Preparation of Activated Carbons from Biomass and their Adsorption of Benzene, Ammonia, Direct Red 23 and Iron Ions

摘要

Three activated carbons were prepared from biomass (agriculture and wood industry by-products) and subsequently modified by treatment with liquefied petroleum gas at 900 degrees C. The primary properties of the activated carbons before and after modification were investigated by nitrogen adsorption isotherms and FT-IR techniques. Modification of the activated carbons by liquefied petroleum gas led to a significant decrease in the content of micropores with diameters less than 1 nm. The prepared activated carbons exhibited improved adsorption capacities towards benzene due to their non-polar surface chemical groups and narrower micropore distributions; however, their adsorption capacities towards ammonia were diminished. The adsorption extent of iron ion was determined by the surface chemical properties of the activated carbons and showed a smaller relationship to the pore Volume. The adsorption extent of Direct Red 23 was influenced by micropore sizes in the range 1-1.5 nm.