Showing papers on "Sodium sulfate published in 2015"
TL;DR: Gd-doped ZnO nanoparticles can be used as a promising catalyst for degradation of organic pollutants with great reusability potential and decolorization efficiency decreased only 6% after 4 repeated runs.
163 citations
TL;DR: Comparisons in the measured protein-protein interaction profiles with previous studies of globular proteins and of antibodies are highlighted providing evidence that the behavior will be common to other protein systems.
Abstract: Better predictive ability of salt and buffer effects on protein-protein interactions requires separating out contributions due to ionic screening, protein charge neutralization by ion binding, and salting-in(out) behavior. We have carried out a systematic study by measuring protein-protein interactions for a monoclonal antibody over an ionic strength range of 25 to 525 mM at 4 pH values (5, 6.5, 8, and 9) in solutions containing sodium chloride, calcium chloride, sodium sulfate, or sodium thiocyante. The salt ions are chosen so as to represent a range of affinities for protein charged and noncharged groups. The results are compared to effects of various buffers including acetate, citrate, phosphate, histidine, succinate, or tris. In low ionic strength solutions, anion binding affinity is reflected by the ability to reduce protein-protein repulsion, which follows the order thiocyanate > sulfate > chloride. The sulfate specific effect is screened at the same ionic strength required to screen the pH dependence of protein-protein interactions indicating sulfate binding only neutralizes protein charged groups. Thiocyanate specific effects occur over a larger ionic strength range reflecting adsorption to charged and noncharged regions of the protein. The latter leads to salting-in behavior and, at low pH, a nonmonotonic interaction profile with respect to sodium thiocyanate concentration. The effects of thiocyanate can not be rationalized in terms of only neutralizing double layer forces indicating the presence of an additional short-ranged protein-protein attraction at moderate ionic strength. Conversely, buffer specific effects can be explained through a charge neutralization mechanism, where buffers with greater valency are more effective at reducing double layer forces at low pH. Citrate binding at pH 6.5 leads to protein charge inversion and the formation of attractive electrostatic interactions. Throughout the report, we highlight similarities in the measured protein-protein interaction profiles with previous studies of globular proteins and of antibodies providing evidence that the behavior will be common to other protein systems.
142 citations
TL;DR: In this paper, the impact of sulfate and alkali on the hydration kinetics and microstructural development of alite was investigated and the results showed that the highest mechanical strength obtained with the combination of alkalis and sulfate is not dependent on the morphology of hydrates.
137 citations
TL;DR: In this article, the properties of concrete (with additional 20% fly ash) subjected to freeze-thaw cycles in water and in sulfate solutions were investigated, and the deterioration considering the weight loss, relative dynamic modulus of elastically (RDME) loss and compressive strength loss of concrete under the coupling effect were also investigated.
97 citations
TL;DR: Alkali activated products were synthesized by activation of kaolinitic clay from Hiswa area, Jordan with a sodium hydroxide solution as mentioned in this paper, and these specimens were subjected to long-term durability tests under different environmental and chemical conditions.
93 citations
TL;DR: In this article, the authors explored the use of sodium sulfate and diatomite to formulate composite materials for high temperature thermal energy storage applications and found that the composite with the optimal formulation has an application window of 890-980 degrees C Failures occur to the composite materials at temperatures above 1000 degrees C.
85 citations
TL;DR: In this paper, the authors evaluated the efficiency of the alumina-coated multi-walled carbon nanotubes in removing the Reactive Red 198 (RR 198) and Blue 19 (RB 19) dyes.
83 citations
TL;DR: In this paper, surfactant-modified pillared montmorillonites (MMT) were prepared using cetyltrimethylammonium bromide (CTAB) by the intercalation method and used as adsorbent to remove bentazon from aqueous solutions.
80 citations
TL;DR: In this article, the deterioration of slag cement blends to those of plain Portland cement was compared and it was shown that this occurs more through loss of surface than macroscopic expansion.
80 citations
TL;DR: In this paper, the performance of electrocoagulation using iron electrodes for the treatment of aqueous solutions containing chromium hexavalent ions using fixed bed electrochemical batch reactor was studied.
