Effect Of Hydrochloric Acid Research Articles

Selective extraction of gold (III) from hydrochloric acid–chlorine gas leach solutions of copper anode slime by tri-butyl phosphate (TBP)

The oxidative leaching causes to dissolve various impurities such as Fe, Cu, Pd, Se in copper anode slime. Organic extractant tri-butyl phosphate (TBP) was used to purify leach solution. Several parameters, such as TBP, HCl and chloride inorganic salt concentrations were chosen in order to determine efficient state for impurities separation. Standard solvent extraction tests for extraction and separation of Au, Pd, Pt, Fe, Cu and Se were conducted with equal volume of aqueous and organic phases in batch experiments. The effect of hydrochloric acid, organic phase and metals initial concentration were examined at ambient temperature. It was found that 0.25 mol/L TBP in the presence of 2.5 mol/L hydrochloric acid can cause high extraction of gold. Meanwhile, in these conditions the extraction of other impurities is negligible. After extraction, pregnant organic phase was scrubbed by distilled water and some impurities were removed. Finally, gold was stripped by sodium thiosulfate solution. The stripping solution does not have any impurities. By adding H2SO4 to stripping solution containing Na2S2O2, SO2 gas is released and Au3+ ions could be reduced.

Vibrational and gravimetric analysis of polyaniline/polysaccharide composite materials

In this paper, we present a comparative study of polyaniline/polysaccharide composites (starch, carboxymethyl cellulose, cellulose acetate, and chitosan) by FTIR, UV-visible, SEM and electrochemical analysis. We propose that simultaneously three different phenomena happen while formation of composite system that may be listed as degradation of polysaccharide, polymerization of aniline, formation of polyaniline- polysaccharide composite. Effects of hydrochloric acid and oxidizing agent (ammonium peroxydisulphate) on the structure of polysaccharides were also investigated. We obtained dissimilar product yield and variable polyaniline and polysaccharide ratio in the composite system even though experimental conditions were same. The possible reasons responsible for the observed differences as well as characteristics and morphology of protonated and deprotonated composite materials are discussed.

Getting glucose syrup from cassava starch Manihot and comparative study of the methods of acid and enzymatic hydrolysis

Starch hydrolysis cassava (Manihot esculenta Crantz) to 30% (w/v) was evaluated by the method of acid and enzymatic hydrolysis. In the acid hydrolysis process was evaluated effect of hydrochloric acid in concentrations of 1%, 3% and 5% on the performance of glucose syrup. For enzymatic hydrolysis fungal amylase α 1% was used. There was significant difference between the percentage of reducing sugars and percentage dextrose equivalent (DE) measured for different temperatures liquefaction starch (65, 70 and 75°C) by the α-amylase enzyme at 1%, with 70°C temperature increased activity. For acid hydrolysis significant difference between the percentage reducing sugars and ED percentage measured for various acid concentrations Hydrochloric being the 5% which had higher yields. Comparing both types of hydrolysis was found that there are significant differences between the percentage of sugars and reducing percentage of ED measure acidic and enzymatic hydrolysis of starch cassava, where the enzymatic hydrolysis being a product of greater value was obtained aggregate. Operating conditions and process steps defined.

Effect of hydrochloric acid on the properties of biodegradable packaging materials of carboxymethylcellulose/poly(vinyl alcohol) blends

ABSTRACTThe main focus of this research was to prepare ecofriendly biodegradable packaging materials with carboxymethylcellulose (CMC) and poly(vinyl alcohol) (PVA). Different blend films were prepared through the variation of the ratios of CMC to PVA (00:100, 30:70, 50:50, 70:30, 100:00 w/w) with and without hydrochloric acid. The mechanical properties, including the tensile strength (TS), percentage elongation at break (Eb), water uptake, and solubility in water, of the films were investigated. A soil burial test was also performed. The prepared films were characterized by attenuated total reflectance (ATR)–Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The highest TS and Eb values of the blend films were recorded as 19.52 MPa and 34.52%, respectively. ATR–FTIR spectroscopy, DSC, and TGA results provided that in the presence of HCl, a chemical reaction occurred between CMC and PVA. In addition, the water uptake, solubility in water, and biodegradability of the films were found to be reduced significantly. With all of these results, in presence of HCl, a blend made up of CMC and PVA with a ratio 30:70 was optimized as a biodegradable packaging material. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42870.

