Abstract
1-(3-bromopropyl)-4-(dimethylamino) pyridinium bromide (DPB) ionic liquid prepared via microwave-assisted synthesis was investigated as a potential corrosion inhibitor for carbon steel in molar hydrochloric acid solution by means of weight-loss method. The obtained results revealed the high inhibitive activity of the prepared ionic liquid with increasing inhibition efficiency reaching ca. 87.1% in the presence of 3x10(-3) M DPB. The adsorptive nature of the inhibition process was proven by kinetics and thermodynamics investigations with a large adsorption constant (K-ads = ca. 3.8 x 10(3) mol(-1). L) and an elevated activation energy (E-a = ca. 83.1 kJ. mol(-1)). DPB was found to show a predominant physical adsorption onto the corroding carbon steel surface (Delta G(ads) = ca. -35.9 kJ. mol(-1)). Electrochemical investigations revealed that DPB acted as a mixed-type corrosion inhibitor hindering both anodic and cathodic processes via blocking their respective active sites. The inhibitor was shown to form a protective layer resulting in increasing charge transfer resistance along with a decreasing double layer capacitance.