Abstract
Water contamination with bromate is a serious environmental issue due to its carcinogenic nature. Aqueous bromate can form during the ozonation in the presence of bromide in a water treatment system. Filtration, biological degradation, adsorption, and electrochemical treatment are widely used technologies to remove the bromate in an aqueous environment. However, these technologies have drawbacks such as the generation of secondary byproducts including sludge, low efficiency, and high cost. Catalytic bromate reduction can be an effective alternative method to reduce aqueous bromate to less harmful bromide. The removal efficiency, cost, recyclability of the catalyst heavily depend on the selection of proper materials. Nanoscale zero-valent iron (NZVI) is a cost-efficient and abundant material and thereby, was selected for the catalytic reduction of bromate. Metal loading on the surface of the support (NZVI) can increase the reactivity further. Therefore, several combinations of NZVI-supported catalysts (Sn, Cu, Ni, In, Zn, Pd on NZVI) were synthesized and tested in a batch reactor for the reactivity of bromate reduction by finding out the most efficient materials for the catalyst. All catalysts demonstrated complete removal of bromate to bromide. However, the Sn/NZVI catalyst demonstrated the fastest removal (0.47 min-1) among other catalysts (0.13 min-1 for Cu/NZVI and 0.40 min-1 for Zn/NZVI, for example). The removal efficiency was in the order of Sn>Zn>Cu>Ni>In. SEM-EDX characterization study of Pd/NZVI revealed a uniform distribution of metal doping on the catalystu2019s surface. The results show that Sn/NZVI is a cost-effective and sustainable solution to treat the water and wastewater contaminated with bromate.