Solubility of chloride in molten magnesium metal

The solubilities of chloride (Cl) in liquid magnesium (Mg) have been determined from the analysis of quenched samples of liquid Mg equilibrated with NaCl-MgCl₂ melts of different compositions at temperatures in the range 650–790 °C. As an example, the solubility of Cl in liquid Mg in contact with pure MgCl₂ at 735 °C was found to be approximately 18 ppm. The Cl solubility was found to be proportional to the square root of the MgCl₂ activity in the NaCl-MgCl₂ melt, indicating that MgCl₂ dissolved according to the reaction 0.5MgCl₂ + 0.5Mg(l) = MgCl (in Mg). The temperature dependency of the solubility also was measured. Thermodynamic values related to the dissolution of MgCl₂ in liquid Mg have been estimated.     

Adsorption of cationic polyacrylamide onto sepiolite

The adsorption of PAM onto sepiolite from aqueous solutions has been investigated systematically as a function of some parameters such as calcination temperature of sepiolite, pH, ionic strength and temperature. The adsorption of cationic polyacrylamide (PAM) increases with pH from 5.50 to 11.00, temperature from 25 to 55 degrees C and ionic strength from 0 to 0.1molL(-1). The sepiolite sample calcined at 200 degrees C has a higher adsorption capacity than the other calcined samples. Adsorption isotherms of PAM onto sepiolite have been determined and correlated with common isotherm equations such as Langmuir and Freundlich isotherm models. The Langmuir isotherm model appeared to fit the isotherm data better than the Freundlich isotherm model. The physical properties of this adsorbent are consistent with the parameters obtained from the isotherm equations. The zeta potentials of sepiolite suspensions have been measured in aqueous solutions of NaCl and different PAM concentrations and pH. From the experimental results: (i) pH strongly alters the zeta potential of sepiolite, (ii) sepiolite has an isoelectric point at about pH 6.6 in water and about pH 8 in 250mgL(-1) PAM concentration, (iii) PAM changes the interface charge from negative to positive for sepiolite. Effect of temperature on adsorption has been quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy. The dimensionless separation factor (R(L)) has shown that sepiolite can be used for adsorption of PAM from aqueous solutions.     

Novel natural food preservatives and applications in seafood preservation: a review

Food preservative additives are natural or synthetic substances which delay degradation in foods caused by microbial growth, enzyme activity, and oxidation. Until recently, the use of synthetic additives in food was more common. However, synthetic additives have not been widely accepted by consumers in recent years due to their assumed adverse effects on their health. Therefore, the tendency of consumers to natural additives is increasing day-by-day. Seafood is an easily perishable food due to its chemical composition. Immediately after harvest, changes in odor, taste, and texture in fishery products can be noticed. For this reason, measures to protect the product must be taken immediately after harvest or catching. Various preservation methods have been developed. In addition to various technological methods, preservative additives are used in fresh or processed seafood as well as in other foods. This review focuses on novel natural preservatives from different sources such as plants, bacteria, fungi, animals and algae, and their use in seafood to protect quality and prolong shelf life. © 2018 Society of Chemical Industry     

Potential for carbon adsorption on concrete: surface XPS analyses

The concrete industry is a contributor to the global carbon cycle particularly with respect to the contribution of carbon dioxide in the manufacturing of cement (calcination). The reverse reaction of carbonation is known to occur in concrete, but is usually limited to exterior surfaces exposed to carbon dioxide and humidity in the air. As alternate concrete uses expand which have more surface area, such as crushed concrete for recycling, it is important to understand surface adsorption of carbon dioxide and the positive impacts it might have on the carbon cycle. X-ray photoelectron spectroscopy (XPS) is used in this study to evaluate carbon species on hydrated cement mortar surfaces. Initial estimates for carbon absorption in concrete using othertechniques predictthe potential for carbonate species to be a fraction of the calcination stoichiometric equivalent The XPS results indicate that there is a rapid and substantial uptake of carbon dioxide on the surfaces of these mortars, sometimes exceeding the calcination stoichiometric equivalents, indicative of carbon dioxide surface complexation species. On pure calcite, the excess is on the order of 30%. This accelerated carbon dioxide surface adsorption phenomenon may be importantfor determining novel and effective carbon sequestration processes using recycled concrete.     

Poly(lactide)/cellulose nanocrystal nanocomposites by high-shear mixing

There is currently considerable interest in developing stiff, strong, tough, and heat resistant poly(lactide) (PLA) based materials with improved melt elasticity in response to the increasing demand for sustainable plastics. However, simultaneous optimization of stiffness, strength, and toughness is a challenge for any material, and commercial PLA is well-known to be inherently brittle and temperature-sensitive and to show poor melt elasticity. In this study, we report that high-shear mixing with cellulose nanocrystals (CNC) leads to significant improvements in the toughness, heat resistance, and melt elasticity of PLA while further enhancing its already outstanding room temperature stiffness and strength. This is evidenced by (i) one-fold increase in the elastic modulus (6.48 GPa), (ii) 43% increase in the tensile strength (87.1 MPa), (iii) one-fold increase in the strain at break (∼6%), (iv) two-fold increase in the impact strength (44.2 kJ/m²), (v) 113-fold increase in the storage modulus at 90°C (787.8 MPa), and (vi) 10³-fold increase in the melt elasticity at 190°C and 1 rad/s (∼10⁵ Pa) via the addition of 30 wt% CNC. It is hence possible to produce industrially viable, stiff, strong, tough, and heat resistant green materials with improved melt elasticity through high-shear mixing.     

