Preparation and characterization of nanocontainers of corrosion inhibitor based on layered double hydroxides

Nanostructured zinc aluminum and magnesium aluminum layered double hydroxide (ZnAl-LDH and MgAl-LDH) intercalated with corrosion inhibitor 2-benzothiazolylthio-succinic acid (BTSA) were prepared using co-precipitation method and characterized by infrared spectroscopy, X-ray diffraction, scanning electronic microscopy and transmission electronic microscopy. BTSA release from ZnAl(BTSA)-LDH and MgAl(BTSA)-LDH in 3 wt.% NaCl and 3 wt.% Na2SO4 solution was investigated with UV–vis spectroscopy, and inhibitive action of ZnAl(BTSA)-LDH and MgAl(BTSA)-LDH on carbon steel was examined by electrochemical methods. It was shown that the formula of synthesized ZnAl(BTSA)-LDH and MgAl(BTSA)-LDH is [Zn2.4Al(OH)6.8](BTSA)0.43(NO3)0.14.4H2O and [Mg2.1Al(OH)5.96](BTSA)0.62.1.5H2O, respectively. The BTSA release was dependent on the anion type in electrolyte and the BTSA release in the presence of SO42 − anion was higher than that in the presence of Cl− anion. The polarization curves obtained on the carbon steel sample showed that the ZnAl(BTSA)-LDH and MgAl(BTSA)-LDH are anodic inhibitors. Inhibition efficiency is higher with ZnAl(BTSA)-LDH, at the concentration of 3 g/l, achieving approximately 97% and 88% for ZnAl(BTSA)-LDH and MgAl(BTSA)-LDH, respectively.

► Corrosion inhibitor 2-benzothiazolylthio-succinic acid (BTSA) was intercalated in ZnAl and MgAl layered double hydroxide.
► BTSA loading was 21.9% in ZnAl(BTSA)-LDH and 33.2% and in MgAl(BTSA)-LDH.
► ZnAl(BTSA)-LDH and MgAl(BTSA)-LDH are anodic inhibitors of the carbon steel.
► Inhibition efficiency was 97% for ZnAl(BTSA)-LDH and 88% for MgAl(BTSA)-LDH at the concentration of 3 g/l.