Mitigation of eco-unfriendly and costly microbial induced corrosion using novel synthesized Schiff base cationic surfactants

Abstract

BACKGROUND: Sulfate-reducing bacteria (SRB) are considered to be the major cause of microbial-induced corrosion. It contributes to many environmental and other costly industrial problems in the petroleum industry. Thus there is always a great need for producing new efficient biocides and biocorrosion inhibitors.

RESULTS: In this work, three Schiff base surfactants (coded Q12, Q14 and Q18) were synthesized and characterized using Fourier transform infrared and 1H-nuclear magnetic resonance techniques. A mixed culture of SRB was collected from an oil field production tank located at the North Bahrya Petroleum Company (NORPETCO), Egypt. The antimicrobial effect of the newly synthesized surfactants was studied against sessile and planktonic SRB over their different growth phases by various methods: viable cell count via most probable number method, estimation of biogenic sulfide concentrations, weight loss of iron coupons in microbial growth medium and biofilm examination on coupon surfaces using scanning electron microscopy. The synthesized surfactants expressed a high inhibition effect on bacterial growth, recording a minimum inhibitory concentration of 750 mg L−1 for Q18 and 1000 mg L−1 for both Q12 and Q14, with a considerable decline in biogenic sulfide productivity from a dose of 500 mg L−1 until complete suppression at a dose of 1000 mg L−1. Also the synthesized surfactants showed an effective metal corrosion inhibition at a concentration of 500 mg L−1.

CONCLUSION: Schiff base cationic surfactants with long hydrophobic chains can be recommended as biocorrosion inhibitors for industrial application in the petroleum sector.