scholarly journals pH-metric method determining the solubility and solubility products of slightly soluble salts of arbitrary composition

2021 ◽  
Vol 3 (2) ◽  
pp. 61-70
Author(s):  
Igor Povar ◽  
◽  
Oxana Spinu ◽  
Boris Pintilie
Keyword(s):  
Ph Value ◽  
High Accuracy ◽  
Saturated Solution ◽  
Potentiometric Method ◽  
Complexing Agents ◽  
Ion Selective Electrodes ◽  
Soluble Salts ◽  
Chemical Methods ◽  
Independent Variables ◽  
Solubility Products

The developed method of determining KS from pH metric data has a number of advantages compared to those used traditionally. First, in place of the residual concentrations of the salt components, only the pH value of the saturated solution is used in the derived expressions. Thus, the number of independent variables, which need to be measured experimentally, is reduced. Furthermore, the potentiometric method, used to determine the pH, is sufficiently accurate, simple and universal and does not necessitate the use of ion-selective electrodes. At the same time, the residual concentrations are usually measured by chemical methods, which are inferior in most cases, for several reasons, compared to the potentiometric method. Second, the KS value calculated by the developed method has a thermodynamic character. The organization of the experiment must be appropriate to the applied equations. Therefore, it is necessary to draw attention to the need for high accuracy in the process of preparing the initial solutions, because the initial concentrations of the precipitate components are included in the calculation formulas. The developed method for determining Ks can be applied for systems of any degree of complexity, which contain additional complexing agents.

scholarly journals Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus
Keyword(s):  
Experimental Data ◽  
Aspartic Acid ◽  
Ph Value ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Zeolite ◽  
X Ray ◽  
Slow Release Fertilizers ◽  
Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

scholarly journals Application of a logarithmic model on a stress - deformation interdependence of the recycled tires

2019 ◽  
Vol 13 (3) ◽  
pp. 180-183
Author(s):  
Anđelko Crnoja ◽  
Željko Kos ◽  
Oleg Popov
Keyword(s):  
Stress Resistance ◽  
Raw Materials ◽  
Technological Development ◽  
Tensile Force ◽  
High Accuracy ◽  
Specific Mass ◽  
Logarithmic Model ◽  
Independent Variables ◽  
Stress Deformation ◽  
Very High

During the last two decades, technological development has led to an extreme increase in transport and connected industries. This has significantly increased the production of automobile tires, which have their life span after which they go to waste. It is therefore necessary to extricate new products from recycled raw materials. For a product to be created, it is necessary, especially in civil engineering, to examine and determine all the properties of this material (pressure, traction, stress resistance, etc.). The results obtained by the research in this paper are mathematically processed by applying a logarithmic model. The aim of this process is to predict stress deformation in terms of tensile force. The model obtained is significant with accuracy of 87.21% and has a very high accuracy of the deformation estimation in relation to the applied stress. Independent variables were granulometric composition, binder (glue) and specific mass.

Bioremediation Condition Optimization of Hydrocarbon in Soil Using Response Surface Methodology by Microbial Consortium KL9-1

2012 ◽  
Vol 518-523 ◽  
pp. 2073-2078 ◽  
Author(s):  
Qi You Liu ◽  
Yun Bo Zhang ◽  
Dong Feng Zhao ◽  
Chao Cheng Zhao
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Microbial Consortium ◽  
Ph Value ◽  
Removal Rate ◽  
Desirability Function ◽  
Nitrogen And Phosphorus ◽  
Predictive Values ◽  
Independent Variables ◽  
Condition Optimization

A response surface methodology was applied to optimize the bioremediation condition of hydrocarbon in soil by microbial consortium KL9-1. A four-level Box-Behnken factorial design was employed to study the relationship of independent variables and dependent variable by applying pH value, inoculation amount of microbial consortium KL9-1, ratio of nitrogen and phosphorus (N/P ) and surfactant (SDBS) concentration as independent variables (factors) and crude oil removal rate as dependent variable (response). Then the statistically significant model was obtained and numerical optimization based on desirability function was carried out for pH 7.0, inoculation amount 50.0 mL, N/P 2: 1 and SDBS concentration 4.0 g, and the hydrocarbon removal rate reached as high as 52.58%. The predictive values showed good agreement with the experimental values under the optimization conditions, by standard variance <1.3%. It showed that the optimal result was reliable.

