CORROSION INHIBITOR AND OXIDANTS EFFECT ON IRON LEACHING FROM CARBON STEEL DURING MERCURY REMOVAL

Abstract

The Iodine/potassium iodide (I2/KI) lixiviant chemical possesses efficient treatment capabilities for elemental mercury (Hg°) removal on carbon steel’s porous surface. However, the mercury removal process on the contaminated carbon steel was observed to cause iron (Fe) to leach on the material’s surface. The results showed that the addition of imidazole as the corrosion inhibitor reduces 78.9% of  Fe leaching with only 55% of Hg° removal. Compared to the oxidants of sodium hypochlorite (NaOCl) and tert-Butyl hydroperoxide (TBHP), only peroxyacetic acid (PAA) possesses a positive influence on the I2/KI reaction. Interestingly, PAA oxidant does not only enhance the Hg° removal up to 99% and reduce 73% of the Fe leaching but also reduces half of the treatment time from 16 to 8 h. While in the addition of NaOCl and TBHP oxidants, the efficiency of the decontamination process was only obtained at 54% and 59% for Hg° removal with 28.4% and 35.8% of Fe leaching, respectively.