Kakitani Tomo, Hata Toshimitsu, Kajimoto Takeshi, Koyanaka Hideki, Imamura Yuji
Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Uji, Kyoto, Japan.
J Environ Manage. 2009 Apr;90(5):1918-23. doi: 10.1016/j.jenvman.2009.01.005. Epub 2009 Feb 8.
The disposal of wood waste treated with chromated copper arsenate (CCA) is a problem in many countries. We have proposed a novel chelating extraction technique for CCA-treated wood using bioxalate, a solution of oxalic acid containing sufficient sodium hydroxide to adjust the pH to 3.2, which is an effective way to obtain an extraction efficiency of 90% for chromium, copper, and arsenic. The purpose of the present study was to investigate the characteristics of bioxalate extraction of CCA-treated wood. Extractions of CCA-treated western hemlock chips with solutions of bioxalate, oxalic acid, and sodium hydroxide were carried out. The use of bioxalate was confirmed as the most effective extraction technique for chromium, copper and arsenic, with an efficiency of 90%. Extraction with simple oxalic acid was ineffective for copper (less than 40% extraction efficiency), but effective for chromium and arsenic, with 90% efficiency. Sodium hydroxide showed a similar tendency, being ineffective for chromium and copper (less than 20% extraction efficiency), but relatively effective for arsenic (around 70-80% efficiency). We also discovered an interesting phenomenon whereby the addition of sodium hydroxide to a simple oxalic acid solution during the oxalic acid extraction progress resulted in dramatically increased extraction efficiency for copper, chromium and arsenic, up to 90%. Although oxalic acid was ineffective for copper extraction, the addition of sodium hydroxide during the oxalic acid extraction process rendered it effective.
在许多国家，处理经铬酸铜砷酸盐（CCA）处理过的木材废料都是一个难题。我们提出了一种使用生物草酸盐从经CCA处理的木材中进行螯合萃取的新技术，生物草酸盐是一种含有足够氢氧化钠以将pH值调节至3.2的草酸溶液，这是一种有效获得90%的铬、铜和砷萃取效率的方法。本研究的目的是探究经CCA处理的木材的生物草酸盐萃取特性。用生物草酸盐、草酸和氢氧化钠溶液对经CCA处理的西部铁杉木屑进行了萃取。结果证实，使用生物草酸盐是萃取铬、铜和砷最有效的技术，萃取效率达90%。用单纯草酸萃取对铜无效（萃取效率低于40%），但对铬和砷有效，萃取效率为90%。氢氧化钠呈现出类似趋势，对铬和铜无效（萃取效率低于20%），但对砷相对有效（效率约为70 - 80%）。我们还发现了一个有趣的现象，即在草酸萃取过程中向单纯草酸溶液中添加氢氧化钠会使铜、铬和砷的萃取效率大幅提高，高达90%。尽管草酸对铜萃取无效，但在草酸萃取过程中添加氢氧化钠使其变得有效。
