Adsorption Characteristics of Biochar for NH4+-N/NO3--N in Rare Earth Tailwater
The"Two-stage Infiltration Coupled Biological System"is widely used tailwater treatment process to treat the tailwater of ion type rare earth mines,with stable treatment effect and controllable cost.The selection of filter materials is the focus of process upgrading and optimization.In this study,sawdust,peanut shell and rice husk biochar were used as adsorption filter materials to study the adsorption characteristics of biochar on NH4+-N and NO3--N and the influencing factors.The experiment shows that the adsorption effect of biochar prepared at 500℃ is better than that at 300℃.Among the raw materials,rice husk biochar(RBC500)has the best adsorption effect on NH4+-N,and the equilibrium adsorption amount is 25.06 mg/g.Peanut husk biochar(PBC500)has the best adsorption capacity for NO3--N,with an equilibrium adsorption capacity of 0.82 mg/g.The adsorption of NH4+-N by RBC500 is in accordance with the quasi-second-order kinetic model,and the adsorption of NO3--N is more in accordance with the quasi-first-order kinetic model.The adsorption of NH4+-N and NO3--N by RBC500 is more in accordance with the Langmuir model,which is mainly single molecule chemical adsorption.The adsorption effect of the biochar used in this study on NH4+-N and NO3--N is better than that of commonly used filter materials such as ceramsite and zeolite,and can be used as an adsorption type filter material for the coupled biological treatment process of infiltration.
万方数据
