Advances in Modelling the Non-Isothermal Behaviour of Multicomponent Chemicals in Unsaturated Soils

The paper presents new developments to an existing model for thermal, hydraulic and chemical (THC) behaviour of unsaturated soils. The primary focus is to address the advancement in the formulation of multicomponent chemical transport due to electrochemical potential resulting from different diffusion coefficients of ions in pore water. The developments provide a non-isothermal transport model for multicomponent chemicals which incorporates an explicit form of thermal diffusion process combined with electrochemical diffusion potential effects. In addition, the chemical transport module is enhanced via coupling geochemical reactions by linking an advanced geochemical model (PHREEQC version 2).