Effects of Pre-Treatment Conditions on Black Tilapia Fish Scales for Gelatin Extraction

Black tilapia (Oreochromis mossambicus) fish scales are good sources of gelatin. Fish scales needs to undergo adequate demineralization (pre-treatment) process in order to be a suitable medium for gelatin extraction. The effect of hydrochloric acid (HCl) concentrations (1-5 %) and pre-treatment time (4-20 h) on the raw tilapia scales have been determined. Scanning Electron Microscopy (SEM) analysis was done on the raw scales before and after pre-treatment process. SEM images reveal the pattern of ridges on the scales that fades away at different treatment conditions. Energy Dispersive X-ray Spectroscopy (EDX) results indicate that 3% of HCl with 12 h of treatment time is adequate for demineralization of the fish scales. These were further proved by Fourier Transform Infrared Spectroscopy (FTIR) analysis, where no any inorganic components been detected in the pre-treated scales in comparison to raw scales.

РОЗРОБКА МЕТОДИК КОНТРОЛЮ ДЛЯ ЛАБОРАТОРНОЇ ТЕХНОЛОГІЇ ГЛЮКОЗОВМІСНИХ ПЕРИТОНЕАЛЬНИХ ДІАЛІЗНИХ РОЗЧИНІВ

<p align="center"><strong>Development of analitical procedures of quality control for labolatory baches of DEXTROSE CONTAINING solutions for peritoneal dialysis </strong></p><p> <strong>N. HUDZ</strong></p><p align="center"><em>Danylo Halytsky Lviv National Medical University</em><em>, Ukraine</em><em><br /> <br /> </em><strong></strong></p><p><strong>Summary</strong>. Laboratory batches are used in the initial stages of pharmaceutical development for the purpose of testing the proposed composition, techniques of quality control, studying features of a medicinal product, excipients impact on its physical and chemical characteristics and etc. Implementation methods of pharmacopoeia monographs of the European Pharmacopoeia for "Solutions for peritoneal dialysis" may be impossible in early stages due to unavailability of expensive analytical equipment or reagents at the site of the development. 5-hydroxymethylfurfural is a product of irreversible dextrose dehydratation. The method of direct spectrophotometric determination of 5-hydroxymethylfurfural is offered for dextrose containing solutions for peritoneal dialysis. Its concentration is calculated on the basis of molar absorption coefficient (16830 L∙mol<sup>-1</sup>∙cm<sup>-1</sup>). This technique enables in the early stages of pharmaceutical development to assess the effect of pH, dextrose, sodium lactate and sterilization on the degree of dextrose degradation in solutions for peritoneal dialysis. Direct argentometric method makes possible to quickly determine the content of chloride ions and establish the relationship between the amount of hydrochloric acid as stabilizer, pH, and content of chloride ions.</p><p><strong>Key words</strong>: peritoneal dialysis, argentometric method, 5-hydroxymethylfurfural</p><p><strong>Introduction.</strong> Peritoneal dialysis solutions are multicomponent systems which include incompatible composition: dextrose and sodium lactate. In the presence of latter dextrose is undergone degradation, the extent of which depends primarily on pH, concentration of sodium lactate and dextrose monohydrate, sterilization regime. Previous studies on the development of dextrosecontaining peritoneal solutions showed that the feature of their composition and technology was the selection of quantities of hydrochloric acid for optimal pH for sterilization to minimize the formation of dextrose degradation products (DDPs) during heat sterilization.</p><p>The purpose of this research is to evolve the available analytical procedures for the initial development of the laboratory technology of solutions for peritoneal dialysis (PD).</p><p><strong>Methods.</strong> We used the methods of analysis, synthesis, systematization, comparison, as well, argentometric, potentiometric, and spectrophotometric methods to reach the purpose and tasks of the research.</p><p><strong>Results and discussion</strong>. We offered the procedure of direct argentometric method for the assay of chloride ions and study of the effect of hydrochloric acid on their content at different pH of solutions (pH 5.2-6.6) (transfer 10.0 ml of Sample solution to a suitable container, add 0.8 ml of potassium chromate, and titrate with 0.1 M solution of silver nitrate. Each ml of 0.1 M solution of silver nitrate is equivalent to 3.545 mg of chloride ions (Cl<sup>-</sup>). Among the priorities in the development of this technique was selection of the volume of sample for analysis, calculation of the volume indicator, which is necessary for a clear color change, and evaluation of its suitability for routine analysis and prospective validation. Experimental data showed that the difference between the content of chloride ions in all the solutions at pH 5.2-6.6 was within the complete uncertainty of analysis (approximately ΔAs = 1,6 %).</p><p> The direct ultraviolet spectrophotometry method is offered for the determination of the main products of dextrose dehydratation (3,4-dideoxyglucosone-3-en and 5-hydroxymethylfurfural). According to experimental data, the wavelength of maximum absorption depends on the pH of the solution. The lower the pH value is, the more the maximum position is shifted to the right (at pH 5.2-6.6 there is maximum position at the range of 283-275 nm). This maximum is caused by forming 5-hydroxymethylfurfural after heat sterilization. With increasing pH from 5.2 to 6.6 absorption at the wavelength 228-230 nm gradually increases, which is consistent with literature data, that degradation process is dominant for 3,4-dideoxyglucosone-3-en at a pH above 3.5.</p><p><strong> Conclusions.</strong> The method of direct ultraviolet spectrophotometry with usage of molar absorption coefficient enables to measure 5-hydroxymethylfurfural as a major dextrose degradation product in solutions for peritoneal dialysis at the early stages of pharmaceutical development and to assess the effect of pH, dextrose, sodium lactate and sterilization treatment on the degree of dextrose degradation. Direct argentometric method makes possible to quickly measure the content of chloride ions and establish the relationship between the amount of hydrochloric acid as stabilizer, pH, and content of chloride ions.</p>