Preparation and Properties of Lanthanide Phosphates

2005 ◽  
Vol 284-286 ◽  
pp. 79-82 ◽  
Author(s):  
Regina Kijkowska ◽  
Racquel Z. LeGeros
Keyword(s):  
Phosphoric Acid ◽  
Acid Solution ◽  
Aqueous Solutions ◽  
Crystallization Process ◽  
Acidic Solution ◽  
Phosphoric Acid Solution ◽  
Precipitation Method ◽  
Crystalline Solids ◽  
Soluble Salts ◽  
Solubility Products

Lanthanide phosphates are known as slightly soluble salts with their solubility products ranging from 10-25 to 10-27. These phosphates can be obtained a) by precipitation from aqueous solutions of their salts using, for example, sodium or ammonium phosphates or b) by crystallization from boiling phosphoric acid solution. Application of crystallization in highly acidic solution instead of precipitation method yields highly crystalline solids of the composition of LnPO4.H2O (Ln: La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu and Y). This paper presents the effect of the acidity of the solution used for the crystallization process on crystallinity and morphology of EuPO4.H2O obtained: the higher the acidity of the solution the larger the crystals obtained. The morphology of the crystals changed from sphere-like particles crystallized in 2M H3PO4 to large hexagonal rods formed 2M H3PO4 with additional 0.4 M of HCl or HNO3.

Preparation ZnS Quantum Dots via Water-Phase Synthesis Method

2013 ◽  
Vol 706-708 ◽  
pp. 230-233
Author(s):  
Wei Liu ◽  
Xian Lan Chen ◽  
Ju Cheng Zhang ◽  
Yun Hui Long ◽  
Ling Shi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ph Value ◽  
Synthesis Method ◽  
Emission Spectra ◽  
Water Phase ◽  
Complexing Agents ◽  
Complex Ions ◽  
Aqueous Synthesis ◽  
Phase Synthesis ◽  
Optimal Reaction

With water as the medium, PVP as stabilizer and ammonia as complexing agents and adjusting pH value of the solution, we report an all-aqueous synthesis of highly photoluminescent and stable ZnS quantum dots (QDs) by water-phase synthesis reaction between ZnCl2 and NaS at different temperatures and times. The optimal reaction conditions of PVP-capped ZnS QDs were obtained through experiment as follows: the concentration ZnCl2 and NaS solution both are 1 mM, (PVP):(ZnCl2) = 0.0167 (v/v), (NH3):(ZnCl2)=1:300 (v/v), the optimal reaction temperature is 40 °C, the optimal reaction time is 30 min. With ammonia as complexing agents, Zn(OH)2 can dissolve in ammonia and form to complex ions ((Zn(NH3)4)2+), which make Zn2+ release slowly to control the nucleus growth rate of ZnS, thus obtain small size of nanoparticles. The fluorescence spectra shows that the emission peaks of ZnS QDs around ~395 nm and ~470 nm on the emission spectra, which are consistent with literatures, so nano-ZnS QDs was synthesized successfully in this paper.

