Kinetics and Mechanism of Fixation of Cu-Cr-As Wood Preservatives. Part III. Fixation of Tanalith C and Comparison of Different Preservatives

X-Ray Diffraction as an Analytical Method in Wood Preservatives

“…3C) as well as pure Cu 2 O (Fig. 1 Brought to you by | University of Arizona Authenticated Download Date | 6/3/15 1:10 AM chromium and copper arsenate as reported by Pizzi (1982), and Dahlgren and Hartford (1972). It is hypothesized that cupric copper form, in the presence of water and reducing groups, such as aldehyde groups in wood, can be reduced to cuprous form.…”

“…It is widely reported that hexavalent chromium is reduced to trivalent chromium in CCA treated wood by oxidation reduction reactions between wood components and hexavalent chromium (Dahlgren and Hartford 1972;Pizzi 1982) Copper dimethyldithiocarbamate (CDDC), which forms solid deposit in wood, is extracted from treated wood with an appropriate solvent and analyzed by using colorimetry for the calculation of the CDDC retention. The chromium retention in chromated copper arsenate (CCA) type C treated wood is expressed as hexavalent chromium oxide rather than trivalent chromium oxide.…”

Formation of dioxins and furans during combustion of treated wood

“…Upon contact of the CCA solution with the wood, a series of fixation reactions is initiated. Pizzi [3][4][5][6][7] and Dahlgren [8][9][10] proposed mechanisms describing this process and their work was recently summarised by Humphrey [2] as: (i) adsorption of Cr(VI) (as HCrO 4 À ) onto functional groups in the wood structure; (ii) the slow reduction of Cr(VI) to Cr(III); (iii) complexation of Cu 2+ with lignin and holocellulose; and (vi) formation of precipitates, e.g., CrAsO 4 and Cr(VI) oxides. Other compounds, including CuCrO 4 and Cu 3 (AsO 4 ) 2 , are possible in the final product through the combination of Cr(VI), Cu(II), and As(VI).…”

Formation and Structure of Metal Complexes with the Fungicides Tebuconazole and Propiconazole

“…For example, the fixation of CCA in wood occurs, in part, through the reaction of its individual copper, chromium and arsenic components to form insoluble, amorphous, copper and chromium arsenates as well as other inorganic compounds. [10,11] There is ample evidence in the literature that triazoles will complex with metals, [12 -14] and thus it seems plausible, depending on pH and the nature and ratio of other formulation components, that metal-centered azole complexes are present in copper-azole treatment formulations and in treated wood. This is not only of fundamental interest, but also has practical implications because of suggestions that the formation of metal azole complexes can either enhance [15,16] or reduce [17] the biocidal efficacy of preservative formulations.…”