Farhod Firouzbehi; Davood Efhamisisi; Yahya Hamzeh; asghar tarmian; Reza Oladi
Abstract
Pyrolysis acid or wood vinegar is a dark liquid derived from the condensation of steam and smoke emitted by thermal pyrolysis of wood or any other lignocellulosic material. In this study, a heating furnace was first designed to allow a precise temperature-time program. The wood from three ...
Read More
Pyrolysis acid or wood vinegar is a dark liquid derived from the condensation of steam and smoke emitted by thermal pyrolysis of wood or any other lignocellulosic material. In this study, a heating furnace was first designed to allow a precise temperature-time program. The wood from three different species including oak, citrus and cypress were pyrolyzed under a specific temperature-time schedule. The smoke emitted from the furnace were cooled and condensed in a 20 m pipe using the flow of cold water, and then was dumped in a container as liquid. Pyrolysis was performed at three different temperature ranges of 200, 260 and 330 ° C. The obtained pyrolysis acids had different color and acidity depending on the temperature and species of wood used. Under the heating conditions used in this study, cypress had lower pyrolysis rate than hardwoods. The weight percentage gain of the treated beech and pine wood varied from 5 to 35%, which was depended to the wood species for treatment, the temperature as well as the wood used for pyrolysis. Acid pyrolysis at higher temperatures resulted in higher weight percentage gain. The acid pyrolysis obtained at lower temperature was leached at higher rates from treated wood. Also the wood types used for pyrolysis had significant effect on the amount of lechant from treated woods.
vahid reza Safdari; Milad Nasiri; Hamid Jodi; seid khalil Hosseini hashemi
Abstract
Wood chemical components are among the most important and effective factors in the fixation of water-borne preservatives in the wood. This research investigated the effect of wood extractive on fixation and leaching of “arsenic copper chromate“(ACC) preservative in beech (Fagus orientalis) ...
Read More
Wood chemical components are among the most important and effective factors in the fixation of water-borne preservatives in the wood. This research investigated the effect of wood extractive on fixation and leaching of “arsenic copper chromate“(ACC) preservative in beech (Fagus orientalis) wood blocks. Three groups of wood blocks (control, as wood with extractive, wood pre-extracted with hot water and wood pre-extracted with ethanol acetone) were impregnated with 2% ACC and then were placed in an incubator for 0, 192, 384, 576, and 768 hours at 25 ºC and 75% humidity. After removal from the incubator, the blocks were extracted and the preservative solution of each block was analyzed. The Cr(VI) of the extracted preservative, as the indication of the fixed amount in wood was analyzed using UV spectroscopy and the Cu and Cr contents was measured by atomic absorption. The results showed that the effect of hot water-soluble extractive on fixation and leaching of ACC was significant (P<0.01). The lowest content of unfixed Cu and Cr components was detected from control samples which indicate that the extractive imparts positive effect on fixation. The percentage of unfixed ACC in control samples was significantly lower than in pre-extracted samples.
font�X e9���h��bidi-font-size:11.0pt;font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:"B Lotus"; color:black;mso-bidi-language:FA'>ACC دو درصد (2%) اشباع و در زمانهای صفر، 192، 384، 576 و 768 ساعت در داخل انکوباتور تحت رطوبت 75% و دمای 25 درجه سانتیگراد قرار گرفتند تا در چوب تثبیت شوند. سپس از مواد حفاظتی هر یک از بلوکهای چوبی عصارهگیری و مقدار کروم شش ظرفیتی موجود در عصاره که مبین تثبیت ماده حفاظتی است از طریق دستگاه اسپکتروسکوپی (UV-V) و مقدار عناصر مس و کروم کلی موجود در عصاره که نشانگر مقدار مواد تثبیت نشده در چوب میباشد بهوسیله دستگاه جذب اتمی اندازهگیری شدند. نتایج نشان داد که ماده استخراجی محلول در آب در تثبیت ماده حفاظتی ACCاثرهای مطلوب و معنیداری داشته است. به‌طوری‌که کمترین مقدار مس (Cu) و کروم کلی (Cr) در نمکهای حفاظتی عصارهگیری شده از نمونه چوبهای شاهد (واجد ماده استخراجی) مشاهده شد که مبین تثبیت بهتر مواد حفاظتی در این دسته از بلوکهای چوبی است (P<0.01). همچنین نتایج حاصل از آبشویی نمونه بلوکهای چوبی نشان داد که نمونههای شاهد (دارای ماده استخراجی) پس از آبشویی در مقایسه با نمونههای عاری از مواد استخراجی مقدار نمک کمتری را از دست داده است و تفاوت آنها از این لحاظ معنیدار بوده است (P<0.01).