79 citations
TL;DR: In this article, the root causes associated with ammonium nitrate (AN) explosions during storage were investigated and the effects of different types of fertilizer compatible additives on AN thermal decomposition was studied.
Abstract: Runaway reactions present a potentially serious threat to the chemical process industry and the community; such reactions occur time and time again often with devastating consequences. The main objective of this research is to study the root causes associated with ammonium nitrate (AN) explosions during storage. The research focuses on AN fertilizers and studies the effects of different types of fertilizer compatible additives on AN thermal decomposition. Reactive Systems Screening Tool (RSST) has been used for reactivity evaluation and to better understand the mechanisms that result in explosion hazards. The results obtained from this tool have been reported in terms of parameters such as “onset” temperature, rate of temperature and pressure rise and maximum temperature. The runaway behavior of AN has been studied as a solid and solution in water. The effect of additives such as sodium sulfate (Na 2 SO 4 ) and potassium chloride (KCl) has also been studied. Multiple tests have been conducted to determine the characteristics of AN decomposition accurately. The results show that the presence of sodium sulfate can increase the “onset” temperature of AN decomposition thus acting as AN thermal decomposition inhibitor, while potassium chloride tends to decrease the “onset” temperature thus acting as AN thermal decomposition promoter.
TL;DR: In this paper, it was found that sulfate solution attack caused a small decrease in strength of geopolymer mortars, and it was also found that treatment of the geopolymers with the Na2SO4 solution caused breaking of the aluminosilicate gel structure.
Abstract: In this paper, geopolymers based on two different fly ash samples were exposed to sodium sulfate (Na2SO4) solution (50 g/l) over a period of 365 days. It was found that sulfate solution attack caused a small decrease in strength of geopolymer mortars. Analysis of the Na2SO4 solutions by optical emission spectroscopy indicated that exposing of the geopolymer samples to the Na2SO4 solution had caused leaching of one of the elements of the aluminosilicate gel, silicon. Mineralogical analyses of geopolymer samples did not show formation of any new phases due to a reaction with sulfate ions. Changes in aluminosilicate geopolymer gel due to sulfate attack were investigated by electron microscopy and nuclear magnetic resonance. It was found that treatment of geopolymer samples with the sulfate solution caused breaking of –Si–O–Si– bonds in aluminosilicate gel structure. Breaking of the –Si–O–Si– bonds and leaching of Si were consequences of the increase in the pH value of sulfate solution during testing.
TL;DR: Carbide slag and reactive magnesia activated ground granulated blast furnace slag (GGBS) were used to stabilise soft clay subjected to accelerated magnesium sulfate (MgSO4) attack as discussed by the authors.
Abstract: Carbide slag (CS)– and reactive magnesia (MgO)–activated ground granulated blast furnace slag (GGBS) were used to stabilise soft clay subjected to accelerated magnesium sulfate (MgSO4) attack. The results indicated that the CS–GGBS-stabilised clay had a higher resistance to magnesium sulfate attack than magnesia–GGBS-stabilised clay; this was contrary to findings from a previous study subjected to sodium sulfate attack. The formation of gypsum and the decomposition of calcium silicate hydrate (CSH) occurred in both stabilised clays after the magnesium sulfate attack, which is primarily responsible for the deterioration. Since the magnesia–GGBS-stabilised clay had a lower pH buffering capacity and calcium/silicon ratio of CSH than CS–GGBS-stabilised clay, it was more susceptible to magnesium sulfate attack.
TL;DR: The salt system that gave the best results compared to NaCl was (NH4)2SO4/NaH2PO4, in the highest of the four amounts evaluated, with factor increases between 1.2 and 4.1-fold, and the SPME extraction efficiency was assessed, confirming that overall it performed better than NaCl.
TL;DR: In this paper, the corrosion behavior of steel has been evaluated through anodic polarization study by conducting potentiodynamic linear sweep test on bare steel specimens immersed in electrolytic concrete powder solutions contaminated with different concentrations of chloride and sulfate ions.
