Kartal S Nami
Department of Forest Biology and Wood Protection Technology, Forestry Faculty, Istanbul University, Bahcekoy 80895, Istanbul, Turkey.
Waste Manag. 2003;23(6):537-46. doi: 10.1016/s0956-053x(02)00143-5.
Ethylenediaminetetracetic acid (EDTA) is one of the most common chelators used to bind the metal ions in extremely stable complexes in heavy metal contaminated soils and thus to remediate such substrates. EDTA forms water soluble complexes with many metal ions and it is used to release the various metals. In this study, EDTA extraction of copper, chromium, and arsenic from chromated copper arsenate (CCA-C) treated wood was evaluated using batch leaching experiments. CCA-treated wood samples were extracted with eight different concentrations of EDTA for 4, 8, 18, and 24 h at room temperature. Exposing CCA-treated chips and sawdust to EDTA extraction enhanced removal of CCA components compared with extraction by deionized water. Grinding CCA-treated wood chips into 40-mesh sawdust provided greater access to and removal of CCA components. Extraction with 1% EDTA solution for 24 h removed 60% copper, 13% chromium, and 25% arsenic from treated chips. EDTA extraction of treated sawdust samples resulted in 93% copper, 36% chromium, and 38% arsenic removal. CCA leaching from treated wood blocks was also evaluated according to modified AWPA E11-99 standard test method of determining the leachability of wood preservatives. Leaching of CCA components from treated wood blocks with 1% EDTA solution for 14 days caused more copper leaching compared to leaching with deionized water. Leaching with 1% EDTA for 14 days removed 53% copper from the blocks whereas 14% copper was leached from the blocks with deionized water. The results suggest that EDTA extraction removes significant quantities of copper from CCA-treated wood. Thus, EDTA could be important in the remediation of wood waste treated with the newest formulations of organometalic copper compounds and other water-borne wood preservatives containing copper.
乙二胺四乙酸（EDTA）是最常见的螯合剂之一，用于在重金属污染土壤中与金属离子结合形成极其稳定的络合物，从而修复此类基质。EDTA与许多金属离子形成水溶性络合物，并用于释放各种金属。在本研究中，通过批量浸出实验评估了从铬酸铜砷酸盐（CCA-C）处理过的木材中提取铜、铬和砷的EDTA方法。用八种不同浓度的EDTA在室温下对CCA处理过的木材样品进行4、8、18和24小时的提取。与用去离子水提取相比，将CCA处理过的木屑和锯末暴露于EDTA提取中可增强CCA成分的去除。将CCA处理过的木屑磨成40目锯末可更便于接触和去除CCA成分。用1%EDTA溶液提取24小时可从处理过的木屑中去除60%的铜、13%的铬和25%的砷。对处理过的锯末样品进行EDTA提取可去除93%的铜、36%的铬和38%的砷。还根据测定木材防腐剂可浸出性的改良AWPA E11-99标准测试方法评估了从处理过的木块中沥出CCA的情况。与用去离子水浸出相比，用1%EDTA溶液对处理过的木块进行14天的浸出会导致更多的铜被浸出。用1%EDTA浸出14天可从木块中去除53%的铜，而用去离子水浸出时，木块中有14%的铜被浸出。结果表明，EDTA提取可从CCA处理过的木材中去除大量铜。因此，EDTA对于修复用最新配方的有机金属铜化合物和其他含铜水性木材防腐剂处理过的木材废料可能很重要。
