  We consider the spin k/2 analogue of the XXZ quantum spin chain. We compute
the entanglement entropy S associated with splitting the infinite chain into
two semi-infinite pieces. In the scaling limit, we find S ~ c_k/6
(ln(xi))+ln(g)+... . Here xi is the correlation length and c_k=3k/(k+2) is the
central charge associated with the sl_2 WZW model at level k. ln(g) is the
boundary entropy of the WZW model. Our result extends previous observations and
suggests that this is a simple and perhaps rather general way both of
extracting the central charge of the ultraviolet CFT associated with the
scaling limit of a solvable lattice model, and of matching lattice and CFT
boundary conditions.