Leaching kinetics of lead from galena with acidified hydrogen peroxide and sodium chloride solution

The leaching of lead from galena in acidic hydrogen peroxide in presence of sodium chloride solution has been investigated with respect to the effects of hydrochloric acid and hydrogen peroxide concentrations, by changing the stirring speed, leaching temperature and the particle size. It was observed that leaching rate increases with increasing hydrochloric acid concentration, hydrogen peroxide concentration and the temperature. However, it decreases with increase in the particle size. The kinetic study showed that the leaching process is represented by shrinking core model with mixed kinetic. The activation energy (Ea) for the leaching reaction was calculated as 14·60 kJ mol−1, which is suggestive of the mixed controlled kinetics for the leaching reaction.

Designed synthesis and formation mechanism of CeO2hollow nanospheres and their facile functionalization with Au nanoparticles

In this work, a facile one-step solvothermal method with the assistance of hydrochloric acid has been developed to prepare well-dispersed CeO2 hollow nanospheres with high surface areas. The effects of hydrochloric acid on the growth mechanism and the size distribution are investigated in detail. It is found that the hydrogen ions expedite the nucleation rate of the CeO2 nuclei in the nucleation course, while the chloride ions accelerate the Ostwald ripening in the acidic environment. Both the hydrogen ion (H+) and the chloride ion (Cl−) are confirmed to play a key role in the formation of hollow morphology. Based on our experiments, a HCl-assisted oxidation–nucleation with an Ostwald ripening process mechanism was proposed. Furthermore, Au nanoparticles with a size of 2.5–6 nm were uniformly deposited on the surface of the ceria support by a simplified reduction process with sodium borohydride (NaBH4). The synthesized Au/CeO2 nanospheres exhibit a higher catalytic activity in CO oxidation than pure ceria nanospheres due to the existence of different Au species (metallic Au0 and positively charged Auδ+) and the strengthened interfacial interactions between the Au NPs and the ceria support.

Effect of Hydrochloric Acid on the Surface Integrity of HotRolled Stainless Steel Sheets During Pickling Process

Effect of Hydrochloric Acid on the Surface Integrity of HotRolled Stainless Steel Sheets During Pickling Process

Effect of hydrochloric acid solvent vapor annealing on spray coated silver electrode

Hydrochloric acid solvent vapor annealing (SVA) was incorporated to modify the spray coated silver electrode, and the effect of hydrochloric acid on the performance of silver electrode was systematically studied. The morphology changes of silver electrode were characterized by metallographic microscope and scanning tunneling microscope. The results showed that hydrochloric acid SVA could improve the conductivity of spray coated silver electrode and eliminate the boundary diffraction effect during spray coating process, resulting in a significant decrease of electrode boundary width from 4.91 to 1.14 μm. Furthermore, the component of silver electrode was analyzed by energy dispersive X-ray spectroscopy. It showed that hydrochloric acid could eliminate the boundary of silver electrode through etching the conductive polymer, which was the main component of electrode boundary. Based on the silver electrode of hydrochloric acid SVA, the application for electronic devices as electrode had also been realized for the fabrication of polymer solar cells.

