2-Thiophene Carboxaldehyde as Corrosion Inhibitor for Zinc in Phosphoric Acid Solution

Abstract

The inhibitive effect of 2-thiophene carboxaldehyde (TCAl) on zinc corrosion in 1 M H 3 PO 4 solutions has been studied by weight loss, potentiodynamic polarisation and open-circuit potential (OCP) methods. The obtained results revealed that TCAl is an effective corrosion inhibitor for zinc in H 3 PO 4 solutions. Inhibition efficiency values obtained from gravimetric and electrochemical measurements were in good agreement. The inhibition efficiency increases with increasing inhibitor concentration and decreases with increasing temperature. Potentiodynamic polarisation studies showed that TCAl acts as a mixed type inhibitor. Scanning electron microscopy (SEM), OCP measurements and the thermodynamic data of dissolution and adsorption processes showed that inhibition of zinc corrosion in phosphoric acid solutions by TCAl is due to the formation of a physisorbed film on the zinc surface. Adsorption of the compound studied on zinc surface obeys to Langmuir adsorption isotherm.

Protection of metals in phosphoric acid solutions by corrosion inhibitors. A review

“…For zinc protection in dilute H 3 PO 4 solutions (0.01-0.15М) at ambient t, aniline [137], urotropine [138] and 4-aminoantipyrine [139] are used. In 1 М H 3 PO 4 (25), zinc corrosion is inhibited by adding 0.5-7.0 mM 2-thiophenecarboxaldehyde (TPhCA) with Z = 53-96% [140]. Increasing t to 65С weakens metal protection by the inhibitor, and at 1 mM TPhCA, the Z value decreases from 65 to 35%.…”

“…(-G ads ) = 17.3 kJ/mol for the mixture of compounds produced from the Dendrocalamus brandisii plant [132], and even lower (4.7-5.8 kJ/mol) for unsaturated ketones [128]. Better adsorption is observed for TPhCA on zinc with (-G ads ) = 28.9 kJ/mol [140] and for 1-butyl-4-methylpyridinium tetrafluoroborate on copper (23.3-24.7 kJ/mol) [144]. In all the cases, adsorption is described by the Langmuir isotherm.…”

The Study of Composite Substituting Mercury Corrosion Inhibitors for Zinc in Zinc-Manganese Battery

“…At the field of metal corrosion and protection, many substances have been investigated as the metal's corrosion inhibitors, such as benzaldehyde and quinoline derivatives [5], imidazole compounds [6][7][8], organic amine compounds [9], ethoxylated fatty alcohols or acids [10,11], surfactants [12][13][14][15], organic chelating inhibitor [16,17], and so on [18]. But it was hardly used in practical industrial application of the zinc-manganese dry battery.…”