负载γ-Fe2O3椰壳活性炭催化剂的制备与表征

Preparation and characterization of supported γ-Fe2O3 coconut shell activated carbon catalyst

以椰壳活性炭为原料,硝酸为氧化改性剂,通过化学沉淀法将γ-Fe2O3负载到硝酸改性的活性炭上制得γ-Fe2O3/AC催化剂,探讨硝酸改性与负载金属氧化物γ-Fe2O3对活性炭物理性质和化学性质的影响。对催化剂采用XRD、SEM、BET、FTIR、XPS等手段进行表征。结果表明:实验制备的γ-Fe2O3晶粒纯度高,结晶性能好,Fe—O键特征峰明显,具有磁性的γ-Fe2O3可以成功地负载到活性炭表面;椰壳活性炭在经过硝酸改性后,孔隙结构遭到部分烧蚀,炭骨架收缩,虽然微孔数量和微孔孔容降低,比表面积减小了16.98%,但是含氧酸性官能团羧基与酯基增多,O元素含量增加;在负载了γ-Fe2O3后,γ-Fe2O3晶体可以附着在活性炭的表面和中大孔的孔壁上,同时在孔道内堆积叠加构造出更多的微孔,降低了γ-Fe2O3/AC的平均孔径,比表面积增大了8.11%。

Taking coconut shell activated carbon as raw material and nitric acid as oxidation modifier, γ-Fe2O3/AC catalyst is prepared by loading γ-Fe2O3 on nitric acid modified activated carbon by chemical precipitation method, and the nitric acid modification and loading metal oxide γ-Fe2O3 are discussed. The effects of nitric acid modification and loading γ-Fe2O3 on the physical and chemical properties of the obtained activated carbon are investigated. The catalyst samples are characterized by XRD, SEM, BET,FTIR and XPS. The results show that the prepared γ-Fe2O3 crystal particles have high purity and good crystallization performance,the characteristic peak of the Fe—O bond is conspicuous, and the magnetic γ-Fe2O3 can be successfully loaded on the surface of activated carbon. After the nitric acid modification, the pore structure of the coconut shell activated carbon is partially ablated and the carbon skeleton shrinks. Although the number of micropores and the micropore volume reduce and the specific surface area is decreased by 16.98%, both the carboxyl group and the lactone group of the oxygen-containing acidic functional group of the activated carbon increase, as well as the content of the O element also increases. After the γ-Fe2O3 loaded on the activated carbon, the γ-Fe2O3 crystals can be stacked in the pores of the activated carbon to form more micropores, which reduceds the average pore diameter of γ-Fe2O3/AC and increases the number of micropores, and the specific surface area increases by 8.11%.