In contrast, biochar with highly stable C
may help alleviate geochemical environment in the tailings
(Li et al., 2013). At medium pH (7–8), addition of
greenwaste biochar increased adsorption capacity, enhanced
adsorption of NH+4
-N/NH3-N and lowered NH3
volatilization in bauxite-processing residue amended
with di-ammonium phosphate, while at high pH (9),
the majority of NH+4
-N/NH3-N pools was lost via NH3
volatilization due to the strong acid-base reaction at
this pH (Chen et al., 2013).