Catalytic deposition of nanocarbon onto palygorskite and its adsorption of phenol

A novel palygorskite/carbon sorbent was synthesized by hydrothermal carbonization of glucose onto palygorskite using ammonium ferrous iron (Fe2+) sulphate hexahydrate as catalyst under mild conditions. The resulting palygorskite/carbon nanocomposites were characterized by field-emission scanning electron microscopy, X-ray diffraction patterns, Fourier transform infrared spectroscopy and total carbon content analysis. It was found that the nano-carbon with diameter of 30–50 nm was successfully loaded onto the palygorskites crystal surfaces, accompanied by abundant C―H groups. The mechanism of formation of nanocomposites was proposed as follows. Two carbonization routes of glucose coexisted, namely random carbonization and adsorption-induced carbonization on palygorskite surfaces. The formation of palygorskite/carbon was determined by competition of the two carbonization routes which could be controlled by hydrothermal conditions, i.e. reaction time, temperature and catalyst. The resultant modified palygorskite demonstrated a substantially high adsorption capacity for phenol in comparison with unmodified palygorskite.