Pulp and paper mill wastes: utilizations and prospects for high value-added biomaterials

Abstract

A wide variety of biomass is available all around the world. Most of the biomass exists as a by-product from manufacturing industries. Pulp and paper mills contribute to a higher amount of these biomasses mostly discarded in the landfills creating an environmental burden. Biomasses from other sources have been used to produce different kinds and grades of biomaterials such as those used in industrial and medical applications. The present review aims to investigate the availability of biomass from pulp and paper mills and show sustainable routes for the production of high value-added biomaterials. The study reveals that using conventional and integrated biorefinery technology the ample variety and quantity of waste generated from pulp and paper mills can be converted into wealth. As per the findings of the current review, it is shown that high-performance carbon fiber and bioplastic can be manufactured from black liquor of pulping waste; the cellulosic waste from sawdust and sludge can be utilized for the synthesis of CNC and regenerated fibers such as viscose rayon and acetate; the mineral-based pulping wastes and fly ash can be used for manufacturing of different kinds of biocomposites. The different biomaterials obtained from the pulp and paper mill biomass can be used for versatile applications including conventional, high performance, and smart materials. Through customization and optimization of the conversion techniques and product manufacturing schemes, a variety of engineering materials can be obtained from pulp and paper mill wastes realizing the current global waste to wealth developmental approach.

Keywords: Biomass; Biomaterials; Biorefinery; High value-added; Paper mill; Pulping waste.

Fig. 1

Yearly trend and future forecast on world paper production

Fig. 2

Global consumption of paper by major countries

Fig. 3

Process flow in pulp and paper manufacturing mills

Fig. 4

Sites of waste generation in pulp and paper manufacturing

Fig. 5

Black liquor: a Gross structure of black liquor; b Black liquor separation

Fig. 6

Major wastes generated from pulp and paper mills: a sawdust; b sludge; c waste paper; d inorganic wastes (dregs, lime mud, grits); e Fly ash

Fig. 7

Current utilization of pulp and paper mill inorganic wastes (GLD green liquor dregs, SG slacker grits, LM lime mud, BFA boiler fly ash)

Fig. 8

Major precursors of lignin (a) typical structural model of lignin (b)

Fig. 9

Spinning of lignin into carbon fiber (Gbenebor and Adeosun 2019)

Fig. 10

Xylan to PLA route

Fig. 11

Multitude application of CNC biomaterial

Fig. 12

Extracting CNC from trees

Fig. 13

Dissolving pulp beneficiation: regenerated fibers

Fig. 14

Possible applications of biocomposites from pulp and paper mill waste