The characteristic of coagulation sludge was altered by the pretreatment of high temperature. The appearance and crystallization of coagulation were respectively characterized by SEM and XRD and the samples with pretreatment and without pretreatment were compared.The adsorption characteristic of pretreated sludge for adsorption of ammonia-nitrogen from the aqueous solution was also evaluated using the theory of thermodynamics and kinetics.The adsorption model of ammonia-nitrogen was fitted with the Freundlich equation.The kinetic equations of pseudo-first-order

pseudo-second-order and intra-particle diffusion were adopted to examine the mechanism of the adsorption process and the pseudo-second-order models provided the better correlation of adsorption data.Thermodynamic parameters including ΔG0

ΔH0

ΔS0

Ea

and S* were calculated.The values of ΔG0 at 30

40 and 50℃ were-1.915

-1.744 and-1.719 kJ·mol-1 respectively

indicating the spontaneous nature was happened in ammonia adsorption on altered coagulation sludge.The negative value of ΔH0 proved the existence of the exothermic nature in the modified sludge absorption process.The negative value of ΔS0 represented that the adsorption was a declining process for entropy.The S* value at 0.0812 ranged from 0 to 1 demonstrated that the adsorption was a physical process.