Effect of hydrochloric acid on electrochemical behaviour of 430 stainless steel

The hydrochloric acid pickling process ensures high speeds with little pollution, for which a systematic study of the electrochemical behaviour of stainless steel in the oxidised hydrochloric electrolytes is of great significance. In this research, proper oxidiser was introduced into pickling solution with different concentrations of hydrochloric. Research indicated that as the concentration of hydrochloric acid rose, the charge transfer resistance Rt decreased, and that the decrease was more significant with high HCl content. When the HCl concentration was below 15%, the reaction was controlled by the anodic reaction, while the reaction was controlled by the cathodic reaction when the HCl concentration was above 15%. As the concentration of hydrochloric acid rose, the residue of oxide scales reduced and the surface of the stainless steel became soomther.

Effect of Hydrochloric Acid on the Structural of Sodic-Bentonite Clay

The objective of this work is to determine changes of surface properties of a bentonite after acid activation, using hydrochloric acid solutions (HCl) at room temperature. XRD, FX, FTIR, MEB, and BET analyses of the samples have been carried out to examine the structure of bentonite before and after acid activation. It is found that the raw bentonite is composed of dioctahedral montmorillonite with predominant quantity and certain amounts of quartz, albite and illite, etc. It has an cation exchange capacity (CEC) of 74.32 meq/g which allows it to be characterized as typical sodium bentonite. The changes, at low acid concentrations, are the result from from cation exchange (exchangeable cations with H+ ions). Differences of surface area at high acid concentrations (0.25 - 0.4 M) were caused by structural changes and partial decomposition of the samples. Data of surface area measurements have showed that with increase of concentration of hydrochloric acid, the surface area increased. The maximum value (837.11 m2/g) was reached by the sample activated with 0.4 M HCl. By against, activation with higher concentration (0.6 M) caused a decrease in the surface area.

Effect of hydrochloric acid in different concentrations and temperatures up to some properties of organic cassava starch

The main objective of the present work was to study the thermal properties and rheological behavior of natural and modified organic cassava starch with standard solutions of hydrochloric acid in concentrations 0.1 and 0.2 mol L -1 and in temperatures 25 and 45oC, respectively, as well as verify the structural changes up to the surface of granules. The results allowed us to establish the relationship between the viscosity (RVA), the thermal properties (TG-DTA, DSC) and changes in the morphology of granules (NC-AFM). The major modifications in all the studied properties of the starch granules occurs in those treated with standard HCl at room temperature (25 oC), proportionally to higher concentrations.

The Effect of Hydrochloric Acid on the Surface Area, Morphology and Physico-Chemical Properties of Sayong Kaolinite Clay

The effects of hydrochloric acid (HCL) modification of the surface area, morphology and physico-chemical properties of Sayong kaolinite clay was investigated in this study. Sayong kaolinite clay was refluxed with different concentration of HCL (1M, 5M and 10M) at 100 °C for 4 hours and followed by calcination at 500 °C at 1 hour. The samples of untreated and treated clay were characterized by different analytical equipment such as BET Surface Area Analyzer, X-Ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), Thermogravimetric Analyzer (TGA) and Field Emission Scanning Electron Microscopy (FESEM). The acid treatment increased the surface area of the Sayong kaolinite clay almost three times from 24.46 m2/g to the maximum value which is 64.04 m2/g once treated with 5M HCL. The increasing of the surface area is due to the formation of amorphous silica phase and removal of the octahedral Al3+cations and other impurities (such as Mg2+, K+, Ca+etc.) when the acid strength is increasing as reported in XRF analysis. FTIR study shows the change of the peak intensity of several types of structural OH groups that presently in the untreated and acid treated samples. TGA-DTA profiles shows that acid treatment increased the amount of physisorbed water as the acid concentration is increased. There are three of endothermic peaks was observed in the untreated sample which centered at 49 °C, 275 °C and 520 °C. However, when the clay samples treated with acid, it has increased the physisorbed water and decreased the structural and coordinated water which caused the change in the endothermic curves in the treated sample.

The effect of hydrochloric acid on the conversion of glucose to 5-hydroxymethylfurfural in AlCl3–H2O/THF biphasic medium

The effect of hydrochloric acid (HCl) on the conversion of glucose to 5-hydroxymethylfurfural (HMF) in AlCl3–H2O/THF biphasic system was investigated. The route via isomerization to fructose followed by tandem dehydration to HMF is the dominant pathway. Lewis acid sites of Al3+ aqua/hydroxo complexes play the leading role for the dehydration step. The introduction of a suitable amount to HCl increases the amount of Brønsted acid sites and improves the selectivity for HMF. The maximum HMF yield from glucose is enhanced from 51% to 62% in the presence of 0.1M HCl. The introduction of HCl lowers the reaction rate of glucose-to-fructose isomerization but enhances the reaction rate of fructose dehydration. Higher loading of HCl (1.0M) leads to increased direct dehydration of glucose to humins and results in lower selectivity to HMF.

