Effect of precursor concentration on the characteristics of nanoscale zerovalent iron and its reactivity of nitrate

Abstract

Differing precursor concentrations, 1.0, 0.1, and 0.01 M FeCl 3·6H 2O, were performed to produce nanoscale Fe 0 and the results were discussed in terms of the specific surface area, particle size and electrochemical properties. The results indicated that the nanoscale Fe 0 prepared by 0.01 M FeCl 3 had absolutely reduced in size (9–10 nm) and possessed the greatest specific surface area (56.67 m 2 g −1). These synthesized nanoscale Fe 0 particles were attempted to enhance the removal of 40 mg-N L −1 unbuffered nitrate solution. The first-order degradation rate constants ( k obs) increased significantly (5.5–8.6 times) with nanoscale Fe 0 prepared by 0.01 M precursor solution ( Fe 0.01 M 0 ) . When normalized to iron surface area concentration, the specific rate constant ( k SA) was increased by a factor of approximately 1.7–2.4 using Fe 0.01 M 0 (6.84×10 −4 L min −1 m −2 for Fe 0.01 M 0 , 4.04×10 −4 L min −1 m −2 for Fe 0.1 M 0 and 2.80×10 −4 L min −1 m −2 for Fe 1 M 0 ). The rise of reactivity of the reactive site on the Fe 0.01 M 0 surface was indicated by the specific rate constant ( k SA) calculation and the i 0 value of the electrochemical test.