Electrodeposition of Copper-Indium-Diselenide (CuInSe2) Thin Films

2011 ◽  
Vol 214 ◽  
pp. 378-382 ◽  
Author(s):  
Ming Jer Jeng ◽  
Wen Kai Lei
Keyword(s):  
Ph Value ◽  
Sodium Dodecyl ◽  
Selenium Dioxide ◽  
Indium Content ◽  
Atomic Ratio ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Deposition Parameters ◽  
Copper Indium ◽  
Electrolyte Ph

The electrodeposited CuInSe2 films were investigated in this paper. The deposition parameters of various solution concentrations, applied potential, pH value and complexing agent were examined to characterize film quality. The electrolyte solution was formed by mixing an appropriate proportion of copper sulfate, indium sulfate and selenium dioxide. Sodium citrate was used as complexing agent. Citric and sulfuric acids were used for adjusting electrolyte pH value. The experimental results revealed that the deposited and annealed CIS films have an atomic ratio of [Cu]：[In]：[Se] = 26.94：26.74：46.31. It is near to the stoichiometry of an atomic ratio ([Cu]：[In]：[Se] = 1：1：2). Unfortunately, this film has a poor adhesion problem. In order to overcome the adhesion problem, the triethanolamine and sodium dodecyl sulfate are used as complexing agents and wetting agents, respectively. A good adhesion was obtained. However, these additives result in a shortcoming of insufficient indium content in the formation film.

scholarly journals Ultrafiltration treatment of wastewater contained heavy metals complexed with palygorskite

2020 ◽  
Vol 22 (4) ◽  
pp. 1-9
Author(s):  
Jun Ren ◽  
Tianyi Cao ◽  
Xin Yang ◽  
Ling Tao
Keyword(s):  
Heavy Metals ◽  
Ionic Strength ◽  
Ph Value ◽  
Rejection Rate ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Low Molecular Weight ◽  
Sodium Tartrate ◽  
Removal Of Heavy Metals ◽  
Ultrafiltration Process

AbstractPalygorskite was applied in complexation-ultrafiltration treatment of heavy metals in wastewater under different pH and ionic strength. The results indicated that the rejection of heavy metals increased significantly with pH value, and decreased slightly with an increase of ionic strength of Na+ and Cl–. A certain concentration of NaCl significantly reduced the rejection rate of Cu2+. The rejection of Cu2+, Zn2+ and Cd2+ could reach over 86.8%, 93.6% and 93.7% at pH of 7 and 0.1 mol/L NaCl. The rejection of heavy metals was severely affected by low molecular weight competing complexing agents and the effect of sodium tartrate was greater than triethanolamine. In the presence of sodium tartrate, the rejection of Cu2+, Zn2+ and Cd2+ could arrive over 81.4%, 57.6% and 60.5% at pH of 7 in 20 min. Palygorskite was offered a potential complexing agent for the removal of heavy metals in wastewater at the complexation-ultrafiltration process.

scholarly journals Nanosilver against fungi. Silver nanoparticles as an effective biocidal factor.

1970 ◽  
Vol 60 (4) ◽  
Author(s):  
Jolanta Pulit ◽  
Marcin Banach ◽  
Renata Szczygłowska ◽  
Mirosław Bryk
Keyword(s):  
Silver Nanoparticles ◽  
Antifungal Activity ◽  
Aspergillus Niger ◽  
Reduction Method ◽  
Ph Value ◽  
Chemical Reduction ◽  
Silver Ions ◽  
Chemical Reduction Method ◽  
Stabilizing Agents ◽  
Independent Variables

The work presents a method of obtaining an aqueous raspberry extract as well as its physicochemical and analytical characteristics. The paper also contains a description of the method of preparation of nanosilver suspensions based on this extract. The raspberry extract served as a source of phenolic compounds which acted as both reducing and stabilizing agents. Suspensions of silver nanoparticles were obtained with the use of chemical reduction method. The silver ions concentration, pH value and temperature of samples incubation were independent variables. The next step of the research was to measure the antifungal activity of the received silver nanoparticles as well as to perform a mycological efficacy resistance analysis of the tested preparations in relation to different concentrations of nanostructured silver. Tests were conducted in compliance with the Eucast guidelines. The results of microbiological study of (the samples') biocidal effect against Cladosporium cladosporoides and Aspergillus niger are described. It was found that using nanosilver suspension at the concentration of 50 ppm inhibited the growth of Cladosporium cladosporoides and Aspergillus niger by 90% and 70%, respectively.

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