Previous studies have used the COSMO and SMD continuum solvation models to treat the effect of the solvent on reactions. Even though these types of solvation models have demonstrated considerable reliability in predicting equilibrium solvation energies and transition state (TS)/reaction barrier (RB) for many environmental degradation reactions, they may introduce potential sources of errors when charged ions are involved in the reactions, which is challenging because the water molecules surrounding the ion are strongly polarized. In such cases, the most natural approach is to use full AIMD simulations. However, because AIMD can be computationally expensive, it is often advantageous to use hybrid approaches such as mixed discrete continuum solvation models, QM/MM, and AIMD/MM as alternatives.