Removal of CCA from treated wood by oxalic acid extraction, steam explosion, and bacterial fermentation
Removal of CCA from treated wood by oxalic acid extraction, steam explosion, and bacterial fermentation
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DOI：
10.1038/sj.jim.2900516
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发表时间：
1998-03-01
影响因子：
3.4
通讯作者：
Smith, RL
中科院分区：
文献类型：
--
作者：
Clausen, CA;Smith, RL
在美国生产和消费的大多数经过防腐剂处理的木材都是用含有铜、铬和砷的有毒无机化合物处理的。由于铬化砷酸铜（CCA）固定在木材上，经CCA处理的木材不被认为是有毒或危险的，目前它被处理在经批准的垃圾填埋场。公众对处理过的木材污染环境的担忧日益增加，加上大量CCA处理过的木材从服务中被移除，这对这种纤维来源提出了处理挑战。并对铜、铬和砷的去除进行了评估，铜在这些处理中最容易去除，而铬最难以去除。将CCA处理过的木材暴露在地衣芽孢杆菌CC01的持续培养中，当酸萃取先于细菌发酵时，与标准混合培养相比，CCA成分的去除效果并没有提高。蒸汽爆炸，单独或与酸提取和细菌发酵一起，也不能提高CCA成分的去除；铬和砷成分难以去除。将CCA处理过的木屑磨成20目木屑，在所有过程中都能更好地接触和去除CCA成分，然而，如果在细菌发酵之前用酸处理过的木屑，则没有必要进行研磨，用草酸作为细菌发酵的前体，用B，地衣虫CC01从处理过的木屑中去除90%的铜（CuO）， 80%的铬（CrO3）和100%的砷（As2O5）。酸萃取和细菌发酵的结合将这些金属从cca处理过的木材中去除80-100%。
Most preservative-treated wood produced and consumed in the United States is treated with toxic inorganic compounds containing copper, chromium, and arsenic. Because chromated copper arsenate (CCA) is fixed to the wood, CCA-treated wood has not been considered toxic or hazardous and it is currently disposed of in approved landfills, Growing public concern about environmental contamination from treated wood combined with the removal of greater quantities of CCA-treated wood from service have presented a disposal challenge for this fiber source, In this study, CCA-treated wood was processed by acid extraction, steam explosion, and bacterial fermentation and evaluated for removal of copper, chromium, and arsenic, Copper was the easiest to remove by these treatments and chromium the most resistant to removal, Exposing CCA-treated wood to steady-state bacterial growth by continuous culture with Bacillus licheniformis CC01 did not enhance removal of CCA components compared to standard mixed culture when acid extraction preceded bacterial fermentation. Nor did steam explosion, alone or in conjunction with acid extraction and bacterial fermentation, enhance removal of CCA components; the chromium and arsenic components resisted removal. Grinding CCA-treated wood chips into 20-mesh sawdust provided greater access to and removal of CCA components by all processes, However, grinding the chips was unnecessary if they were treated with acid prior to bacterial fermentation, Extraction with oxalic acid as a precursor to bacterial fermentation with B, licheniformis CC01 removed 90% copper (CuO), 80% chromium (CrO3), and 100% arsenic (As2O5) from treated chips. The combination of acid extraction and bacterial fermentation removed 80-100% of these metals from CCA-treated wood.