• Corpus ID: 108290229

Adsorption-desorption Study of Heavy Metals on Sandy-loam Soil of Sapele Metropolis Chokor

@inproceedings{2017AdsorptiondesorptionSO,
  title={Adsorption-desorption Study of Heavy Metals on Sandy-loam Soil of Sapele Metropolis Chokor},
  author={},
  year={2017}
}

• Published 2017

Adsorption – desorption processes controls the fate and bioavailability of heavy metals in soils. In this study, adsorption-desorption characteristics of aggregated soil samples from Sapele was studied using batch process in order to ascertain how heavy metals cations (Mn, Cu, Zn, Pb, Cd & Cr) are adsorbed and desorbed onto and from soil solid phase in a competitive situation. For all metals, we noted a general increase in metal adsorbed as equilibrium concentrations increases. The distribution coefficients (Kd) also increases with decrease concentration of soil solution. Kd values for Zn, Cu, and Mn were particularly higher compared to Pb, Cd, and Cr suggesting that soil loading of the later group are of greater environmental concern in this soil, than the formal ; and that the latter could easily leached to nearby waters and aquifers. The adsorption isotherms were fitted to the Freundlich and Langmuir equations with the Freundlich given a better fit. The three adsorption sequences found for the soil were: Zn > Cu > Mn > Pb > Cd > Cr; Cu > Zn >Mn > Pb > Cd > Cr; and Cu > Mn > Zn > Pb > Cd > Cr. Neither electronegativity, electrostatics, Misono softness parameter nor hydrolysis properties could explain explicitly any of these orders. The soil parameters such as clay type and contents, Fe and Al oxides as well as organic content of the soil seems to have a major function in dictating the orders of adsorption. Adsorption of metals by soil increases with increase in hour of contact time and decrease with increase concentration of EDTA in soil solution. Desorption of metals from soil follow a similar pattern of initial fast phase reaction followed by slow phase reaction observed for the adsorption of metal onto soil. However, within the time frame, desorption was not completely reversible suggesting an evidence of hysteresis.