Adsorption processes of Cu~(2 ) to dark-brown soil were studied by batch equilibrium technique under different pH

ionic strength

temperature

Cu~(2 ) concentration and contact time.The results showed:(1) The adsorption rate of Cu~(2 ) increased with an increase of solution pH.When the solution pH was 8

the ad- sorption rate achieved 91%.(2)With an increase of ionic strength

the adsorption of Cu~(2 ) reduced firstly

and then increased.(3)The amount adsorbed increased with an increase of the Cu~(2 ) concentration

and in- creased rapidly at low concentration.The Langmuir model was better than the Freundlich and Temkin mod- els for describing the Cu~(2 ) adsorption isotherms.According to k_L value of Langmuir model

the thermody- namic parameters were calculated

which indicated that the reaction was a spontaneous and endothermic process

but its disorder was the same.(4)The kinetics of adsorption experiment could be divided into two stages

rapid and slow adsorption.The dual-constant models can be the best model that used to describe the Cu~(2 ) adsorption rate on dark-brown soil.According to k_Dvalue from the first-order kinetic model

activation energy and thermodynamics parameter were calculated

which confirmed a fact that increasing temperature was propitious to improve the reactive rate.