

Shibayama

2018

Sci Rep

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A novel macrocyclic calix[4]arene extractant having a long alkyl chain thioamide, 25,26,27,28-tetrakis(N-n-octylthiocarbamoyl)methoxy-5,11,17,23-tetra-tert-butylcalix[4]arene (1), was synthesized from 25,26,27,28-tetrakis(N-n-octylcarbamoyl)methoxy-5,11,17,23-tetra-tert-butylcalix[4]arene (2) using Lawesson’s reagent. Extractant 1 was characterized using 1H NMR, 13C NMR, FT-IR spectroscopy, and elemental analysis. The Pd(II) extraction abilities of 1 and 2 were studied in high-boiling-point and environmentally friendly hydrocarbon diluents. Pd(II) extraction experiments were conducted using single-metal Pd(II) solutions, simulated mixed palladium group metal (PGM) solutions, and acid-leached automotive catalyst residue solutions. Different experimental conditions, including the shaking time, HCl/HNO3 concentration, Pd(II) concentration, extractant concentration, and the organic/aqueous phase ratio, were studied systematically. Extractant 1 showed very selective (> 99.9%) Pd(II) extraction from the mixed PGM/base metal solutions and the acid-leached automotive catalyst residue solution. Conversely, the Pd(II) extraction ability of extractant 2 was found to be negligible. Extractant 1 showed very fast extraction kinetics and a high extraction capacity as compared to those of the commercial extractant di-n-octyl sulfide. Effective stripping of Pd(II) from 1 was performed using HCI, HNO3, NH3, and HCl-thiourea solutions. Furthermore, 1 was successfully recycled over five extraction/stripping cycles. The Pd(II) extraction mechanism of 1 was studied using FT-IR spectroscopy. Extractant 1 exhibited very selective Pd(II) extraction and high acid stability, demonstrating its industrial applicability for the extraction of Pd(II) from leached automotive catalyst liquors containing PGMs and base metals.

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Selective extraction of Pd(II) ions from automotive catalyst residue in Cl− media by O-thiocarbamoyl-functionalized thiacalix[n]arenes

Cited by 31 publications

References 33 publications

Comparative Study on Palladium(II) Extraction Using Thioamide-Modified Acyclic and Cyclic Extractants

Comparative Study on Palladium(II) Extraction Using Thioamide-Modified Acyclic and Cyclic Extractants

PGM recovery from a pregnant leach solution using solvent extraction and cloud point extraction: a preliminary comparison

Rapid and selective recovery of palladium from platinum group metals and base metals using a thioamide-modified calix[4]arene extractant in environmentally friendly hydrocarbon fluids

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