Recently

more and more people pay close attention to humic acid.Purpose of this research was offering basic data for the production of humic acid slow-release fertilizers.The effects of P concentration

equilibrium time

ratio of solid to liquid and pH value on characteristics of the P adsorption on humic acid extracted from brown coal and its absorptive regularity was studied by isothermal adsorption methods and the characteristics of isothermal adsorption and kinetics adsorption on humic acid was discussed too.Results showed that pH increase of medium was of great disadvantage of P adsorption and could decrease the velocity of adsorption reaction.As to sample one

the distribution coefficient and adsorption capacity was the maximum at pH was 4.7.Even the pH was higher

as to sample two

the distribution coefficient and adsorption capacity was decreased.Besides

the distribution coefficient and adsorption capacity of the experimental humic acid treated by nitric was significant lower than that of the brown coal without treated.With the increase of P concentration in the medium

adsorption capacity of P increased too.Adsorption capacity rose markedly in the beginning of the adsorption process

however

it slowed down later.Suitable ratio of solid to liquid could increase the unit adsorption.The adsorption of P on humic acid could be well described by Langmuir equation and its kinetics adsorption fit Elovich equations best.