Alkali treatment of birch kraft pulp to enhance its TEMPO catalyzed oxidation with hypochlorite

Alkali treatment was used to increase the reactivity of birch kraft pulp prior to its 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) catalyzed oxidation with hypochlorite, which is a process commonly applied to prepare nanofibrillated cellulose. On contrary to the traditional use of NaBr as a cocatalyst, TEMPO was activated with HOCl prior to the oxidation. Commonly, the lack of bromide increases the oxidation time and impairs the formation of carboxylic groups. However, the reaction time of the bromide-free TEMPO catalyzed oxidation could be shortened from 2.5 to 0.5 h when the pulp was treated with 1 M NaOH prior to the oxidation (2.4 mmol NaOCl/g pulp). The beneficial effect was obtained even if the alkali treatment was executed at room temperature and only for few minutes. Moreover, the alkali pretreatment enabled selective production of a pulp with carboxylate content as high as 1.6 mmol/g with NaOCl dosage of 4.4 mmol/g. The changes in the cellulosic raw material during the alkali treatment were assessed by water retention value and carbohydrate analysis.     

Enhancing the effectiveness of a laccase–TEMPO treatment has a biorefining effect on sisal cellulose fibres

Enhancing the effectiveness of a laccase–TEMPO treatment on sisal pulp by increasing pulp consistency was for the first time found to increase the biorefining potential of this enzyme–mediator system. The operating conditions used were those previously found to maximize oxidative functionalization and paper strength. Prior to the enzyme treatment, the pulp was refined at a variable intensity (0, 3,000 and 4,500 revolutions) in order to ascertain whether the increased surface area would lead to enhanced functionalization and boost the refining effect as a result. Increasing pulp consistency increased the contents in aldehyde and carboxyl groups by 130% and 94%, respectively. Also, it resulted in more marked reduction of pulp viscosity during the enzyme treatment, especially at a high refining intensity; this had a detrimental effect on fibre strength and significantly reduced tear strength in the refined pulp. Oxidized pulp exhibited a considerably increased water retention value with respect to the initial pulp, particularly after refining. Dry tensile index was increased by 21, 18 and 12%, and burst index by 23, 16 and 13% at 0, 3,000 and 4,500 rev, respectively, by the laccase–TEMPO treatment as a result of increased inter-fibre hydrogen bonding offsetting the loss of fibre strength, an effect that can provide substantial savings in refining energy. Based on the results, a laccase–TEMPO treatment is an enzymatic booster of mechanical refining with the added advantages of providing unaltered drainability and increased air permeability. The most salient effect of the laccase–TEMPO treatment was an increase in wet tensile strength (by 160, 553 and 588% at 0, 3,000 and 4,500 rev, respectively) that can be ascribed to inter-fibre covalent bonding through hemiacetal linkages promoted by aldehyde groups. The improvement was much greater than that obtained at a lower consistency under identical conditions.     

A comparison of softwood and birch kraft pulp fibers as raw materials for production of TEMPO-oxidized pulp, MFC and superabsorbent foam

This study compares the suitability of using birch kraft pulp or softwood kraft pulp in the preparation of TEMPO-oxidized pulp, MFC and superabsorbent foam. TEMPO oxidation was performed using five different dosages of primary oxidant. The time of disintegration treatment was varied to study its influence on the properties of the produced MFCs and foams. Both the birch and the softwood pulps could be used for producing superabsorbent foams, depending on the process conditions, the absorption capacities were about the same for the two pulps and varied between 25 and 55 g saline solution/g absorbent. The foams based on birch pulp had, however, on average, 30 % higher retention capacity than the foams based on softwood pulp. The maximum retention capacity obtained was 16.6 g saline solution/g absorbent. The greater retention capacity of birch-based foams is not fully understood, but a smaller pore size may be the reason, which in turn would generate greater capillary forces. In addition to this, it was found that birch pulps, contrary to softwood pulps, had a substantial amount of fibers that were relatively unaffected by the disintegration treatment. These oxidized fibers are likely to reinforce the foam, thereby making the foam more resistant to external pressures, which is in accordance with earlier findings.     

