Exploring the absorption and desorption behavior of 2-mercaptopyrimidine as an inhibitor in CO2-containing solution

摘要

The injection of corrosion inhibitors is widely employed as an effective method to mitigate the corrosion rate [1 -3]. The corrosion inhibition performance of inhibitors in the formation water may be affected by factors such as the inhibitor dosing, solubility and shear stress [4-6]. This work focuses on investgating the effect of inhibitor dosing and Cl - content in solution on the 2-mercaptopyrimidine (2-MP) inhibitor film integrity. In this study, the corrosion inhibition efficiency of 2-MP on L360 carbon steel was evaluated using Electrochemical Impedance Spectroscopy (EIS), weight loss measurements, and the adsorption beha vior of 2-MP on an Au surface was explored via Quartz Crystal Microbalance (QCM). All experiments were conducted in CO 2- saturated formation water containing varying concentrations of 2 -MP. Solutions with varying Cl - content were selected to analyze the ion ic influence on the corrosion inhibition behavior of 2 -MP. The inhibition performance of 2 -MP at 20 ppm in CO 2- saturated solutions with varying NaCl contents on L360 carbon steel was assessed through electrochemical, weight loss, and surface analytical methods. The desorption behavior of 2-MP was monitored using QCM and Ultraviolet-Visible Spectroscopy (UV-vis). In addition, molecular dynamics (MD) simulations were employed to investigate the surface adsorption configurations of 2 -MP. The Dynamic Light Scat tering (DLS) technique was used to analyze the changes in micelle size and the diffusion coefficients of desorbed 2-MP molecules in varying NaCl content solutions. The main conclusions are as follows: (1) As 2-MP concentration rises, corrosion inhibition efficiency increases and then stabilizes, peaking at 100ppm due to saturation; (2) As the NaCl content increases, corrosion inhibition performance of 2 -MP declines, and the corrosion rate of L360 carbon steel escalates from 0.0405 mm/a to 0.0914 mm/a; (3) As NaCl content increases, it facilitates 2 -MP desorption on the Au surface, which indicates intensified desorption and promotes the formation of 2-MP micelles.