  Through Monte Carlo simulations we study two-dimensional Potts models with
$q=4, 6$ and 8 states on Voronoi-Delaunay random lattice. In this study, we
assume that the coupling factor $J$ varies with the distance $r$ between the
first neighbors as $J(r)\propto e^{-a r}$, with $a \geq 0$ . The disordered
system is simulated applying the singler-cluster Monte Carlo update algorithm
and reweigting technique. In this model both second-order and first-order phase
transition are present depending of $q$ values and $a$ parameter. The critical
exponents ratio $\beta/\nu$, $\gamma/\nu$, and $1/\nu$ were calculated for case
where the second-order phase transition are present. In the Potts model with
$q=8$ we also studied the distribution of clusters sizes.
