Effectiveness of Biochar Obtained from Corncob for Immobilization of Lead in Contaminated Soil

摘要

Background. Recent studies have explored the potential for using biochar as a soilamendment in agriculture. However, it can also be used as a gentle remediation option forcontaminant reduction. Biochar is a by-product obtained from the pyrolysis of biomass(organic matter). It is known for its long-lasting chemical properties, wide surface area values,and carbon-richness, which make it an efficient method for the immobilization of organicand inorganic contaminants such as heavy metals.Objective. The aim of the present study was to analyze the efficiency of biochar, obtainedfrom the gasification of corncob, for the immobilization of lead in contaminated soils.Methods. In the present study, biochar from corncob was used as an amendment for soilcontaminated with lead (extracted from the municipality of Malambo, Colombia) in orderto estimate its ability to immobilize leaching lead. A comparison laboratory test applied amodified biochar produced with a 10% hydrogen peroxide chemical treatment. In addition,a pot experiment was done with both biochar by sowing seeds of Pennisetum clandestinumfor 33 days. During this period, plant growth was measured for the different amendments ofbiochar concentrations.Results. Laboratory tests indicated that unmodified biochar obtained a maximum retentionof 61.46% of lead, while the modified biochar obtained only 44.53% retention. In the potexperiments, the modified biochar indicated high germination and growth of seeds (up to89.8%).Conclusions. Although the lead immobilization in soil was positive for both cases, the use ofsoil with high concentrations of lead (167.62 g/kg) does not indicate biochar’s effectivenessfor purposes of comparison with the current United States Environmental Protection Agency(USEPA) limit value (400 ppm for bare soil in urban play areas). Therefore, further studies arerecommended using soil with lower lead concentration levels.Competing Interests. The authors declare no competing financial interests. One author is anemployee of Pure Earth.