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

Differing precursor concentrations, 1.0, 0.1, and 0.01 M FeCl(3) x 6H(2)O, 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 (9-10nm) 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-NL(-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 x 10(-4) L min(-1) m(-2) for Fe(0.01 M)(0), 4.04 x 10(-4) L min(-1) m(-2) for Fe(0.1 M)(0) and 2.80 x 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.