News media attention in Climate Action: latent topics and open access

Scientometrics - In this study we investigated whether open access could assist the broader dissemination of scientific research in Climate Action (Sustainable Development Goal 13) via news...     

Elimination of mercury by adsorption onto activated carbon prepared from the biomass material

Following the previous work (Kaghazchi et al., 2010 [11]), dealing with applying a combination of two kinds of agricultural wastes to produce a new adsorbent, this study is dedicated to investigate the details of mercury adsorption process from aquatic medium by this adsorbent. So the Mix-ZC activated carbon (the sample prepared by chemical activation of a mixture of pistachio-nut shells and licorice residues impregnated with zinc chloride) was selected for doing a series of batch adsorption experiments on it. Equilibrium isotherms, such as Freundlich, Langmuir, Dubinin–Redushkevich and Temkin have been tested. Kinetic studies based on Lagergren first-order, pseudo-second-order rate expressions and intra-particle diffusion studies have been done. The mechanisms of mercury adsorption onto this adsorbent under the operating conditions were also studied.     

The ITZ microstructure,thickness, porosity and its relation with compressive and flexural strength of cement mortar; influence of cement fineness and water/cement ratio

A new insight into the interfacial transition zone (ITZ) in cement mortar specimens (CMSs) that is influenced by cement fineness is reported. The importance of cement fineness in ITZ characterizations such as morphology and thickness is elucidated by backscattered electron images and by consequences to the compressive (F_c) and flexural strength (F_f), and porosity at various water/cement ratios. The findings indicate that by increasing the cement fineness the calcium silicate hydrate formation in the ITZ is favored and that this can refine the pore structures and create a denser and more homogeneous microstructure. By increasing cement fineness by about 25% of, the ITZ thickness of CMSs was reduced by about 30% and F_c was increased by 7%–52% and F_f by 19%–40%. These findings illustrate that the influence of ITZ features on the mechanical strength of CMSs is mostly related to the cement fineness and ITZ microstructure.     

Effects of humic acid and electrolytes on photocatalytic reactivity and transport of carbon nanoparticle aggregates in water

The effects of naturally occurring macromolecules such as humic acid (HA) and electrolytes on four fullerene nanoparticle suspensions (i.e., C₆₀, C₆₀(OH)₂₄, single- and multiwall carbon nanotubes) were explored with respect to: (1) characteristics of nanoparticle aggregates, (2) transport of the aggregates through a silica porous media, and (3) production of reactive oxygen species (ROS) from the photosensitized fullerene aggregates. The presence of HA and salts increased the size of aggregates and relative hydrophobicity associated with transport through silica beads, while decreasing ROS production. These data illustrate the importance that transformation of engineered nanomaterials (ENMs) through interactions with aquatic solutes may have in altering the environmental behavior of nanomaterials.     

YSZ electrolyte coating on NiO–YSZ composite by electrophoretic deposition for solid oxide fuel cells (SOFCs)

A thick dense film of YSZ has been fabricated on a porous NiO–YSZ substrate from the YSZ powders in the mixtures of absolute acetyl acetone–ethanol suspensions by electrophoretic deposition (EPD) method. Parameters affected on substrate porosity like pre-sintering temperature and percentage of starch and parameters affected on EPD process like applied voltage and time of deposition have been investigated. Linear dependence between weights of deposition, deposition time and applied voltage were observed. A crack-free dense thick film of YSZ was obtained on porous NiO–YSZ substrate. Adhesion between the two layers was observed by SEM. The ability of ionic transfer and permeability of the YSZ electrolyte were investigated by EIS, as well.     

On the Largest Possible Mobility of Molecular Semiconductors and How to Achieve It

A large database of known molecular semiconductors is used to define a plausible physical limit to the charge carrier mobility achievable within this materials class. From a detailed study of the desirable properties in a large dataset, it is possible to establish whether such properties can be optimized independently and what would be a reasonably achievable optimum for each of them. All relevant parameters are computed from a set of almost five thousand known molecular semiconductors, finding that the best known materials are not ideal with respect to all properties. These parameters in decreasing order of importance are the molecular area, the nonlocal electron–phonon coupling, the 2D nature of transport, the local electron–phonon coupling, and the highest transfer integral. It is also found that the key properties related to the charge transport are either uncorrelated or “constructively” correlated (i.e., they improve together) concluding that a tenfold increase in mobility is within reach in a statistical sense, on the basis of the available data. It is demonstrated that high throughput screenings, when coupled with physical models of transport produce both specific target materials and a more general physical understanding of the materials space.     

Review on effective parameters in electrochemical hydrogen storage

Today, energy has become one of the most important concerns of developing countries. The use of non-renewable energy sources, as well as the production of pollution, has led to growing efforts to replace fossil fuels, which are the most important energy sources in the modern world. Hydrogen as a clean fuel has attracted a lot of attention in recent years. Various methods have been reported for the production and storage of hydrogen. According to their advantages and disadvantages, it can be said that electrochemical hydrogen storage method is superior to other methods in terms of cost, safety, and optimum condition. The electrochemical hydrogen storage is done in a variety of techniques, and in recent years, the chronopotentiometry method has become one of the most popular methods for scientists. In chronopotentiometry technique, several parameters such as the reference electrode, the counter electrode, the working electrode, electrolyte, and current density are important. In this review, we investigated the articles that have been done in this regard from 2000 to 2020. This review can help scientists to better understand the electrochemical hydrogen storage system.     

Green facile thermal decomposition synthesis,characterization and electrochemical hydrogen storage characteristics of ZnAl2O4 nanostructure

The ZnAl₂O₄ spinel was synthesized by a facile thermal decomposition method using green chemistry. For the first time, the electrochemical hydrogen storage performances and mechanisms of the ZnAl₂O₄ was studied by the galvanostatic charge-discharge method in 6 M KOH aqueous medium under 1 mA current. Anionic, cationic and polymeric surfactants were used to increase of hydrogen storage and specific area of ZnAl₂O₄ spinel. The composition, structure, morphology and specific surface area of the samples were characterized. The maximum measured discharge capacities of ZnAl₂O₄, ZnAl₂O₄/CTAB, ZnAl₂O₄/PVP and ZnAl₂O₄/SDS were 1250, 3000, 3250 and 4000 mAh/g, respectively. These samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray energy dispersive spectroscopy (EDS), N₂ adsorption (BET) and transmission electron microscope (TEM).     

Homogeneous and two phase sulphonation of some aromatic hydrocarbons

The two phase sulphonation of benzene, toluene and p-xylene with concentrated sulphuric acid has been studied in a one litre batch reactor. The kinetic rate constants as a function of sulphuric acid concentration and the overall mass transfer coefficient times the interfacial area per unit volume of the acid phase as a function of agitation speed have been determined. The rates of sulphonation of toluene and p-xylene relative to that of benzene in the range 15.5–17 mol/litre sulphuric acid have been found to be 64 and 280 respectively. Finally, it has been shown that in aromatic sulphonation no linear relationship exists between the logarithms of the partial rate factors and the relative cation localisation energies. This is in contrast to the behaviour of some other electrophilic aromatic substitution such as halogenation, but is similar to aromatic nitration.