Recent research progress in developing metal-doped porous matrices for hydrogen storage

The lack of fuels and the increasing pollution caused by fossil fuels have led to the quest for new efficient and clean energy. Hydrogen is recognized as an ideal substitute for conventional sources of energy. However, traditional methods for hydrogen storage have some disadvantages, so hydrogen has not been available for industrial or commercial use. Porous materials with high surface areas are actively being developed as promising candidates for hydrogen storage. Recent advances in the application of porous matrices with doped-metals have shown superiority over net porous materials in hydrogen storage. The progress towards hydrogen storage in these metal-doped materials is reviewed. A spillover effect, which enhances hydrogen storage using metal elements, is also discussed. Suggestions to the further enhancement of efficiency of hydrogen storage are given.     

Electrochemical Oxidation of Carbon‐Containing Fuels and Their Dynamics in Low‐Temperature Fuel Cells

Fuel cells can convert the energy that is chemically stored in a compound into electrical energy with high efficiency. Hydrogen could be the first choice for chemical energy storage, but its utilization is limited due to storage and transport difficulties. Carbon‐containing fuels store chemical energy with significantly higher energy density, which makes them excellent energy carriers. The electro‐oxidation of carbon‐containing fuels without prior reforming is a more challenging and complex process than anodic hydrogen oxidation. The current understanding of the direct electro‐oxidation of carbon‐containing fuels in low‐temperature fuel cells is reviewed. Furthermore, this review covers various aspects of electro‐oxidation for carbon‐containing fuels in non‐steady‐state reaction conditions. Such dynamic investigations open possibilities to elucidate detailed reaction kinetics, to sense fuel concentration, or to diagnose the fuel‐cell state during operation. Motivated by the challenge to decrease the consumption of fossil fuel, the production routes of the fuels from renewable resources also are reviewed.     

Pyrochemical treatment of spent nitride fuels for MA transmutation

Nitride fuels have several advantages including high thermal conductivity and high metal density(like metallic fuels) and high melting point and isotropic crystal structure(like oxide fuels). Since the late 1990 s, the partitioning and transmutation of minor actinides(MA) has been studied to decrease the long-term radio-toxicity of high-level waste and to mitigate the burden of final disposal. Japan Atomic Energy Agency(JAEA) has proposed a dedicated transmutation cycle using an accelerator-driven system(ADS) with nitride fuels containing MA. The nitride fuel cycle we have developed includes a pyrochemical process. Our focus is on the electrolysis of nitride fuels and their refabrication from the recovered actinides; other processes are similar to the technology for metal fuel treatment and have been studied elsewhere. Here, we summarize our activity on the development of the pyrochemical treatment of spent nitride fuels.     

Analytical strategies for chemical characterization of bio‐oil

Bio‐oils, produced by biomass pyrolysis, have become promising candidates for feedstocks of high value‐added chemicals and alternative sources for transportation fuels. Bio‐oil is such a complicated mixture that contains nonpolar hydrocarbons and polar components which cover almost all kinds of organic oxygenated compounds such as carboxylic acids, alcohols, aldehydes, ketones, esters, furfurals, phenolic compounds, sugar‐like material, and lignin‐derived compounds. Comprehensive characterization of bio‐oil and its subfractions could provide insight into the conversion process of biomass processing, as well as its further utilization as transportation fuels or chemical raw materials. This review focuses on advanced analytical strategies on in‐depth characterization of bio‐oil, which is concerned with gas chromatography, high‐resolution mass spectrometry, FTIR spectroscopy and NMR spectroscopy, offering complementary information for previous reviews.     

Contributions of Flow Analysis for Quality Control of Automotive Fuels: A Review

Automotive fuels require strict quality control to assure best energy use with minimal environmental pollution. Fuels can be modified before consumption by inadequate transport, storage, and handling, as well as illegal adulteration. Continuous monitoring is of paramount importance to reduce such irregularities, thus requiring reliable analytical methods, which should be simple, fast, and minimize both reagent consumption and waste generation. The potential for in-situ monitoring is also highly desirable. Flow analysis plays an important role in this sense, by means of automated sample processing in closed systems, under highly reproducible conditions. In spite of this potential, application for routine fuel analysis is yet limited and wide dissemination is desirable. This review focuses on analytical approaches for in-line sample pretreatment and determination of organic and inorganic contaminants in automotive fuels by flow analysis. Applications in gasoline, diesel oil, biodiesel, and ethanol fuels are critically discussed.     

