NH4OH- KOH Pulping and Single-Stage Bleaching Processes of Banana Pseudostem Waste: A Feasibility Study for Molded Pulp Packaging Use

Abstract

The NH4OH-KOH pulping was a highly efficient process for extracting banana pseudostem waste (BNW) pulp. Besides, this greener pulping process allowed NH4OH recovery and KOH can be later used as fertilizer, reducing the environmental impact. It was found that the optimal BNW pulping condition was using 8.3 wt% NH4OH and 3.3 wt% KOH at a cooking temperature of 155°C for 1 h, and liquid to solid ratio 6:1. From the results, this process allowed low chemical usage and provided high pulp yield (44%) with a high delignification degree (80%) and low Kappa no. (22). After pulping, the single-stage bleaching of BNW pulp using 8 wt% H2O2 and 1.5 wt% NaOH at 90°C for 1 h was shown to improve the whiteness and brightness of the BNW molded pulp samples to 69.7% and 28.7%ISO (3-fold increase), respectively. As compared to commercial molded pulp food packaging, the present BNW molded pulp exhibited a superior tensile index of 54.3 Nm/g and Young’s modulus of 4.8 GPa.