Highly efficient activation of persulfate by encapsulated nano-Fe0 biochar for acetaminophen degradation: Rich electron environment and dominant effect of superoxide radical

•An embedded nZVI biochar (BC-Fe0) with excellent properties was synthesized.•BC-Fe0 exhibited a highly catalytic performance on the activation of PDS to degrade ACT.•Multi factors from BC-Fe0created an electron-rich environment to favor of the redox.•·O2−, 1O2 and electron transfer played major roles in PDS/BC-Fe0 system.•BC-Fe0 had a long durability and reusability.