Approaching a Low-Cost Production of Cellulose Nanofibers for Papermaking Applications

Abstract

The use of cellulose nanofibers (CNF) as an additive in papermaking is an attractive alternative to improve paper's strength. However, the costs of CNF production need to be competitive compared to other approaches aimed at reducing mechanical beating. Five different types of CNFs were prepared following different pretreatments: TEMPO-mediated oxidation at basic and neutral conditions, soft acid hydrolysis, enzymatic treatment, and mechanical beating. All of the pretreated fibers were later passed through a high-pressure homogenizer. The resulting CNFs were each applied to a papermaking pulp to investigate their reinforcing ability. Results indicated that the TEMPO-oxidized CNFs offered the highest increase at the same nanofiber content compared to the other types of CNFs. However, an analysis of the cost of increasing paper's breaking length by 75% indicated that TEMPO-oxidized CNFs were more expensive than the other CNF grades, whereas CNFs from mechanical and acid pretreatment offered similar increases at lower prices. The results indicated that CNFs of high fibrillation degree were not necessary to induce dramatic increases in paper strength. This finding offers a new possibility for the escalation of CNF production to industrial levels with competitive prices.

The feasibility of incorporating cellulose micro/nanofibers in papermaking processes: the relevance of enzymatic hydrolysis

“…3 Evolution of the breaking length of different CNFreinforced papers as the enzyme dosage and time of the treatments increase for mechanically refined pulps (Henriksson et al 2007;Pääkkö et al 2007), but with higher effectiveness. The environmental advantages of using cellulose nanofibers for the enhancement of the mechanical properties of paper instead of using conventional processes such as mechanical refining have been previously discussed (Delgado-Aguilar et al 2015b), as have some of the economic aspects (Delgado-Aguilar et al 2015d). Accordingly, it must be pointed out, as described in the experimental section, that each CNF in the present work was produced applying the same mechanical energy during the nanofibrillation process.…”

“…Thus, among the explored treatments that lead to CNFs that impart an about 100 % increase of tensile strength when 3 wt% is added for unrefined pulps, the more environmentally friendly and economically sustainable ones should be determined in further research. However, regarding the cost of producing this type of CNF, the total cost per kilo of obtaining enzymatically hydrolyzed CNF has been previously published (Delgado-Aguilar et al 2015d). In that work, the total cost of enzymatic CNF was 13.66 €/kg, and the result was CNFs with lower efficiency in terms of property enhancement.…”

“…These nomenclatures always refer to the pretreatment applied to the fiber. Each type of CNF can be used for many applications depending on its intrinsic properties such as the transparency, dimensions or strengthening potential (Delgado-Aguilar et al 2015d). Considering their role in papermaking processes, it must be taken into account that the added value of paper products is usually low.…”

“…In this regard, the present work attempted to improve the effectiveness of the pretreatment step (enzymatic hydrolysis, in this case) with the purpose of easing the nanofibrillation step, obtaining CNF suspensions with yields of nanofibrillation equal to or even higher than those obtained by mechanical treatments (Delgado-Aguilar et al 2015d) with lower energy consumption for their production.…”

High‐Performance Virus Removal Filter Paper for Drinking Water Purification

“…The advances in nanocellulose science allow today for cost‐efficient production of this material . Recently, a highly cost‐efficient virus removal filter paper, aka mille‐feuille filter paper, was described for applications in biotechnology .…”