Study on scale inhibition and corrosion inhibition of silkworm sand extract in brine solution

The harmful effects of most synthetic corrosion inhibitors on the environment are the motivation for the study of environmentally friendly extracts. The main components of silkworm sand extract (SSE) were studied by infrared spectroscopy (FTIR) and ultraviolet visible spectroscopy (UV-vis). The scale inhibition effect of SSE as scale inhibitor in calcium chloride solution was studied by means of electrical conductivity, static scale inhibition and scanning electron microscopy (SEM). Electrochemical impedance (EIS) and potentiodynamic polarization curve (PDP) were used to study its corrosion inhibition performance in simulated cooling water. The results showed that chlorophyll was the main component of SSE. When the concentration of SSE was more than 30 mg/L, the scale inhibition efficiency of calcium carbonate and calcium sulfate was both more than 90%. SSE could inhibit the supersaturation of calcium carbonate, prolong the nucleation time, and change the crystal shape of calcium scale. SSE had a good corrosion inhibition effect on Q235 steel in salt solution, and its corrosion inhibition mechanism was that SSE formed a protective film on the surface of Q235 steel. SSE could play a dual role of scale inhibition and corrosion inhibition, which was a potential new, environmentally safe corrosion and scale inhibitor for cooling water system.