Remediation of CCA-treated wood by chitin and chitosan
S N Kartal, Y Imamura
Chitin and chitosan are naturally abundant biopolymers which are interest of to research concerning the sorption of metal ions since the amine and hydroxyl groups on their chemical structures act as chelation sites for metal ions. This study evaluated the removal of copper, chromium, and arsenic elements from chromated copper arsenate (CCA)-treated wood via biosorption by chitin and chitosan. Exposing CCA-treated sawdust to various amounts of chitin and chitosan for 1, 5, and 10 days enhanced removal of CCA components compared to remediation by deionized water, only. Remediation process with 2.5 g chitin-containing solution for 10 days removed 74% copper, 62% chromium, and 63% arsenic from treated sawdust. Remediation of treated sawdust samples using same amount of chitosan resulted in 57% copper, 43% chromium, and 30% arsenic removal. The results suggest that chitin and chitosan are able to remove copper from CCA-treated wood. Thus, these most abundant natural amino polysaccharides could be important in the remediation of waste wood treated with the newest formulations of organometallic copper compounds and other water-borne wood preservatives containing copper.