Adsorption and Regeneration of Volatile Organic Compounds(VOCs) on Coal-Based Activated Carbon by Ferric Nitrate Modification

In this study,the Heishan coal was used to prepare a series of activated carbon (AC) samples via a vapor deposition method.The effects of the Fe(NO3)3/coal weight ratio on the physicochemical properties of the activated carbon were systematically investigated,and the AC samples were analyzed by the N2adsorption–desorption technique,the scanning electron microscopy,the X-ray diffraction,the Raman spectroscopy,and the Fourier transform infrared spectroscopy.Furthermore,the adsorption properties of ethyl acetate were investigated.The results indicated that as the Fe(NO3)3/coal mass ratio increased from 1:8 to 1:2,the specific surface area,the total pore volume and the micropore volume initially increased and then decreased.The specific surface area increased from 560.86 m~2/g to 685.90 m~2/g,and then decreased to 299.56 m~2/g.The total pore volume and micropore volume increased from 0.29 cm~3/g and 0.17 cm~3/g to 0.30cm~3/g and 0.22 cm~3/g,and then decreased to 0.16 cm~3/g and 0.10 cm~3/g,respectively.The optimized ratio was 1:8.During the activation process,iron ions infiltrated the activated carbon to promote the development of the pore structure,the pore size of which was between 2.5 nm and 3 nm in daimeter.This approach could enhance the capacity for adsorption of ethyl acetate.It is worth noting that the ACs displaying the largest specific surface area and total pore volume (685.90 m~2/g and 0.30cm~3/g) were formed under the optimized activation conditions (950°C,20%(volume) of CO2,ratio 1:5),and the maximum AC capacity for adsorption of ethyl acetate was 962.62 mg/g.After seven repeated thermal regeneration experiments,the saturated AC adsorption capacity was still above 90%.