Effect of enzyme concoctions on fiber surface roughness and deinking efficiency of sorted office paper

Abstract

Bio-deinking of sorted office paper (SOP) by various enzyme concoctions having cellulase, xylanase, amylase and lipase was investigated. The effect of various enzyme concoctions on pulp brightness, effective residual ink concentration (ERIC), deinkability factor based on brightness (DB), deinkability factor based on ERIC (DE), dirt counts, strength properties and effluent characteristics was studied and compared with their respective control. Also, the effect of different enzyme concoctions on fiber surface and fiber morphological changes during the deinking process were studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results showed that, compared to control, a maximum improvement in brightness by 13.30% (ISO), DB 37.79%, and DE 83.0% and a reduction in ERIC and dirt counts by 68.18 and 88.04%, respectively, were achieved with a concoction of cellulase+xylanase+amylase+lipase at a dosage of 6, 3, 1.5 and 6 IU/mL, respectively. This indicated that there was a synergistic deinking effect among the concoctions of these enzymes as fiber surface roughness increased by 159% compared to control.