Novel trimeric surfactants containing heterocyclic moiety as inhibitors for acidic corrosion of carbon steel and alternative antimicrobial Agents

This study investigates the corrosion protection of carbon steel in 1.0 M HCl solution using two newly synthesized tricationic surfactants with heterocyclic structures, CS1 and CS2, as model inhibitors for highly corrosive acidic media in oil industry applications. The inhibition performance was evaluated using electrochemical techniques. Surface-active properties of the surfactants were determined from surface tension measurements obtained by axisymmetric drop shape analysis. The results confirmed the strong adsorption of CS1 and CS2 onto the steel surface, leading to high inhibition efficiency even at low concentrations. At 250 ppm, the maximum inhibition efficiencies of CS1 and CS2 reached 96.64% and 98.36%, respectively. Both surfactants acted as mixed-type inhibitors, and their adsorption behavior followed the Langmuir isotherm model. Quantum chemical calculations were performed to further support the experimental findings. Additionally, antimicrobial activity tests based on inhibition zone diameter revealed that both compounds exhibit strong antibacterial and antifungal properties.