The highly advance usage of an agricultural waste of rice husk ash (RHA) from Oryza sativa L. was developed by extracting the nanosilicate contained in RHA as a corrosion inhibitor for carbon steel in 0.5 M NaCl media. The corrosion measurement was studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), surface analysis, and adsorption isotherm study. The extracted nanosilicate powder from RHA was analyzed using Fourier Transform Infrared Spectroscopy (FTIR) to identify the presence of functional groups (SiO2), whereas X-ray diffraction (XRD) to identify the phase of silica from RHA. The particle size of nanosilicate was confirmed by transmission electron microscopy (TEM) and Zetasizer analysis, and the results show particle size of nanosilicate in the range of 5–10 nm. The maximum inhibition efficiency (IE%) is up to 88% in NaCl media. On the other hand, the inhibitor adsorption properties follow Temkin isotherm with mixed type of inhibition properties. Surface analysis on specimen that was treated with nanosilicate was smoother with fewer pits and pores than untreated specimen. In future perspectives, nanosilicate from RHA has a promising advantages and imminent applications for industries revolving with composites, biomedicine, and many more.
Part of the book: Rice
This research was focused on discovering the utilization of Dioscorea hispida (gadong tuber) starch as a potential green corrosion inhibitor for SAE 1045 carbon steel in 0.6 M NaCl media. Raw starch from gadong tubers was obtained through the extraction and precipitation process prior to drying in producing fresh starch powder. The insoluble starch powder was then dissolved in 90% dimethyl sulfoxide (DMSO) solvent and was ready for corrosion inhibitor testing. The extraction of starch powder was analyzed using Fourier Transform Infrared Spectroscopy (FTIR) to identify the presence of functional groups that may contribute to the inhibition of the carbon steel sample. The inhibitive performance of gadong tuber starch (GTS) as a green corrosion inhibitor was studied by weight loss measurement and potentiodynamic polarization in a corrosive medium using 0.6 M sodium chloride (NaCl) solution. Effect of GTS concentration on corrosion behavior was investigated. Based on the findings, 1500 ppm of GTS demonstrated the highest corrosion inhibition performance as the corrosion rate of carbon steel immersed in plain 0.6 M NaCl was reduced from 0.131 to 0.018 mm/year, which is up to 86.3 IE% of inhibition efficiency in the presence of the green corrosion inhibitor. According to potentiodynamic polarization analysis, corrosion current density (Icorr) was also decreased from 1.13 × 10−5 to 1.55 × 10−6 mA/cm−2.
Part of the book: Corrosion Inhibitors, Principles and Recent Applications