Phosphoric acid activation of nutshells for metals and organic remediation: Process optimization
✍ Scribed by Christopher A. Toles; Wayne E. Marshall; Mitchell M. Johns
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1998
- Tongue
- English
- Weight
- 326 KB
- Volume
- 72
- Category
- Article
- ISSN
- 0268-2575
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✦ Synopsis
Almond, pecan, English walnut, black walnut and macadamia nut shells were chosen as hard, lignocellulosic precursors for the production of granular activated carbons (GACs). They were activated with under a H 3 PO 4 variety of conditions. Following activation, a portion of each GACs was oxidized in air at 300¡C for 4 h in order to create a carbon surface presumably with more oxygen functional groups for the adsorption of metal cations. Also investigated was a streamlining of the production techniques used. Several of the samples were subjected to a "ContinuousÏ process in which the carbon was activated and upon cooling to 300¡C was oxidized with air. Beyond this activation, methods were developed wherein the activation process took place under air and without a discrete, separate oxidation step. These processes were designed to determine if any of the carbonÏs capabilities would be lost or enhanced in comparison to the more standard activateÈcoolÈwashÈoxidize method. The carbons produced from these various activation/oxidation methods consistently, and without regard to precursor composition, sequestered over 90% of available copper from a 3 mM copper chloride test solution and often adsorbed organic contaminants as e †ectively as some commercial carbons.
1998 SCI (