Analytical & Bioanalytical Electrochemistry
Volume:16 Issue: 11, Nov 2024

This work addresses the issue of anode corrosion in an aluminum-air battery operating with aqueous alkaline electrolytes. To avoid this problem, an additive known to be an amphoteric surfactant was used. To this end, the surfactant cocamidopropyl betaine (CAPB) was examined as a corrosion inhibitor for the anode of the aluminum-air battery in a 1 M KOH solution. This investigation includes various techniques such as gravimetric measurements, potentiodynamic polarization, electrochemical impedance, surface analysis, and theoretical calculations. The gravimetric tests have shown that the corrosion rate (CR) of aluminum significantly decreases with the addition of CAPB molecules. Polarization curve analysis shows that CAPB acts as a cathodic inhibitor, and EIS data indicate a notable increase in polarization resistance with higher inhibitor concentration. Electrochemical results indicate that the CAPB additive provides substantial anticorrosion protection. At its optimal concentration, CAPB achieves an inhibition efficiency of 84.73%, and even at elevated temperatures (55°C), the efficiency remains around 70%. CAPB adsorption follows the Langmuir isotherm, combining both physisorption and chemisorption, with a primary emphasis on physical adsorption. To assess the inhibitory effect of the CAPB additive, the surface features and depth profiles are analysed. The formation of a surfactant-based layer is confirmed through FTIR-ATR. Based on the review of the various experimental and theoretical results, a mechanism of inhibition of the surfactant CAPB is proposed.

A sensitive, simple, cost-effective, and eco-friendly method has been suggested for the determination of the drug diphenhydramine (DPH) in pure and pharmaceutical formulations. The method depended on the preparation of the nano-aluminum oxide (Al2O3 NPs) and nano-iron oxide (Fe2O3 NPs) using the Melissa plant extract. The main purpose of this study is to determine the extent of change in electrical potential by using copper wire and aluminum wire, four electrodes were prepared. All electrodes showed Nernstian response, the best response was equal to 57.75 mv/decade for the electrode made from (sodium tetraphenylborate STPB- diphenhydramine)  as an ion pair with TBP as a plasticizer and (Al2O3 /Fe2O3) NPS with the aluminum wire membrane electrode, also the concentration range was 1.0×10-2  to 1.0×10-8 mole.L-1 with detection limit near to 2.07×10-7 mole.L-1. The value of the correlation coefficient (R2) was 0.9998. In this study, we succeeded in producing nanomaterials from green sources, with applied them in the potentiometric determination of the drug (DPH) to increase the sensitive of the preparation electrodes. These methods have become more desirable because they are characterized by ease of preparation, low cost, and do not use materials harmful to the environment.

The escalating threat of heavy metal contamination in water sources necessitates the development of efficient and cost-effective detection methods. This study explores the possibility of nickel slag waste (NSW) as a sustainable electrode material for the electrochemical sensor of Pb²⁺ ions through cyclic voltammetry (CV) and square wave voltammetry (SWV). The composition and morphology of the SNW were characterized using X-ray Fluorescence (XRF) and Scanning Electron Microscopy Energy Dispersive X-ray Spectroscopy (SEM-EDX). The analysis revealed a complex composition dominated by silica (SiO₂), magnesium oxide (MgO), and iron (Fe) with significant amounts of other elements such as nickel (Ni), aluminum (Al₂O₃), and titanium dioxide (TiO₂). The presence of these elements contributes to the electrode's high conductivity, structural integrity, and catalytic activity, which are crucial for efficient electrochemical sensing. Optimal detection was achieved at pH 5 being the optimal condition for Pb²⁺ detection due to favorable speciation and surface chemistry. The Gr/SNW composite electrode exhibited high sensitivity, with a limit of detection (LOD) as low as 0.005 ppm, and demonstrated strong linearity in Pb²⁺ concentration measurements. Additionally, the electrode showed excellent repeatability in performance, with RSD value, which was found to be 0.09%. These findings suggest that nickel slag waste is a promising candidate for developing low-cost, efficient electrochemical sensors for heavy metal detection.

In the present study, erbium-doped nickel ferrites, Ni0.5Sr0.5ErxFe2-xO4 (x=0.00<x<0.09) spinel nanoparticles were synthesized by the self-propagation method. Er3+ ions successfully doped into the spinel lattice of Ni0.5Sr0.5ErxFe2-xO4 without any distortion. The influence of Er3+ ions on the structure, surface morphology, and magnetic behaviour has been determined by powder XRD, EF-SEM, DSC-TGA, VSM, etc., and PXRD confirmed the spinel nanocrystalline structure. SEM analysis showed the size is between 27-30 nm with irregular morphology and grain boundaries. EDAX confirms elements in the expected percentage. The weight loss due to the degradation of synthesised nanoparticles (NPs) was studied by TGA-DSC. VSM at room temperature confirms the cubic spinel structure and soft magnetic in nature and can be altered with a variation of Er3+ ions. The glassy carbon electrode (GCE) was modified by coating a layer of synthesized Ni0.5Sr0.5ErxFe2-xO4 to detect the electron transfer reactions using cyclic voltammetry and also to sense the presence of Hg2+ in the polluted sample.