Assessment of Cu (II)-bearing montmorillonite on Cd adsorption.

The abilities of montmorillonite (MMT) and Cu (II)-bearing montmorillonite (Cu-MMT) for adsorption of Cd from aqueous solutions have been studied at different optimized conditions of shaking time, pH value, and initial concentration, respectively. The results showed that the adsorbability of Cu-MMT onto Cd is stronger than the MMT. The amount of Cu-MMT necessary to remove Cd from solution was about 0.5 g for 100-200 mg/L Cd solution at a pH of 4.0. The maximum adsorption (94%) was 20 min of shaking time using Cu-MMT as adsorbent. The maximum adsorption of Cd = 95% at a pH of 4.0. By increasing the initial concentration, the adsorption amount of Cd onto Cu-MMT increased. Animal experiment of this study indicated that the addition of Cu-MMT to the Cd-contaminated diet of pigs reduced significantly the Cd levels in tissues (p < 0.05) and increased contents in feces (p < 0.01), improving the safety of animal products. Thus, the overall results established the use of Cu-MMT as a heavy metal adsorbent in animal's diets, implying a potential protective role against heavy metal toxicities.