Application of Organo-Ceramic Adsorbents Functionalized With Imidazole for Noble Metal Separations

Lee, J. S.; Tavlarides, Lawrence L.

doi:10.1081/sei-120004814

Cited by 24 publications

(16 citation statements)

References 19 publications

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“…In the last few years, chemically modified silica gel adsorbents have become attractive materials for the extraction of metal ions and different types of compounds, due to the fact that these materials do not swell, nor shrink, like in the case of polymeric resins. Moreover, the modified silica has both good thermal stability and high metal removal efficiency [30]; because of this new procedures to produce adsorbent materials have been developed, among which the ones that use hybrid and functionalized adsorbents via the sol-gel process [31], [32] is proposed. These adsorbents contain an inorganic matrix which can be silica, alumina, titania or zirconia, to which functional organic groups are adhered such as thiols, amine, phosphonates, carboylates, halides, etc., which play the role of ligand agents for metal ions, metalloids, non-metal cations (like NH4 + ) or of non-metal anions (like seleniate) [33].…”

Section: Introductionmentioning

confidence: 99%

Hybrid functionalized phosphonate silica: insight into chromium removal chemistry from aqueous solutions

et al. 2019

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Abstract. Insight into Cr(III) ions removal chemistry from aqueous solutions was gained by using hybrid phosphonate-functionalized silica adsorbents synthesized through a modified route of sol-gel processing (SPMF). Evaluation of the degree of metal removal was obtained from kinetics and batch experiments. Elemental analysis, FTIR, NMR and XPS techniques were used to study the nature of surface complex formed on adsorbent. Adsorption equilibrium results showed a maximum Cr(III) removal of 78.639 mg g-1Cr(III) at pH 3.6 on adsorbent SPMF04; kinetics measurements indicated that equilibrium was reached in 80 min contact time. The achievement of 2.923 mmol P/g as phosphonate groups was obtained. A Langmuir-type mechanism explained the adsorption equilibrium results whereas kinetic measurements were explained through a pseudo-second order mechanism. FTIR measurements indicated a strong influence of Cr(III) adsorbed on surficial functional groups. 29Si CP MAS NMR results indicated that Cr(III) interacted not only with phosphonate surface groups but also with a large of amount of geminal OH surface groups. XPS studies suggested that Cr(III) was removed through the formation of the surface complex R as monovalent chromium acetate and/or divalent. The adsorbent SPMF04 can be potentially employed in industrial applications. Resumen. Información sobre la química de remoción de Cr(III) de soluciones acuosas fue obtenida usando adsorbentes de sílice hibrida funcionalizada con fosfonato sintetizados a través de una ruta modificada del proceso sol-gel (SPMF). La evaluación del grado de remoción de metal fue obtenida a partir de experimentos de cinética y por lotes. Técnicas de análisis elemental, FTIR, NMR y XPS fueron usadas para estudiar la naturaleza del complejo de superficie formado sobre el adsorbente. Los resultados del equilibrio de adsorción mostraron una remoción máxima de Cr(III) de 78.639 mg g-1 Cr(III) a pH 3.6 sobre el adsorbente SPMF04; las mediciones cinéticas indicaron que el equilibrio fue alcanzado en 80 min de tiempo de contacto. El logro de 2.923 mmol P/g como grupos fosfonato fue obtenido. Un mecanismo tipo Langmuir explicó los resultados del equilibrio de adsorción mientras que las mediciones cinéticas fueron explicadas a través de un mecanismo de pseudo-segundo orden. Los resultados de 29Si CP MAS NMR indicaron que Cr (III) interactuó no solamente con grupos fosfonato de superficie sino también con una gran cantidad de grupos OH de superficie geminales. Los estudios de XPS sugirieron que Cr(III) fue removido a través de la formación del complejo de superficie R como acetato de cromo monovalente y/o divalente. El adsorbente SPMF04 puede ser potencialmente empleado en aplicaciones industriales.

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Section: Introductionmentioning

confidence: 99%

Hybrid functionalized phosphonate silica: insight into chromium removal chemistry from aqueous solutions

et al. 2019

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“…The column fails after that as a result of an excessive pressure drop, possibly caused by precipitation of thiourea on the adsorbent and dissolution of silica. 7 Even though the column fails after 17 operations, this study shows that SOL-PzPs-BD-5 has strong operational stability because the degradation occurs primarily during the regeneration processes.…”

Section: Materials Stabilitymentioning

confidence: 94%

“…The assumption of quasi-monodentate adsorption mechanism was successfully used to describe the adsorption of Pd(II) and Pt(IV) chlorides on a functionalized imidazole. 7 The adsorption mechanism (Eq. 2) for Pd(II), Pt(IV), and Au(III) chlorides can be rewritten based on the assumption as…”

Section: Adsorption In Equilibriummentioning

confidence: 99%

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Pyrazole functionalized organo‐ceramic hybrids for noble metal separations

Lee

Tavlarides

2005

AIChE Journal

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“…New publications on Au and PGM ions are regularly appearing []. Noble metals are most often sorbed as their chloride complexes and (rarer) as bromide complexes [].…”

Section: Sorbentsmentioning

confidence: 99%

Solid‐phase extraction in the determination of gold, palladium, and platinum

Mladenova

Karadjova²,

Tsalev³

2012

J of Separation Science

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A simple classification of various sorbents and solid-phase extraction procedures used for preconcentration of trace levels of Au, Pd, and Pt from different sample types is proposed in this review article. The large variety of available sorbents/procedures has been organized according to expected mechanisms of sorption process (complex formation; ion exchange; adsorption; ion-imprinted or molecularly imprinted polymers); according to the kind of monomeric units of the polymer matrix as well as on the basis of the kind of functional group responsible for main performance characteristics (selectivity, capacity) of the sorbent. Advantages of chemically modified sorbents, sulfur-containing sorbent extractants, and ion-imprinted polymers, together with rational pretreatment by means of microwave treatments, scaling down of enrichment, and quantification by means of flow and flow injection approaches are given. Preferred instrumental techniques for quantification of ppb levels of Au, Pd, and Pt in prepared concentrates/column eluates are multielement instrumental techniques: inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICPMS). Excellent limits of detection at picogram levels of these analytes are provided by electrothermal atomic absorption spectrometry (ETAAS), generally in single-element mode and the neutron activation analysis (NAA), while X-ray fluorescence spectrometry and flame AAS are rarely applied because of lack of sensitivity at sub-ppm levels of Au, Pd, and Pt. Some problems of atomic spectrometric quantification techniques and their representative limits of detection are given. Recent applications to geological, industrial, pharmaceutical, biological, and other materials are tabulated. References have been selected mostly from the period 1995 to 2010.

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Application of Organo-Ceramic Adsorbents Functionalized With Imidazole for Noble Metal Separations

Cited by 24 publications

References 19 publications

Hybrid functionalized phosphonate silica: insight into chromium removal chemistry from aqueous solutions

Hybrid functionalized phosphonate silica: insight into chromium removal chemistry from aqueous solutions

Pyrazole functionalized organo‐ceramic hybrids for noble metal separations

Solid‐phase extraction in the determination of gold, palladium, and platinum

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