pH dependence of copper adsorption in vineyard soils of Geneva

Copper adsorption by vineyard soils of the Geneva canton was evaluated by batch equilibration experiments in a pH range from 4 to 6. The adsorption curves fit significantly to Freundlich function log q = n log C + log Kf, where q is adsorbed Cu concentration on the solid phase and C is solution Cu concentration at the end of the equilibration time. Moreover, we found that Freundlich parameters n and log Kf are moderately correlated to pH, yielding the following equations: log Kf = 0.23 pH + 0.51 (R2 0.59) and n = −0.12 pH + 1.06 (R2 0.59). Such equations may be useful to predict Cu mobility for risk assessment studies.