Corrosion inhibition of pure iron by Eurohypnum leptothallum extract in 0.5 mol L−1 H2SO4: an experimental and GC-MS based study

Abstract In this work, the functional groups of Eurohypnum leptothallum extract (ELE) were extracted by aqueous immersion and identified by FTIR. The corrosion inhibitory effect of ELE as a natural plant corrosion inhibitor on pure iron in 0.5 mol L −1 H 2 SO 4 solution was investigated by test methods such as the weight loss method, electrochemical behaviour and detection of metal surface topography. The results show that ELE has a positive inhibitory effect on the corrosion behaviour of pure iron in 0.5 mol L −1 H 2 SO 4 solution, and the higher the concentration of ELE, the greater the corrosion inhibitory effect. It can still reach 83.97 % at high temperatures. The results of SEM examination and contact angle measurements show that the corrosion degree of the metal decreases significantly after the additon of ELE and that the hydrophobicity of the metal surface increases. The adsorption of ELE on the surface of pure iron tends to isothermal Langmuir adsorption and, as a mixed corrosion inhibitor, the charge transfer resistance of the system increases significantly and the capacitance value of the electrical double layer decreases significantly.