The report presents an original study of Cadmium adsorption based on experimental data. The effect of operating variables, like solution pH, sediment dose, contact time and particle size on the adsorption of cadmium ions on bed sediments of the highly polluted Kali river in western Uttar Pradesh has been studied.
The role of the coarser sediment fraction has been compared to those of clay and silt fractions. The optimum contact time needed to reach equilibrium is of the order of 30 and 60 minutes for 0-60 and 210-250 μm size of the sediment respectively. The extent of adsorption increases with an increase of pH. Furthermore, the adsorption of cadmium increases with increasing adsorbent doses and decreases with adsorbent particle size.
The present study has shown the potentiality of freshly deposited sediments in adsorbing cadmium ions, which may enter the river system through the disposal of municipal & industrial effluents or by biological & chemical degradation. The study indicates that though the cadmium ions have more affinity for the clay and silt fraction of the sediment, the overall contribution of coarser fraction to adsorption is more than the former.
The adsorption data further suggests that the pH of the solution is the most important parameter in the control of cadmium ions adsorption onto the bed sediments. The two important geochemical phases, iron and manganese oxide, also play an important role in the adsorption process and act as the active support material for the adsorption of cadmium.
The results of the experimental study are highly useful and may be extended to other rivers of the world, especially to the rivers with coarser sediments.
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/articles/adsorption-cadmium-bed-sediments-research-report-national-institute-hydrology