A meta-analysis of heavy metal bioavailability response to biochar aging: Importance of soil and biochar properties

Marked Changes in Biochar’s Ability to Directly Immobilize Cd in Soil: Implication for Biochar Remediation of Cd Contaminated Soil

“…It has been reported that the application of biochar to soil could lead to Cd transformation and in uence the bioavailability of Cd in soil Yuan et al, 2021). However, there was little research about the in uence of soil aging on changes of Cd species on biochar.…”

“…Normally, the BHM in soil would be varied based on the increase or reduction of the active sites in biochar. The increase of biochar's CEC, oxygen-containing functional groups and speci c surface area can decrease the BHM through increasing adsorption sites, while the decrease of biochar's pH and speci c surface area can lead to the opposite effects due to the reduction of active sites (Yuan et al, 2021).…”

“…Biochar is a carbon-rich solid product obtained by pyrolysis of biomass materials under oxygen-limited condition (Yuan et al, 2021). Due to its special physical-chemical properties, biochar has been widely used to immobilize soil heavy metals in recent years Yuan et al, 2021). Biochar can immobilize heavy metals in soil by direct and indirect interaction.…”

“…First, biochar can interact with heavy metals in soil solution through complexation, precipitation, and cation exchange processes (Liu and Fan, 2018). Second, biochar can also change soil's properties, such as increasing the soil pH, changing the soil redox potential, microbiological compositions, and indirectly decrease the bioavailability of heavy metals (BHM) in soil (Cai et al, 2020;Cheng et al, 2020;Yuan et al, 2021). Hence, the e ciency of biochar on heavy metal immobilization in soil is closely related to the properties of biochar.…”

Persistent Organic Pollutants in Urban Soils of Central of London, England, UK: Measurement and Spatial Modelling of Black Carbon (BC), Petroleum Hydrocarbons (TPH), Polycyclic Aromatic Hydrocarbons (PAH) and Polychlorinated Biphenyls (PCB)

“…The occurrence of BC at high concentrations in surface soils has both positive and negative environmental implications. Owing to its high porosity BC and particularly the charcoal fraction can adsorb pollutants including PAH, PCB, dioxins and polybrominated diphenyl ethers (PBDE) as well as heavy metals thereby reducing their bioavailability to ecology and humans [58,62,[64][65][66]. Similarly, the presence of BC in soils has also been reported to increase cation exchange capacity as well as physically stabilise humic acids which in turn increases soil fertility [67].…”