This paper presents a one-dimensional simulation model which aims to trace the concentration profile observed by two laboratory columns, filled with soil and biochar, crossed by a solution contaminated with Lead. The laboratory columns are characterized by an alternation of layers, the first of sand and soil and the second of sand, biochar, and soil. Soil is considered the target of contamination. The experimental investigations made it possible to verify that the soil layer induces a delay in the transport process which is further amplified by the presence of the biochar which therefore acts by immobilizing the contaminated solution at least partially. The simulation model was built starting from the transport equation in which the delay factor was simulated with first-order kinetics for the action of the soil and with pseudo-second-order kinetics for the biochar. In the latter case, the kinetics were experimentally determined with appropriate batch tests; the constant characteristics determined experimentally were used within the simulation model. The results of the model satisfactorily simulate the experimental results; the model could therefore usefully simulate different operating conditions and be a useful tool for remediation activities.