THE MODELING OF REACTIVE SOLUTE TRANSPORT WITH SORPTION TO MOBILE ANDIMMOBILE SORBENTS .1. EXPERIMENTAL-EVIDENCE AND MODEL DEVELOPMENT

Modeling carrier-influenced transport needs to take into account the r eactivity of the carrier itself. This paper presents a mathematical mo del of reactive solute transport with sorption to mobile and immobile sorbents. The mobile sorbent is also considered to be reactive. To jus tify the assumptions and generality of our modeling approach, experime ntal findings are reviewed and analyzed. A transformation of the model in terms of total concentrations of solute and mobile sorbents is pre sented which simplifies the mathematical formulations. Breakthrough da ta on dissolved organic carbon are presented to exemplify the need to take into account the reactivity of the mobile sorbent. Data on hexach lorobiphenyl and cadmium are presented to demonstrate carrier-introduc ed increased mobility, whereas data on anthracene and pyrene are prese nted to demonstrate carrier-introduced reduced mobility. The experimen tal conditions leading to the different findings are pointed out. The sorption processes considered in the model are both equilibrium and no nequilibrium processes, allowing for different sorption sites and nonl inear isotherms and rate functions. Effective isotherms, which describ e the sorption to the immobile sorbent in the presence of a mobile sor bent and rate functions, are introduced and their properties are discu ssed.