TL;DR: In this article, the authors studied the nucleation and crystal growth of CaSO4·2H2O (gypsum) under simulated conditions of scale formation using a reverse osmosis desalination technique.
Abstract: Nucleation and crystal growth of CaSO4·2H2O (gypsum) was studied under simulated conditions of scale formation using a reverse osmosis desalination technique. Calcium chloride and sodium sulfate were mixed with concentrated sodium chloride solution (40 g/L), and the reaction mixture turbidity was measured at different time intervals to determine the induction time of precipitated gypsum. Induction time was measured under different high supersaturation ratios ranging from 3.92 to 6.71. The induction time decreases exponentially with increasing the supersaturation. Using crystallization equations that relate induction times with supersaturation ratios, the free energy barrier and critical nuclei radius were calculated with and without addition of a scale inhibitor (trisodium phosphate, TSP). Rates of nucleation at a 4.47 supersaturation ratio are 0.4 × 1028 and 0.5 × 1028 nuclei/cm3·s with and without TSP addition, respectively.
TL;DR: Surfactant-modified montmorillonites were prepared using trimethyloctylammonium bromide and employed as a nanosized adsorbent to remove diazinon from aqueous solutions and the affinity sequence for ion adsorption on TMOAB/MMT was in the order: without anion> sodium carbonate> sodium bicarbonate>.
Abstract: Surfactant-modified montmorillonites (MMT) were prepared using trimethyloctylammonium bromide (TMOAB) and employed as a nanosized adsorbent to remove diazinon from aqueous solutions. The prepared adsorbent was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The dependence of removal efficiency on initial diazinon concentration, amount of adsorbent, pH of the solution and ionic strength was investigated. The affinity sequence for ion adsorption on TMOAB/MMT was in the order: without anion> sodium carbonate> sodium bicarbonate> sodium sulphate> sodium chloride. The adsorption kinetic and isotherm were best fit by a pseudo-second-order kinetic and Langmuir isotherm models, respectively.
TL;DR: In this paper, the authors investigate the mechanisms of electrochemical disinfection of artificial wastewater contaminated by Escherichia coli culture using electrocoagulation and find that the most favorable supporting electrolyte type for this method of disinfection is sodium chloride, a fact which can be explained by the formation of disinfectant by-products such as chlorine dioxide, hypochlorite ions and perchlorate ions.
Abstract: Laboratory experiments were carried out to investigate the mechanisms of electrochemical disinfection of artificial wastewater contaminated by Escherichia coli culture (5 × 105 UFC/100 mL) using electrocoagulation. In order to go deeply into the mechanism of the process, the behaviors of two dissolved-type electrodes (ordinary steel and aluminum) and a non-dissolved-type (carbon graphite) electrode were compared. The ordinary steel electrode was found more efficient for E. coli cells destruction compared to aluminum and carbon graphite electrodes. In order to determine the most favorable condition for the treatment, the effect of various supporting electrolytes including, sodium chloride, sodium sulfate and sodium nitrate, was scrutinized. E. coli is inactivated by 5 log units for a charge loading of 37.30 F/m3 for sodium sulfate, 24.87 F/m3 for sodium nitrate and 12.43 F/m3 for sodium chloride. It thus appears that the most favorable supporting electrolyte type for this method of disinfection is sodium chloride, a fact which can be explained by the formation of disinfectant by-products such as chlorine dioxide, hypochlorite ions and perchlorate ions. From the results obtained, electrocoagulation applied to the elimination of E. coli proceeds through three combined effects: the electric field, the actions of oxidants electrogenerated during the process and the adsorption by the metallic hydroxides formed in solution.
TL;DR: It is demonstrated that chitosan-based hydrogels have a potential as local curcumin carriers and their cell viability assays exhibited low toxicity and the localized in situ gel formation was detected after subcutaneous injections in rat.
