Perencatan Kakisan Kuprum Oleh Tanin Bakau (Rhizophora Apiculata) Dalam Pelbagai Larutan Agresif Melalui Kaedah Elektrokimia

Tanin bakau (TB) daripada kulit kayu bakau telah diekstrak menggunakan 70 % aseton. TB tersebut kemudian telah diuji potensinya sebagai perencat kakisan kuprum dalam pelbagai larutan agresif melalui kaedah elektrokimia dan dibandingkan dengan kaedah pengukuran gravimetri konvensional. Daripada kaedah pengukuran gravimetri dalam larutan berasid (HCl dan H2SO4), didapati kecekapan perencatan (IE) bagi kakisan kuprum meningkat dengan peningkatan kepekatan TB. Pengukuran polarisasi potensiodinamik menunjukkan kehadiran TB dalam larutan berasid dan garam (NaCl dan Na2SO4) memberi kesan yang lebih kepada tindak balas katod dengan plot Tafel menunjukkan penurunan ketumpatan arus pada bahagian katod keluk

Synergy between iodide ions and mangrove tannins as inhibitors of mild steel corrosion

International audienceContext Corrosion of materials is a problem faced by many industries. One of the solutions to this problem is to apply corrosion inhibitors.Aims In this study, the synergy between iodide ions and mangrove tannin extracted from mangrove bark (waste products of the charcoal industry) was tested on the inhibition of corrosion of mild steel in 0.5 M HCl and 0.25 M H2SO4. It was compared with the inhibition provided by mimosa and chestnut tannins.MethodsPotentiodynamic and electrochemical impedance were recorded under various temperatures from 30 to 60°C in order to obtain the activation energy (Ea), the activated enthalpy (ΔH) and the activated entropy (ΔS).ResultsT he results showed that there was an increase in inhibition efficiency when iodide ions were added to corrosive media in the presence of mangrove tannin. The effect decreased when temperature increased. Mangrove tannins showed comparable inhibitive properties to those of commercial mimosa and chestnut tannins.Conclusion Inhibition efficiency of tannins as inhibitors of corrosion for mild steel in acidic media was improved by the addition of iodide ions. Tannins extracted from mangrove bark were more efficient than those from mimosa and chestnuts

Antioxidant and anticorrosive properties of oil palm frond lignins extracted with different techniques

International audienceContext Oil palm (Elaeis guineensis Jacq.) fronds are produced as waste during the harvest of oil palm fruits. It mainly consists of cellulose, lignin, and hemicelluloses. Lignins like other polyphenols are potent free radical scavengers and are considered to be a valuable source of antioxidant phenolic compounds. AimsThe aim was to quantify the antioxidant properties of lignins extracted from oil palm biomass using Kraft, soda, and organosolv pulping. The potential of the extracted lignins as inhibitors of mild steel corrosion was also assessed. Methods Ground and dried 1–3-mm-mesh-size oil palm fronds were submitted to Kraft, soda, and organosolv pulping in rotary digesters. The extracted lignin was characterized and oxygen uptake was measured. Anticorrosion properties of extracted lignins were monitored via electrochemical measurements and surface analysis.Results Soda-extracted lignins displayed the highest antioxidant activities as compared to Kraft and ethanol organosolv lignins. The highest inhibition of corrosion of mild steel was reached in the presence of soda-extracted lignins.Conclusion Oil palm fronds are potential sources of lignins usable as green antioxidant for corrosion inhibition of mild steel

Condensed Tannins from Mangrove and Grape Pomace as Renewable Corrosion Inhibitors and Wood Adhesive

International audienc