scholarly journals Acid-base properties of fibrous polyampholytes with aminodiacetic functional groups

2020 ◽  
Vol 64 (3) ◽  
pp. 300-307
Author(s):  
E. G. Kosandrovich ◽  
P. V. Nesteronok ◽  
L. N. Shachenkova ◽  
V. S. Soldatov
Keyword(s):  
Cation Exchange ◽  
Anion Exchange ◽  
Potentiometric Titration ◽  
Functional Groups ◽  
Supporting Electrolyte ◽  
Experimental Results ◽  
Monochloroacetic Acid ◽  
Polyacrylonitrile Fiber ◽  
Acid Base ◽  
Amination Reaction

Polyampholytes, containing aminodiacetic functional groups, on the base of polyacrylonitrile fiber Nitron C were obtained by the amination reaction of nitrile groups with polyamines (number of repeating units from 1 to 5) and subsequent alkylation with monochloroacetic acid. The experimental results of potentiometric titration and sorption of supporting electrolyte (kCl) ions by synthesized ion exchangers were obtained, which made it possible to determine the acidity parameters of functional groups: the presence of four types of cation exchange and two types of anion exchange groups was detected in polyampholytes, the sequence of their neutralization in the titration process was established.

Selective Sensing Platform Utilizing Graphitized Multi-Walled Carbon Nanotubes for Monitoring of Ondansetron and Paracetamol

2020 ◽  
Vol 16 ◽  
Author(s):  
Biljana Nigović ◽  
Iva Šimunić ◽  
Ana Mornar
Keyword(s):  
Carbon Nanotubes ◽  
Cation Exchange ◽  
Supporting Electrolyte ◽  
Polymer Concentration ◽  
Fixed Dose ◽  
Sensing Platform ◽  
Multi Walled Carbon Nanotubes ◽  
Electroanalytical Method ◽  
Walled Carbon Nanotubes

Background: Ondansetron and paracetamol are often co-administrated to prevent and treat nausea and vomiting caused by anaesthesia and to control of postoperative pain. In addition, ondansetron is used as the first-line antiemetic in paracetamol overdose. Therefore, selective and sensitive method for their simultaneous analysis is of a great importance. The electroanalytical methods are highly sensitive and offer many possibilities for new sensor platform design. However, at present, no electroanalytical method for simultaneous determination of these drugs has been proposed. Objective: The aim of this study was to develop a novel nanosensor for selective monitoring of ondansetron and paracetamol in pharmaceutical and biological samples without expensive and time-consuming pretreatments. Methods: The graphitized multi-walled carbon nanotubes embedded in a cation exchange polymer matrix was selected, among various surface functionalizations evaluated, to design novel sensor. Based on its excellent sensing performance, the first electroanalytical method was developed for rapid concurrent determination of investigated drugs. Results: The scanning electron microscopy study showed interlinked nanoporous network structure and highly enlarged active surface. The developed sensor facilitated electron transfer in the oxidation of both drugs and tremendously enhanced the adsorption capacity for ondasetron, thus exhibiting significant increase of drug responses and sensitivity. To obtain much sensitive response of investigated drugs the effect of pH values of supporting electrolyte, dispersed nanomaterial amount, the cation exchange polymer concentration, drop-casting volume of nanocomposite suspension, accumulation potential and deposition time on the peak current was evaluated. The developed electroanalytical method was validated and practical utility of the proposed nanosensor was tested. Conclusion: The developed sensor is promising sensing platform with a fast response time for analysis of ondansetron and paracetamol at very different concentration levels found in their fixed-dose combination and human serum sample after recommended daily doses showing its potential usage in pharmaceutical quality control and clinical research.

Preparation and Aplication of Cation Adsorbent by Canada Goldenrod (Solidago canadensis L.)

2011 ◽  
Vol 396-398 ◽  
pp. 75-87
Author(s):  
Zai Fu Yang ◽  
Xiao Jing Yang ◽  
Li Hong Sun ◽  
Lian Lian Xu
Keyword(s):  
Sulfuric Acid ◽  
Cation Exchange ◽  
Agricultural Land ◽  
Reaction Medium ◽  
Volume Ratio ◽  
Second Order ◽  
Experimental Results ◽  
Solidago Canadensis ◽  
Order Kinetic ◽  
Pseudo Second Order

ABSTRACT: Cation adsorbent was prepared from the Solidago Canadensis（which are abandoned agricultural land of alien invasive plants）by Sulfuric acid esterification modified , isoamyl alcohol as reaction medium. Design L934 orthogonal experiment, the Solidago canadensis cation exchange adsorbent, the optimal preparation conditions. Experimental results show that at 15°C, concentrated sulfuric acid and amyl alcohol volume ratio of 5:6 obtained under conditions of Solidago canadensis cation exchange adsorbent for Pb(II) exchange best. The experimental results of Pb(II) adsorption onto the Solidago Canadensis based cation adsorbent showed that the best conditions are: the initial pH 5, the concentration of Pb(II) 300mg/L，the dosage of cation adsorbent 1.2mg/L and adsorption time 3h. The adsorption data were analyzed by using pseudo-first-order and pseudo-second-order kinetic models were found to follow the pseudo-second-order kinetic model.

