Optimization of Soil washing process in the presence of Tween 80 and EDTA compounds in removing PAHs and Cadmium contaminants from contaminated soil by method BBD

Pollution caused by petroleum compounds (PAHs) and heavy metals due to their properties Cumulative and High toxicity Causing major environmental problems. These compounds, although detected in air and water, are the final and main receptive soil. Soil washing process using surfactants is a high-performance physicochemical technology for the removal of phenanthrene and cadmium from the soil environment and transferring them to the aqueous phase.

In this study, the efficiency of the process with the BBD method, with RSM, was designed to optimizing parameters such as surfactant concentration in the range 1000,1500 and 2000 mg/L, washing Time 2,12, 24 hours with L/S 10, 20 and 30 ml/g. To contaminated soil samples were added high concentrations Phenanthrene (500 mg/kg) and Cadmium (80 mg/kg), surfactant Tween 80 and EDTA.

The final concentration of Phenanthrene and Cadmium was measured by HPLC and atomic absorption spectrometry (ASS). The results showed that the efficiency of the process under optimal conditions for the separation of 76% Phenanthrene and 81% Cadmium in separate concentrations of Tween 80 and EDTA was reached in 2000 mg/L, L/S 30 ml/g (v/w), washing time 2 hours. Surfactant concentration was the most influential variable in this regard (p< 0.0001).

The separation of phenanthrene and Cadmium from the soil through the help of surfactants is an effective technique for remediation of contaminated soil.