Adsorption study of 4-nitrophenol onto kaolinite (001) surface: A van der Waals density functional study

Using clay materials as adsorbents for removing hazardous materials using adsorption has been gaining interest because of the efficiency, ecology, easy access, and low cost of these aluminosilicate materials. Thus, we investigate the possibility of removing 4-nitrophenol, a material present in industrial wastewater that can cause problems to the environment. The adsorption process on the kaolinite (001) surface is investigated via the density functional theory (DFT) using non-local van der Waals functional. We evaluate the structural and electronic properties of several models in terms of adsorption energy. The energy-most stable energy orientation of 4-nitrophenol on the surface under investigation is achieved when the adsorbate forms conventional and unconventional hydrogen bonds with the adsorbent. We show that the investigated clay has the potential to be used as an adsorbent for the removal of environmentally hazardous systems.