Adsorption of quaternary ammonium gemini surfactants on zinc and the inhibitive effect on zinc corrosion in vitriolic solution

Adsorption of the quaternary ammonium gemini surfactants alkanediyl-α,ω-bis-(dimethyl dodecyl ammonium bromide), referred as C12-s-C12·2Br (s = 2,3,4,6), on the zinc surface in 0.5 mol/L H2SO4 solution was investigated using gravimetric measurements. The adsorption of C12-s-C12·2Br on the zinc surface accorded to the Frumkin isotherm model. The maximal inhibition efficiency for zinc was reached at the saturated adsorption concentration Cc that was larger than its critical micelle concentration in 0.5 mol/L H2SO4 solution. The inhibition efficiency for zinc slightly reduced with increasing s since C12-s-C12·2Br formed different morphologies of the surface aggregates. The adsorption ability and the inhibition efficiency for corrosion reduced with increment of temperature.