Reversible and irreversible retention of heavy metals in saturated porous media: association with kaolin.

Contamination of heavy metals (HMs) has caused increasing concern due to their ecological toxicities and difficulties in degradation. The transport, retention, and release of HMs in porous media are highly related to their environmental fate and risk to groundwater. Column transport experiments and numerical simulations were conducted to investigate the retention and release behaviors of Cu, Pb, Cd, and Zn in the presence and absence of kaolin under varying ionic strengths and cation types.

Dual roles of goethite coating on the transport of plastic nanoparticles in heterogeneous porous media: The significance of collector surface roughness.

This study systematically examines the roles of positive goethite on the retention and release of negative plastic nanoparticles (PSNPs) with different surface functional groups (Blank, -COOH, and -NH). It provides the first evidence for the dual roles of goethite coatings on colloid transport; e.g.