State of the Art in Separation and Analysis of Energies

A topical collection in Separations (ISSN 2297-8739). This collection belongs to the section "Analysis of Energies".

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Collection Editor
MEET Battery Research Center, University of Münster, Corrensstrasse 46, 48149 Münster, Germany
Interests: gas chromatography; high-performance liquid chromatography; ion chromatography; capillary electrophoresis; mass spectrometry; sample preparation; solid-phase extraction and microextraction; ionic liquids; battery electrolytes; lithium ion batteries
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Collection Editor
MEET-Battery Research Center Office, Munster, Germany
Interests: analytics; electrolyte; hyphenation techniques; elemental analysis

Topical Collection Information

Dear Colleagues,

We are pleased to introduce a new topical collection of Separations on the topic “State of the Art in Separation and Analysis of Energies”.

In general terms, “energies” can be defined as all developments and applications with regard to energy supply, conversion, application and storage. 

In the topical collection “State of the Art in Separation and Analysis of Energies”, we are welcoming original research and review articles on the development and application of separation methods in this field.

The Separation and analysis of energies is a broad field and can cover all separation techniques and detection methods. These methods can be based on analysis approaches or chemical/physical separations of elements or compounds. The identification/quantification or enhanced separation of elements and compounds are of particular interest. Reports on quality control and the standardization of energy products or materials will also be considered on the basis of their significance in the field.

In all cases, novelty will be the major suitability criterion of submitted articles. Authors should always address the novelty of their proposed methodology and draw a comparison with previously reported methods.

Dr. Sascha Nowak
Dr. Yannick Philipp Stenzel
Collection Editors

Manuscript Submission Information

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Keywords

  • analysis of energies
  • gas chromatography
  • high-performance liquid chromatography
  • ion chromatography
  • capillary electrophoresis
  • mass spectrometry
  • sample preparation
  • solid-phase extraction and microextraction
  • ionic liquids
  • battery electrolytes
  • lithium-ion batteries

Published Papers (7 papers)

