Purpose Electrochemical measurements were used to characterize the inhibiting effectiveness of Curcuma and saffron, considered as green inhibitors in a corrosive environment 3% NaCl on A106 Gr B carbon steel. Design/methodology/approach This study/paper aims to polarization and potentiodynamic impedance spectroscopy techniques were performed on A106 Gr B carbon steel in the 3% NaCl environment only and containing various concentrations of Curcuma and Saffron (0.005, 0.01, 0.02, 0.04, g/L) after 30 min of immersion; these measures were taken at a temperature of (298 ± 1)K. A voltlab PGZ 301 assembled by A 106 Gr B carbon steel working electrode, a platinum counter electrode (CE) and a saturated calomel electrode as the reference electrode were used in the experiment. In this research, potentiodynamic polarization and electrochemical impedance spectroscopy were used. Findings The inhibition efficiencies increased with increase in the concentrations of the inhibitor but decreased with rise in temperature. The obtained results show an optimal efficiency with 0.04 g/L which are ordered of 78 and 96 per cent successively for the two inhibitors. Curcuma and saffron acts as a mixed type inhibitor. Adsorption of the inhibitor molecules corresponds to Langmuir adsorption isotherm. Mechanism of inhibition was also investigated by calculating the thermodynamic and activation parameters like (ΔG), (Ea), (ΔHa) and (ΔSa). The inhibitor molecules followed physical adsorption on the surface of carbon steel. Originality/value The present trend in research on environmental friendly corrosion inhibitors is concentrating on products of natural origin due principally to non-toxicity and eco-friendliness. Among these natural products are curcuma and saffron.

Heterogeneous photocatalysis is an advanced oxidation process (AOP). This technique is used to degrade a wide range of pollutants in water. In this study, photocatalytic oxidation and mineralization of malachite green in an aqueous suspension containing nickel-based catalysts and copper supported on TiO2 prepared by wet diffusional impregnation was studied using two sources of irradiation: solar and microwave. Photodegradation kinetics were studied according to several parameters, such as catalyst type, dye concentration, photocatalyst mass and microwave power. The results showed that the photodegradation of malachite green is faster in the presence of CuO/TiO2 catalyst than NiO/TiO2 catalyst than TiO2. Dye degradation by microwave irradiation is faster than that by solar irradiation.

Purpose Corrosion and corrosion inhibition of alloyed zinc electrode were investigated in neutral chloride solution using electrochemical techniques. The purpose of this study is to study the corrosion inhibition of acetanilide and para hydroxy acetanilide as organics inhibitors for corrosion control of alloyed zinc electrode in NaCl 3 per cent solution. Design/methodology/approach A volt lab PGZ 301, assembled using alloyed zinc working electrode, a platinum counter electrode and a saturated calomel electrode as the reference electrode, was used in the experiment. This research was conducted using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. Findings Acetanilide, para hydroxy acetanilide and their mixture provided inhibitions efficiencies of 88 per cent at 40 ppm, 87 per cent with 80 ppm and 99.86 per cent with (40 ppm AC + 80 ppm PHA), respectively. The study also discusses the corrosion inhibition mechanism of the protective layers. The adsorption of acetanilide and para hydroxy acetanilide on metal surface obeyed Langmuir’s adsorption isotherm. Polarization measurements showed that the acetanilide and the para hydroxy acetanilide, and their mixture acted as cathodic inhibitors in NaCl solution, and the inhibitor molecules followed physical adsorption on the surface of alloyed zinc. Originality/value The other new inhibitors which are very efficient inhibitors and to be applied in the field of prevention and control against corrosion.