Professor Volodymyr Zaitsev

Professor, D.Sc., PhD, Corr. Member Acad. of Sci. of Ukraine

Olena Artiushenko

Silica-based Adsorbents with Immobilized Derivatives of Phosphonic, Hydroxamic and Pyridinecarboxylic Acids for Dispersive Solid Phase Extraction and Separation of Rare Earth Elements

https://doi.org/10.17771/PUCRio.acad.48221

Tese de Doutorado Thesis presented to the Programa de Pós-graduação em Química of PUC-Rio in partial fullfilment of the requirements for the degree of Doutor em Química.
Rio de Janeiro Novembro de 2019

Advisor: Prof. Volodymyr Zaitsev

Abstract

Rare earth elements (REEs) have been increasingly used in modern industry as essential components of many catalysts, high-performance magnets, superconductors, telecommunication systems. Clean energy development will further boost the demand for REEs since they are used in the production of batteries and solar panels. Environmentally sustainable production process shall substitute or supplement current ore sources. Thus, separation and recycling of REEs are of great importance to diversify the sources of REEs. Most existing technologies for enrichment of REEs are based on solvent extraction and ion exchange. They are not sustainable and are not applicable to electronic waste (ewaste) treatment. One of the first selective adsorbent for REEs SPE extraction was proposed recently (Callura et al., 2018). The research proposed demonstrates other organo-silica adsorbents (OSAd) with covalently immobilized fragments of N-Benzoyl-N-phenylhydroxylamine (BPHA), 2,6-pyridine-dicarboxylic acid (PdCA) and amino-di(methylene-phosphonic) acid (AdMPA) can be successfully used both for preconcentration and separation of REEs, without utilization of any solvents and surfactants. This research demonstrates high affinity of the adsorbents to REE (La³⁺, Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺, Yb³⁺, and Lu³⁺), Sc³⁺ and Y³⁺. Competitive adsorption of REEs from multielement solution and pH dependence, isotherm and kinetics studies, metal ion recovery and desorption, as well as the adsorbent reusability have been investigated. The research is accomplished with qualitative and quantitative characterization of the adsorbent, physical and chemical properties using Fourier transform infrared spectroscopy, high-resolution X-ray photoelectron spectroscopy, solid-state NMR, BET measurements, elemental and thermogravimetric analysis. It has been demonstrated that the proposed OSAd can be successfully used to remove REE ions from aqueous solution within 10 min. Sharp changes of REEs recovery has been observed in a narrow range of the pH that allows developing a methodology for removal of REEs from solution. The adsorbents demonstrate an essential difference in REE affinity that allows utilization of the OSAd for various purposes, including pre-concentration for determination of REE traces in natural water, separation of REE from color and other metals in e-waste, separation of individual REE. It is demonstrated that SiO₂-BPHA can recover all REE from solution with pH ≥ 5.0 and release them to solution under treatment with 0.1 M HNO3 with efficiency more than 95%. Other OSAd - SiO₂-PdCA and SiO₂-AdMPA the only adsorbents that can remove REE ions from aqueous solution with pH ≥ 2. Because of this SiO₂-PdCA and SiO₂- AdMPA can be used for recycling of rare earth elements from electronic waste. It was demonstrated that SiO₂-PdCA can be used for selective recovery of rare earth elements (Y, Eu, Tb) from waste fluorescent lamps. SiO₂-PdCA demonstrates high selectivity that allows complete (>95%) recovery of all REE in the presence of 50-fold excess of Ba2+ ions that is used for analytical determination of REE traces by ICP-MS. Also, SiO2-PdCA is useful for selective adsorption of REE from environmental objects since 200-fold excess of such ions as Fe3+, Cu2+, Ca2+, Mg2+, Na+ , K+ and Al3+ which are predominate in environmental objects cause little or no interference on the adsorbent removal efficiency. SiO2-BPHA demonstrates higher selectivity towards heavy REEs. In optimal conditions selectivity factor is about 80 (for Lu/La and Yb/La pairs) and about 60 (for Tm/La pair), which demonstrates the high potential of SiO2-BPHA in separation of individual REEs. Reusability test demonstrates that SiO2-BPHA can be used for quantitative adsorption of almost all REEs (average adsorption of Ce and Pr ions is about 90%) from multielement solution with pH=5.0 without lost in adsorption capacity and selectivity for at least in five consecutive cycles. It is demonstrated that adsorption of metals on the OSAd takes place due to complex formation between immobilized ligand and metal ions. For example, adsorption of Eu3+ and Tb3+ ions on SiO2-PdCA and SiO2-AdMPA generates strong red and green luminescence, respectively. Adsorption of Fe3+ on SiO2-BPHA leads to development of red color of the adsorbent which intensity is proportional to metal loading. Immobilized metal complexes are very stable in water and organic media that can be used for further development of optical sensors for REE and stationary phases for ligand-exchange chromatography.
maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=48221@2

Keywords: Silica-based Adsorbent; Solid Phase Extraction; Separation; Rare Earth Elements

ADSORVENTES À BASE DE SÍLICA GEL MODIFICADA COM DERIVADOS DE ÁCIDO FOSFÔNICO, HIDROXÂMICO E PIRIDINOCARBOXÍLICO PARA EXTRAÇÃO EM FASE SÓLIDA DISPERSIVA E SEPARAÇÃO DOS ELEMENTOS TERRAS RARAS

https://www.maxwell.vrac.puc-rio.br/colecao.php?strSecao=resultado&nrSeq=48221@1

Laboratório de adsorventes para análise química, proteção de ambiente e biomedicina (LAQAPAB)
Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
tel: +55 21 980551969,
e-mail: vnzaitsev@puc-rio.br,
http://zaitsev.usuarios.rdc.puc-rio.br

ORCID