To explore the effect of hydroxyapatite (HAP) on the solidification of heavy metals in mining areas

this study conducted the adsorption experiments to study the kinetic adsorption and isothermal adsorption of Cd

2+

and Zn

2+

in the soil of Pb-Zn mines with HAP. The results showed that the adsorption of Cd

2+

and Zn

2+

increased with the increase of initial concentrations of Cd

2+

and Zn

2+

; under acidic conditions

the amount of adsorption increased with the increasing pH values; the quasi-second-order kinetic equation could well describe the adsorption pro

cess of Zn

2+

and Cd

2+

soil adsorption capacities increased with the addition of HAP. In the Zn-Cd coexistence system

when the initial concentration was

<

20 mg/L

the adsorption of Zn

2+

and Cd

2+

in the soil was not significantly different. The competitiveness of the two metal ions was small

and the competition was obvious as the initial concentrations increased. The maximum adsorption capacities of Zn

2+

reached 79%~87% in a single system

while the maximum adsorption capacities of Cd

2+

was only 57%~72% in a single system. The competitiveness of Zn

2+

was better than that of Cd

2+

and Zn

2+

seriously inhibited the adsorption of Cd

2+

. In summary

HAP could improve the adsorption performance of soil in the mining area

and enhance the adsorption and retention ability of soil to Zn

2+

in Zn and Cd contaminated soils.