鉻化砷酸銅防腐劑之注入與流失（Ⅰ）－柳杉材中CCA各成分之注入比與流失性

Retention and Leachability of CCA (Ⅰ)－Retention and Leachability of CCA Components in Specimens of ＂Japanese Cedar＂

林亞立(Ya-Lih Lin)

《林產工業》 14卷2期 (1995/06) Pp. 58-70

https://doi.org/10.6561/FPI.1995.14(2).4

摘要

本試驗利用柳杉試材，探討鉻化砷酸銅（CCA）處理材及處理液中CCA各成分比例之差異，並對由處理前後木材重量差做為推算CCA注入量的方法加以討論。另利用經CCA Type B處理之試材進行28天的模擬流失試驗，以了解CCA各成分在試材中之固著性、移動性與流失性。結果顯示，以處理前後重量差所推估之CCA注入量與實際測得者成正比，然而後者較前者平均約高出60%，表示CCA對木材可能具有主動吸附的能力。處理試材中CCA各成分比與處理液中之比並不相同。各類型CCA處理材與處理溶液比較，試材中含CrO_3之比例較處理液中者高，CuO較低，As_2O_5則依CCA種類不同而異，Type A或C處理時，試材中有較低的比例，Type B處理時，試材中As_2O_5的含量比例較處理液中者高。試材中CCA Type B 的流失主要發生在流失試驗的前14天（17.4%, 1.24%/天）；後14天流失較少（2.6%, 0.19%/天）。依此推測，大約有18%的CCA並未固著於試材中。經28天的流失，試材中CCA的各成分的流失百分比依序為As_2O_5 (26.3%), CuO (17.6%)及CrO_3 (12.5%)，顯示CrO_3的固著性最佳，CuO次之，As_2O_5最差。各成分的流失速率皆為前14天較快，後14天較慢。試材中CCA各成分於流失過程皆有移動的現象，其中以CuO最明顯，As_2O_5次之，CrO_3最不明顯。

關鍵字

鉻化砷酸銅 ； 成分比 ； 流失性

並列摘要

Specimens of ＂Cryptomeria japonica＂ treated with different types of chromated copper aresnate (CCA) preservative were prepared and analyzed for the retention of each CCA component to understand the adsorption of Cu, Cr and As in the treated samples. The CCA retention estimated by the traditional weight diffenence of the specimen before and after treatment was compared with the retention calculated by the concentration of Cu, Cr and As in the specimen measured by X-Ray Fluorescsnce (XRF) to clarify the validity of the traditional retention estimating mathod. Also, a 28-day leaching test was conducted to understand the leaching profile of each CCA component along with leaching time. Results indicate a positive relationship between retentions estimated by weight difference and calculated by the concentration of Cu, Cr and As measured. However, the CCA retention calculated from XRF measurement was 60% higher than the retention estimated by weight difference before and after treatment, which indicates the possibility of active adsorption of CCA components to the wood specimen. The proportion of CCA components retented in the treated specimen was different from the proportion of components of the treating solution. Proportion of CrO_3 in the treated specimen was higher than the proportion of CrO_3 of the treating solution, while in the case of CuO was the opposite of the situation of CrO_3. The difference of As_2O_5 between the treated specimen and the treating solution varied with types of CCA used. Specimens treated with CCA type A or C obtained an As_2O_5 proportion lower than that is in the treating solution, while treated with CCA type B the proportion of As_2O_5 in the specimen was higher than the proportion in the treating solution. After 28 days of leaching, the CCA type B treated specimen lost 26.3% of As_2O_5, 17.6% of CuO and 12.5% of CrO_3 which indicates that CrO_3 has the best fixation efficiency to wood than the other two components and As_2O_5 is the worst of the three. The leaching rate of CCA type B as a whole was higher the in the first 14 days (17.4 %, 1.24%/ day) and lower in the next 14 days (2.6%, 0.19%/day), which leads to an estimated CCA fixation rate of 82%. Movements of CCA components in the specimen during leaching period was also noticed.

並列關鍵字

CCA ； proportion of CCA components ； leachability