A brief overview on the dissolution mechanisms of sulfide minerals in acidic sulfate environments at low temperatures: Emphasis on electrochemical cyclic voltammetry analysis

2020 ◽  
Vol 158 ◽  
pp. 106586 ◽  
Author(s):  
Yisheng Zhang ◽  
Hongbo Zhao ◽  
Lu Qian ◽  
Menglin Sun ◽  
Xin Lv ◽  
...  
Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2349
Author(s):  
Alain Salvador Conejo-Dávila ◽  
Marco Armando Moya-Quevedo ◽  
David Chávez-Flores ◽  
Alejandro Vega-Rios ◽  
Erasto Armando Zaragoza-Contreras

The development of anilinium 2-acrylamide-2-methyl-1-propanesulfonate (Ani-AMPS) monomer, confirmed by 1H NMR, 13C NMR, and FTIR, is systematically studied. Ani-AMPS contains two polymerizable functional groups, so it was submitted to selective polymerization either by free-radical or oxidative polymerization. Therefore, poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonic) [Poly(Ani-AMPS)] and polyaniline doped with 2-acrylamide-2-methyl-1-propanesulfonic acid [PAni-AMPS] can be obtained. First, the acrylamide polymer, poly(Ani-AMPS), favored the π-stacking of the anilinium group produced by the inter- and intra-molecular interactions and was studied utilizing 1H NMR, 13C NMR, FTIR, and UV-Vis-NIR. Furthermore, poly(Ani-AMPS) fluorescence shows quenching in the presence of Fe2+ and Fe3+ in the emission spectrum at 347 nm. In contrast, the typical behavior of polyaniline is observed in the cyclic voltammetry analysis for PAni-AMPS. The optical properties also show a significant change at pH 4.4. The PAni-AMPS structure was corroborated through FTIR, while the thermal properties and morphology were analyzed utilizing TGA, DSC (except PAni-AMPS), and FESEM.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Noer Abyor Handayani ◽  
Elsa Anisa Krisanti ◽  
Sutrasno Kartohardjono ◽  
Kamarza Mulia

A proper understanding of the properties of iron could increase the effectiveness of programmes for alleviating iron deficiency. Recently, encapsulation has been considered an appropriate method for protecting iron from injurious reactions. However, several events may occur during encapsulation processes, including changes in the iron’s oxidation state. Oxidation of ferrous iron is not desirable since the intestines can only absorb iron in the ferrous form. In this study, a cyclic voltammetry method was applied to investigate the likelihood of ferrous gluconate oxidation for the preparation of chitosan-tripolyphosphate microparticles. Then, the electrochemical properties of ferrous gluconate were confirmed experimentally. The oxidation rate of ferrous gluconate is also discussed in this paper. All the experimental solutions were formulated in detail to produce conditions similar to those of microparticle production. Cyclic voltammetry analysis was conducted using a configuration of three electrodes connected to an electrochemical analyser. Graphite, platinum wire, and Ag/AgCl were employed as the auxiliary, working, and reference electrodes, respectively. The cyclic voltammetry results show that the observed potential for each anodic peak shifted negatively in the presence of chitosan and sodium tripolyphosphate. Moreover, the rate of ferrous oxidation tended to increase during 75 min of experiments due to the presence of chitosan and sodium tripolyphosphate. These behaviours indicate the transformation of ferrous iron to ferric iron during iron microparticle preparation. Furthermore, these findings suggest that spray drying is a preferable method to minimise the oxidation reaction.


2015 ◽  
Vol 761 ◽  
pp. 452-456 ◽  
Author(s):  
Raja Noor Amalina Raja Seman ◽  
Rose Farahiyan Munawar ◽  
Jeeferie Abd Razak ◽  
Nor Najihah Zulkapli ◽  
Mohd Shahril Amin Bistamam ◽  
...  

In this study, a mixture of activated carbon (AC) and graphene (G) was coated onto the stainless steel (SS) mesh to produce an electrode for the electrochemical capacitor (EC). Different materials, such as carbon nanotube (CNT) mixed with G, were also used in this experiment to compare the electrochemical properties of both electrodes. The electrochemical properties of the electrode were determined by using cyclic voltammetry (CV). The CV curves of the AC/G electrodes showed good capacitive behaviour, and the highest capacitance values obtained for AC/G and CNT/G electrodes in 1M H2SO4 at 1 mVs-1 were 13 Fg-1 and 4.34 Fg-1, respectively. Meanwhile, the highest capacitance values obtained in 6M KOH at 1 mVs-1 were 14 Fg-1 and 12.07 Fg-1 for AC/G and CNT/G electrodes, respectively.


2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Intan Frina Utamiyanti

<p>The development of material-based glucose sensor SiO<sub>2</sub>-CuO using Screen Printed Carbon Electrode (SPCE) had been done. Three types of materials were used to detect glucose, i.e Multi Wall Carbon Nanotube (MWCNT)-SiO2-CuO, SiO2-CuO (A) dan SiO2-CuO (B). The differences composition of SiO<sub>2</sub>-CuO(A) and SiO<sub>2</sub>-CuO(B) occurred during the addition of NaOH in synthesis process of SiO2-CuO (B). The prepared materials were analyzed by Scanning Electron Microscopy (SEM), cyclic voltammetry method and chrono-amperometry. Cyclic voltammetry analysis was conducted at a potential range of -1.0 - 1.5 V with Ag/AgCl as reference electrode. The scan rate was 100 mV/sec and the potential was varied at (-0.6), (-0.5) and (-0.4) V, in which the duration of each analysis was 5 second. Based on the result of analysis, whether by SEM, cyclic voltammetry and chrono-amperometry, the SiO<sub>2</sub>-CuO (B) was found to be the best material for detection of glucose.</p>


2015 ◽  
Vol 119 (22) ◽  
pp. 12174-12182 ◽  
Author(s):  
Cyrille Costentin ◽  
Jean-Michel Saveant

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