澳洲坚果壳生物活性炭的活化调控及其吸波性能

以澳洲坚果壳作为碳源,采用高温碳化技术制备澳洲坚果壳生物活性炭材料,研究了磷酸、氢氧化钾、氯化锌作为活化剂对澳洲坚果壳生物活性炭材料微观形貌和吸波性能的影响。结果表明：活化剂对澳洲坚果壳生物炭造孔效果明显,可获得丰富的孔隙结构;与未活化的澳洲坚果壳生物炭相比,活化方式调控的澳洲坚果壳生物活性炭吸波性能得到了改善,氯化锌活化的澳洲坚果壳生物活性炭反射损耗达-16 dB;氢氧化钾活化的澳洲坚果壳生物活性炭反射损耗达-26 dB,通过调节厚度,有效吸收带宽最高可以覆盖14 GHz。澳洲坚果壳生物活性炭良好的吸波性能归因于活化造孔产生的多孔结构,多孔结构进一步促进传导损耗、界面极化、多重散射等对电磁波进行衰减。经分析讨论进一步确定了不同活化方式调控澳洲坚果壳生物炭吸波性能强弱的顺序为MNAC-K（氢氧化钾活化）> MNAC-Zn（氯化锌活化）> MNAC-H（磷酸活化）> MNC（未活化）。

Activation Regulation of Activated Carbon from Macadamia Nut Shell Biomass and Its Microwave Absorbing Properties

High-temperature carbonization technology was used to prepare Macadamia nut shell biomass activated carbon (MNAC) materials. The effects of phosphoric acid, potassium hydroxide and zinc chloride as activators on the microscopic morphology and microwave absorbing properties of MNAC materials were studied. The activators had obvious pore-forming effect on the Macadamia nut shell biochar (MNC) and could facilitate the formation of pore-rich structure. Compared with MNC, the microwave absorption performance of the activated was improved. Specifically, the reflection loss of the biocarbon was activated by zinc chloride reaches -16 dB. The reflection loss of the biocarbon activated by potassium hydroxide was up to -26 dB, and the effective absorption bandwidth could cover 14 GHz by adjusting the thickness. The good absorbing performance of MNAC could be attributed to the porous structure resulted by the activation process. The porous structure further promoted the attenuation of electromagnetic waves, such as conduction loss, interface polarization, and multiple scattering. The order of the MNC microwave absorbing properties regulated by different activators was finally determined as: MNAC-K (KOH activation) > MNAC-Zn (ZnCl₂ activation) > MNAC-H (H₃PO₄ activation) > MNC (no activation).