scholarly journals Computer Simulation of Amino Acid Oligomerization in Aqueous Solutions Induced by Condensing Agent

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Maxim Lubov ◽  
Yuri Trushin ◽  
Igor Eliseev ◽  
Ivan Terterov ◽  
Michael Dubina
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Growth Model ◽  
Physical Features ◽  
Attachment Energy

Physical features of the amino acid oligomerization were studied. Growth model of the L-Glu monomer chain induced by the condensing agent in the aqueous solutions with and without metal ions was proposed. Computer simulation of oligomerization process was conducted and from the comparison of the calculated and experimental data attachment energy of the Leuchs anhydride of L-Glu to the oligomer was estimated.

Competitive Sorption of Pb, Cd, and Ni on Chicken Feathers from Binary Aqueous Solutions

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Hilda Elizabeth Reynel-Avila ◽  
Adrian Bonilla-Petriciolet ◽  
Guadalupe de la Rosa
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Low Cost ◽  
Competitive Sorption ◽  
Equilibrium Studies ◽  
Sorption Data ◽  
Competitive Effects ◽  
Chicken Feathers ◽  
Isotherm Equations

In this paper, we report the competitive removal of Pb, Cd, and Ni ions from binary metal solutions using chicken feathers. These heavy metals are very toxic for human being and are present in wastewaters of several industrial activities. Therefore, multi-component sorption studies are required to identify the capabilities and limitations of chicken feathers as low-cost sorbent for the simultaneous removal of these metal ions from wastewaters. To the best of our knowledge, sorption equilibrium studies involving chicken feathers and Pb, Cd, and Ni in binary aqueous solutions have not been reported. Therefore, the binary sorption data for systems Pb - Cd, Pb – Ni, and Cd - Ni at different pH conditions are reported in this paper. Our experimental data are modeled using multi-component isotherm equations and desorption studies were also performed. In summary, this study provides new experimental data to identify the competitive effects of these metal ions onto the multi-component sorption performance of chicken feathers.

scholarly journals Study of the effect of temperature on the electrical conductivity of aqueous solutions of amino acids

2019 ◽  
Vol 57 (1) ◽  
pp. 91-94
Author(s):  
Vera A. Petrukhina ◽  
◽  
Pavel I. Fedorov ◽  
Tatiana A. Kirillova ◽  
Ludmila Yu. Tcareva ◽  
...  
Keyword(s):  
Experimental Data ◽  
Amino Acids ◽  
Electrical Conductivity ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Arrhenius Equation ◽  
Effect Of Temperature ◽  
Acid Solutions ◽  
Hydrogen Ions ◽  
Amino Acid Solutions

It is well-known fact that water is a universal solvent due to its physicochemical properties and dielectric constant. Therefore, the majority of substances with a crystalline structure and the structure close to it are well soluble in water due to the dissociation of molecules into ions. Amino acids are organic ampholytes – substances capable of being in ionic forms in water. The quantitative and qualitative composition of ampholytes depends on the structure and composition of amino acids and pH of solution. The interaction of amino acid ions in solution with hydrogen ions and hydroxyl leads to the formation of complex cations and anions. The presence of amino and carboxyl groups in amino acid molecules contributes to the formation of inter-ion positively and negatively charged complexes which leads to the decrease in their mobility and electrical conductivity of solutions. It is observed with increasing concentration of amino acid solutions. The conductivity of amino acid solutions is also influenced by temperature which has a non-linear relationship. We have proposed the approach based on studying the effect of temperature on the equivalent electrical conductivity at infinite dilution λ∞ and describing the experimental data λ∞(Т) by the exponential Arrhenius equation. This article studies the possibility of describing the experimental data λ∞(Т) for aqueous solutions of a number of amino acids by this equation. It is shown that the Arrhenius equation with the found activation energy values adequately describes the dependences of limiting equivalent conductivity on temperature for aqueous solutions of valine, leucine, isoleucine, threonine, lysine, methionine, phenylalanine, L-aspartic and D-aspartic acids, histidine, arginine.

