Activated carbons, RS-1, RS-2, and RS-3, prepared from rice straw with ( NH4 )2 HPO4 activation were used as adsorbents for removing phenols from aqueous solutions. The maximum adsorption capacities of phenol for RS-1, RS-2, and RS-3 were 163.9, 172.9, and 200.0 mg/g, respectively. The equilibrium data were analyzed by the Langmuir, Freundlich, and Temkin models. It displayed that Langmuir isotherm fitted to the results best. The dimensionless parameter RL indicated the favorable nature of the adsorption of phenol. Otherwise, the kinetic rates were well explained by pseudo-second-order model. According to the results, activated carbon derived from waste rice straw can be a high-performance adsorbent for wastewater treatment. [ABSTRACT FROM AUTHOR]