Chromatographic characterization of thermally upgraded products from alternative fuels

An overview is presented of the analytical approaches developed by our research group over the last ten years for analysis of alternative fuel, both biomass and fossil. The alternative fuels are analyzed successively by PLC-8 (preparative liquid chromatography–group-type) fractionation and high resolution gas chromatography. Some of the possibilities for fractionation and characterization of alternative fuels are herein exemplified with sugar cane bagasse pyrolysis products.     

The composition-explicit distillation curve technique: Relating chemical analysis and physical properties of complex fluids

The analysis of complex fluids such as crude oils, fuels, vegetable oils and mixed waste streams poses significant challenges arising primarily from the multiplicity of components, the different properties of the components (polarity, polarizability, etc.) and matrix properties. We have recently introduced an analytical strategy that simplifies many of these analyses, and provides the added potential of linking compositional information with physical property information. This aspect can be used to facilitate equation of state development for the complex fluids. In addition to chemical characterization, the approach provides the ability to calculate thermodynamic properties for such complex heterogeneous streams. The technique is based on the advanced distillation curve (ADC) metrology, which separates a complex fluid by distillation into fractions that are sampled, and for which thermodynamically consistent temperatures are measured at atmospheric pressure. The collected sample fractions can be analyzed by any method that is appropriate. The analytical methods we have applied include gas chromatography (with flame ionization, mass spectrometric and sulfur chemiluminescence detection), thin layer chromatography, FTIR, corrosivity analysis, neutron activation analysis and cold neutron prompt gamma activation analysis. By far, the most widely used analytical technique we have used with the ADC is gas chromatography. This has enabled us to study finished fuels (gasoline, diesel fuels, aviation fuels, rocket propellants), crude oils (including a crude oil made from swine manure) and waste oils streams (used automotive and transformer oils). In this special issue of the Journal of Chromatography, specifically dedicated to extraction technologies, we describe the essential features of the advanced distillation curve metrology as an analytical strategy for complex fluids.     

On the role of analytical chemistry in solvent extraction processing

Analytical chemistry plays a vital role in both the development and operation of any chemical process, and the process of solvent extraction as applied in hydrometallurgical operations is no exception. Because of the increasing attention being given today to solvent extraction as a means of separating metals in solution, it seemed appropriate that the analytical chemistry associated with solvent extraction studies, process development, and operations be reviewed. In this review, consideration is given only to analysis of the aqueous and organic phases for the determination of solvent components, rather than to the determination of metals in these phases. Furthermore, the major emphasis is placed on analytical methods which are applicable to process studied and plant control, and which require a minimum of instrumentation and operator skill. The importance of sampling is discussed first, and problems encountered in obtaining representative samples from the solvent, aqueous, and slurry phases are considered in some detail. This is followed by a review of methods of analysis which are directly applicable, or are considered as having application, to the analysis of the organic and the aqueous phases of the solvent extraction process. Analytical methods for the determination of the various extractants, modifiers, and diluents presently being used, or considered for use, in commercial solvent extraction processes are surveyed. First, those methods which are applicable to the determination of reagents in the solvent phase are considered, followed by those which are available for analysis of the aqueous phase for the determination of soluble components of the solvent phase. In both cases extractants, modifiers, and diluents are considered separately. Finally, some of the more obvious analytical needs, and areas where research is required in order that a more complete understanding of the solvent extraction process can be obtained, are discussed.     

Application of ICP-MS and HR-ICP-MS for the characterization of solutions generated from corrosion testing of spent nuclear fuel

Summary The corrosion behavior of spent nuclear fuels under simulated geologically unsaturated and oxidizing conditions are being studied by subjecting both unirradiated and irradiated nuclear fuels to dripping groundwater. Solutions and solid materials are periodically sampled and subsequently analyzed to determine concentrations of groundwater and fuel components in these materials to elucidate corrosion mechanisms. The analyses are performed primarily by inductively coupled plasma mass spectrometry (ICP-MS). For ICP-MS we use the method of internal standardization with direct external calibration with multi-elemental standards possessing natural isotopic abundances for the determination of concentrations groundwater components and indirect instrumental response calibration for the determination of fuel components. Additionally, we are utilizing high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) to enhance our ability to determine concentrations of low-solubility actinides at ultratrace concentrations.     

N,N-Dialkyl amides as extractants for spent fuel reprocessing: an overview

Reprocessing of spent nuclear fuel is vital for the long-term global nuclear power growth and is the major motivation for developing novel separation schemes. Conventionally, PUREX and THOREX processes have been proposed for the reprocessing of U and Th based spent fuels employing tri-n-butyl phosphate (TBP) as extractant. However, based on the experiences gained over last five–six decades on the reprocessing of spent fuels, some major drawbacks of TBP have been identified. Evaluation of alternative extractants is, therefore, desirable which can overcome at least some of these problems. Extensive studies have been carried out on the evaluation of N,N-dialkyl amides as extractants in the back-end of the nuclear fuel cycle for addressing the issues related to the reprocessing of U and Th based spent fuels. Under advanced fuel cycle scenario, efforts are also being made by countries with a developed nuclear technological base to provide safe nuclear power to other countries and to minimize proliferation concerns worldwide. This paper presents an overview of studies carried out in our laboratory on different aspects of reprocessing of U and Th based spent fuels employing N,N-dialkyl amides as extractants.     

