Activated carbons from low-density agricultural waste

US6537947B1 · kind B1 · utility

Assignees

• The United States of America, as represented by the Secretary of Agriculture · US
• The Board of Supervisors of Louisiana State Univ. and Agricultural and Mechanical College · US

Inventors

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

Key dates

• Filing date: Apr 11, 1997
• Grant date: Mar 25, 2003
• Expiry date: May 22, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B32/336
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

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.