Application of Borassus flabellifer lignin extract as an inhibitor of low carbon steel (LCS) corrosion rate

Abstract

The consumption of LCS in Indonesia was recorded at 1,100,000 million tons in 2018. The decrease in the corrosion rate is inhibited by the lignin-inhibition method. This study was conducted on the effectiveness of Borassus flabellifer fiber lignin extract as a green inhibitor of corrosion in LCS. Literature review using relevant articles based on bibliometric and molecular designs simulation method omits was used. The molecular design simulation shows that inhibition of LCS by lignin occurs through an electron exchange reaction between oxygen atoms in aromatic rings of lignin and the d-orbitals of Fe atoms on the LCS surface in acidic media. The lignin coats LCS and blocks oxygen atom from direct contact, so the corrosion rate decreases by up to 37.5% compared with untreated LCS. Borassus flabellifer fiber is widely distributed in Indonesia that is not utilized and rich in lignin content. It is estimated that 93,000-186,000 tons of Borassus flabellifer fiber are produced 17,670-35,340 tons of lignin every day, which can coat 476.16-952.32 million m2 LCS. This is high to be developed as a prevention method of LCS corrosion in the future because of (1) high raw material reduction, (2) high lignin extraction product from Borassus flabellifer fiber, (3) inhibitor application in LCS, and (4) its inhibitory power against high corrosion rates.