Temperature-driven migration of heavy metal Pb2+ along with moisture movement in unsaturated soils

Nonlinear coupled heat-moisture-contaminant transport equations are established to analyze the temperature-driven movement of moisture and migration of heavy metal Pb2+ in unsaturated soils. A new soil–water characteristic curve (SWCC) with hysteretic effects is constructed, which can directly give the scanning curve equations starting from any point on the boundary curves without introducing a new equation or new parameters. The theoretical …