2023

Jump to: 2022

18 pages, 4752 KiB  
Article
Shaping of HKUST-1 via Extrusion for the Separation of CO2/CH4 in Biogas
by Muhamad Tahriri Rozaini, Denys I. Grekov, Mohamad Azmi Bustam and Pascaline Pré
Separations 2023, 10(9), 487; https://doi.org/10.3390/separations10090487 - 6 Sep 2023
Cited by 2 | Viewed by 1839
Abstract
HKUST-1 is a metal-organic framework (MOF) that is widely studied as an adsorbent for CO2 capture because of its high adsorption capacity and good CO2/CH4 selectivity. However, the numerous synthesis routes for HKUST-1 often result in the obtention of [...] Read more.
HKUST-1 is a metal-organic framework (MOF) that is widely studied as an adsorbent for CO2 capture because of its high adsorption capacity and good CO2/CH4 selectivity. However, the numerous synthesis routes for HKUST-1 often result in the obtention of MOF in powder form, which limits its application in industry. Here, we report the shaping of HKUST-1 powder via the extrusion method with the usage of bio-sourced polylactic acid (PLA) as a binder. The characterization of the composite was determined by XRD, FTIR, TGA and SEM analyses. The specific surface area was determined from the N2 adsorption isotherm, whereas the gas adsorption capacities were investigated via measurements of CO2 and CH4 isotherms of up to 10 bar at ambient temperature. The material characterization reveals that the composite preserves HKUST-1’s crystalline structure, morphology and textural properties. Furthermore, CO2 and CH4 adsorption isotherms show that there is no degradation of gravimetric gas adsorption capacity after shaping and the composite yields a similar isosteric adsorption heat as pristine HKUST-1 powder. However, some trade-offs could be observed, as the composite exhibits a lower bulk density than pristine HKUST-1 powder and PLA has no impact on pristine HKUST-1’s moisture stability. Overall, this study demonstrates the possibility of shaping commercial HKUST-1 powder, using PLA as a binder, into a larger solid-state-form adsorbent that is suitable for the separation of CO2 from CH4 with a well-preserved pristine MOF gas-adsorption performance. Full article
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23 pages, 5456 KiB  
Article
High-Degree Oxidative Desulfurization of a Commercial Marine Fuel Using Deep Eutectic Solvents and Their Recycling Process
by Olga Thoda, Efstratios Svinterikos, Konstantinos Miltiadis Sakkas, Anastasia Maria Moschovi and Iakovos Yakoumis
Separations 2023, 10(8), 445; https://doi.org/10.3390/separations10080445 - 9 Aug 2023
Viewed by 1282
Abstract
Escalating environmental concerns have dictated the need to develop innovative methods for efficiently desulfurizing marine fuels (heavy fuel oils). In this work, the oxidative desulfurization method using deep eutectic solvents (DESs) was applied to reduce the sulfur content in a commercially available heavy [...] Read more.
Escalating environmental concerns have dictated the need to develop innovative methods for efficiently desulfurizing marine fuels (heavy fuel oils). In this work, the oxidative desulfurization method using deep eutectic solvents (DESs) was applied to reduce the sulfur content in a commercially available heavy fuel oil (HFO) below 0.5 wt.%, as current regulations demand. Initially, the S-compounds in the fuel were oxidized using an oxidative mixture of H2O2 with carboxylic acid (either acetic or formic acid). Subsequently, the oxidized S-compounds were extracted from the fuel using a series of environmentally friendly deep eutectic solvents (DESs), the best of which was proven to be a mixture of choline chloride with ethylene glycol at a 1/2 molar ratio. The process was optimized by investigating the effect of several process parameters on the desulfurization efficiency, namely, the H2O2/S molar ratio, the H2O2/acid molar ratio, the acid type, the oxidation temperature and oxidation time, the solvent/fuel mass ratio, the extraction time, and the extraction temperature. A desulfurization efficiency of 75.7% was achieved under the optimized conditions, reducing the S content in the fuel to 0.33 wt.%. Furthermore, different methods to recycle the DESs were investigated, and consecutive desulfurization and solvent regeneration cycles were performed. The most efficient recycling method was determined to be the anti-solvent addition of excess water, which resulted in 89.5% DES purification by causing precipitation of the dissolved solids. After three cycles of desulfurization and regeneration using different recycling routes, it was found that the regeneration degree declines gradually; however, it is more than 79.3% in all cases. Full article
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14 pages, 3557 KiB  
Article
Selective Aqueous Extraction and Green Spectral Analysis of Furfural as an Aging Indicator in Power Transformer Insulating Fluid
by Hyunjoo Park, Eunyoung Kim, Byeong Sub Kwak, Taehyun Jun, Riko Kawano and Sang-Hyun Pyo
Separations 2023, 10(7), 381; https://doi.org/10.3390/separations10070381 - 28 Jun 2023
Viewed by 1161
Abstract
Furfural is an intermediary and aldehyde compound degraded from paper insulation, which is used with liquid fluid in power transformers. It can be utilized as an important indicator to evaluate the degradation degree of the paper insulation and the condition of transformers to [...] Read more.
Furfural is an intermediary and aldehyde compound degraded from paper insulation, which is used with liquid fluid in power transformers. It can be utilized as an important indicator to evaluate the degradation degree of the paper insulation and the condition of transformers to predict their lifetime. However, the conventional methods are inevitably inconvenient as they require additional derivatization with hazardous agents and time-consuming chromatographic separation and processes. In this work, a facile and green analysis method for the determination of furfural concentration in the insulating fluid of operating power transformers was developed. As furfural was selectively extracted from the insulting fluid by deionized water, the aqueous solution could be directly subjected to a UV spectral analysis without any derivatization using hazardous agents or hindrance of the fluid in the UV spectrum. The results showed that the spectral method could obtain a favorable linear relationship between the concentration of furfural and its characteristic absorbance at 280 nm (λ max). The limit of detection (LOD) was below 0.1 ppm, which is a sufficient detection level to evaluate the condition of the insulating fluid. Furthermore, the method was compared with the conventional HPLC and colorimetric analyses, revealing satisfactory accuracy and verification of the results. It is possible to measure the furfural concentration in situ using a portable UV-spectrometer at a single wavelength, 280 nm, after simple extraction in the field. This approach offers a novel and green analytical method to quantitatively determine the aromatic furan compounds in a power transformer’s insulating fluid in place without the use of an organic extraction solvent or hazardous reagents for derivatization and analysis. Full article
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2022