Highly sensitive colorimetric detection of HgII and CuII in aqueous solutions: from amino acids toward solid platforms

The Analyst ◽  
2015 ◽  
Vol 140 (3) ◽  
pp. 744-749 ◽  
Author(s):  
Jooyoung Park ◽  
Byunggyu In ◽  
Lok Nath Neupane ◽  
Keun-Hyeung Lee
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Colorimetric Detection ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Fluorescence Change

A chemosensor (NBD-H) based on an amino acid with 7-nitro-2,1,3-benzoxadiazole was used for selective detection of HgII and CuII among 15 metal ions in aqueous solutions by a colorimetric change and fluorescence change.

scholarly journals Synthesis and characterization of silica gel microspheres encapsulated by salicyclic acid functionalized polystyrene and its adsorption of transition metal ions from aqueous solutions

2010 ◽  
Vol 8 (1) ◽  
pp. 214-222 ◽  
Author(s):  
Qiang Xu ◽  
Ping Yin ◽  
Guifang Zhao ◽  
Gui Yin ◽  
Rongjun Qu
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Silica Gel ◽  
Transition Metal Ions ◽  
Synthesis And Characterization ◽  
Maximum Adsorption Capacity ◽  
Salicyclic Acid

AbstractThe present study was undertaken to develop a novel adsorbent for heavy metal ions, and this paper presents the synthesis and characterization of a composite material-silica gel microspheres encapsulated by salicyclic acid functionalized polystyrene (SG-PS-azo-SA) with a core-shell structure. SG-PS-azo-SA was used to investigate the adsorption of Mn(II), Co(II), Ni(II), Fe(III), Hg(II), Zn(II), Cd(II), Cr(VI), Pd(II), Cu(II), Ag(I), and Au(III) from aqueous solutions. The results revealed that SG-PS-azo-SA has better adsorption capacity for Cu(II), Ag(I) and Au(III). Langmuir and Freundlich isotherm models were applied to analyze the experimental data, the best interpretation for the experimental data was given by the Langmuir isotherm equation with the maximum adsorption capacity for Cu(II), Ag(I), and Au(III) at 1.288 mmol g−1, 1.850 mmol g−1 and 1.613 mmol gt-1, respectively. Thus, silica gel encapsulated by salicyclic acid functionalized polystyrene (SG-PS-azo-SA) is favorable and useful for the removal of Cu(II), Ag(I) and Au(III) metal ions.

Chitosan-based Magnetic Composites - Efficient Adsorbents for Removal of Pb(II) and Cu(II) from Aqueous Mono and Bicomponent Solutions

2018 ◽  
Vol 69 (9) ◽  
pp. 2323-2330 ◽  
Author(s):  
Daniela C. Culita ◽  
Claudia Maria Simonescu ◽  
Rodica Elena Patescu ◽  
Nicolae Stanica
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Chemical Properties ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Magnetic Adsorbent ◽  
Magnetic Composites ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Physical And Chemical

A series of three chitosan-based magnetic composites was prepared through a simple coprecipitation method. It was investigated the influence of mass ratio between chitosan and magnetite on the physical and chemical properties of the composites in order to establish the optimum conditions for obtaining a composite with good adsorption capacity for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions. It was found that the microspheres prepared using mass ratio chitosan / magnetite 1.25/1, having a saturation magnetization of 15 emu g--1, are the best to be used as adsorbent for the metal ions. The influence of different parameters such as initial pH values, contact time, initial concentration of metal ions, on the adsorption of Pb(II) and Cu(II) onto the chitosan-based magnetic adsorbent was investigated in details. The adsorption process fits the pseudo-second-order kinetic model in both mono and bicomponent systems, and the maximum adsorption capacities calculated on the basis of the Langmuir model were 79.4 mg g--1 for Pb(II) and 48.5 mg g--1 for Cu(II) in monocomponent systems, while in bicomponent systems were 88.3 and 49.5 mg g--1, respectively. The results revealed that the as prepared chitosan-based magnetic adsorbent can be an effective and promising adsorbent for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions.

Comparison of the fixation of several metal ions onto a low-cost biopolymer

2002 ◽  
Vol 2 (5-6) ◽  
pp. 217-224 ◽  
Author(s):  
Z. Reddad ◽  
C. Gérente ◽  
Y. Andrès ◽  
P. Le Cloirec
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Low Cost ◽  
Operating Conditions ◽  
Order Kinetic ◽  
Adsorption Mechanisms ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Beet Pulp ◽  
Removal Of Metal Ions

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ > Cd2+ > Zn2+ > Cu2+ > Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.

