Waste Paper as Feedstock for Dissolving Grade Pulp Production. Challenges and Opportunities: A Review

Abstract

Dissolving-grade pulp (DGP) is a high-purity cellulose feedstock used in the manufacture of regenerated cellulose fibers and cellulose derivatives. Global DGP production is concentrated in regions with established forest-based industries and relies primarily on virgin lignocellulosic resources, including cotton linters, hardwoods, softwoods, and bamboo. These raw materials are typically processed through acid sulfite or prehydrolysis kraft pulping to achieve alpha-cellulose contents above 90%. Compared with virgin feedstocks, recycled fibers exhibit greater variability in morphology and chemical composition, including shorter fiber lengths, lower cellulose quality, and higher levels of residual lignin, ash, inks, fillers, coatings, and other papermaking additives. Consequently, major waste paper streams, such as old corrugated container (OCC), old newspaper (ONP), old magazine (OMG), sorted office paper (SOP), and mixed paper (MP), present distinct challenges for meeting DGP quality specifications. Producing DGP from these secondary fiber resources requires the application of key pulp and paper processing technologies, including repulping, screening, advanced washing and deinking, delignification and bleaching, selective hemicellulose removal through alkaline and enzyme-assisted treatments, and cellulose reactivity enhancement. This review evaluates the technical feasibility of producing DGP from waste paper and highlights both the challenges and opportunities associated with valorizing recycled fibers as a sustainable source of high-purity cellulose.