Abstract: Activated carbons derived from low-density lignocellulosic agricultural waste, and for use in absorption of metals, are prepared utilizing carbon dioxide or steam activation at 800° C. to 950° C. for 3 to 12 hours and subsequent oxidation with air at 260° C. to 400° C. for 3 to 6 hours. Granular carbons are formed by the inclusion of a preliminary two-step process involving the admixture of a binder selected from molasses, coal tar or wood tar to form pellets, briquettes or extrudates and converting them into a char under an inert atmosphere at 700° C. to 750° C. for 1 to 2 hours.

Abstract: Activated carbons derived from nutshells, and for use in adsorption of metallic cations, are prepared utilizing phosphoric acid activation with concurrent oxidation under air. The acid activation is carried out utilizing a one or two-step heating regime subsequent to the infusion of the phosphoric acid into the nutshell material during which concurrent oxidation is achieved by exposure to atmospheric oxygen. Further oxidation is optionally achieved by equilibration of the nutshell carbons to room temperature under air. Prior to utilization, a washing step is employed to remove unwanted acid from the carbon product.