Diah Riski Gusti, Ratih Dyah Puspitasari, Harizon, Jesi Pebralia, Intan Lestari, R. Restu Luky Anggara, Ika Ayu Wulandari, M. Ardi Daya, Imelda
An eco-friendly corrosion inhibitor has been successfully developed by combining makaranga sap extract and maltodextrin (MGS-Mal). The resulting MGS-Mal was then applied to suppress the corrosion rate of mild steel in a 0.75M sulfuric acid medium. The success of corrosion inhibition on the mild steel surface was proven by analysis using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and confirmed by scanning electron microscope (SEM) images. The results show that the higher the temperature of the MGS-Mal solution, the higher the inhibition efficiency, reaching above 80% at 333 K. In the isotherm models tested, the Langmuir isotherm model provided fairly good regression coefficients at each temperature. The Langmuir isotherm model was then used to examine the thermodynamic parameters of MGS-Mal adsorption on mild steel surfaces. The Langmuir isotherm model was then used to explore the thermodynamic parameters of MGS-Mal adsorption on mild steel surfaces. The free energy of adsorption (-ΔG° ads ) at temperatures of 303-333 K was around 17.66-23.14 kJ mol−1, the enthalpy of adsorption (ΔH° ads ) was 37.91 kJ mol −1 , and the adsorption entropy (ΔS° ads ) was 126.081 J mol −1 . A study of the quantum aspects of various parameters examined in relation to maltodextrin, glyasperin-A, and Apigenin molecules shows that glyasperin-A is more readily adsorbed or donates its electrons to mild steel surfaces than maltodextrin and Apigenin, thereby suppressing corrosion on mild steel.