用于烧结烟气脱硫脱硝的活性炭理化性质

活性炭烟气净化技术是一种适合于烧结烟气治理并能使废物资源化利用的先进技术,SO2、NOx 等污染物在活性炭孔道内被吸附和催化,其吸附和催化性能主要由活性炭物理结构和化学性质所决定。本研究表征并分析了椰壳、果壳和煤质活性炭的比表面积、孔隙结构、表面形貌、物相组成、组成元素以及表面官能团等理化性能。结果表明:3 种活性炭的比表面积均较大,都是以微孔为主的无定型碳材料;主要元素是碳和氧,还含有少量的硫元素和氯元素;椰壳活性炭孔道排列整齐,清晰可见,果壳和煤质活性炭表面凹凸不平,难于清晰观察到微孔结构;表面含有与吸附和催化性能密切相关的含氧官能团。研究结果作为活性炭相关改性研究的基础性研究,可为优化改性技术提供参考依据。

Low-Temperature Denitrification Performance of Cu2O/Activated Carbon Catalysts for Selective Catalytic Reduction of NOx by CO

To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.

Modification Mechanism of Coconut Husk Activated Carbon Using FeSO4 and Fe(NO3)3

Modification conditions determine the surface topography and the active material phase composition of a catalyst.To study the influence of modification on a carbon-based sorbent,coconut husk activated carbon(AC)which was activated using HNO3 and modified by FeSO4 and Fe(NO3)3 was examined.The pore textures and surface chemical characteristics of the carbon materials were examined by scanning electron microscopy(SEM),Brunner-Emmet-Teller(BET),X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy.The surface topography,the pore structure,active materials,and functional groups of AC,AC modificated by HNO3(HNO3/AC for short),and AC modificated by FeSO4 and Fe(NO3)3(Fe/AC for short)were systematically studied.Subsequently,the mechanism of modifying the conditions for the carbon materials was determined.Results showed that the surface micro topography of HNO3/AC became unsystematic and disordered.After modification with FeSO4,the ferriferous oxide was mainly present as a near-spherical crystal.Ferriferous oxides from Fe(NO3)3 modification mainly exhibited a plate shape.HNO3 modification could enlarge the pores but decrease the specific surface area of AC.FeSO4 modification resulted in a new net post structure in the pore canal of AC.Fe(NO3)3 modification caused the pore space structure to develop in the interior,and a higher calcination temperature was useful for ablation.The ash content of the AC was substantially reduced upon HNO3 modification.Upon FeSO4 modification,α-FeOOH,α-Fe2O3 andγ-Fe2O3 coexisted under the condition of a lower concentration of FeSO4 and a lower calcination temperature,and a higher FeSO4 concentration and calcination temperature generated moreα-Fe2O3.The same Fe(NO3)3 modification and a higher calcination temperature were beneficial to the minor chipping formation ofγ-Fe2O3.A higher Fe(NO3)3 loading produced a lower graphitization degree.HNO3 modification formed various new oxygen-containing functional groups and few nitrogen-containing groups.Based on the cover,FeSO4 and Fe(NO3)3 modification could decrease the oxygen-containing and nitrogen-containing functional groups.These results could optimize the modification condition and improve physical and chemical properties of carbon-based sorbents.