To obtain the basic engineering data such as equilibrium relationship and intraparticle diffusion coefficients for the design of activated carbon treatment plant, adsorption test of Korean activated carbon was performed with phenol, ONP, MNP and PNP. Through this experiment adsorption equilibrium relation was correlated by Frundlich equation and its n values were ranged from 4.0 to 6.8. Also the intraparticle diffusion coefficients were determined from adsorption rate measurement in a stirred tank. The effective diffusion coefficients of phenol and three nitrophenol isomer were in the range of 0.36-1.2×10^-12㎡/s at 293 K and the activation energy for diffusion was evaluated as 7.1-8.3 kcal/mol.