The water was removed by squeezing and procedure was repeated several times.
After the presoaking step, waste paper was dried overnight in an oven at 50 °C.
Dry matter was then dray-defibrated with a mill designed to shear them by blades rotating at 1500 rpm for 5 min in order to remove the most physical barriers of cellulose structure [23].
Finally, waste paper was treated with diluted phosphoric acid (3 g L−1 ) for 2 h at 60 °C, washing with deionized water to a neutral pH and then dried again in an oven at 50 °C up to a constant weight.