Sorption Properties of Ni²⁺ Loaded Iron Hydroxide Toward Phosphate and Cd²⁺ Ions

Abstract

Ni²⁺ ion loaded iron hydroxide was used for sorption of both Phosphate and Cd²⁺ ions from aqueous solution at 303 K and pH range 3–7 in 0.1 M KNO₃ as a background electrolyte. The surface charge density of the loaded surface was computed from potentiometric titrations both in the presence of 0.1 M KNO₃ and 0.01 M Phosphate. It was noted that the presence of phosphate alters the surface and decreases the point of zero charge toward lower pH. The sorption of phosphate was observed to increase with concentration and decrease with increase in pH of the system. However, the sorption of Cd²⁺ was observed to increase both with increase in concentration and pH of the system. The Freundlich equation was successfully applied to the sorption data which gives a straight line with the R² (regression coefficient) values in between 0.94 to 0.99.

Keywords:

• Cd²⁺ exchange
• Freundlich equation
• phosphate sorption
• PZC
• surface charge

Notes

pHi = initial pH adjusted.

pHe = equilibrium pH after sorption.