State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, Yunnan 650093, China; Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093, China; Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, Yunnan 650093, China; National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming, Yunnan 650093, China.
State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, Yunnan 650093, China; Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, Yunnan 650093, China; National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming, Yunnan 650093, China; Faculty of Chemistry and Environment, Yunnan Minzu University, Kunming, Yunnan 650093, China.
J Hazard Mater. 2017 May 15;330:36-45. doi: 10.1016/j.jhazmat.2017.02.010. Epub 2017 Feb 7.
Dielectric properties of spent adsorbent with zinc sulfate are investigated by cavity perturbation technique at 2450MHz from 20°C to approximately 1000°C. Two weight loss stages are observed for spent adsorbent by thermogravimetric-differential scanning calorimeter (TG-DSC) analysis, and zinc sulfate is decomposed to ZnO·2ZnSO and ZnO at about 750°C and 860°C. Microwave absorption capability of ZnSO increases with increasing temperature and declines after ZnO generation on account of the poor dielectric properties. Dielectric properties of spent adsorbent are dependent on apparent density and noticed an interestingly linearly relationship at room temperature. The three parameters increase gently from 20°C to 400°C, but a sharp increase both in real part and imaginary part are found subsequently due to the volatiles release and regeneration of carbon. And material conductivity is improved, which contributes to the π-electron conduction appearance. Relationship between penetration depth and temperature further elaborate spent adsorbent is an excellent microwave absorber and the microwave absorption capability order of zinc compounds is ZnO·2ZnSO, ZnSO and ZnO. Heating characteristics suggest that heating rate is related with dielectric properties of materials. The pore structures of spent adsorbent are improved significantly and the surface is smoother after microwave-regeneration.
采用微扰空腔谐振法，在 2450MHz 下，从 20℃到 1000℃，对硫酸锌负载型吸附剂的介电性能进行了研究。通过热重-差示扫描量热法（TG-DSC）分析，观察到废吸附剂有两个失重阶段，硫酸锌在约 750°C 和 860°C 分解为 ZnO·2ZnSO 和 ZnO。由于介电性能较差，ZnSO 的微波吸收能力随温度升高而增加，在 ZnO 生成后下降。废吸附剂的介电性能取决于表观密度，在室温下呈现出有趣的线性关系。三个参数在 20°C 到 400°C 之间缓慢增加，但由于挥发物的释放和碳的再生，随后在实部和虚部都出现了急剧增加。同时，材料的电导率得到了提高，这有助于出现π电子传导。穿透深度与温度之间的关系进一步说明了废吸附剂是一种优良的微波吸收剂，锌化合物的微波吸收能力顺序为 ZnO·2ZnSO、ZnSO 和 ZnO。加热特性表明，加热速率与材料的介电性能有关。微波再生后，废吸附剂的孔结构得到了显著改善，表面更加光滑。