Synthesis and acid digestion of biomorphic ceramics: determination of alkaline and alkaline earth ions

Ceramic and glass are some of the more recent engineering materials and those that are most resistant to environmental conditions. They belong to advanced materials in that they are being developed for the aerospace and electronics industries. In the last decade, a new class of ceramic materials has been the focus of particular attention. The materials were produced with natural, renewable resources (wood or wood-based products). In this work, we have synthesised a new biomorphic ceramic material from oak wood and Si infiltration. After the material characterization, we have optimized the dissolution of the sample by acid attack in an oven under microwave irradiation. Experimental designs were used as a multivariate strategy for the evaluation of the effects of varying several variables at the same time. The optimization was performed in two steps using factorial design for preliminary evaluation and a Draper-Lin design for determination of the critical experimental conditions. Five variables (time, power, volume of HNO3, volume H2SO4 and volume of HF) were considered as factors and as a response the concentration of different metal ions in the optimization process. Interactions between analytical factors and their optimal levels were investigated using a Draper-Lin design.     

The Kalman filter in analytical chemistry

During the past ten years, the means by which more information can be extracted from experimental data have become an important area of research in analytical chemistry. Digital filters have been demonstrated to have a number of applications to analytical problems. These techniques typically involve a least-squares fit of experimental data to some model of the process being filtered. One method for filtering experimental data is based on the Kalman filter, a recursive, linear digital filter first developed for use in navigation, but now used in many fields. This paper discusses the implementation of Kalman filters in analytical chemistry. The principles of state-space digital filtering are reviewed, and the development of state/space models is discussed. Discussion is focused on the discrete Kalman algorithms. Two examples are provided to demonstrate the operation of the discrete Kalman filtering algorithm. Similarities between Kalman filtering and weighted least-squares methods are considered, and the specific advantages and disadvantages of linear and nonlinear Kalman filtering approaches are evaluated. To illustrate the range of problems which benefit from use of the filter, a comprehensive literature survey of the application of Kalman filtering to chemical problems is provided.     

Application of photo catalysis for mitigation of carbon dioxide

Photo catalytic reduction of carbon dioxide by water or artificial photosynthesis to yield hydrocarbons (methane and methanol, etc., termed “solar fuels”) is being studied extensively, with the twin objectives of developing an effective means of limiting atmospheric CO₂ levels and evolving a sustainable alternative route for production of fuels and chemicals. This short review covers the origin and thermodynamic and kinetic features of the process, the basic photocatalytic principles involved, the rationale behind the choice of different catalysts and their performance, the effect of process conditions, the effect of the structural and photophysical properties of the different catalysts on their performance, mechanistic pathways, surface transformations, challenges involved in the practical application of the process, and future directions for research.     

Applications of Near Infrared Spectrometry Technique in Petroleum Products Analysis

Near infrared (NIR) spectroscopy has become a popular technique for process analytical chemistry and is being studied extensively in the petrochemical industry fields. NIR spectroscopy has several attractive properties:hardly any sample preparation is required,it is a nondestructive method, and it has a high signal-to-noise ratio. Furthermore, NIR spectroscopy has the possibility of remote sensing using optical fibers. All these advantages make NIR spectroscopy very suitable for on-line quality control in process analytical chemistry. In this paper some recent applications of NIR in analysis of petroleum products are reviewed.     

Hairs,criminals, moonrocks,metals diseases,polluters! Where next for nuclear analytical chemistry?

Nuclear methods of analysis have advanced dramatically in recent years, and in many ways, techniques that once were viewed as a scientific curiosity and the toys of a few scientists working in large nuclear research establishments, are now semi-routine and can be applied even by young students. Large amounts of good analytical data are outputted from instruments having sophisticated embedded software. It is interesting to speculate on the directions that nuclear analytical techniques may take next: whether more multielement; more automation for vastly larger sample suites; extension to minor and major components of samples as well as trace components; coupling of nuclear methods to hyphenated methods. However, in some respects the resources needed to continue to develop and apply radioanalytical methods are on the wane: reactors and accelerators are being closed and fewer radiochemical specialists are being trained. The open question, is whether instrumental analysis techniques will offer more and better results with less effort, or be less equipment intensive? In this paper some personal reflections on nuclear actcivation methods and their trends are presented and discussed. Some mileposts in the development of the field and some unique and interesting applications (as implied by the paper title) are cited and discussed.     

