The Study On Corrosion Inhibition Performances Of Gemini Surfactants

The corrosion protection is an important topic in the area of material.There are various methods to control corrosion.Adding inhibitiors is regarded as one of the cost-effective methods for corrosion inhibition.Gemini surfactants are one kind of excellent corrosion inhibitors in acid medium and therefore have potential research values in terms of metal corrosion inhibition.In this thesis,the corrosion inhibition performances of gemini surfactants 12-n-12(EtOH)(n=4,6),n-Ph-n(n=12,14,16)and binary surfactants system 16-4-16/SDS on zinc in acid medium were investigated by the weight loss method.According to experimental data obtained by weight loss method,some thermodynamic and kinetics parameters were calculated,and the inhibition mechanism was studied preliminarily.The main conclusions are as follow:1、Gemini surfactants 12-n-12(EtOH)(n=4,6)show good inhibition properties on zinc in sulfuric acid solution.12-4-12(EtOH)exhibits better inhibition effect than12-6-12(EtOH).12-n-12(EtOH)adsorbed on the zinc surface physically forms a layer of dense protective film.The adsorptions of 12-n-12(EtOH)obey the Langmuir adsorption isotherm.Because of the shorter length of the spacer group,the molecular arrangement of 12-4-12(EtOH)on zinc is more compact than 12-6-12(EtOH),and the protective film formed by 12-4-12(EtOH)is also denser than 12-6-12(EtOH).Thus12-4-12(EtOH)has better inhibition effect.2、Gemini surfactants n-Ph-n(n=12,14,16)exhibit fine inhibition properties on zinc in sulfuric acid solution,and the inhibition effect shows the order: 16-Ph-16>14-Ph-14>12-Ph-12.n-Ph-n adsorbed on the zinc surface physically form a layer of dense protective film.The adsorptions of n-Ph-n obey the Langmuir adsorption isotherm.When n-Ph-n contain longer hydrophobic tail chain,the thicker and denser protective film is formed on the zinc surface.Thus the inhibition effect of n-Ph-n increase with increasing the length of the hydrophobic group.3、Gemini surfactant 16-4-16 and binary surfactants system 16-4-16/SDS show excellent inhibition performance on the zinc surface in hydrochloric acid solution,but16-4-16/SDS exhibits better inhibition effect.16-4-16 and 16-4-16/SDS adsorbed on the zinc surface physically form a layer of dense protective film.The adsorption of16-4-16 and 16-4-16/SDS obey the Langmuir adsorption isotherm.Due to thesynergistic adsorption of 16-4-16/SDS,the adsorption layers of 16-4-16/SDS are more denser than 16-4-16,therefore 16-4-16/SDS exhibits better inhibition property.