Study on phosphorous adsorption characteristics by three substrates

The phosphorous adsorption characteristics of three substrates(shale,haydite,gravel) in constructed wetland were studied by isotherm adsorption and adsorption kinetics experiment.The results showed that both Freundlich and Langmuir equations were well fitted for describing the adsorption characteristics of these substrates.The phosphorous theoretical saturated adsorption capacity of three substrates followed shale(527.992mg/kg) haydite(328.165mg/kg)gravel(129.729mg/kg).The process of adsorption could be divided into fast,middle and slow stages.The rate of adsorption followed that shale haydite gravel.Pseudo second order kinetics,dual constant and Elovich equations could be suitable to describe adsorption characteristics of three substrates.In terms of correlation coefficient,Pseudo second order kinetics equation is the best model.