Abstract: In this paper, a series of injectable in situ forming chitosan-based hydrogels were prepared by chemical crosslinking of chitosan and genipin with the cooperation of ionic bonds between chitosan and sodium salts at room temperature. Four hydrogels (A, B, C, and D) were obtained by mixing chitosan, genipin and a sodium salt of trisodium phosphate (Na3PO4·12H2O), sodium sulfate (Na2SO4), sodium sulfite (Na2SO3), or sodium bicarbonate (NaHCO3) and examined for their characteristics, morphology, and rheological properties. Their cell viability assays exhibited low toxicity and the localized in situ gel formation was detected after subcutaneous injections in rat. Curcumin which possesses many pharmaceutical potentials but has low bioavailability, was chosen as a drug model. In vitro curcumin release profiles exhibit sustained release properties with initial burst release for all hydrogels with about 3 to 6 times higher cumulative release than other gel controls. The results of this study demonstrate that our hydrogels have a potential as local curcumin carriers.
TL;DR: In this article, the authors studied the crystallization of sodium sulfate during the drying of various porous materials at different temperatures and experiments were conducted such that the Peclet number was smaller than one, where the ion transport in the porous material is dominated by diffusion.
TL;DR: The electrochemical treatment of low-salinity reverse osmosis (RO) concentrates was investigated using tramadol (100 μM) as a model substance for persistent organic contaminants, demonstrating that transformation rather than mineralization was taking place.
TL;DR: Based on the results the sulfate and chloride retention of nanofiltration membranes for processing of saturated sodium chloride solutions can now be obtained from a simple characterization experiment.
TL;DR: The results obtained in the study show that solute-solvent interactions of nonionic organic compounds and proteins in poly methylene glycol-sodium sulfate aqueous two-phase system differ from those in polyethylene gly col-dextran system.
Patent•
09 Sep 2015
TL;DR: In this article, a phase transition temperature adjusting cup is proposed, which comprises a cup body outer casing, a cup inner casing, and a top cover, and the composite phase transition material is filled between the inner casing and the outer casing.
Abstract: The invention relates to a phase transition temperature adjusting cup, which comprises a cup body outer casing, a cup body inner casing and a top cover, and the composite phase transition material is filled between the inner casing and the outer casing. The composite phase transition material comprises phase transition material, a nucleating agent, heat conduction filling material and a thickening agent. The phase transition material is selected from one or more of sodium acetate trihydrate, sodium thiosulfate pentahydrate, twelve disodium hydrogen phosphate, sodium sulfate decahydrate and decahydrate. The nucleating agent is selected from one or more of borax, sodium phosphate dibasic anhydrous, diatomaceous earth, silica, sodium silicate, eight water strontium hydroxide, hexahydrate chloride strontium. The heat conduction filling material is selected from one or more of graphite, carbon nanotube, expanded graphite, carbon fiber, graphene, three-dimensional graphite foam, silicon carbide, copper powder. The thickening agent is selected from one of polyacrylic acid emulsion or carboxymethylcellulose sodium. Compared with existing temperature adjusting cups, the phase transition temperature adjusting cup of the present invention has the advantages of rapid cooling, simple structure convenient operation, 3-4 hours of comfort temperature zone, and not being restricted from external environment.
TL;DR: In this article, a novel process for separating iron and titanium from Indonesian beach titanomagnetite (TTM) concentrates is proposed, where pellets are embedded under the coal to be reduced, and Na2SO4 was used as an additive.
Abstract: A novel process for separating iron and titanium from Indonesian beach titanomagnetite (TTM) concentrates is proposed. This process involves several steps, including mixing the TTM concentrate and additive, pressing the mixture into pellets, embedding direct reduction of the pellets, and magnetic separation. Given that coal and additives are the main factors influencing the coal-based direct reduction of beach TTM, this study employed embedding reduction, where pellets are embedded under the coal to be reduced, and Na2SO4 was used as an additive. The best result was obtained when the Na2SO4 dosage was 4%, and the direct reduction iron powder (DRI powder) with an iron grade of 94.45%, iron recovery of 85.18%, and TiO2 content of 0.44% were obtained. Titanium concentrate assay yielded 40.43% TiO2 containing main titanium minerals of ilmenite and ferrous pseudobrookite. The results showed that a suitable Na2SO4 addition (4–6%), DRI powder and titanium concentrate presented better iron recovery and TiO2 grade as compared without addition, while this advantage disappeared as Na2SO4 addition increased (>6%). The characteristics of roasted pellets were analyzed through X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Results showed that FeS and nepheline are formed by addition of Na2SO4, thereby benefiting the migration and growth of metallic iron particles in the redox system and separation of titanium and iron. While a suitable dosage of Na2SO4 could promote porosity and induce a reducing atmosphere, but more liquid phase formed by an excessive Na2SO4 was unfavorable and caused expansion of the pellets.
