An adsorbent was first prepared from used hot pack

and adsorption of phosphate on it studied. The interaction between pH

adsorption performance and zeta potential was also investigated and the adsorption mechanism at different pH values did.The results showed that the adsorbent were mainly composed of mix phases of magnetite and goethite.The isotherm of phosphate adsorption could be well described by Langmuir equation.The capacity of its equilibrium adsorption was 12.57 mg·g-1 at temperature 25℃ and pH 2.The studies also indicated that adsorption of phosphate on the adsorbent was dominated by solution pH.Inner-sphere complexing

electrostatic attraction and direct precipitation on surface were jointly driving force for adsorption of phosphorus at lower pH.At higher pH

inner-sphere complexing decreased and electrostatic attraction became electrostatic exclusion

which was unfavorable for phosphate adsorption

however

co-adsorption with inner-sphere complexing and indirect precipitation on surface promoted adsorption of phosphate

and total effect is decline of phosphorous removal.