Reductive Treatment of Bromate by Cast Iron
Date
2023-09-07
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Abstract
Bromate is an undesirable by-product of ozonating bromide-containing water and is a probable human carcinogen. Given the associated adverse effects of bromate on the environment and public health, it is important to treat and remove bromate from drinking water. Zero-valent iron particles have the potential to reduce bromate to bromide. However, they get oxidized rapidly and fail to completely reduce bromate to bromide. In this study, we analyzed the reduction characteristics of cast iron granules to treat bromate and its potential to be regenerated and re-used. Two different particle sizes of cast iron were analyzed in batch and in column tests to treat bromate-spiked deionized water and groundwater. Both particle sizes showed promising bromate treatment capacity. In batch tests, when the bromate concentration decreased, the bromide concentration increased, indicating the reduction of bromate to bromide using cast iron. In the column tests, it was observed that the bromate concentration in influent and the residence time affect the bromate-reduction capacity of the column. Decreasing the bromate concentration in influent and increasing residence time increased the total amount of bromate reduced. At low initial bromate concentrations, the columns continued to completely reduce bromate into bromide for 36 to 59 consecutive days without any decrease in the bromate reduction capability of the columns. It was also observed that cast iron granules could be regenerated using sulfuric acid and re-used multiple times with minimal impact on efficiency. Mathematical models were developed to identify pilot-scale column dimensions and predict bromate occurrence in column effluent. This research reveals that cast iron is a viable option to reduce bromate produced during ozonation.
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Citation
Khosravi Zadeh, S. (2023). Reductive treatment of bromate by cast iron (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.