What happens to iron(III) sulfate (ferric sulfate) in aqueous solution?
In aqueous solution $\ce{Fe2(SO4)3}$ dissociates into $\ce{Fe^{3+} (aq)}$ and $\ce{SO4^{2-} (aq)}$ ions. The sulphate ions will be solvated by hydrogen bonding with the water and the iron ions will form the hexaaquairon(III) complex, $\ce{[Fe(H2O)6]^{3+}}$.

As @Mithoron mentioned, the $\ce{Fe^{3+}}$ ions cannot easily be further oxidised so no additional reaction takes place.