Exploring the anticorrosion properties of wastewater from a winemaking process for the protection of carbon steel in acid environments

This study investigates the potential conversion and application of the wastewater from a winemaking industry for the corrosion protection of metallic materials. Grain-soaked wastewater extract (herein called SOW) was collected from the leached grain wastewater of Sichuan-style Xiaoqu Baijiu. The elemental analysis results indicated that SOW was an oxygen rich compound containing N and S heteroatoms, and Fourier transform infrared spectroscopy also confirmed that SOW was rich in multiple functional groups. The effect of SOW on the corrosion suppression of Q235B carbon steel in 0.5 M H2SO4 solution was investigated through electrochemical measurements, weight loss experiments and surface analysis technology. The results revealed that SOW was an excellent anticorrosion material for Q235B carbon steel, especially after the combination of SOW and potassium iodide (KI), the corrosion inhibition efficiency was up to 94.07% at 30 degrees C. Surface analysis further demonstrated the corrosion inhibition effect of SOW on Q235B carbon steel in H2SO4 solution. Moreover, the thermodynamic and kinetic parameters were calculated to reveal the corrosion inhibition mechanism of SOW.