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以废弃生物质松子壳为原料,利用水热碳化法在180~250℃下制备生物炭,考察添加金属离子(Ca~(2+)、Zn~(2+)、Al~(3+)和Fe~(3+))对松子壳生物炭的影响。通过元素分析、傅里叶红外光谱、扫描电子显微镜等技术对松子壳生物炭的结构进行了分析和表征。结果表明,4种金属离子均对松子壳水热碳化起到促进作用,金属离子的加入可在较低温度下得到具有较高碳含量及热值的生物炭。添加金属离子的水热炭化过程在180~230℃以脱水为主,伴随脱羧反应,在230~250℃以脱甲烷化为主。在4种金属离子中,Fe~(3+)对松子壳水热碳化的促进作用最大,温度180℃时,添加Fe~(3+)所得生物炭的碳含量和热值分别为66.59%和24.40 MJ·kg~(-1),是在纯水中180℃时生物炭的碳含量的1.29倍,热值的1.31倍。在扫描电镜中发现添加Fe~(3+)生成的生物炭出现的球形结构较多。通过调节温度以及添加适合的金属离子可实现对炭微球的粒径及数量的控制。
The biochar was prepared at 180 ~ 250 ℃ by using hydrothermal carbonization method with waste biomass of pine nuts as raw material. The effects of metal ion (Ca 2+, Zn 2+, Al 3+ and Effect of Fe ~ (3 +) on Biochar of Pinus. The structure of the pine shell biochar was analyzed and characterized by elemental analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed that all the four metal ions promoted the hydrothermal carbonation of pine shell, and the addition of metal ions could obtain biochar with higher carbon content and calorific value at lower temperature. The hydrothermal carbonization process of adding metal ions is mainly dehydration at 180 ~ 230 ℃, with the decarboxylation reaction, demethanization mainly occurs at 230 ~ 250 ℃. Of the four metal ions, Fe ~ (3+) played the most important role in promoting the hydrothermal carbonation of pine shell. At 180 ℃, the carbon content and calorific value of biochar obtained by adding Fe ~ (3+) were 66.59% and 24.40 MJ · kg -1, which is 1.29 times carbon content and 1.31 times calorific value of biochar at 180 ℃ in pure water. It was found by scanning electron microscopy that the spherical structure of biochar formed by adding Fe ~ (3+) appeared more. By adjusting the temperature and adding suitable metal ions can be achieved on the carbon microspheres particle size and quantity control.