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Highly efficient low-cost adsorbent was applied for copper (II) ions uptake from aqueous solution. Characteristics of natural adsorbent were established using scanning X-ray diffraction (XRD), X-ray fluorescence, electron microscope (SEM) and Fourier Transform Infra-Red (FTIR). Various physicochemical parameters such as contact time, initial copper(II) ions concentration, adsorbent dosage, pH of copper (II) ions solution and temperature were investigated. The result showed that the adsorption of copper (II) ions by natural clay was favorable at pH=5,5. The adsorption was found to increase with increase in initial copper (II) ions concentration, and contact time. Equilibrium adsorption data were fitted using three isotherms and kinetic data tested with four kinetic models. Freundlich isotherm best described the adsorption of copper (II) ions onto utilised clay, the maximum monolayer adsorption capacity (qmax) was 8 mg/g. Pseudo-second-order model best described the kinetics of the adsorption process. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy were determined. It was found that copper (II) ions adsorption was spontaneous (ΔG°<0) and endothermic (ΔH°>0).

The corrosion inhibition of carbon steel in a 1.0 M HCl solution, using 4-amino-2-(4 chlorophenyl)-8-(2,3-dimethoxyphenyl)-6-oxo-2,6-dihydropyrimido [2,1b][1,3]thiazine-3,7-dicarbonitrile (ACMPT) was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and quantum chemical calculations. Polarization curves indicate that the studied compound was acting as a mixed inhibitor with predominant cathodic effectiveness. The inhibition efficiency decreased with an increased temperature, and the thermodynamic and activation parameters obtained from this study were discussed. The adsorption behavior of ACMT follows Langmuir's isotherm. In addition, Density Function Theory (DFT) calculations were performed on the studied molecule. The theoretical parameters obtained from this method are in good agreement with the experimental results.