Novel porous carbon/clay nanocomposites derived from kaolinite/resorcinol-formaldehyde polymer blends: synthesis, structure and sorption properties

Abstract

A series of organics mixed with kaolinite as well corresponding chars were synthesized by modification of kaolinite with resorcinol–formaldehyde polymer and subsequent carbonization under inert atmosphere at 800 °C. The hybrid organo-clay nanocomposites were prepared via two routes: (i) rapid simultaneous copolymerization of the components, (ii) through prolonged contact of monomer solutions with clay in order to improve morphological and structural characteristics of nanocomposites to be used as adsorbents. The composites were characterized using X-ray diffraction, Raman spectroscopy, thermal analysis (with simultaneous DSC), nitrogen adsorption–desorption, scanning electron microscopy and small-angle X-ray scattering (SAXS) methods. It was shown that the nanohybrid polymeric composites are micro- and mesoporous. The adsorption ability of both polymer/kaolinite and carbonized composites was investigated using such cationic dyes as methylene blue (MB) and rhodamine 6G. There is an increase in adsorption affinity of nanocomposites toward MB. A low adsorption of rhodamine 6G could be explained by steric effects in narrow pores for relatively large molecules. The obtained results show that suggested synthesis method considerably improves the morphology and textural characteristics of nanocomposites. The characteristics of polymer/kaolinite and related carbon/metakaolinite nanocomposites confirm that the developed routes are promising to obtain high-performance adsorbents.