New mitigation approach for microbiological corrosion of carbon steel by facile separation of sodium chlorite from brine electrolysis

The novelty of this study is the electrolysis of brine (NaCl) solution (sustainable source is the saline seawater). The generated chlorine dioxide (ClO2) at the anode was absorbed into NaOH giving efficient biocide sodium chlorite (NaClO2). Carbon steel exposed to industrial water faced (MIC) because sulphate reducing bacteria (SRB) colonize as biofilm adherent to the metal surface. A model of plug-flow electrolyzer was used for continuous NaCl feed and removal of electrolysis products. Using new porous cathode (graphite, pencil and sulpher-Fe2O3 doped NiO (spin coated on graphite) at small anode: cathode distance achieved 98% yield. SRB cultured and isolated using Postgate B specified media at pH 7, incubation temperature range 30-37oC for 7 days. Black FeS precipitation indicating bacteria growth. Different parameters affecting corrosion were discussed. Carbon steel corrosion coupons of known composition and dimensions were placed in several falcon tubes contained SRB media broth under de-aerated and sterile conditions to evaluate SRB influence on corrosion rate in the absence and the presence of NaClO2 biocide obtained at 200 mAcm-1electrical current passed in pure brine 0.5M NaCl solution for 30 min. electrolysis using dimensional stable anode and different types of cathodes. Inhibition efficiency to MIC (%IE) reached 96% for chlorine species (at adjusted pH range: 6.5- 7.5.