Chemical remediation of contaminated soils with heavy meatals

الملخص EN

This work represents a trial towards ameliorating soil polluted with some heavy metals (Ni, Co and Cd) resulted from some anthropogenic activities, i.e., human domestic and industrial wastes.

To archive this target, an incubation pot experimental was conducted on two contaminated soil samples collected from El-Gabal El-Asfar farm (Qalubia Governorate) and El-Saff (Giza Governorate), which irrigated with sewage effluent and industrial wastewater, respectively.

Before executing this experiment, the studied two soils were thoroughly mixed with two soil amendments, i.e., rock phosphate and calcium carbonate at a rate of 2 % for each one, and then daily wetted with distilled water to constant moisture content (field capacity).

Soil samples were taken at incubation periods of 0, 25, 50 and 75 days to determine EDTA extractable Ni, Co and Cd for evaluating the effective role of the tested soil amendments in immobilizing the dominant heavy metal ions.

The obtained results could be summarized in the following: 1.

increasing time of incubation period between the studied two soils and rock phosphate caused progressively decreased in the values of EDTA-extractable Ni, Co and Cd.

The sorbet amounts of Ni, Co and Cd increased with prolonging time of contact between rock phosphate and soil, with the removal percentages followed the descending order: Cd > Ni > Co.

The later sequence was changed at the incubation period of 75 days in El-Gabal El-Asfar soil, where the sequence of removal percentages became : Cd > Co ≥ Ni.

Also, El-Gabal El-Asfar soil could be adsorbed higher amounts of Ni, Co and Cd than El-Saff soil, while the reverse was true for the sorption percentages of these metal ions in El-Saff soil, except for Cd at the incubation period of 75 days.

2.

Increment of incubation time between soils and CaCO3 led to markedly decreased in the amounts of EDTA-extractable Ni, Co and Cd, which seemed a highest capacity with Ni, lowest with Co and intermediate with Cd.

Consequently, it could be categorized these metal ions according to their removal amounts into the following the descending order: Ni > Cd > Co regardless of type of soil.

The later sequence also represented the removal capacity of CaCO3 for the studied metal ions.