Bio-bleaching of Anthocephalus cadamba Kraft Pulp through Direct Fungal Treatment by FEQP Sequence

Abstract

Aims: The study aims at mitigating pulp kappa number before bleaching to minimize pollution load. Study Design: An experimental study. Methodology: The various parameters of direct fungal (Coprinellus disseminatus MLK01) treatment (F-stage) of unbleached kraft pulp of Anthocephalus cadamba were optimized and compared with the results of enzymatically pre-bleaching. Finally, the pulp was bleached by EQP three-stage and XECEHH six stages bleaching sequences. Results: Direct fungal treatment (F-stage) delignified the Anthocephalus cadamba kraft pulp more selectively with Coprinellus disseminatus MLK01 compared to xylanase prebleached pulp from the same fungus and oxygen delignification. F-stage mitigated the unbleached pulp kappa number by 55.0% and improved brightness and viscosity by 17.3 and 7.63% respectively. Kappa number reduction and brightness improvement were 22.1 and 6.3% more in F-stage compared to XE-stage. The kappa number and pulp brightness of oxygen delignified were 0.9 and 5.2% less compared to F-stage. The viscosity of oxygen delignified pulp reduced drastically due to alkaline peeling reactions compared to XE-stage (‒26.86%) and F-stage (‒27.09%). The brightness and viscosity of XECEHH bleached pulp were 80.1% and 7.4 cps at a chlorine demand of 4.3% while FEQP bleached pulp produced brightness of 79.7% and viscosity 8.2 cps. COD and colour values in effluent generated during FEQP bleaching were 53.29% and 54.36% less compared to CEHH bleaching.