Activated nutshell carbons from agricultural waste

US6033573A · kind A · utility

Assignee

• The United States of America, as represented by the Secretary of Agriculture · US

Inventors

• Christopher Arend Toles · Escondido, US
• Wayne Marshall · Slidell, US
• Mitchell M. Johns · Metairie, US

Key dates

• Filing date: May 29, 1997
• Grant date: Mar 7, 2000
• Expiry date: May 29, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C02F2101/20
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

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.