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A Novel Extractant for Removal of Hazardous Metals from Preservative‐Treated Wood Waste
Author(s) -
Kakitani Tomo,
Hata Toshimitsu,
Kajimoto Takeshi,
Imamura Yuji
Publication year - 2006
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0318
Subject(s) - chromated copper arsenate , arsenic , chemistry , copper , sodium hydroxide , extraction (chemistry) , preservative , chromium , hazardous waste , pulp and paper industry , oxalic acid , nuclear chemistry , waste management , inorganic chemistry , chromatography , organic chemistry , engineering
The purpose of this study was to develop a one‐step metal extraction process that would effectively remove hazardous elements from wood powder or chips of western hemlock [ Tsuga heterophylla (Raf.) Sarg.] treated with chromated copper arsenate (CCA) preservative. In addition, we tested this method for wood treated with other copper‐based preservatives such as ammoniacal copper quaternary (ACQ) and copper, boron, and azole (CuAz). A bioxalate solution consisting of 0.125 M oxalic acid adjusted to pH 3.2 with sodium hydroxide was tested for its ability to extract chromium, copper, and arsenic from wood treated with CCA and copper from ACQ, CuAz, or a mixture of CCA‐, ACQ‐, and CuAz‐treated wood in single step. The extraction proceeded efficiently with 6 h of treatment, and was insensitive to the differences in chemical characteristics, including solubility of individual elements. After 6 h of treatment, approximately 90% of chromium, copper, and arsenic were effectively removed from wood treated with CCA or a mixture of CCA, ACQ, and CuAz and 90% of copper from ACQ‐ and CuAz‐treated wood. These results demonstrate that the solvent extraction technique using pH‐adjusted bioxalate solution with sodium hydroxide is a promising method for pollution minimization by various types of wastes contaminated with heavy metals and arsenic.