WOOD RESEARCH Volume 71, Number 3, 2026
SAIP NAMI KARTAL, EKİM ELÇİN SOYTÜRK, YUKO ITO, and WAKAKO OHMURA

Preliminary Evaluation of Copper Leaching from Commercially Available Wood Species in Japan Treated with Copper Azole Wood Preservative

This study examined copper fixation and leaching in wood treated with copper azole (CuAz) and copper sulfate (CuSO₄), emphasizing the effects of wood species and post-treatment conditions. Five Japanese softwoods, including Sugi, Hinoki, and Douglas fir, were assessed under three conditions: unfixed, ambient-fixed, and heat-treated (60°C for 3 days). Copper fixation was defined as the proportion of non-leachable copper remaining after standardized leaching, with release rates measured via leachate analysis. Results showed that post-treatment condition is the dominant factor controlling copper stabilization. Heat treatment significantly enhanced fixation and reduced leaching across all species and preservative types, indicating improved bonding between copper ions and wood components. Ambient fixation was often insufficient. Sugi sapwood showed the highest leaching, while Hinoki heartwood exhibited the greatest retention. Overall, CuAz outperformed CuSO₄, underscoring the importance of formulation in improving copper stability and durability.

WOOD RESEARCH Volume 63, Number 5, 2018
Mehmet Yeniocak and Suleyman Kahveci

Investigation leaching performance of wood materials coated with cotinus coggygria extracts and liquid glass (SiO2) mixture

The purpose of this study was to develop durable natural colorant modified with liquid glass (SiO2) to be used on wooden materials and determine their desorption performance using the leaching method. For this purpose, the natural colorant was extracted from the smoke tree (Cotinus coggygria) performing boiling method. Then, mordants; oak ash (3% by weight), and vinegar (10% by weight) (CH3COOH) were added to mixture. As the last, liquid glass (20% by weight) were added to mixture. The obtained mixture was applied to the Scots pine (Pinus sylvestris L.) and beech (Fagus orientalis) wood samples by using classic dipping and vacuum method. Leaching test was performed at pH3-22°C, at pH7-10°C, 22°C, 40°C and at pH 11-22°C. The results showed that the liquid glass did not protect wood materials in leaching as planned. The effective results can be obtained by changing the application method and amount of the liquid glass. The nature-based colorants can be an eco-friendly alternative to synthetics.

WOOD RESEARCH Volume 63, Number 3, 2018
Mehmet Yeniocak, Osman Goktas, Ertan Ozen, Mehmet Colak, and Mehmet Ugurlu

Determination of leaching features of wood surfaces colored by eco-friendly red beetroot (Beta vulgaris) extract

The aim of this study to develop an eco-friendly wood stain and to determine the adsorption and desorption on surfaces. In this context; plant dyestuff was extracted from the red beetroot by using ultrasonic assisted method and applied to wood blocks of Turkish oriental beech, Scots pine, oak, and walnut with immersion (classic) and ultrasonic-assisted immersion methods. As mordants, ferrous sulphate, aluminum sulphate, copper sulphate, and vinegar were chosen. In the study, the effect of such parameters as the medium pH (3, 7 and 9), temperature (22°C and 40°C), velocity of agitation (10 and 30 rpm) in leaching was investigated. As a result of experiments; red beetroot extracts performed good desorption, vinegar and copper sulphate were reduced the best desorption on surfaces. Ultrasonic-assisted method was not affect the leaching performance positively, but general leaching results showed that red beetroot can be used for wood surface stain and they can be alternative to chemical dyes.