Effects of functional groups on the crystallization of ferric (oxyhydr)oxides

Effects of four functional groups on the crystallization of ferric (oxyhydr)oxides were investigated in this paper. Hydroxyl (OH), amino (NH2), methyl (CH3) and mercapto (SH) were used to modify the surfaces. Substrates were immersed into the biomineral solution for 40 h. The biominerals crystallized on the surfaces have been examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Atomic force microscope (AFM) was used to observe the morphology of the functional group surfaces, which turned out to be of the same density. Growth of orthorhombic FeOOH was identified on all four functional group surfaces, hematite was also detected on the NH2 surface. While on the controlled surface of Au, no deposition of iron compounds was found. These results demonstrated different crystallization process of ferric (oxyhydr)oxides induced by functional groups.

► Crystallization of iron (oxyhydr)oxides was proven possible under ambient temperature.
► Different effects of groups on the growth of biomineral were found out.
► Growth of orthorhombic FeOOH was identified on all the four functional surfaces.
► Hematite was detected on the NH2 surface.