TL;DR: In this paper, the corrosion behavior of Mg-Al-Zn-Mn (GA9) alloy in sodium sulfate solutions was studied over a range of concentrations and solution temperatures at different pH conditions by electrochemical techniques like Tafel extrapolation and electrochemical impedance spectroscopy (EIS).
TL;DR: Using modulated FT-IR Raman spectroscopy and classical molecular dynamics simulations (MD), this paper studied the solute speciation in solutions of 10 wt % Na2SO4, at conditions close to the saturation limit.
Abstract: Saline aqueous solutions at elevated pressures and temperatures play an important role in processes such as supercritical water oxidation (SCWO) and supercritical water gasification (SCWG), as well as in natural geochemical processes in Earth and planetary interiors. Some solutions exhibit a negative temperature coefficient of solubility at high temperatures, thereby leading to salt precipitation with increasing temperature. Using modulated FT-IR Raman spectroscopy and classical molecular dynamics simulations (MD), we studied the solute speciation in solutions of 10 wt % Na2SO4, at conditions close to the saturation limit. Our experiments reveal that ion pairing and cluster formation are favored as solid saturation is approached, and ionic clusters form prior to the precipitation of solid sulfate. The proportion of such clusters increases as the phase boundary is approached either by decreasing pressure or by increasing temperature in the vicinity of the three-phase (vapor-liquid-solid) curve.
Patent•
11 Nov 2015
TL;DR: In this article, a high-salinity wastewater recovery treatment method is described by recovering sodium sulfate, sodium chloride and sodium nitrate through four treatment steps, namely primary evaporative crystallization, cooling crystallization and freezing crystallization.
Abstract: The invention discloses a high-salinity wastewater recovery treatment method. The method is characterized by recovering sodium sulfate, sodium chloride and sodium nitrate through four treatment steps, namely primary evaporative crystallization, cooling crystallization, secondary evaporative crystallization and freezing crystallization. The method has the beneficial effects that sodium chloride, sodium sulfate and sodium nitrate in high-salinity wastewater can be respectively recovered; obtained sodium chloride, sodium sulfate and sodium nitrate achieve the industrial level and can be directly recovered and reused or be sold as byproducts, thus not only achieving the aim of treating high-salinity wastewater and meeting the current situation requirement of environmental protection but also turning waste into wealth, achieving resource utilization of salt and increasing the profits of factories.
TL;DR: Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins.
Patent•
06 May 2015
TL;DR: In this article, a recycling method of high-salinity wastewater was proposed, where sodium sulfate and sodium chloride are recycled through three steps of primary evaporative crystallization, cooling crystallization and secondary evaporation crystallization.
Abstract: The invention discloses a recycling method of high-salinity wastewater. Sodium sulfate and sodium chloride are recycled through three steps of primary evaporative crystallization, cooling crystallization and secondary evaporation crystallization. According to the method disclosed by the invention, sodium sulfate and sodium chloride in the high-salinity wastewater of coal chemical industry can be effectively recycled; the method is simple and stable in technological conditions; industrial popularization is facilitated; the recycled sodium sulfate and sodium chloride meet the quality requirements of industrial products, and can be directly recovered and applied mechanically or sold as byproducts, so that the target of treating the high-salinity wastewater is reached; the requirements of the current environment-friendly situation are met; waste is changed into treasures; resource utilization of salts is achieved; and benefits of factories are improved.