Competitive effect of copper, zinc, cadmium and nickel on ion adsorption and desorption by soil clays

• Published in: Water, air, and soil pollution air, and soil pollution, 1999-07, Vol.113 (1/4), p.115-125
• Main Author: Atanassova, I
• Format: Article
• Language: English
• Subjects: acrisols; adsorption; Applied sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; Cadmium; Clay; clay fraction; clay soils; Clays; Competition; Copper; Desorption; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental hazards; Environmental monitoring; equations; Exact sciences and technology; gleyic acrisols; Heavy metals; interactions; Mathematical analysis; metal ions; mixtures; Nickel; planosols; Pollution; Pollution sources; Pollution, environment geology; Soil (material); Soil and sediments pollution; Sorption; Vertisols; Zinc
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1023/A:1005076821325

This study evaluated the effect of competing copper, zinc, cadmium and nickel ions in 0.01 M Ca(NO sub(3)) sub(2) on heavy metal sorption and desorption by soil clay fractions. Initial Cu addition levels varied from 99 mg kg super(-1) to 900 mg kg super(-1) and Zn, Cd and Ni levels were 94, 131 and 99 mg kg super(-1), respectively. Sorption of Cu conformed to a Freundlich equation. The amounts of metals not displaced by successive 48 h desorption cycles with 0.01 M Ca(NO sub(3)) sub(2) were considered 'specifically adsorbed'. Total sorption of Zn and Cd generally decreased in the order: Vertisol > Gleyic Acrisol > Planosol clay. More than 70% of the copper was specifically sorbed. Specific sorption of Zn was depressed by competition with Cu in the three clays investigated. At surface coverages higher than 200 mg Cu per kg of soil clay, zinc sorption in the Planosol and Gleyic Acrisol clays took place at low affinity sites. The exchangeable component of sorbed cadmium accounted for >:60% of the sorption in the Vertisol clay, >70% in the Gleyic Acrisol clay and was almost 100% in the Planosol clay. Nickel was not retained by the Planosol and Gleyic Acrisol clays and was ionexchangeably adsorbed by the Vertisol clay. At the conditions studied, Ni and Cd remain a ready source of pollution hazard.