The role of cement dust in chemical remediation of the sludge treated soil

الملخص EN

Remediation of toxic metals has been considered as an important research subject for environmental studies.

This study investigated the effect of cement dust (CD) applied with two levels i.

e.

2.5 and 5 % on the remediation of Pb, Cd, Ni and Cr in sludge treated soil using the kinetic approach represented by the modified Freundlich, Elovich, the first order, Z (t), and the parabolic diffusion equations through the electrical stirred flow unit (ESFU) technique.

Field experiment was also carried out on El-Gabal El-Asfar region to evaluate and assess the potential effect of cement dust by using corn (Zea maize L.) as an indicator.

The obtained results showed that application of sludge significantly accumulated and showed increases in studied heavy metals especially in high applied level i.e.

20 m3 .fed-1 compared with the low level one i.

e.

10 m3 fed-1.

The application of CD showed a significant decrease in the studied heavy metals represented by the decreasing order of the kinetic parameters of used equations.

The fractionation of heavy metals showed that the residual fraction increased compared with other fractions with increasing the applied level of CD material.

Also, the remediation success of the studied heavy metals represented by remediation index (RI), showed that application of CD led to a decrease in the heavy metal availability in the CD treated soils.

Moreover, the RI showed that there is a priority of CD in minimizing Cr availability in the sludge treated soil followed by Pb, Cd and Ni which gave the highest RI value with respect of the available form of the studied metals.

In the field experiment the results revealed that CD treatments generally led to a significant decrease in the uptake of heavy metals by corn, especially for Ni and Cr and less extent for Pb and Cd.

The applied kinetic models are trusted technique for evaluating the remediation success of the applied material to contaminated soils because it was highly correlated with heavy metal uptake by corn.

The remediation mechanisms of CD was discussed in more details.