Chinese fir (Cunninghamia lanceolata Hook.) wood cubes (19 × 19 × 19 mm3)
were treated with amine copper quat-type D (ACQ-D) solution and fixed with different hot air post-treatments.
The effects of temperature, relative humidity, duration, air circulation of post-treatment as well as
the copper retention in the treated wood on copper leaching were investigated. With the help of ultraviolet
or visible spectroscopy (UV/VIS), the valence conversion of copper in treated wood post-treated with
optimal post-treatment conditions was investigated, and its relation with copper leaching was also discussed.
The results showed that besides temperature and relative humidity, air circulation during hot air post-treatments
also had a significant effect on accelerating copper fixation in ACQ-D treated wood. 70 °C,
80% R.H. with good air circulation provided a suitable condition for complete fixation of copper
in a short period. After the applied post-treatments, up to 11.3% cupric copper reduced to cuprous
form. A higher copper conversion rate usually corresponds to lower copper leaching, which is consistent
with the contribution of lower water solubility cuprous copper.