scholarly journals Investigation of NiFe-Based Catalysts for Oxygen Evolution in Anion-Exchange Membrane Electrolysis

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1720
Author(s):  
Sabrina Campagna Zignani ◽  
Massimiliano Lo Faro ◽  
Stefano Trocino ◽  
Antonino Salvatore Aricò
Keyword(s):  
Single Cell ◽  
Anion Exchange ◽  
Oxygen Evolution ◽  
Current Density ◽  
Electrochemical Behaviour ◽  
Stress Test ◽  
Supporting Electrolyte ◽  
Anion Exchange Membrane ◽  
Operating Conditions ◽  
Exchange Membrane

NiFe electrodes are developed for the oxygen evolution reaction (OER) in an alkaline electrolyser based on an anion exchange membrane (AEM) separator and fed with diluted KOH solution as supporting electrolyte. This study reports on the electrochemical behaviour of two different NiFe-oxide compositions (i.e., Ni1Fe1-oxide and Ni1Fe2-oxide) prepared by the oxalate method. These catalysts are assessed for single-cell operation in an MEA including a Sustainion™ anion-exchange membrane. The electrochemical polarization shows a current density of 650 mA cm−2 at 2 V and 50 °C for the Ni1Fe1 anode composition. A durability test of 500 h is carried out using potential cycling as an accelerated stress-test. This shows a decrease in current density of 150 mA cm−2 mainly during the first 400 h. The performance achieved for the anion-exchange membrane electrolyser single-cell based on the NiFeOx catalyst appears promising. However, further improvements are required to enhance the stability under these operating conditions.

scholarly journals Viologen-Decorated TEMPO for Neutral Aqueous Organic Redox Flow Batteries

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shuzhi Hu ◽  
Liwen Wang ◽  
Xianzhi Yuan ◽  
Zhipeng Xiang ◽  
Mingbao Huang ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Supporting Electrolyte ◽  
Linear Sweep Voltammetry ◽  
High Energy ◽  
Crystal Structure Analysis ◽  
Anion Exchange Membrane ◽  
High Energy Density ◽  
Favorable Effect ◽  
Flow Battery ◽  
Exchange Membrane

A novel electroactive organic molecule, viz., 1-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-1′-(3-(trimethylammonio)propyl)-4,4′-bipyridinium trichloride ((TPABPy)Cl3), is synthesized by decorating 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) with viologen, which is used as the positive electrolyte in neutral aqueous redox flow battery (ARFB). Extensive characterizations are performed to investigate the composition/structure and the electrochemical behavior, revealing the favorable effect of introducing the cationic viologen group on the electroactive TEMPO. Salient findings are as follows. First, the redox potential is elevated from +0.745 V for TEMPO to +0.967 V for decorated TEMPO, favoring its use as the positive electrolyte. Such an elevation originates from the electron-withdrawing effect of the viologen unit, as evidenced by the nuclear magnetic resonance and single crystal structure analysis. Second, linear sweep voltammetry reveals that the diffusion coefficient is 2.97×10−6 cm2 s−1, and the rate constant of the one-electron transfer process is 7.50×10−2 cm s−1. The two values are sufficiently high as to ensure low concentration and kinetics polarization losses during the battery operation. Third, the permeability through anion-exchange membrane is as low as 1.80×10−11 cm2 s−1. It is understandable as the positive-charged viologen unit prevents the molecule from permeating through the anion exchange membrane by the Donnan effect. Fourth, the ionic nature features a decent conductivity and thus eliminates the use of additional supporting electrolyte. Finally, a flow battery is operated with 1.50 M (TPABPy)Cl3 as the positive electrolyte, which affords a high energy density of 19.0 Wh L-1 and a stable cycling performance with capacity retention of 99.98% per cycle.

scholarly journals ATLaS: Assistant Software for Life Scientists to Use in Calculations of Buffer Solutions

2021 ◽  
Vol 15 (4) ◽  
pp. 541-545
Author(s):  
Ugur Comlekcioglu ◽  
Nazan Comlekcioglu
Keyword(s):  
Programming Language ◽  
Life Science ◽  
Source Code ◽  
Experimental Results ◽  
Acid Base ◽  
Buffer Solutions ◽  
Python Programming Language ◽  
Science Laboratories ◽  
Executable File ◽  
Python Programming

Many solutions such as percentage, molar and buffer solutions are used in all experiments conducted in life science laboratories. Although the preparation of the solutions is not difficult, miscalculations that can be made during intensive laboratory work negatively affect the experimental results. In order for the experiments to work correctly, the solutions must be prepared completely correctly. In this project, a software, ATLaS (Assistant Toolkit for Laboratory Solutions), has been developed to eliminate solution errors arising from calculations. Python programming language was used in the development of ATLaS. Tkinter and Pandas libraries were used in the program. ATLaS contains five main modules (1) Percent Solutions, (2) Molar Solutions, (3) Acid-Base Solutions, (4) Buffer Solutions and (5) Unit Converter. Main modules have sub-functions within themselves. With PyInstaller, the software was converted into a stand-alone executable file. The source code of ATLaS is available at https://github.com/cugur1978/ATLaS.

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