Abstract
Chromated copper arsenate (CCA) has been the predominant wood preservative used in North America in recent years. The emission of volatile metals and leaching from the combustion ash of CCA-treated wood pose serious concerns. In this work, mineral sorbents were evaluated for their capabilities to control both problems. Results of thermodynamic analyses suggested that alkali and alkaline earth metal-based sorbents can potentially react with the metals during combustion. Experiments were conducted by mixing and burning mineral sorbents including lime and soda ash with CCA-treated wood in a fixed bed. Calcium-based sorbents showed great increase in the retention of arsenic (from 60 to 85%) and chromium (from 55 to 80%) and reduction in the leaching of arsenic (from 200 down to 0.1 mg/L) and copper (from 100 down to 1 mg/L). Sodium-based sorbents successfully retained metals in the ash below 750°C, but the products were highly leachable (over 1000 mg/L). The speciation of the products plays a critical role in...
Published Version
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