热处理对竹炭远红外发射率的影响

竹炭是一种优良的可再生生物质碳材料,具有独特的孔隙结构和吸附性能,常用于制备各种功能复合材料,而竹炭因其优异的远红外反射性能被广泛应用于保暖织物和健康保健等领域。通过元素分析、FT-IR、BET和XRD等表征方法分析了热处理后竹炭的性能特征,并研究了竹炭远红外发射率的影响因素。结果表明:对竹炭进行热处理后,随着温度的上升,竹炭红外发射率呈现先维持相对稳定阶段而后上升的趋势,然后保持在较高值的现象。对竹炭进行表征后发现:当热处理温度低于600℃时,竹炭固定碳等组分相对稳定,其红外发射率保持稳定且无显著变化;在温度600~800℃时,其红外发射率与温度则呈线性正相关;当温度超过800℃时,竹炭红外发射率保持在较高值;比表面积试验表明800℃热处理时比表面积达到最大值,竹炭远红外发射率与其比表面积呈正相关,而与其平均孔径则呈负相关;XRD结果表明竹炭的结晶度会影响其远红外发射率,但关联性较弱。由此可知,竹炭热处理可以提高其远红外发射率,热处理以800℃为宜,远红外发射率性达到0.95,且竹炭远红外发射率主要受其固定碳质量分数影响,此外还受比表面积和孔径的影响。

Effect of heat treatment on bamboo charcoal far-infrared emissivity

Bamboo charcoal is a renewable carbonaceous biomass with unique pore structure and adsorption properties.It is commonly used in the preparation of various functional composites,such as warm-keeping fabrics and health care products due to its excellent far infrared reflection properties.In this paper,the far-infrared emissivity performance of the heat-treated bamboo charcoal was studied.The far infrared(FIR)emissivity of bamboo charcoals(BCs)that were prepared through a heat treatment in advance was investigated systematically.The elemental analysis,Fourier transform infrared spectroscopy(FT-IR),specific surface area test,and X-ray diffraction(XRD)characterizations were respectively conducted to analyze the FIR emissivity properties of heat-treated bamboo charcoals,and the factors’effect on the FIR emissivity of bamboo charcoals were also discussed.The results showed that,with the increase of the heat treatment temperature,the FIR emissivity of bamboo charcoals increased gradually,and then maintained at a relatively high level after a rapid rise.Characterization results of bamboo charcoals also illustrated that the carbon content of bamboo charcoals remained stable with a heat treatment temperature below 600℃.No notable changes were observed for the FIR emissivity of bamboo charcoals and a linear correlation between the FIR emissivity and carbon content was found at a temperature ranged from 600℃to 800℃,in which,the FIR emissivity reached a plateau when the heat treatment continued to above 800℃.BET measurements showed that the specific surface area was maximized for bamboo charcoals when the heat treatment temperature was 800℃.It was demonstrated a positive correlation between the FIR emissivity and specific surface area of bamboo charcoals,while a negative correlation between the FIR emissivity and the average pore size of bamboo charcoals.The XRD patterns suggested that there was a weak correlation between the FIR emissivity and crystallinity of bamboo charcoals.It can be concluded that,the FIR emissivity of bamboo charcoals can be greatly improved with a heat treatment,reaching up to 0.95 at a temperature of 800℃,which was the most versatile for warm-keeping textiles and health-care applications.The FIR emissivity of bamboo charcoals was mainly determined by the carbon content of bamboo charcoals,for that matter,the specific surface area as well as the average pore size also severed as indispensable factors affecting the FIR emissivity of bamboo charcoals.