Degradation of 3,3′-iminobis-propanenitrile in aqueous solution by Fe0/GAC micro-electrolysis system

The degradation of 3,3′-iminobis-propanenitrile was investigated using the Fe0/GAC micro-electrolysis system. Effects of influent pH value, Fe0/GAC ratio and granular activated carbon (GAC) adsorption on the removal efficiency of the pollutant were studied in the Fe0/GAC micro-electrolysis system. The degradation of 3,3′-iminobis-propanenitrile was affected by influent pH, and a decrease of the influent pH values from 8.0 to 4.0 led to the increase of degradation efficiency. Granular activated carbon was added as cathode to form macroscopic galvanic cells between Fe0 and GAC and enhance the current efficiency of the Fe0/GAC micro-electrolysis system. The GAC could only adsorb the pollutant and provide buffer capacity for the Fe0/GAC micro-electrolysis system, and the macroscopic galvanic cells of the Fe0/GAC micro-electrolysis system played a leading role in degradation of 3,3′-iminobis-propanenitrile. With the analysis of the degradation products with GC-MS, possible reaction pathway for the degradation of 3,3′-iminobis-propanenitrile by the Fe0/GAC micro-electrolysis system was suggested.

► Effect of Fe0/GAC ratio and influent pH on treatment efficiency. ► Proposed reaction pathway for the degradation of 3,3′-iminobis-propanenitrile. ► Analysis the passivation of the iron and GAC after 60 d continuous run. ► Macroscopic galvanic cells formed by the contact of Fe0 and GAC.