Jump to: 2023

12 pages, 4759 KiB  
Article
New Approach for Trace Thallium Removal in High Purity Ammonium Rhenate Solution by P204 Extraction
by Aifei Yi, Ying Liu, Xingwu Lu, Song Chen, Honglin Jiang, Chuanbing Shao, Xuetao Yuan and Yanxi Yin
Separations 2022, 9(8), 221; https://doi.org/10.3390/separations9080221 - 17 Aug 2022
Cited by 2 | Viewed by 1408
Abstract
Thallium (Tl) is an extremely toxic rare metal to the eco-environment. Trace thallium impurity in ammonium perrhenate is harmful to the high-temperature mechanical properties of rhenium metal used for aeroengine single crystal blade. The di(2-ethylhexyl) phosphoric acid (P204) extraction to remove thallium in [...] Read more.
Thallium (Tl) is an extremely toxic rare metal to the eco-environment. Trace thallium impurity in ammonium perrhenate is harmful to the high-temperature mechanical properties of rhenium metal used for aeroengine single crystal blade. The di(2-ethylhexyl) phosphoric acid (P204) extraction to remove thallium in ammonium perrhenate solution without additive was innovatively proposed. The migration behavior of trace thallium with the concentration of P204, saponification degree and organic/aqueous phase (O/A) ratio, distribution law of thallium in the extraction system of P204, and mechanism of thallium removal were revealed. It was found Tl removal was rapidly increased to 98.5%, at conditions of P204 0.75 mol/L saponified 70% by ammonia, Tl 3.27 mg/L, O/A 1:1, T 298.15 ± 2 K, 250 rpm, and 3 min. McCabe-Thiele Tl extraction equilibrium isotherms indicates Tl concentration of raffinate less than 18.7 μg/L, a theoretical extraction of two stages and a theoretical stripping of two stages are required when both O/A work lines were at 1.0. Therefore, the method of the P204 solvent extraction system can effectively extract Tl in the forms of TlA(org), TlA3(org), TlOHA2(org), and Tl(OH)2A(org). Meanwhile, the new approach can be a promising process for ammonium rhenate refining. Full article
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14 pages, 2212 KiB  
Article
Effects and Mechanism of Fe3+ on Flotation Separation of Feldspar and Epidote with Sodium Oleate at Natural pH
by Weiwei Zeng, Guofan Zhang, Qing Shi and Leming Ou
Separations 2022, 9(5), 110; https://doi.org/10.3390/separations9050110 - 28 Apr 2022
Cited by 5 | Viewed by 2111
Abstract
The most common beneficiation method for feldspar is flotation with a cationic (amine) collector under acidic conditions. However, there are several disadvantages to this, such as environmental pollution and equipment corrosion. In order to resolve such problems, it is important to study the [...] Read more.
The most common beneficiation method for feldspar is flotation with a cationic (amine) collector under acidic conditions. However, there are several disadvantages to this, such as environmental pollution and equipment corrosion. In order to resolve such problems, it is important to study the flotation of feldspar using anionic collectors under natural pH conditions. The purpose of this paper is to study the effects and mechanism of Fe3+ on flotation separation of feldspar and epidote using sodium oleate (NaOL) at a natural pH. Through flotation experiments, adsorption measurements, zeta potential testing, FTIR analysis and X-ray photoelectron spectroscopy (XPS), the mechanism of Fe3+ on the surface of feldspar and epidote is revealed, and the reason behind the difference in flotation of the two minerals is discussed. The flotation test results show that Fe3+ can significantly improve the flotation behavior of minerals when NaOL is used as a collector under natural pH, and the highest recovery rates of feldspar and epidote are 90% and 43%, respectively. Analysis of the solution and adsorption measurement results show that Fe3+ is adsorbed on the minerals′ surface in the form of Fe(OH)3, which promotes the adsorption of NaOL on the minerals’ surface through Fe(OH)3, activating the flotation of feldspar and epidote. The difference in adsorption of Fe3+ between feldspar and epidote is the reason for this difference in flotation behavior. The results of the zeta potentials show that after being treated with Fe3+, the electrostatic adsorption of NaOL displays a significant negative shift on the surface of feldspar, while there is almost no electrostatic adsorption of NaOL on the surface of Fe3+-treated epidote. FTIR analysis confirmed that the difference in the adsorption of Fe3+ and NaOL on the surface of feldspar and epidote is due to the fact that there are more active particles (metal bonds) on the surface of feldspar than on the surface of epidote, and the properties of these metal bonds can be changed by Fe3+, which allows NaOL to be more easily adsorbed on the mineral surface through –COO. The possible adsorption form is “mineral-Fe3+–COO“. Compared with the infrared spectrum of epidote, there is a new absorption peak at 1713.68 cm−1, which can be attributed to the C=O characteristic peak of NaOL in the infrared spectrum of Fe3+–NaOL-treated feldspar, which is why the floatability of feldspar is better than epidote. XPS confirmed that the Fe on the surface of feldspar is Fe3+ in the form of Fe(OH)3, while Fe on the surface of epidote is mainly Fe2O3 (Fe–O) contained in mineral crystals. Furthermore, there is less adsorption of Fe3+ on the surface of epidote, and this discrepancy leads to the difference in the adsorption of NaOL on the minerals’ surface, which itself leads to the difference in flotation behavior between feldspar and epidote. These findings indicate that the flotation separation of feldspar and epidote can be achieved using Fe3+ and NaOL under natural pH. This study may provide a reference for the flotation mechanism of feldspar and epidote under natural pH. Full article
