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Growth in industry creates environmental problems. This has been an important subject of debate during recent decades. At present, a consideration or polluting agents and conducting research on them) are among
imp,)rtant issues.
Leakage of water borne preservatives out of impregnated wood, unavoidable in the process of bleaching, contributes to pollution. In order to minimize leaching processes, preservative salts ought to be fixed in wood.
In this study, fixation rates of ACC (Acid Copper Chromate) in oak sap and heartwood were compared at 17,27 and 50.C temperatures. The reqired 6 cm thick specimens were made out of oak.
In order to' get free preservative solution from sample, the sample was squeezed, the resulted extract being
analvzed to d1;termine concentration of active agents such as Cr6+, total Cr and Cu.
Extracting was continued until the concentration of these materials was lowered to a minimum of their
level, which would indicate full fixation (99.98 percent of Cr6+).
The results indicated the positive effect of temperature on rate of fixation. At higher temeratures fixation rate was more considerable. Amount of Cr6+ in extract lowered with higher fixation rate and that was more pronounced in heartwood as compared with the sap. Fixation time at 50.C temperature was 134 hours for
sapwood(6 days) while for heartwood it was 284 hours (12 days).
Lnder conditions of 27 degrees, measured time was 858 hrs (36 days) for sapwood and 1022 hrs (43 days)
for heartwood. Under conditions of 17degrees, rate of fixation was found to be very slow (about 2877 hours or approximately 4 months). Cr fixation reached 99.97% but Cu and Cr were still measurable in extracts.