One-pot synthesis of magnetic algal carbon/sulfidated nanoscale zerovalent iron composites for removal of bromated disinfection by-product

Abstract

Magnetic algal carbon supported flower-like sulfidated nanoscale zerovalent iron (S-nZVI/AC) composite was firstly synthesized through one-pot method and used for removing bromate. More than 98% of bromate was efficiently removed within 48 min. Compared with the individual S-nZVI treatment, the removal rate constant of the S-nZVI/AC composite treatment was almost doubled. The removal rate constant of bromate increased three times when the S/Fe ratio increased from 0 to 0.3. According to the synergistic effect between the algal carbon and S-nZVI on the bromate removal, the introduction of carbon and sulfide-modification of nZVI were efficient modification approaches for enhancing the removal of bromated using S-nZVI/AC composite. The removal efficiency of bromate increased sharply to more than 98% when the composite dose increased from 0 to 40 mg L−1. The removal rate constant increased linearly from 0.08 to 0.31 min−1 when the initial concentration increased from 50 to 200 μg L−1. The removal efficiency of the bromate still maintained at high level (>85%) after 5 recycles of the S-nZVI/AC composite. Bromate was readily removed under neutral or slight acidic conditions. The bromate removal rate constant increased from 0.10 to 0.27 min−1 when the temperature increased from 15 to 35 °C. The bromate removal rate constant increased almost 4 times when the ionic strength increased from 0 to 3 g L−1. This study demonstrates that S-nZVI/AC composite synthesized through one-pot method is a promising water purification material for efficient removal of bromated disinfection by-product.