Synthesis and optimization of composite coatings based on electrical conductive of polyaniline and polyindole for anti-corrosion protection of carbon steel

In this work, electro-conductive polymers including polyaniline and polyindole were used to protect the carbon steel corrosion (carbon steel with the API5LX52 grade). Electropolymerization of composites containing polyaniline and polyindole on carbon steel was performed in an aqueous solution containing oxalic acid by using cyclic voltammetry (CV) method. In this work, water as a solvent was used due to reducing costs and environmentally friendly issue. Using electrochemical impedance spectroscopy (EIS), it was found that the composite coating provides better protection than polyaniline and polyindole against corrosive materials (in this work, 3.5% NaCl) for carbon steel. FTIR method was used to identify synthesized samples. FTIR peaks of synthesized polyaniline and polyindole are matched with their respective FTIR index peaks at the references. The resulting index peaks in FTIR of composite coating indicate that the coating contains polyaniline and polyindole

Preconcentration and determination of heavy metals in water, sediment and biological samples

In this study, a simple, sensitive and accurate column preconcentration method was developed for the determination of Cd, Cu and Pb ions in river water, urine and sediment samples by flame atomic absorption spectrometry. The procedure is based on the retention of the analytes on a mixed cellulose ester membrane (MCEM) column from buffered sample solutions and then their elution from the column with nitric acid. Several parameters, such as pH of the sample solution, volume of the sample and eluent and flow rates of the sample were evaluated. The effects of diverse ions on the preconcentration were also investigated. The recoveries were >95 %. The developed method was applied to the determination of trace metal ions in river water, urine and sediment samples, with satisfactory results. The 3δ detection limits for Cu, Pb and Cd were found to be 2, 3 and 0.2 μg dm−3, respectively. The presented procedure was successfully applied for determination of the copper, lead and cadmium contents in real samples, i.e., river water and biological samples

Use of Electrochemical Impedance Spectroscopy to Study the Corrosion of Tin in Citrate Solution Analytical & Bioanalytical Electrochemistry

Abstract- The corrosion and passivation of tin anode in citrate (0.01 to 1.0 M) solution was investigated using steady state polarization, impedance spectroscopy and cyclic voltammetric techniques. Before permanent passive region, two anodic peaks were observed in the anodic polarization curve, corresponding to the consecutive electroformation of Sn(II) and Sn(IV) species. The corrosion current was calculated by the Tafel extrapolation procedure at different concentrations of citrate ion and different pH values. Also, the corrosion resistance at the corrosion potential was calculated from the Nyquist diagram of different concentration of citrate ion. It was found the latter gives more precise results

High Current Density Chronopotentiometric Electrosynthesis and SEM Characterization of Hexanethiol-Monolayer-Protected Silver Planar Nanotriangles (Ag@C6SH)

This work reports for the first time electrosynthesis of hexanethiol capped silver nanotriangles cores (Ag@C6SH NCs) by a rapid, clean, and simple Double Pulse Chronopotentiometric (DCP) method in nonaqueous media, using a Taguchi orthogonal array L8 design to identify the optimized experimental conditions. It was found that the size and shape of the product could be tuned by the current density, electrolysis time, electrode distance, and amount of NaBH4% used. The Ag@C6SH NCs in different shapes and sizes (in the range of 30 to 44 nm as an average estimation) were synthesized, under different experimental conditions. Finally, the as-prepared nanoclusters electrosynthesized at optimized conditions were characterized by SEM, XRD, and UV-Vis spectroscopy. The average particle size of the triangular/pyramidal shape (Ag@C6SH NCs), obtained under optimized experimental conditions, was 30.5±2.0 nm but the majority of nanoparticles in TC3 SEM are so much finer