Fluoroquinolone-3-carboxamide Amino Acid Conjugates: Synthesis, Antibacterial Properties And Molecular Modeling Studies

2020 ◽  
Vol 17 (1) ◽  
pp. 71-84
Author(s):  
Riham M. Bokhtia ◽  
Siva S. Panda ◽  
Adel S. Girgis ◽  
Hitesh H. Honkanadavar ◽  
Tarek S. Ibrahim ◽  
...  
Keyword(s):  
Experimental Data ◽  
Antibacterial Activity ◽  
Amino Acid ◽  
Bacterial Infections ◽  
Antibacterial Agents ◽  
Antibacterial Properties ◽  
Computational Studies ◽  
Protecting Group ◽  
Amino Acid Conjugates ◽  
Molecular Modeling Studies

Background: Bacterial infections are considered as one of the major global health threats, so it is very essential to design and develop new antibacterial agents to overcome the drawbacks of existing antibacterial agents. Method: The aim of this work is to synthesize a series of new fluoroquinolone-3-carboxamide amino acid conjugates by molecular hybridization. We utilized benzotriazole chemistry to synthesize the desired hybrid conjugates. Result: All the conjugates were synthesized in good yields, characterized, evaluated for their antibacterial activity. The compounds were screened for their antibacterial activity using methods adapted from the Clinical and Laboratory Standards Institute. Synthesized conjugates were tested for activity against medically relevant pathogens; Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27856) Staphylococcus aureus (ATCC 25923) and Enterococcus faecalis (ATCC 19433). Conclusion: The observed antibacterial experimental data indicates the selectivity of our synthesized conjugates against E.Coli. The protecting group on amino acids decreases the antibacterial activity. The synthesized conjugates are non-toxic to the normal cell lines. The experimental data were supported by computational studies.

An homogeneous growth model of gallium arsenide epitaxial layers from the gas phase

1989 ◽  
Vol 54 (11) ◽  
pp. 2933-2950
Author(s):  
Emerich Erdös ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Experimental Data ◽  
Gallium Arsenide ◽  
Kinetic Study ◽  
Gas Phase ◽  
Growth Model ◽  
Epitaxial Layers ◽  
Inhomogeneous Model ◽  
Homogeneous Models ◽  
Active Centres

This paper represents a continuation and ending of the kinetic study of the gallium arsenide formation, where a so-called inhomogeneous model is proposed and quantitatively formulated in five variants, in which two kinds of active centres appear. This model is compared both with the experimental data and with the previous sequence of homogeneous models.

scholarly journals An Investigation on Design and Characterization of a Highly Selective LED Optical Sensor for Copper Ions in Aqueous Solutions

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1099
Author(s):  
Sheng-Chun Hung ◽  
Chih-Cheng Lu ◽  
Yu-Ting Wu
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Copper Ions ◽  
Incident Light ◽  
Copper Ion ◽  
Intensity Change ◽  
Optical Absorbance ◽  
Sensing System ◽  
Optic Sensor ◽  
Cu Ions

The optical characteristics of copper ion detection, such as the photometric absorbance of specific wavelengths, exhibit significant intensity change upon incident light into the aqueous solutions with different concentrations of metal ions due to the electron transition in the orbit. In this study, we developed a low-cost, small-size and fast-response photoelectric sensing prototype as an optic sensor for copper (Cu) ions detection by utilizing the principle of optical absorption. We quantified the change of optical absorbance from infra-red (IR) light emitting diodes (LEDs) upon different concentrations of copper ions and the transmitted optical signals were transferred to the corresponding output voltage through a phototransistor and circuit integrated in the photoelectric sensing system. The optic sensor for copper (Cu) ions demonstrated not only excellent specificity with other metal ions such as cadmium (Cd), nickel (Ni), iron (Fe) and chloride (Cl) ions in the same aqueous solution but also satisfactory linearity and reproducibility. The sensitivity of the preliminary sensing system for copper ions was 29 mV/ppm from 0 to 1000 ppm. In addition, significant ion-selective characteristics and anti-interference capability were also observed in the experiments by the proposed approach.

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