Effects of Gamma Irradiation on the Kinetics of the Adsorption and Desorption of Hydrogen in Carbon Microfibres

In this study, three types of carbon fibres were used, they were ex-polyacrylonitrile carbon fibres with high bulk modulus, ex-polyacrylonitrile fibres with high strength, and vapour grown carbon fibres. All the samples were subjected to a hydrogen adsorption process at room temperature in an over-pressured atmosphere of 25 bars. The adsorption process was monitored through electrical resistivity measurements. As conditioning of the fibres, a chemical activation by acid etching followed by ¿-ray irradiation with 60Co radioisotopes was performed. The surface energy was deter-mined by means of the sessile drop test. Both conditioning treatments are supplementary; the chemical activation works on the outer surface and the ¿-irradiation works in the bulk material as well. Apparently, the most significant parameter for hydrogen storage is the crystallite size. From this point of view, the mostPeer Reviewe

Innovative processes in the production of inorganic bases and derived salts of current interest

Ammonia and sodium hydroxide are two important inorganic bases which served as the basis or precursors of other compounds with multiple uses. Some of their derived salts, i. e. ammonium nitrate, are of the paramount importance for daily life. Others salts, such as lithium carbonate, are gaining a primary role in the development of smart technologies, i. e. E-cars. This chapter described developments in the production of these useful compounds: ammonia, sodium and potassium hydroxides, related salts, i. e. ammonium nitrate, sodium and potassium carbonates, and finally, lithium carbonate.Peer reviewe

Recent Trends in Metal Liquid-Liquid Extraction

From the first manuscript ever published about the use of any chemical procedures similar to liquid-liquid extraction (LLE) or “solvent extraction” in conjuntion with metallic compounds authored by Peligot in the XIX century, and from the two important landmarks in the XX century for uranium and copper, practically all metals had applications in LLE technology, either for their profit (valuable metals), or their removal (hazardous metals) from any tipe de aqueous solutions. This chapter put at the day recent investigations carried out from the academia, industry and research organizations about this more than known technology in the treatment of aqueous solutions containing any type of metal.Advances in Chemistry Researc

Solvent extraction in the recovery of metals from solutions: entering the third decade of XXI century

Since its first practical application in the mid-forties of XX century on the separation and purification of metals, solvent extraction had matured in this issue, being its usefulness demonstrated by the miriade of works published along the years, and by the number of solvent extraction plants built and into production around the world. Now in the XXI century, its application is moving around a theme, in connection with the above, and related to the recovery-separation–purification of metals from raw materials, as urban mining and the treatment of metal-bearing secondary materials and wastes are. Entering the third decade of XXI century, this work reviews the most advanced contribu-tions in the use of solvent extraction science on metals recovery from a variety of sources, as demanded by the social, environmental and profitability conditions in which the world is living nowadays

Innovative processes in the production of inorganic bases and derived salts of current interest

Edited by: Katarzyna Staszak, Karolina Wieszczycka and Bartosz TylkowskiAmmonia and sodium hydroxide are two important inorganic bases which served as the basis or precursors of other compounds with multiple uses. some of their derived salts, i. e. ammonium nitrate, are of the paramount importance for daily life. Others salts, such as lithium carbonate, are gaining a primary role in the development of smart technologies, i. e. E-cars. This chapter described developments in the production of these useful compounds: ammonia, sodium and potassium hydroxides, related salts, i. e. ammonium nitrate, sodium and potassium carbonates, inally, lithium carbonat

An Approach on the Hydrogen Absorption in Carbon Black after Gamma Irradiation

In this work, different samples of an industrial carbon black are used to study the hydrogen intake from an over pres-surized atmosphere and its changes due to alteration of its level of crystallinity produced by ¿-irradiation. The monitor-ing of the hydrogen adsorption was made by means of thermogravimetric analysis and by measurements of some elec-trical parameters as the Seebeck coefficient. X-ray diffraction shows that the irradiation diminishes the level of crystal-line perfection. These results show interesting possibilities to use carbon black as cheap hydrogen absorbers.Peer Reviewe

"Simplification of Hot Rolling Schedule in Ti-Microalloyed Steels with Optimized Ti/N Ratio" Simplification of Hot Rolling Schedule in Ti-Microalloyed Steels with Optimised Ti/N Ratio

Thermomechanical simulations have been carried out on two Ti-microalloyed steels and one reference steel without Ti. The pinning forces exerted by TiN particles in the Ti-steels have been determined and compared with the driving forces for austenite grain growth and static recrystallisation between hot rolling passes. The driving forces for recrystallisation were found to be approximately two orders of magnitude higher than the pinning forces, which explains why the austenite in these steels barely experiences hardening during rolling and why the accumulated stress prior to the austenite→ferrite transformation is insufficient to refine the ferritic grain. On the other hand, austenite grain size hardly varies during hot rolling, as the TiN precipitates exert a strong control from the reheating temperature to the last pass. A Ti/N ratio close to 2 is able to control austenite grain growth at high austenitisation temperatures. So, both aspects -high driving forces for static recrystallisation and control on austenite grain size-allow reducing the number of passes applied. In this case, ferrite grain refinement should be reached by austenite strengthening and accelerated cooling during the transformation to ferrite

Dynamic Adsorption of H2S onto a Goethite-Based Material

The use of adsorption technology to remove HS from synthetic gas (HS and N) using a goethite-based adsorbent was investigated. The influence of the HS feed concentration (150–600 mg), the adsorbent dosage (1–4 g), and the gas flow rate (210–540 cm/min) on the breakthrough curves and HS adsorption on the adsorbent at the breakthrough point was investigated. Dynamic column experiments were performed to provide data for the theoretical models and to verify the performance of the system in the adsorption process. The theoretical models used in the present work were found to predict the adsorption breakthrough performance reasonably well.This research was funded by MBC Chemical Industries. The authors acknowledge the CSIC (Spain) for support. The authors belong to the CSIC Interdisciplinary Thematic Platform PTI-TRANSENER+