不同原料来源及热解温度下林业废弃物生物炭理化性质差异研究

Study on the Physical and Chemical Properties of Forestry-waste Biochar under Different Raw Material Sources and Pyrolysis Temperature

林业废弃物因其具有环境友好、分布广泛等特点,被视为理想的生物炭制备原料。为实现林业废弃物的多级利用,充分发挥其可再生特点,分别以银中杨树叶、樟子松树叶、银中杨树枝以及樟子松树枝为原材料,于300,500,700℃厌氧条件下制备生物炭,并利用扫描电镜(SEM)、X射线多晶衍射仪(XRD)和X射线光电子能谱仪(XPS)等对生物炭进行表征,从而探究不同原料来源及热解温度对林业废弃物生物炭理化性质的影响,同时为林业废弃物高值化利用提供一定的参考。结果表明:生物炭的pH值均为碱性。随着热解温度升高,4种生物炭的变化规律一致,均为平均孔径减小、比表面积和总孔体积增大。生物炭表面的酸性含氧官能团(-OH、C-OOH、O=C-O及-COOR)的总量也随热解温度的升高而减少,生物炭芳香程度增加,极性和亲水性降低。叶类生物炭具有较高的灰分含量和CaCO_(3)含量;而枝类生物炭具有更高的芳香程度、疏水性以及较弱的极性。银中杨生物炭表面具有丰富的C-C,比樟子松生物炭的芳香程度高。因此,原料来源及热解温度对林业废弃物生物炭理化性质具有显著影响。

Forestry-waste is regarded as an ideal raw material for biochar preparation because of its environmentally friendly characteristics and wide distribution.In order to realize the multistage utilization of forestry-waste,give full play to its renewable characteristics.In this study,the biochar was prepared from Populus alba×P.berolinensis leaves,Pinus sylvestris var.mongolica leaves,Populus alba×P.berolinensis branches,and Pinus sylvestris var.mongolica.branches under anaerobic conditions at 300,500 and 700℃.And then using SEM,XRD and XPS to explore the influence of different raw material sources and pyrolysis temperature on the properties of forestry-waste biochar,and provide a reference for the highvalue utilization of forestry-waste.The results show that the pH of biochar is alkaline.With the increase of pyrolysis temperature,the four kinds of biochar have the same pattern of change,all of which are the decrease of average pore size,the increase of specific surface area and total pore volume.The total amount of acidic oxygen-containing functional groups(-OH,C-OOH,O=C-O and-COOR)on the surface of biochar also decreases with the increase of pyrolysis temperature,and the biochar becomes more aromatic and less polar and hydrophilic.Leaf biochar has higher ash content and CaCO_(3) content;while branch biochar has higher aromatic degree,hydrophobicity and weaker polarity.The surface of biochar from Populus alba×P.berolinensis has abundant C-C,which is more aromatic than the biochar from Pinus sylvestris var.mongolica.Therefore,the raw material source and pyrolysis temperature have significant impacts on the physical and chemical properties of forestry-waste biochar.