Leaching of Pb by dissolved organic carbon derived by sugarcane bagasse and poultry manure

The leaching is an effective method for the removal of heavy metals using water or any other fluid. However, it is vital to identify the environmentally friendly leaching agent. The effectiveness of this technique depends on several factors. The researchers are looking for substances that have the least harmful impact on the environment. There is no reported study on the effects of dissolved organic carbon extract from poultry manure and sugarcane bagasse on leaching of Pb from contaminated soil. Therefore, the objective of this study was to investigate the leaching of Pb from mine contaminated soil as affected by dissolved organic carbon derived from poultry manure and sugarcane bagasse. .

In this study, an experiment was conducted to evaluate the efficiency of dissolved organic carbon derived by poultry manure and sugarcane bagasse to remove Pb from contaminated soil. For this purpose, the leaching and batch equilibrium experiments with the ratio of 1:20 (soil:extract) and different concentrations of dissolved organic carbon (50, 100, 200, 400, 800, 1000, 2000 mg/l), pH (4, 6, 7 , 8, 10) and time (0.5, 1, 2, 4 hours) were carried out. The best results of soil Pb leaching and batch equilibrium experiments were chosen for the leaching column (continuous and intermittent leaching) experiment. In both of continuous and intermittent leaching experiments, the Pb leaching with two types of extracts was investigated.

The results showed that the application of dissolved organic carbon derived from poultry manure initiated highest Pb leaching from mine contaminated soil in the both of continuous and intermittent leaching experiments. The intermittent leaching, resulted in the highest amount of Pb leaching from the contaminated soil (135.65 mg/kg) compare to continuous leaching experiments. In leaching experiment, the content of Pb leaching by dissolved organic carbon derived from bagasse did not change considerably. In the batch equilibrium experiment, the highest Pb leaching (55 mg/kg) was related to the application of 2000 mg/l dissolved organic carbon derived from poultry manure at pH 8. The amount of Pb leaching with the application of 400 mg/l of dissolved organic carbon derived from sugarcane bagasse at pH 7 was 20 mg/kg.

According to the results, the application of dissolved organic carbon derived from poultry manure removed a significant content of Pb from mine contaminated soil. However, the application of dissolved organic carbon from this type of sugarcane bagasse for Pb leaching was not effective.