Treatment of Bromate from an Aqueous System Utilizing Cast Iron Granules

Bromate is a probable human carcinogen which forms a disinfection by-product during ozonation, when water contains bromide. This study investigated the ability of cast iron granules to reduce bromate and compared their performance to nanoscale zero-valent iron particles (nZVI). In the experiments conducted, we observed a simultaneous decrease in bromate concentration and increase in bromide concentration. This observation was accompanied by a relatively constant total bromine species, indicating that bromate is directly reduced to bromide without any intermediates. The effectiveness of nZVI significantly decreased after 24 h, while cast iron granules showed a steady rate of bromate reduction. The capacity of cast iron to reduce bromate was also examined in multi-cycle experiments, and we observed that each gram of cast iron could reduce between 25.7–30.5 mg of bromate, depending on its initial concentration. Additionally, the results revealed that unlike nZVI, cast iron granules are not prone to forming an oxide layer which compromises the bromate reduction potential of iron particles.