This study was conducted to investigate chemical reduction of nitrate by nanoscale zero-valent iron (ZVI) in aqueous
solution and related kinetics and pathways. In the last decade, employment of micro-scale ZVI has gained its popularity
in nitrate reduction. To further study chemical reduction of nitrate, nanosized iron was synthesized and tested in this
work. It has a size in the range of 50–80nm and a BET surface area of 37.83m2 g1. Chemical reduction of nitrate by
nanosized iron under various pHs was carried out in batch experiments. Experimental results suggest that nitrate
reduction by nanosized ZVI primarily is an acid-driven surface-mediated process. A stronger acidic condition is more
favorable for nitrate reduction. Results of the kinetics study have indicated that a higher initial concentration of nitrate
would yield a greater reaction rate constant. Additional test results also showed that the reduction rate of nitrate
increased as the dose of nanosized ZVI increased. In all tests, reaction rate equations developed do not obey the first- or
pseudo-first-order reaction kinetics with respect to the nitrate concentration. Based on the research findings obtained,
two possible reaction pathways for nitrate reduction by nanoscale iron particles have been proposed in this work.
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