木炭的硝酸氧化与应用

发布时间：2018-02-15 19:35

本文关键词： HNO3 氧化孔隙结构炭颗粒粒径碳量子点　出处：《南京林业大学》2015年硕士论文　论文类型：学位论文

【摘要】：分别以微晶纤维素、木质素和杉木屑为原材料,在不同温度下炭化制备了原料炭,然后在不同反应条件下采用硝酸对原料炭进行氧化。通过Boehm滴定、元素分析、N2吸附、激光粒径分析等方法表征了炭的表面化学性质、孔隙结构和粒径分布等特性,研究了HNO3氧化对木炭表面化学性质、孔隙结构和粒度的影响。在此基础上,用HNO3氧化生物质炭的方式研究了碳量子点的基本工艺。研究结果表明,氧化显著增加木炭表面酸性含氧官能团含量,生成的含氧官能团会堵塞木炭内部孔隙,降低木炭的比表面积和比孔容积。炭的炭化温度越高,氧化越困难;氧化温度越高,木炭氧化程度越高。原料炭的制备方法和炭的微观结构对炭的氧化程度有较大的影响。用循环氧化并辅以热处理的方法,可以显著增加木炭的比表面积和比孔容积。以400 oC下管式炉中炭化得到的炭为原料,通过改变氧化剂浓度和氧化时间,可得到粒径逐渐减小的炭颗粒。采用硝酸回流氧化生物质炭的方式制备了碳量子点,以400 oC下管式炉中炭化得到的炭为原料制备碳量子点的氧化工艺条件:HNO3溶液浓度为3 mol/L,氧化时间为4 h,氧化温度为100 oC。氧化得到的悬浮液通过中和、微滤、超滤和透析,得到粒径为5~6 nm碳量子点。回流钝化可提高碳量子点溶液的荧光强度,碳量子点溶液的荧光强度随钝化时间的延长和钝化温度的升高增强。常压下,合适的钝化温度为100 oC。
[Abstract]:Using microcrystalline cellulose, lignin and sawdust as raw materials, the raw carbon was carbonized at different temperatures, and then oxidized with nitric acid under different reaction conditions. Boehm titration and elemental analysis of N _ 2 adsorption were performed. The surface chemical properties, pore structure and particle size distribution of carbon were characterized by laser particle size analysis. The effects of HNO3 oxidation on the surface chemical properties, pore structure and particle size of charcoal were studied. The basic process of carbon quantum dots (QDs) was studied by HNO3 oxidation of biomass carbon. The results showed that oxidation significantly increased the content of acidic oxygen-containing functional groups on the surface of charcoal, and the oxygen-containing functional groups formed could block the internal pores of charcoal. Reducing the specific surface area and pore volume of charcoal. The higher the carbonization temperature, the more difficult it is to oxidize; the higher the oxidation temperature, the higher the oxidation temperature. The higher the degree of oxidation of charcoal is, the more influence is on the degree of oxidation of carbon by the method of preparing raw carbon and the microstructure of carbon. The specific surface area and specific pore volume of charcoal can be significantly increased by changing the concentration of oxidant and oxidation time by using carbonized carbon obtained from 400 oC tube furnace as raw material. Carbon quantum dots (QDs) were prepared by refluxing nitric acid to oxidize biomass carbon. Preparation of carbon Quantum Dots from Carbonized carbon in 400oC Tube Furnace the oxidation process conditions are as follows: the concentration of the solution is 3 mol / L, the oxidation time is 4 h, and the oxidation temperature is 100 OC. The suspension obtained by oxidation is neutralized, microfiltrated, ultrafiltration and dialyzed. The fluorescence intensity of carbon quantum dot solution can be increased by reflux passivation, and the fluorescence intensity of carbon quantum dot solution increases with the prolongation of passivation time and the increase of passivation temperature. The suitable passivation temperature is 100 OC at atmospheric pressure.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11

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