Implication of chromium speciation on disposal of discarded CCA-treated wood
Implication of chromium speciation on disposal of discarded CCA-treated wood
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DOI：
10.1016/j.jhazmat.2005.08.004
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发表时间：
2006-02-06
影响因子：
13.6
通讯作者：
Solo-Gabriele, H
中科院分区：
文献类型：
--
作者：
Song, JK;Dubey, B;Solo-Gabriele, H
木材防腐剂铬酸铜砷酸盐（CCA）含有六价铬[Cr（VI）]，并且Cr（VI）转化为三价铬[Cr（III）]促使处理化学品固定到木材纤维上。由于铬的毒性取决于它的价态，在评估处置的影响时，对经CCA处理的木材以及经CCA处理的木材的沥滤液和灰烬中的铬物种进行评估是有帮助的。在这项研究中，新的和风化的木材样本CCA处理的木材和他们的灰烬进行了评估，总铬和铬（VI）内的固体基质和渗滤液。结果表明，无论是新的和风化CCA处理的木材，Cr（VI）发生在0.7-4%的总铬的范围内。在极端pH值下发生更大的Cr浸出，仅在碱性pH值（pH > 9.0）下测量Cr（VI）。从CCA处理过的木材的合成沉淀浸出程序（SPLP）沥滤液中的总铬浓度始终小于3毫克/升，Cr（VI）低于检测限。结果表明，铬（VI）的浸出从废弃的CCA处理的木材不应该是一个问题，在大多数垃圾填埋场环境。一个例外是用碱性浸出液在垃圾填埋场进行处置;在粉碎混凝土的碱性浸出液存在的情况下，观察到经CCA处理的木材中的Cr（VI）浸出。当CCA处理过的木材燃烧时，铬在灰烬中富集。从CCA处理的木材燃烧的灰分中的Cr（VI）被发现之间的4和7%的总铬。在从建筑和拆除（C&D）碎片（其中包含一些CCA处理的木材）回收的木材燃烧产生的灰烬中，Cr（VI）占总Cr的43%。几乎所有的SPLP渗滤液中产生的灰中的Cr（VI）的形式。从灰中浸出的Cr（VI）的程度高度依赖于灰的碱度，较高的灰浸出液pH值导致更高浓度的Cr（VI）。(c)2005 Elsevier B. V.保留所有权利。
The wood preservative chromated copper arsenate (CCA) contains hexavalent chromium [Cr(VI)] and the conversion of Cr(VI) to trivalent chromium [Cr(III)] drives fixation of the treatment chemicals to the wood fibers. Since the toxicity of Cr depends on its valence state, an assessment of the Cr species occurring in CCA-treated wood, as well as leachates and ashes from CCA-treated wood, is helpful when assessing implications for disposal. In this study, both new and weathered wood samples of CCA-treated wood and their ashes were evaluated for total Cr and Cr(VI) within the solid matrices and within leachates. Results show that for both new and weathered CCA-treated wood, Cr(VI) occurred in the range of 0.7-4% of the total Cr. Greater Cr leaching occurred at the pH extremes, with Cr(VI) only measured under alkaline pH values (pH > 9.0). Total chromium concentrations from synthetic precipitation leaching procedure (SPLP) leachates from CCA-treated wood were consistently less than 3 mg/L with Cr(VI) below detection limits. The results suggest that leaching of Cr(VI) from discarded CCA-treated wood should not be a concern in most landfill environments. One exception would be disposal in landfills with alkaline leachate; Cr(VI) was observed to leach from CCA-treated wood in the presence of alkaline leachate from crushed concrete. When CCA-treated wood is combusted, chromium becomes concentrated in the ash. Cr(VI) in ash from the combustion of CCA-treated wood was found between 4 and 7% of the total chromium. In ash from the combustion of wood recovered from construction and demolition (C&D) debris (which contained some CCA-treated wood), Cr(VI) accounted for as much as 43% of the total Cr. Nearly, all of the Cr in SPLP leachates produced from the ash was in the Cr(VI) form. The degree of Cr(VI) leaching from the ash was highly dependent upon the alkalinity of the ash, with higher ash leachate pH resulting in greater concentrations of Cr(VI). (c) 2005 Elsevier B.V. All rights reserved.