Synthesis of nanoscale reaction pits network on zerovalent iron powder surface

A neat and efficient method for controllable and reproducible synthesis of coral-shaped matrix containing abundant nanoscale reaction pits on micrometer-size zerovalent iron powder is described with the study of etching capability of dilute hydrochloric, sulfuric, and nitric acids with concentration ranges from 1 N to 6 N. Characterizations of surface morphology show that the specific surface area of this matrix increases up to 170 times that of the untreated iron powder, and that the reduction efficiency of a PCB congener in subcritical water is enhanced fivefold from 18% for the untreated iron to 92% for that with 170 times its surface area. The nanoscale pits may be a basis for enhancement of reaction cross-section via restriction of molecule mobility in the pits.