Can biochar and designer biochar be used to remediate per- and polyfluorinated alkyl substances (PFAS) and lead and antimony contaminated soils?
By Ludovic Silvania, Gerard Cornelissen, Andreas Botnen Smebye, Yaxin Zhang, Gudny Okkenhaug, Andrew R.Zimmerman, Gorm Thune, Hilmar Sævarsson, and Sarah E.Hale
Science of Total Envionment
August 13, 2019
Designer biochars can be used to remediate organic and inorganic contaminant polluted soils. Here, a waste timber biochar (BC), a coconut shell activated biochar (aBC) and a wood shrub iron enriched designer biochar (Fe-BC) were investigated. Per- and polyfluorinated alkyl substances (PFAS) contaminated soils with different total organic carbon (TOC) contents (1.6 and 34.2%) were amended with six doses of BC and aBC. Two shooting range soils (TOC 5.2 and 10.2%) contaminated with heavy metals (mainly Pb and Sb) were amended with four doses of BC and Fe-BC. An amendment of 20% BC reduced the PFOS leachate concentration by 86% for the low TOC soil but was not effective for the high TOC soil. An amendment of 1% aBC reduced PFOS leachate concentrations by over >96% for both soils. For the low TOC shooting range soil, a 20% amendment of BC reduced Pb and Sb leaching by 61% and 12%, respectively. An amendment of 20% Fe-BC to soil with low TOC reduced Pb and Sb leaching by 99% and 40%, respectively. The need for “designer” biochars using processes such as iron enrichment or activation should be considered depending on the TOC of the soil, the type of contaminants and remediation goals.
• Designer biochars were used to remediate industrially contaminated soils.
• Activated biochar reduced PFAS leachate concentrations more than unactivated biochar.
• Activated biochar was most effective in low TOC soil.
• Iron enriched biochar reduced Pb and Sb leaching more than unactivated biochar.
• Iron enriched biochar was most effective in low TOC soil.