炭化苹果枝皮和木材对水中硝态氮和铵态氮的差异吸附

将苹果枝条的皮层和木材部分开后在450℃下低氧加热制得炭化枝皮和炭化木材,分析其超微结构及对铵态氮和硝态氮的吸附。结果表明,苹果枝皮比其木材部分的纤维素含量高,有更多的微观孔洞和沟壑,炭化后纵向沟壑和孔隙更发达。炭化枝皮对NH4+—N和NO3-—N的饱和吸附量分别为24.11,12.93mg/g,炭化木材的相应参数分别为22.24,11.99mg/g,炭化枝皮对NH4+—N和NO3-—N的吸附能力均比炭化木材的更强。两者对NH4+—N的吸附量比对NO3-—N的更大,吸附过程均能采用Freundlich和Langmuir等温吸附模型、准二级动力学模型和Elovich模型拟合。炭化枝皮的吸附能力比炭化木材更强,与其原料纤维素含量高及微观沟壑发达有关。

Differential Adsorption of Nitrate Nitrogen and Ammonium Nitrogen in Water by Carbonized Apple Bark and Wood

The bark and wood of the apple branches were separated and then made them into carbonized bark and wood in low oxygen at 450℃.The ultrastructural and adsorption to NH4+—N and NO3-—N of them were investigated.The results showed that the cellulose content in carbonized bark was higher than that in carbonized wood,and there were more microscopic holes and gullies in the carbonized bark,and the longitudinal gullies and pores were more developed after carbonization.The saturated adsorption capacity of the carbonized bark to NH4+—N and NO3-—N was 24.11 mg/g and 12.93 mg/g,respectively;while the corresponding parameter of the carbonized wood was 22.24 mg/g and 11.99 mg/g,respectively,and carbonized bark had stronger adsorption capacity to NH4+—N and NO3-—N than that of carbonized wood.The adsorption capacities of these two kinds of materials to NH4+—N were greater than those to NO3-—N.Freundlich and Langmuir isothermal adsorption models,pseudo second-order kinetic model and Elovich model could be used to fit the adsorption processes.Carbonized bark had stronger adsorption capacity,which was related to its higher cellulose content and more developed microscopic gullies.