不同制备条件对蒙古栎人工林地表可燃物生物炭理化性质的影响

Effects of Different Preparation Conditions on the Physicochemical Properties of Biochar of Quercus mongolica Artificial Forest Surface Fuel

以蒙古栎人工林新鲜地表可燃物为原料,制备生物炭,研究其产率、元素质量分数、碳组分以及化学性质、速效养分、官能团类型。采用单因素方差分析、最小显著差异法(LSD)分析各指标组间差异性,为森林可燃物资源再利用提供新途径。结果表明:生物炭产率、去灰分净产率随温度升高而下降;但灰分质量分数、氢元素质量分数、氧元素质量分数、稳定性碳质量分数、pH则随温度升高而上升;不同炭化时间时,生物炭碳质量分数、不溶性碳质量分数、铵氮质量分数表现出不同的变化趋势。氮质量分数、阳离子交换量、硝氮质量分数、速效磷质量分数随温度升高呈先上升后下降趋势。与原生物质材料相比,生物炭电导率显著降低,但其随温度升高表现出缓慢上升趋势。生物炭表面的O—H基团随温度升高而降低,而C—H、—COO、Si—O—Si基团随温度升高逐渐消失,C—O—C、C=C基团随热解温度升高呈先升高后降低趋势。制备过程中的不同温度、炭化时间均影响蒙古栎新鲜地表可燃物生物炭的理化性质,制备温度、炭化时间对各性质及官能团质量分数的影响不同,制备温度对生物炭理化性质影响较炭化时间更明显。

Biochar was prepared from fresh surface fuel of Quercus mongolica artificial forest,and its yield was studiedas well as element content,carbon content and chemical properties,available nutrients functional group types.One-way ANOVA analysis and LSD difference test were used to test the difference among each index group,which would provide a new way for forest fuel resource reuse.The results showed that the yield of biochar and ash removal yield decreased with the increase in temperature,ash,hydrogen,oxygen,stable carbon content,pH,and vice versa.The content changes of biochar carbon,insoluble carbon and ammonium nitrogen were different due to the retention time.The contents of nitrogen,cation exchange capacity,nitrate and available phosphorus first increased and then decreased with the increase in temperature.Compared with the biomass,the conductivity of biochar decreased significantly,and it showed a slow increase with the increase in temperature.The O—H group on the biochar surface decreased with increasing temperature,while the C—H,—COO,and Si—O—Si groups gradually disappeared with increasing temperature.The C—O—C and C C groups increased first and then decreased with increasing pyrolysis temperature.Different temperatures and carbonization time during the preparation process affected the physical and chemical properties of fuel biochar from the fresh surface of Quercus mongolica.The preparation temperature and carbonization time had different effects on the properties and content of functional groups.