Determination of calcium leaching behavior of cement pastes exposed to ammonium chloride aqueous solution via an electrochemical impedance spectroscopic approach

2019 ◽  
Vol 196 ◽  
pp. 267-276 ◽  
Author(s):  
Zijian Song ◽  
Yongqi Liu ◽  
Linhua Jiang ◽  
Mingzhi Guo ◽  
Jianguo Chen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ammonium Chloride ◽  
Electrochemical Impedance ◽  
Leaching Behavior ◽  
Cement Pastes ◽  
Calcium Leaching ◽  
Electrochemical Impedance Spectroscopic

Research developments in carbon materials based sensors for determination of hormones

2021 ◽  
Author(s):  
Jamballi G. Manjunatha ◽  
Girish Tigari ◽  
Hareesha Nagarajappa ◽  
Nambudumada S. Prinith
Keyword(s):  
Carbon Materials ◽  
Electrochemical Sensors ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Supporting Electrolyte ◽  
Electroanalytical Methods ◽  
Repeatability And Reproducibility ◽  
Electrochemical Impedance Spectroscopic ◽  
Structural Aspects

Various carbon-based sensors (graphene, carbon nanotubes, graphite, pencil graphite, glassy carbon, etc.) have distinctive behavior and a broad range of importance for identifying sex hormones like estriol, estradiol, estrone, progesterone, and testosterone. The current review emphasizes voltammetric, amperometric, and electrochemical impedance spectroscopic methods for detecting some of these hormones. The existence, structural aspects, nature, and biological importance of each hormone were analyzed in detail and their analysis with different electroanalytical methods was considered. Unique methodologies and innovations of electrochemical sensors for hormones based on carbon materials modified by different agents were examined. In this review, the interaction among various sensor materials and analytes in different supporting electrolyte media is premeditated. The most important significances of the electroanalytical methodologies were discussed based on sensor selectivity, sensitivity, stability, the limit of detection, repeatability, and reproducibility.

THE POLAROGRAPHY OF THE MAGNESIUM-ALIZARIN SYSTEM

1963 ◽  
Vol 41 (7) ◽  
pp. 1695-1702 ◽  
Author(s):  
D. G. Brewer ◽  
John A. Page
Keyword(s):  
Aqueous Solution ◽  
Diffusion Coefficient ◽  
Ammonium Chloride ◽  
Polarographic Determination ◽  
Reduction Wave ◽  
Soluble Complex ◽  
Reversible Process ◽  
Complex Species ◽  
Polarographic Wave

The polarography of alizarin alone, and alizarin in the presence of magnesium, has been studied in an ammonia–ammonium chloride electrolyte. Alizarin was found to give a reduction wave with E1/2 = −(0.14 + 0.059 pH) volts vs. S.C.E. and a polarographic diffusion coefficient D, equal to 1.20 × 10−6 cm2 sec−1 over a range of pH from 7.4 to 10.0 in aqueous solution at 25 °C. The slope of the wave corresponded to a two-electron reversible process. The addition of magnesium caused a decrease in the polarographic wave for alizarin, but the combining ratio of magnesium to alizarin was a function of pH, ranging from 1.02 at pH 9.0 to 1.28 at pH 10.1. The combining ratio greater than unity could be attributed to alizarin adsorbed on a 1:1 (MgAlz) precipitate. The removal of alizarin from the solution was not quantitative in the presence of excess magnesium, and there is evidence of the formation of soluble complex species. The reaction is potentially useful for the indirect polarographic determination of magnesium.

The Effect of Fly Ash on Calcium Leaching Properties of Cement Pastes in Ammonium Chloride Solution

2010 ◽  
Vol 163-167 ◽  
pp. 1162-1170 ◽  
Author(s):  
Hu Yang ◽  
Lin Hua Jiang ◽  
Yan Zhang
Keyword(s):  
Fly Ash ◽  
Ammonium Chloride ◽  
Chloride Solution ◽  
Strength Loss ◽  
Ammonium Chloride Solution ◽  
Cement Pastes ◽  
Calcium Leaching ◽  
Two Factors ◽  
Damage Process ◽  
Cementing Material

The damage process of pure cement pastes with water to cementing material ratios of 0.30, 0.40, 0.50 and 0.60 and fly ash modified pastes with mass fraction of 10%, 30%, 40% and 55% were studied by using ammonium chloride solution with concentrations of 6 mol/l. The total leaching depth, leaching depth, porosity and compressive strength of these pastes leached for 14, 28, 56, 91 and 140 days were tested. The influences of W/C ratio and fly ash content on these properties were analyzed, the relationship between the two factors and the corrosion resistance of pastes was summarized. The results show that the total leaching depth of fly ash modified paste is larger than that of pure cement paste. However, the fly ash modified paste suffers various degree of lowered increment in porosity and strength loss (in percentage) in connection with the added content.

Predicting the calcium leaching behavior of cement pastes in aggressive environments

2012 ◽  
Vol 29 ◽  
pp. 88-96 ◽  
Author(s):  
Hu Yang ◽  
Linhua Jiang ◽  
Yan Zhang ◽  
Qi Pu ◽  
Yi Xu
Keyword(s):  
Leaching Behavior ◽  
Cement Pastes ◽  
Calcium Leaching
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