B–S–I performs much better than B–I in Hg0 removal under the same conditions.
KI can be oxidized to I2 by air and starch–iodine complex can be formed on B–S–I.
Starch–iodine complex can provide I2 for Hg0 to form iodated mercuric compounds.
O2 promotes Hg0 removal and B–S–I shows a higher extent of Hg0 removal than B–I.
SO2 shows distinct effects on B–S–I and B–I, and mainly shows promotable for B–S–I.