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12 pages, 2325 KiB  
Article
Identification of Soluble Degradation Products in Lithium–Sulfur and Lithium-Metal Sulfide Batteries
by Fabian Horsthemke, Christoph Peschel, Kristina Kösters, Sascha Nowak, Kentaro Kuratani, Tomonari Takeuchi, Hitoshi Mikuriya, Florian Schmidt, Hikari Sakaebe, Stefan Kaskel, Tetsuya Osaka, Martin Winter, Hiroki Nara and Simon Wiemers-Meyer
Separations 2022, 9(3), 57; https://doi.org/10.3390/separations9030057 - 24 Feb 2022
Viewed by 3173
Abstract
Most commercially available lithium ion battery systems and some of their possible successors, such as lithium (metal)-sulfur batteries, rely on liquid organic electrolytes. Since the electrolyte is in contact with both the negative and the positive electrode, its electrochemical stability window is of [...] Read more.
Most commercially available lithium ion battery systems and some of their possible successors, such as lithium (metal)-sulfur batteries, rely on liquid organic electrolytes. Since the electrolyte is in contact with both the negative and the positive electrode, its electrochemical stability window is of high interest. Monitoring the electrolyte decomposition occurring at these electrodes is key to understand the influence of chemical and electrochemical reactions on cell performance and to evaluate aging mechanisms. In the context of lithium-sulfur batteries, information about the analysis of soluble species in the electrolytes—besides the well-known lithium polysulfides—is scarcely available. Here, the irreversible decomposition reactions of typically ether-based electrolytes will be addressed. Gas chromatography in combination with mass spectrometric detection is able to deliver information about volatile organic compounds. Furthermore, it is already used to investigate similar samples, such as electrolytes from other battery types, including lithium ion batteries. The method transfer from these reports and from model experiments with non-target analyses are promising tools to generate knowledge about the system and to build up suitable strategies for lithium-sulfur cell analyses. In the presented work, the aim is to identify aging products emerging in electrolytes regained from cells with sulfur-based cathodes. Higher-molecular polymerization products of ether-based electrolytes used in lithium-sulfur batteries are identified. Furthermore, the reactivity of the lithium polysulfides with carbonate-based solvents is investigated in a worst-case scenario and carbonate sulfur cross-compounds identified for target analyses. None of the target molecules are found in carbonate-based electrolytes regained from operative lithium-titanium sulfide cells, thus hinting at a new aging mechanism in these systems. Full article
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15 pages, 1951 KiB  
Review
Separation and Recycling Potential of Rare Earth Elements from Energy Systems: Feed and Economic Viability Review
by Ajay B. Patil, Viktoria Paetzel, Rudolf P. W. J. Struis and Christian Ludwig
Separations 2022, 9(3), 56; https://doi.org/10.3390/separations9030056 - 24 Feb 2022
Cited by 25 | Viewed by 5469
Abstract
This review explores the potential of separating and recycling rare earth elements (REEs) from different energy conversion systems, such as wind turbines, electric vehicles batteries, or lighting devices. The REEs include 17 elements (with global production of 242 kilometric tons in 2020) that [...] Read more.
This review explores the potential of separating and recycling rare earth elements (REEs) from different energy conversion systems, such as wind turbines, electric vehicles batteries, or lighting devices. The REEs include 17 elements (with global production of 242 kilometric tons in 2020) that can be found abundantly in nature. However, they are expensive and complicated to extract and separate with many environmental challenges. The overall demand for REEs is continuously growing (with a 10% yearly increase) and it is quite clear that recycling has to be developed as a supply strategy in addition to conventional mining. However, the success of both mining and recycling depends on appropriate separation and processing technologies. The overall REE recycling situation today is very weak (only 2% of REEs are recovered by recycling processes compared with 90% for iron and steel). The biggest recycling potentials rely on the sectors of lamp phosphors (17%), permanent magnets (7%), and NiMH batteries (10%) mainly at the end-of-life stage of the products. The profitability of rare earth recycling mostly depends on the prices of the elements to accommodate the processing costs. Therefore, end-of-life REE recycling should focus on the most valuable and critical REEs. Thus, the relevant processes, feed, and economic viability warrant the detailed review as reported here. Full article
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