We envisage a new process that combines the utilities of H3PO4 and KOH, avoids the high ash content arising from H3PO4 activation and the low yield resulting from KOH activation.This work has explored the possibility of using such an activated carbon for adsorption of RhB from aqueous solution. The influences of initial RhB concentration, temperature and pH on the adsorption capacity were examined. The adsorption kinetics, isotherms models and thermodynamics parameters were investigated.