Preparation and characterization of amidoxime resins based on poly(acrylonitrile-co-vinylidene chloride-co-divinylbenzene)

The poly(acrylonitrile-co-vinylidene chloride-co-divinylbenzene) beads with macroporous morphology were synthesized by suspension polymerization. The use of dichloroethane as a solvating diluent resulted in copolymer beads having highly porous structures. These have been reacted with hydroxylamine in methanol, which generates amidoxime groups. The precursory resins were readily functionalized within 0.5–1 h. A detailed analysis is made of the pore structure of resins in the anhydrous state including pore size distribution and specific surface area. © 1994 John Wiley & Sons, Inc.     

Large-scale radon hazard evaluation in the Oslofjord region of Norway utilizing indoor radon concentrations, airborne gamma ray spectrometry and geological mapping

We test whether airborne gamma ray spectrometer measurements can be used to estimate levels of radon hazard in the Oslofjord region of Norway. We compile 43,000 line kilometres of gamma ray spectrometer data from 8 airborne surveys covering 10,000 km² and compare them with 6326 indoor radon measurements. We find a clear spatial correlation between areas with elevated concentrations of uranium daughters in the near surface of the ground and regions with high incidence of elevated radon concentrations in dwellings. This correlation permits cautious use of the airborne data in radon hazard evaluation where direct measurements of indoor radon concentrations are few or absent. In radon hazard evaluation there is a natural synergy between the mapping of radon in indoor air, bedrock and drift geology mapping and airborne gamma ray surveying. We produce radon hazard forecast maps for the Oslofjord region based on a spatial union of hazard indicators from all four of these data sources. Indication of elevated radon hazard in any one of the data sets leads to the classification of a region as having an elevated radon hazard potential. This approach is inclusive in nature and we find that the majority of actual radon hazards lie in the assumed elevated risk regions.     

Separation of fluoride from aqueous solution by electrodialysis: effect of process parameters and other ionic species

Removal of fluoride from aqueous solution by electrodialysis was studied. Applied voltage, feed flow rate, fluoride concentration in the solution and effect of the other anions as sulfate, chloride were investigated as experimental parameters on fluoride removal from aqueous solution. The separation performance was evaluated in terms of mass transfer and energy consumption. It was obtained that the separation performance increased when the initial concentration of fluoride in the feed solution increased. Percent removal of fluoride increased as the applied potential increased. However, the effect of feed flow rate was not apparent in the range of applied feed flow rate. Separation of fluoride was influenced by chloride but not by sulfate ions.     

The effect of additives on the oxidation stability of biodiesel

In the present study, it was aimed to examine the degradation of biodiesel and the changes that occur in the cold flow characteristics of biodiesel obtained from safflower oil as a result of the modification of the production process steps that leads to a state in which the process is not realized completely despite the addition of antioxidant additives that stabilize the cold flow characteristics of the fuel and the effects of the modification of the production process steps on fuel characteristics. The study is focused on the modification of the production process. Some samples showed very rapid decomposition in the first 3 hours but the rest took nearly 3 days to reach 200 microsiemens. But then the derivative this value due to the rate of oxidation 0.04 h showed.     

The synthesis of covalent bonded single‐walled carbon nanotube/polyvinylimidazole composites by in situ polymerization and their physical characterization

Single‐walled carbon nanotube (SWCNT) polyvinylimidazole (PVI) composites have been prepared by in situ emulsion polymerization. Dispersion of raw SWCNTs in the PVI matrix was improved by surface modification of the SWCNTs using nitric acid treatment and air oxidation. The carbonyl‐terminated SWCNTs were covalently bonded to PVI by in situ polymerization and the SWCNT/PVI composite was thus obtained. The morphological and structural characterizations of the surface‐functionalized SWCNTs and SWCNT/PVI composites were carried out by Fourier transform infrared spectroscopy, X‐ray diffraction, conductivity measurements, scanning, and transmission electron microscopy. Thermograms of the materials were determined by the differential scanning calorimetry technique. The characterization results indicate that PVI was covalently bonded to SWCNTs and a new material was then obtained. The functionalized SWCNTs showed homogenous dispersion in the composites, whereas purified SWCNT resulted in poor dispersion and nanotube agglomeration. SWCNT/PVI composites exhibited chemical stability enhancement in many common solvents. I–V curves of the samples exhibit an ohmic character. Conductivity values for pure SWCNTs, pure PVI and SWCNT/PVI composite were measured to be 3.47, 2.11 × 10⁻⁹, and 2.3 × 10⁻³ S/m, respectively. Because of resonance, a large dielectric constant is obtained for SWCNT/PVI composite, which is not observed for ordinary materials. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers