scholarly journals The swelling of collagen in alkaline solutions. 1. Swelling in solutions of sodium hydroxide

1950 ◽  
Vol 46 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Joane H. Bowes ◽  
R. H. Kenten
Keyword(s):  
Sodium Hydroxide ◽  
Alkaline Solutions

scholarly journals Nanofiltration of Succinic Acid in Strong Alkaline Conditions

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 147 ◽  
Author(s):  
Schlackl ◽  
Herchl ◽  
Samhaber
Keyword(s):  
Electron Microscopy ◽  
Succinic Acid ◽  
Sodium Hydroxide ◽  
Alkaline Solutions ◽  
Fiber Production ◽  
Degree Of Dissociation ◽  
Alkaline Conditions ◽  
Separation Behavior ◽  
Scanning Electron ◽  
Disodium Succinate

Nanofiltration is considered to be an appropriate separation technique in the production of bio-based materials. For the utilization of process streams from the viscose-fiber production, understanding the separation behavior of organic compounds in highly alkaline solutions is necessary. Experiments with succinic acid in sodium hydroxide (NaOH) solutions with varying concentrations up to 5 mol L−1 were performed with the NP030 membrane from Microdyn Nadir. Furthermore, experiments with aqueous disodium succinate and solutions of sodium sulfate in sodium hydroxide were carried out. The influence of concentration ratios and temperature was studied. The Spiegler and Kedem model as well as the Pusch model were applied to fit the experimental data. Additionally, scanning electron microscopy (SEM) and infrared (ATR–IR) measurements were performed to validate the chemical and thermomechanical stability of the membrane. The succinic acid retention varies with its degree of dissociation. In a fully dissociated form, the NaOH concentration shows no impact on the retention. In contrast, the retention of sulfate decreases with increasing NaOH concentration.

The Role of Sodium Hydroxide in the System C3A-CaSO4-H2O at 30°C

1986 ◽  
Vol 85 ◽  
Author(s):  
Hanaa Youssef Ghorab ◽  
Safaa Hussein Abou El Fetouh
Keyword(s):  
Solid Solution ◽  
Sodium Hydroxide ◽  
Calcium Hydroxide ◽  
Hydration Product ◽  
Ion Concentration ◽  
Molar Ratio ◽  
Alkaline Solutions ◽  
Hydration Reaction ◽  
X Ray Diffraction

ABSTRACTThe hydration reaction of C3A with gypsum (molar ratio = 1:1.5) has been studied in water and in sodium hydroxide solutions at 30°C. The hydration product were analyzed microscopically and by means of X-ray diffraction. The concentration of sulfate and aluminum in solution was determined spectrophotometrically. In the absence of alkali, the amount of ettringite formed passes through a maximum and is accompanied by almost complete consumption of sulphate ion in solution. Alkali depresses the formation of ettringite and accelerates that of calcium hydroxide. The monosulfate hydrate appears immediately in alkaline solutions and water then reappears after a day as a solid solution with the tetracalcium aluminate hydrate. The formation of the monophase solid solution is accompanied by the consumption of C3A, ettringite, and calcium hydroxide and by an increase in the amount of the dissolved aluminum. The presence of alkali markedly increases the initial sulfate ion concentration from solution.

Recovery of Sulfur-Alkaline Waste by Processing into Cellular Silicate Material

2018 ◽  
Vol 22 (10) ◽  
pp. 24-27
Author(s):  
Ya I. Vaisman ◽  
I.S. Glushankova ◽  
Yu.A. Ketov ◽  
L.V. Rudakova ◽  
M.P. Krasnovskikh
Keyword(s):  
Amorphous Silicon ◽  
Sodium Hydroxide ◽  
Silicon Oxide ◽  
Silicate Glasses ◽  
Alkaline Solutions ◽  
Organosulfur Compounds ◽  
Silicate Material ◽  
Mechanism Of Formation ◽  
Alkaline Waste ◽  
Amorphous Silicon Oxide

The formation of cellular silicate glasses from sulfide-alkaline solutions and amorphous silicon oxide has been studied. The mechanism of formation of silicates from sodium hydroxide and amorphous silicon oxide and processes of gasification with the participation of the organic component of waste are considered. Technological solutions for recovery of sulfide-alkaline solutions are proposed. At the same time, the process of recovery consists in mixing sulfuralkaline waste with natural amorphous silicon oxide, tripoli, and further roasting the resulting composition at glass formation temperatures. As a result of heat treatment, sulfur from organosulfur compounds is oxidized to sulfur (IV), and sodium hydroxide, after dehydration, enters in composition of the resulting vitreous silicate cellular material.

scholarly journals Durability of geopolymer concrete exposed to acidic environment – a review

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Lathi Karthi ◽  
Peter Cibi
Keyword(s):  
Sodium Hydroxide ◽  
Silica Fume ◽  
Sodium Silicate ◽  
Structural Integrity ◽  
Water Soluble ◽  
Superior Performance ◽  
Alkaline Solutions ◽  
Geopolymer Concrete ◽  
Chemical Action ◽  
Acidic Solutions

Acids attack concrete by dissolving both hydrated and unhydrated cement compounds as well as calcareous aggregates and the subsequent chemical reaction forms water soluble calcium compounds which are then leached away. The aggressiveness of the reaction depends on the pH of the acidic medium and the types of salts formed. Concrete pipes made of ordinary portland cement (OPC) carrying sewage water have always the presence acidic solutions in it. They deteriorate and service life of the pipes is affected along with the increased maintenance costs and that process cause environmental impacts.  Geopolymer binders are novel binders that relies on alumina silicate rather calcium silicate bonds for structural integrity so they have been reported as being acid resistant. Those could be produced by the chemical action between alumino-silicate material such as fly ash(FA), granulated blast furnaces slag (GGBS), metakaoline or silica fume with alkaline solutions like sodium silicate or sodium hydroxide. Geopolymers show superior performance in terms of corrosion and fire resistance due to the absence of water and calcium in their structure.Utilisation of waste materials like FA and GGBS makes geopolymer    concrete (GPC) an environment friendly construction material. This review paper looks in to the effect of various acids such as sulphuric acid, acetic acid, nitric acids on durability properties of OPC specimens, GPC specimens and GPC composite specimens when immersed in acidic solutions for certain period. The performance of geopolymer is analysed by the visual inspection and studying the parameters like weight loss, loss in compressive strength and maximum depth of penetration. Keywords- Geopolymer concrete, Sodium hydroxide, sodium silicate, metakaoline, silica fume, alumina silicate

scholarly journals Effect of Alkaline Activators, Binders and Fibers on Strength Development of Geopolymer Mortar

2019 ◽  
Vol 8 (3) ◽  
pp. 4773-4780
Keyword(s):  
Portland Cement ◽  
Environmental Pollution ◽  
Sodium Hydroxide ◽  
Construction Industry ◽  
Sodium Hydroxide Solution ◽  
Alkaline Solutions ◽  
Strength Development ◽  
Fine Aggregate ◽  
Hydroxide Solution ◽  
By Products

Nowadays Environmental pollution is the major problem faced by the world. The emission of pollutants by construction industry during production of Portland cement are the main causes for environmental pollution. With the increase in use of industrial by products in our construction industry the pollution effect on environment can be reduced. Geopolymer is the one which uses by products and are environmentally friendly. In the present study to produced geopolymer the Portland cement is replaced with fly ash and fine aggregate is replaced with quarry dust and for binding materials alkaline are used. In this study for polymerization the alkaline solutions used are sodium hydroxide (NaOH) and Sodium silicate (Na2Sio3) solution. To prepare different mixes different molarities of sodium hydroxide solution i.e. 6M and 8M and comprehensive strength is calculated for each mix. The size of cube specimen considered are 150 mm x 150mm x 150mm.The comprehensive strength of geopolymer concrete specimen are tested at the age of 7,28 and 56 days. Mixes of different molarities 6M and 8M are prepared by varying the sodium hydroxide flakes amount in grams which are then cured in lab atmosphere and their strengths are calculated for 7,28 and 56 days. The results show that with the increase of the molarity of sodium hydroxide solution the comprehensive strength increases

Inhibition of Corrosion of Commercial Aluminum In Alkaline Solutions

CORROSION ◽  
1961 ◽  
Vol 17 (1) ◽  
pp. 39t-44t ◽  
Author(s):  
J. SUNDARARAJAN ◽  
T. L. RAMA CHAR
Keyword(s):  
Sodium Hydroxide ◽  
Metal Surface ◽  
Anodic Polarization ◽  
Corrosion Process ◽  
Alkaline Solutions ◽  
Corrosion Rates ◽  
Mixed Control ◽  
Polarization Studies ◽  
Percent Manganese

Abstract The corrosion rates for commercial aluminum, containing 4 percent manganese and 3 percent iron, have been determined in sodium hydroxide solutions under different conditions. The inhibitor efficiencies have been calculated for the following substances, the efficiency decreasing from 90 to 60 percent in the order: agar-agar, gum-acaciae, dextrin, gelatin, glue. Corrosion potentials have been measured with and without dextrin inhibitor, and cathodic and anodic polarization studies made. The results show that the dissolution of the metal is electrochemical in character. The corrosion process appears to be under mixed control with predominance of action of dextrin inhibitor on the anodic areas of the metal surface. 6.4.2, 4.3.3, 5.8.2

The Static and Dynamic Interfacial Tensions Between Crude Oils and Caustic Solutions

1983 ◽  
Vol 23 (04) ◽  
pp. 645-656 ◽  
Author(s):  
Edward M. Trujillo
Keyword(s):  
Sodium Chloride ◽  
Interfacial Tension ◽  
Mathematical Models ◽  
Sodium Hydroxide ◽  
Oil Recovery ◽  
Mass Action ◽  
Wettability Alteration ◽  
Crude Oils ◽  
Alkaline Solutions ◽  
Pendant Drop

Trujillo, Edward M.; SPE; Marathon Oil Co. Abstract One method to achieve EOR is chemical alteration of the reservoir environment so that previously trapped oil cam begin to flow freely. Under certain conditions, caustic or alkaline solutions can do this. The work reported here shows that interfacial tension (IFT) between various crudes and caustics increases with time because of desorption of the surface-active species from the interface. The desorption rate is temperature-dependent. Four kinds of crude oil were used-a California crude, a Wyoming crude, an Illinois crude, and an Alaska crude. Only with crude oils with a high concentration of crude acids, such as the California crude, is the ultralow IFT maintained for any reasonable period of time, namely 24 hours. The presence of calcium ions at concentrations of 200 ppm or more destroys the capability of caustic to reduce the IFT's, even for the California crude. Mass-action relationships are presented that describe the equilibrium IFT at constant ionic strength between crude oils and sodium hydroxide solutions as a function of pH and calcium. Techniques are presented for evaluating time-dependent IFT's obtained by the spinning- drop apparatus. A transient mathematical model shows that IFT can increase by several orders of magnitude over a period of several days. Good agreement between the model and experimental data is obtained. The parameters obtained from these mathematical models describe crude parameters obtained from these mathematical models describe crude reactivity to caustic more accurately than conventional crude acid numbers. The transient effects observed in the laboratory may or may not be significant in the field. Introduction Several investigators have studied the reaction of caustic with crude oils. In one of the earliest publications, Reisberg and Doscher in 1956 measured IFT's between a California crude and various sodium hydroxide solutions by the pendant-drop method. The IFT was lowered by a factor of 1,000 with a 0.5% NaOH solution but increased at higher and lower concentrations. The pendant-drop ages were on the order of 5 seconds. They observed a change pendant-drop ages were on the order of 5 seconds. They observed a change in IFT with time, but no model for such a change was proposed. Jennings et al. determined a minimum IFT with a North American crude at about 0.1% NaOH, also with the pendant-drop technique. Several of their values were too low to be mea.sured (0.003 dyne/cm). Their data showed that only a small amount of calcium (25 ppm) increased the IFT between caustic and crude considerably. At 247 ppm calcium, sodium hydroxide was ineffective in reducing IFT at all concentrations up to 1%. Sodium chloride reduced the amount of caustic required to give maximum surface activity. All IFT measurements were made at 74F and at an interface age of 20 seconds. Jennings stated, "We selected 10 seconds because a study of the time variable showed that most of the decay of interfacial tension with time in these systems had occurred by the end of 10 seconds." Measurements were made on 164 crudes from 78 fields. An attempt to relate the interfacial properties to crude acid number was not very successful. One article stated that the "interfacial tension must fall below about 0.01 dynes/cm if oil recovery is to show a significant increase due to caustic injection." Cooke et al. proposed that wettability alteration plus IFT reduction was a factor in oil recoveries with caustic. They suggested a less restrictive criterion in IFT for oil recovery, stating that "No combination in which the interfacial tension was greater than 2 dynes/cm was ever found to be successful in an alkaline water flood." They also confirmed that sodium chloride is beneficial but calcium is detrimental. SPEJ p. 645

Study of Geopolymeric Binders of Fly Ash/Metakaolin Mixtures Cured at Room Temperature

2014 ◽  
Vol 600 ◽  
pp. 338-344 ◽  
Author(s):  
Alexandre Silva de Vargas ◽  
Ruby M. de Gutierrez ◽  
João Castro-Gomes
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
Precursor Material ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Geopolymerization is a chemical process in which aluminosilicate materials are precursors to obtain binders that have a low environmental impact. Fly ash has been used as a precursor for the development of these binders. However, thermal curing is needed to accelerate the polycondensation of aluminosilicate, which limits the application of this new binder in the construction industry. Thus, the objective of this study was to evaluate the feasibility to obtain such binders with good mechanical properties when cured at room temperature. The precursor material consisted of different mixtures of fly ash and metakaolin that were activated using combined sodium hydroxide and sodium silicate alkaline solutions. The effect on the compressive strength of different proportions of the alkaline solutions was studied. Compressive strengths of about 40 MPa were achieved at 91 days for the samples containing 70% fly ash and 30% metakaolin, activated using an alkaline solution of 50% sodium hydroxide and 50% sodium silicate. X-ray diffraction analysis showed the formation of natrite in geopolymeric samples, as well as the presence of crystalline compounds, such as quartz, mullite and hematite, in fly ash and metakaoline. Scanning electron microscopy analysis showed that in geopolymeric mixtures with higher compressive strength dissolution of fly ash and metakaolin particles occurred almost completely and that aluminosilicate dense gel has been formed extensively.

Moments analysis of restricted ternary diffusion: sodium sulfite + sodium hydroxide + water

1985 ◽  
Vol 63 (11) ◽  
pp. 2933-2939 ◽  
Author(s):  
Derek G. Leaist
Keyword(s):  
Sulfur Dioxide ◽  
Sodium Hydroxide ◽  
Diffusion Coefficients ◽  
Sodium Sulfite ◽  
Pure Water ◽  
Alkaline Solutions ◽  
Coupled Flow ◽  
Ternary Diffusion ◽  
Aqueous Sodium ◽  
Ternary Diffusion Coefficients

Ternary diffusion coefficients can be determined from restricted-diffusion experiments by evaluating zeroth and first time moments of the difference in a concentration-dependent property measured at two levels along the diffusion column. The method is used to determine ternary diffusion coefficients for aqueous sodium sulfite + sodium hydroxide solutions from conductance measurements. It is shown that these data can be analyzed to obtain the ternary diffusivity of sulfur dioxide in strongly alkaline solutions where sulfite is the major transporting species for the sulfur dioxide component. At high pH values, coupled flow of hydroxide ions leads to a significant increase in the diffusivity of the sulfur dioxide component relative to its diffusivity in pure water. Binary diffusion coefficients for aqueous sodium sulfite solutions are also reported.

scholarly journals The Redox Chemistry of Ruthenium Dioxide: A Cyclic Voltammetry Study—Review and Revision

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Sebastian Chalupczok ◽  
Peter Kurzweil ◽  
Helmut Hartmann ◽  
Christian Schell
Keyword(s):  
Cyclic Voltammetry ◽  
Sulfuric Acid ◽  
Electrochemical Properties ◽  
Sodium Hydroxide ◽  
Diffusion Coefficients ◽  
Alkaline Solutions ◽  
Ruthenium Dioxide ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion ◽  
Charge Calculations

By cyclic voltammetry at high scan rates, the electrochemical properties of RuO2 in acidic and alkaline solutions were investigated in detail. Thirteen current peaks can be distinguished in sulfuric acid and sodium hydroxide. With respect to the pH sensitivity of RuO2 electrodes, we considered charge calculations, peak currents, and apparent diffusion coefficients. The nature of the Ru(II) oxidation was clarified by Ru(I)−Ru(III) species.

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