Synthesis of PPy/silica nanocomposites with cratered surfaces and their application in heavy metal extraction

A simple fabrication method for a polypyrrole (PPy)/silica nanocomposite with a cratered surface using templated synthesis is described. This nanocomposite was prepared by a modified silica-templated oxidation/polymerization of pyrrole in the presence of FeCl3 oxidant and was characterized by various methods, including Fourier-transform infrared spectroscopy; BET specific surface area; and transmission electron microscopy (TEM). The PPy/silica nanocomposite with surface craters looked like a golf ball in TEM images. The highest BET surface area of PPy/silica nanocomposite with craters was 306 m2/g at 4 mL silica sol solution (Ludox SM-30) loading through the fabrication process, whereas a PPy/silica nanocomposite without craters had a specific surface area of only 85 m2/g with no Ludox SM-30 introduced. In addition, the material's adsorption capacity for heavy metal ions (Hg2+, Ag+, and Pb2+) and its recycling mechanism were investigated.