Peroxyformic acid/peroxyacetic acid (PFA/PAA) treatment
After pulping, FA/AA treated pulps were further delignified by treating them with a mixture of PFA/PAA solution in hot water bath at 80 ◦C for 2h.
PFA/PAA solution mixture was prepared by adding 8ml 35% H2O2 with 85% formic acid/acetic acid mixture.
Finally, the delignified fibers were filtered to separate cooking liquor (lignin and hemicellulose mixed with formic acid) from cellulose and washed with hot water.