Effect of partially substituting MgO for NaOH on bleaching of pine (Pinus massoniana) thermomechanical pulp

► In this work, MgO was partially used in alkaline peroxide bleaching process of pine (pinus massoniana) TMP. ► The bulk of the bleached pine TMP can increase from 3.45 cm3/g to 3.69 cm3/g. ► The opacity of the bleached pine TMP can improve from 84.7% to 89.1%. ► The cationic demand of the effluent can decrease by 31%. ► The CODCr of the effluent can decrease by 22%.