Sorption of cadmium, nickel, and zinc by kaolinite and montmorillonite suspensions

Journal Article · · Soil Science Society of America Journal; (USA)

OSTI ID:5568157

Puls, R W; Bohn, H L ^[1]

---

1. Kerr Environmental Research Lab., Ada, OK (USA)

Sorption is the predominant process governing metal ion movement in soils and includes the following physical and chemical mechanisms: adsorption, precipitation and absorption. This research attempts to use the hard-soft-acid-base principle to explain sorption selectivity of the metal cations Cd, Ni, and Zn by kaolinite and montmorillonite clays. The hard-soft character of the clay surfaces, which is due to their surface functional groups, may be inferred by cation sorption selectivity experiments where pH and complex ion formation are controlled and monitored. Calcium saturated clays were suspended in Ca(ClO{sub 4}){sub 2}, CaCl{sub 2} or CaSO{sub 4} and spikes of the above metals as divalent cations were added and their reactivity assessed within the framework of the HSAB Principle. For kaolinite in Ca(ClO{sub 4}){sub 2}, metal sorption followed the sequence Cd > Zn > Ni. For montmorillonite in Ca(ClO{sub 4}){sub 2}, metal sorption followed the sequence Cd {approx} Zn > Ni. In CaCl{sub 2} and CaSO{sub 4}, the selectivity was different due to the presence of Cl and SO{sub 4}{sup 2} which competed with the mineral surfaces for the divalent metal cations.

• OSTI ID: 5568157
• Journal Information: Soil Science Society of America Journal; (USA), Journal Name: Soil Science Society of America Journal; (USA) Vol. 52:5; ISSN SSSJD; ISSN 0361-5995
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CADMIUM
CHEMISTRY
CLAYS
ELEMENTS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
KAOLINITE
MATERIALS
METALS
MINERALS
MONTMORILLONITE
NICKEL
OXYGEN COMPOUNDS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SOIL CHEMISTRY
SOILS
SORPTION
TRANSITION ELEMENTS
ZINC