Natural soil mineral nanoparticles are novel sorbents for pentachlorophenol and phenanthrene removal

Natural soil montmorillonite and kaolinite nanoparticles (NPs) were tested as efficient sorbents for organic contaminant (OC) removal through mimicking their natural environmental dispersive states. Sorption of both mineral NPs decreased with increasing pH with ionizable pentachlorophenol (PCP), but increased with pH with non-ionizable phenanthrene (PHE), within the pH range of 4-10. In contrast, sorption decreased consistently for both PCP and PHE, as a function of increasing ion concentration (0.001-0.1 mol L−1). Sorption differences were likely caused by the electrolytic conditions dependent upon surface chemistry of OCs and mineral NPs. The results confirmed that the highly dispersive soil mineral NPs would prevail over both engineered NPs and their regular μm-sized colloids for OC removal, due to their ecological advantages and higher sorption properties. This finding provided a realistic assessment of the environmental function of soil natural minerals in water once they are released from soil into OC polluted aqueous systems.