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以木薯茎秆为生物质原料,利用无轴螺旋连续热解装置制备木薯茎秆炭,针对原料及热解炭的组织结构、酸碱性质、表面官能团属性和表面形貌特征进行特性分析;开展木薯茎秆炭吸附溶液中亚甲基蓝、碘、苯酚和醋酸的试验,研究热解温度、粒径、振荡时间、表面清洗4个因素对炭吸附特性的影响。结果表明:随着热解温度的升高,木薯茎秆炭中挥发分含量减小,灰分及固定碳含量增大;表面逐渐形成芳香化结构,酸性官能团减少,p H值逐渐增大,碱性增强;原料表面结构不断被破坏,部分区域塌陷出现凹凸不平的表面形态。热解温度对木薯茎秆炭的吸附特性影响较大,低温热解炭的亚甲基蓝、碘和苯酚吸附值较大,高温热解炭吸附值减小,醋酸吸附值变化趋势与前三者相反。炭的粒径越小,对4种物质的吸附效果越好;振荡时间对木薯茎秆炭的吸附特性有显著影响,苯酚吸附的最佳振荡时长为60 min,醋酸为30 min。醇-水表面清洗后的木薯茎秆炭p H值减小,虽然亚甲基蓝吸附值基本不变,但碘、苯酚和醋酸吸附值增大,吸附效果改善。
Using cassava stalks as raw material of biomass, the tapioca stalk charcoal was prepared by a non-axial spiral pyrolysis unit, and its structure, acid-base properties, surface functional group properties and surface topography were analyzed according to the characteristics of the raw materials and pyrolytic carbon. The experiments of the adsorption of methylene blue, iodine, phenol and acetic acid in cassava stalk charcoal were carried out. The effects of pyrolysis temperature, particle size, shaking time and surface cleaning on the adsorption characteristics of carbon were studied. The results showed that with the increase of pyrolysis temperature, the content of volatile components decreased and the content of ash and fixed carbon increased. The aromatization structure gradually formed on the surface, the number of acidic functional groups decreased and the value of p H gradually increased. Sexual enhancement; continuous destruction of the surface structure of raw materials, partial area collapse appeared rugged surface morphology. The pyrolysis temperature had a great influence on the adsorption characteristics of cassava stalk carbon. The adsorption values of methylene blue, iodine and phenol were the highest in low temperature pyrolysis coal, while those in pyrolysis carbon decreased. The smaller the particle size of charcoal, the better the adsorption effect on the four substances. The oscillation time had a significant effect on the adsorption characteristics of charcoal stalk charcoal. The optimal oscillation time of phenol adsorption was 60 min and acetic acid was 30 min. The p H value of cassava stalk charcoal after alcohol-water surface cleaning decreased. Although the adsorption value of methylene blue remained unchanged, the adsorption values of iodine, phenol and acetic acid increased, and the adsorption efficiency improved.