Characterization of purified <Superscript>241</Superscript>Am for common impurities by instrumental neutron activation analysis

Americium is an important actinide element having versatile applications based on its alpha and gamma emissions. Multi-element determination of radioactive samples using ICP-AES technique may be affected by the presence of americium due to its rich emission spectra. With a view to characterize plutonium based fuels containing americium for trace metals by ICP-AES technique accurately, a high purity ²⁴¹Am (using a separation procedure developed in our laboratory) was prepared. To ascertain its chemical purity it is essential to determine its impurity contents accurately. Instrumental neutron activation analysis (INAA), being a sensitive multi-elemental technique, was employed to determine the concentrations of impurities in purified ²⁴¹Am. Detection limits for the common elements and rare earth elements have also been determined. Comparison is made with the analytical data obtained by the ICP-AES method.     

TG–FTIR analysis of oxidation kinetics of some solid fuels under oxy-fuel conditions

A possible technology that can contribute reduction of carbon dioxide emission is oxy-fuel combustion of fossil fuels enabling to increase CO₂ concentration in the exhaust gas by carrying out the combustion process with oxygen and replacing air nitrogen with recycling combustion products to obtain a capture-ready CO₂ stream. The laboratory studies and pilot-scale experiments discussed during the last years have indicated that oxy-fuel combustion is a favorable option in retrofitting conventional coal firing. Estonian oil shale (OS) with its specific properties has never been studied as a fuel in oxy-fuel combustion, so, the aim of the present research was to compare thermo-oxidation of OS and some coal samples under air and oxy-fuel combustion conditions by means of thermal analysis methods. Experiments were carried out in Ar/O₂ and CO₂/O₂ atmospheres with two oil shale and two coal samples under dynamic heating conditions. FTIR analysis was applied to characterize evolved gases and emission dynamics. Kinetic parameters of oxidation were calculated using a model-free kinetic analysis approach based on differential iso-conversional methods. Comparison of the oxidation characteristics of the samples was given in both atmospheres and it was shown that the oxidation process proceeds under oxy-fuel conditions by all studied fuels with lower activation energies, however, it can last longer as the same temperatures are compared.     

Inorganic-organic Composite Membranes with Novel Microstructure for High Temperature Proton Exchange Membrane Fuel Cells

Nowadays,more and more fossil fuels are consumed and air pollurion has become a threat to the survival of people.Therefore,we need some other power sources to provide energy without damaging the environment.Proton exchange membrane fuel cells(PEMFCs)have received wide attention due to their advantages Such as high energy density and zero emission[1].Particularly, direct methanol fuel cells (DMFCs)were considered as the most suitable energy sources for electric vehicles(EVs)and portable electronics.     

Comprehensive two-dimensional gas chromatography for the analysis of Fischer-Tropsch oil products

The Fischer-Tropsch (FT) process involves a series of catalysed reactions of carbon monoxide and hydrogen, originating from coal, natural gas or biomass, leading to a variety of synthetic chemicals and fuels. The benefits of comprehensive two-dimensional gas chromatography (GC×GC) compared to one-dimensional GC (1D-GC) for the detailed investigation of the oil products of low and high temperature FT processes are presented. GC×GC provides more accurate quantitative data to construct Anderson-Schultz-Flory (ASF) selectivity models that correlate the FT product distribution with reaction variables. On the other hand, the high peak capacity and sensitivity of GC×GC allow the detailed study of components present at trace level. Analyses of the aromatic and oxygenated fractions of a high temperature FT (HT-FT) process are presented. GC×GC data have been used to optimise or tune the HT-FT process by using a lab-scale micro-FT-reactor.     

Catalytic biodiesel synthesis under supercritical conditions

Increasing atmospheric pollution with greenhouse gases, a large proportion of which are transport pollutants, is forcing the search for new fuels from renewable sources. Biodiesel is currently produced by transesterification of plant oils over heterogeneous catalysts under gentle conditions. The other recent technology dealing with the transesterification with alcohols under supercritical conditions, i.e., at high temperature and pressure, can be more efficient, the cost of the resulting biodiesel having been lower, and lower quality feedstocks having been used. Supercritical transesterification can be performed catalytically or catalyst-free. This paper provides an overview of the catalytic lipid transesterification under supercritical conditions. The influence of raw material, alcohol and catalyst, as well as process parameters on biodiesel yield is analyzed.