Influence of Intraluminal Acidification on Esophageal Secondary Peristalsis in Humans

Secondary peristalsis contributes to clearance of retained refluxate or material from the esophagus. The goal of our study was to investigate the effects of hydrochloric acid (HCl) on physiological characteristics of esophageal secondary peristalsis in healthy adults. After recording esophageal motility baseline for primary peristalsis, secondary peristalsis was stimulated with slow and rapid air injections in the mid-esophageal in 16 healthy subjects. Normal saline and HCl (0.1 N) were separately infused into the esophagus to test whether they had effects on secondary peristalsis. After infusion of HCl, the threshold volume to generate secondary peristalsis was significantly decreased during rapid and slow air infusions (both P < 0.05). The frequency of secondary peristalsis was increased after HCl infusion (90 % [72.5-100 %] versus 85 % [72.5-90 %], P = 0.002). Infusion of HCl significantly increased pressure wave amplitude during rapid and slow air infusions (both P < 0.05). Infusion of saline did not affect any parameters of secondary peristalsis. The occurrence of heartburn was generated in 7 of 16 subjects after infusion of HCl with an increase in visual analogue scale score (12.5). Our data show that acute esophageal acid infusion enhances sensitivity of distension-induced secondary peristalsis and enhances secondary peristaltic activity. The study supports the evidence of the presence of acid-sensitive afferents in the modulation of distension-induced secondary peristalsis in humans.

Effect of Hydrochloric Acid on Formation of Nanocrystalline Bismuth Phosphate Synthesized via Hot Injection Method

Effect of Hydrochloric Acid on Formation of Nanocrystalline Bismuth Phosphate Synthesized via Hot Injection Method

Controlled synthesis and Li-electroactivity of rutile TiO2 nanostructure with walnut-like morphology

Herein, we report on the synthesis of phase-pure rutile walnut-like TiO(2) (W-TiO(2)) spheres composed of single-crystalline nanorod-building blocks using a surfactant-free non-aqueous acidic modified "benzyl alcohol route". Based on the various HCl concentration- and reaction time-dependent experiments, an effect of hydrochloric acid on the phase formation mechanism in a non-aqueous system is suggested. As anodes for Li-ion batteries, the W-TiO(2) sphere electrodes exhibited superior cycling performance at a rate of 0.2 C without any conducting layers coated onto the anodes; this result is attributed to their high crystallinity and large surface area.

Preparation of Bamboo Charcoal/Polyvinyl Formal Foam as Biological Support Material

Biological material was prepared by adhering different amount of bamboo charcoal filler into the matrix of polyvinyl formal foam by manual controlled foaming process. The material bears properties of low density, high strength, and good adsorption ability from the advantage of polyvinyl formal. It can be used as new efficient biological supporting material in sewage disposal system. The effects of hydrochloric acid, formaldehyde, bamboo charcoal, and temperature on the preparation were investigated.

Experimental model of smoking and simulation of reflux with acid and pepsin in rats

PURPOSE: To develop experimental models to evaluate the effects of hydrochloric acid associated with the pepsin instilled in the mucosa of the upper esophagus and the esophagogastric junction of young male rats Wistar, simulating injury caused by gastroesophageal reflux on the mucosa of aero-digestive tract in humans as well as the action of the risk exposure of mucosa to cigarette smoke. METHODS: Fifty young male Wistar rats divided in 5 groups with 10 animals each one, respectively simulating pharyngo-laryngeal reflux and gastroesophageal reflux, pharyngo-laryngeal reflux and smoking, smoking only, gastroesophageal reflux and control group. RESULTS: The histopathologic studies no recorded neoplasias, only mild changes and no significant alterations. The hemo-oximetry (carboxyhemoglobin and methemoglobim) and CO2 concentration confirm that the animals were submitted to high intensity of exposure to carcinogens in tobacco and its derivatives. CONCLUSION: The experimental models were highly efficient, practical, easy to use and economical and can be employed in other similar studies to determine the harmful effects by smoking and reflux.