玉米秸秆生物质炭基肥的结构与性质表征

Structure and Performance Characterization of Maize Straw Biochar-Based Fertilizer

为了解玉米秸秆生物质炭基肥的结构与性质,通过实验室自制玉米秸秆生物质炭基化肥,研究生物质炭添加量对炭基肥的形貌特征、pH、表面官能团种类和元素组分的影响。结果表明:玉米秸秆生物质炭具有丰富的孔隙结构,化学肥料添加量越大,结构表面无序化程度越高;总孔容和平均孔径的变异范围分别为2.1~3.3cm^3/kg和2.7~3.2 nm,平均为2.8 cm^3/kg和2.9 nm。生物质炭化后,C-O-C、-COOH、-CH3,-CH2消失,化学肥料并不影响生物质炭缓释载体原有的分子结构,只是影响其元素含量。与未加化肥的生物质炭对照相比,炭基肥中C、H元素含量降低,而 N、O 元素含量升高,变幅分别为 47.7%~ 68.4%,20.2%~ 28.2%,59.5%~ 82.6%和 164.0%~ 228.8%,平均为 59.4%、24.1%、71.9%和196.5%;而元素组分的H/C、O/C和(N + O)/C都有所增大。总之,化学肥料存在于生物质炭表面和孔隙之中,其添加并未改变生物质炭的骨架结构和官能团种类,而元素组分含量和原子比(H/C、O/C和(N + O)/C)的改变将可能更有利于增强生物质炭基肥的保水与吸附性能。

In order to investigate the characteristics and structure of maize straw biochar-based fertilizer, this study self-prepared maize straw biochar-based fertilizer, and further identified the effects of biochar addition on appearance features, surface functional groups and compositions of biochar-based fertilizers. The results showed that there was an abundant pore volume, and the disorder surface was increased with increased amount of chemical fertilizer added. The total pore volume and average pore size were ranged in the range of 2.1-3.3 cm^3/kg and 2.7-3.2 mm, and 2.8 cm^3/kg and 2.9 nm, respectively. The C-O-C,-COOH,-CH3 and -CH2 were disappeared after the biomass was carbonized, which implied that the chemical fertilizer only affected the elemental composition but didn't affect its original molecular structure of biochar. Compared with biochar, the biochar-based fertilizer had lower C and H contents and higher contents of N and O, which were in the range of 47.7%-68.4%, 20.2%-28.2%, 59.5%-82.6% and 164.0%-228.8%, respectively. For element components, there's an increase trend for H/C, O/C and (N+O)/C of biochar-based fertilizer. In conclude, chemical fertilizer has been adsorbed onto the pores of biochar without changing the framework, structure and functional group contents of biochar, however, the changes in element components can increase the water retention and adsorption capability of biochar-based fertilizer.