The present paper aims to investigate water purification of phenol by walnut green hull adsorbent.The surface characteristics of the adsorbent were studied using Fourier transform infra-red (FTIR), scanning electron microscope, and X-ray diffraction (XRD) techniques. The presence of functional groups such as hydroxyl and carbonyl onto walnut green hull surface was proved by FTIR analysis. . Also, the adsorption kinetics of phenol on the adsorbent were studied. The rates of sorption were found to conform to pseudo-second-order kinetics with good correlation.