The corrosion inhibition mechanism of modified lignosulfonate GCL2-D1 was studied by using methods of GPC

titration

differential UV-absorption spectrum

ESEM

EIS

etc.The results showed that the structure and corrosion inhibition properties of the lignosulfonate changed greatly after modification.The molecular weight changed from 11048 to 29381.The sulfonic content increased from 9.04% to 11.2%

and the carboxyl content increased from 5.81% to 15.84%.Through modification

the lignosulfonate extended itself in the solution from spherical shape to linear chains.When adsorbed on metal surface

the contents of S

Ca

and C had an obvious increase in the interfacial film

indicating the increase of adsorption points and adsorption amount of the modified lignosulfonate GCL2-D1.Electrochemical analysis demonstrated that GCL2-D1 belonged to mixed inhibitor.When the dosage of GCL2-D1 was 100 mg8226;L-1

the charge transfer resistance increased from 564 Ω to 20680 Ω

and the interfacial capacity between metal and solution reduced distinctly from 2.84 mF to 0.041 mF.It indicated that the GCL2-D1 formed a compact film on the metal surface

resulting in inhibition of metal corrosion.