Role of Prosopis juliflora biochar in poly-aromatic hydrocarbon remediation using Trifolium alexandrinum L.

Biochar possesses a number of characteristics that make it suitable for remediation of organic and inorganic pollutants from soil. Biochar acts as a suitable amendment to the soil as it increases the surface negative charge, nutrient retention capacity, high adsorption affinity, porosity, resistance to degradation and a high internal surface area. The present research is based on pot experiment, from October 2015 to April 2016. A probe sonicator extraction procedure was used for the determination of naphthalene and phenanthrene in dried soil and plant samples using gas-chromatography coupled with flame ionization detector. Fortification was carried out by spiking the 50 mg/kg naphthalene and 100 mg/kg phenanthrene in soil. The extraction efficiency observed for phenanthrene was 74.62% and 66.59% for naphthalene with relative standard deviation in the range of 0.39 to 0.26, respectively. Naphthalene was not detected in soil and plant samples. BCF value significantly decreases with increasing the biochar concentration in soil as compared to control (non-biochar-amended soil). BCF level decreased significantly (P ≤ 0.05) from 123.1 to 4.46 in phenanthrene-contaminated soil and 19.3–1.32 in mixed contaminated soil with time period. The maximum phenanthrene removal efficiency is observed to be 10% in biochar-amended soil as compared to other treatments (10% > 5% > 1% > control). Biochar significantly helps to increase plant height, dry biomass and total available nutrients. Above results showed that biochar derived from Prosopis juliflora effectively enhanced the PAHs surface adsorption capacity, removal efficiency and plant growth parameters. This study shows the effectiveness of biochar on contaminant remediation with the help of Trifolium alexandrinum.