Surface hydrophobization of cotton via laccase-mediated polydopamine deposition and dodecyl gallate grafting

Natural fibers containing components with phenolic hydroxyl groups, such as jute, wool, and silk, can be directly modified by laccase-catalyzed grafting. However, cellulosic fibers like cotton cannot be functionalized in this manner. In this work, we developed a facile two-step method to graft polymers on cotton fabric via laccase catalysis. First, polydopamine (PDA) coating was deposited on the surface of the cotton fabrics via catalysis of laccase/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) system. Then, the newly formed PDA coating acted as the secondary reaction platform for subsequent laccase-mediated grafting of hydrophobic monomer dodecyl gallate (DG). The oxidation of dopamine (DA) catalyzed with the laccase/TEMPO system was investigated using UV–visible (UV–vis) spectroscopy. The scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) results verified that the PDA was coated on the surface of cotton fibers. Fourier transform infrared (FTIR) spectra indicated that the PDA-coated cotton was successfully grafted with DG (DG-PDA-cotton). According to the weighting method, the grafting percentage was about 1.06%. The hydrophobicity of the DG-PDA-cotton fabrics was greatly improved with a contact angle of 133°. Also, the grafted cotton fabrics show repellency of water-soluble stains like coffee, milk, and tea. This study provides a new strategy for surface modification of cotton by laccase-mediated grafting, which offers the references for the green fabrication of cotton fabrics with improved functionalization.     

Qualitative evaluation of microfibrillated cellulose using the crill method and some aspects of microscopy

It has been a challenge to develop rapid online characterisation techniques for nanocellulose given the fibrillar structure of the nanoparticles. The crill optical analyser uses optical response signals in the infrared (IR) and ultraviolet (UV) wavelength ranges to evaluate the particle size properties of micro/nanofibrillar cellulosic materials. In this work, the crill analyser was used to measure the projected areas of UV and IR light sources by measuring the light blocked by nanocellulosic particles. This work uses the crill methodology as a new, simplified technique to characterise the particle size distribution of nanocellulosic material based on chemi-thermomechanical pulp (CTMP), thermomechanical pulp (TMP), and sulphite pulp (SP). In the first part, hydrogen peroxide pretreatment of CTMP and TMP in a wing mill refiner followed by high-pressure homogenisation to produce microfibrillated cellulose (MFC) was evaluated using the crill method. In the second part, TEMPO oxidation of CTMP and SP combined with high-shear homogenisation to produce MFC was studied using the crill method. With 4 % hydrogen peroxide pretreatment, the crill values of the unhomogenised samples were 218 and 214 for the TMP and CTMP, respectively, improving to 234 and 229 after 18 homogenisation passes. The results of the TEMPO method indicated that, for the 5 mmol NaClO SP-MFC, the crill value was 108 units at 0 min and 355 units after 90 min of treatment, a 228 % improvement. The CTMP and TMP fibres and the MFC were freeze dried and fibrillar structure of the fibres and microfibrils was visualised using scanning electron and transmission electron microscopy.     

Enhanced removal of hemicelluloses from cellulosic fibers by poly(ethylene glycol) during alkali treatment

Enhancing removal of hemicelluloses from cellulosic fibers is of decisive importance for producing high-purity cellulose. In this study, poly(ethylene glycol) (PEG) was added to a cold caustic extraction (CCE) process to promote removal of hemicelluloses from a softwood sulfite dissolving pulp. The content of hemicelluloses was considerably decreased from 11.4 % in the original sample to 5.3 % in the PEG/CCE-treated sample under the studied conditions. This positive result of PEG addition can be explained by (1) improved inward penetration and diffusion of NaOH into the fiber structure and outward diffusion of hemicelluloses from the fiber structure to the bulk phase, and (2) enhanced fiber swelling due to inclusion of PEG in the fiber walls and improved NaOH diffusion. Moreover, the effects of PEG/CCE treatment on the distribution of hemicelluloses in the fiber walls and the molecular weight of the residual hemicelluloses in the resulting pulp were investigated.     

Immobilized Laccase on Activated Poly(Vinyl Alcohol) Microspheres For Enzyme Thermistor Application

Poly(vinyl alcohol) (PVA) microspheres were prepared by inverse suspension crosslinked method, with glutaraldehyde as a crosslinking agent. PVA microspheres activated with aldehyde groups were employed for Trametes versicolor laccase immobilization. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize the activated PVA microspheres and PVA microspheres with immobilized laccase (Lac/PVA microspheres), which show that laccase was successfully immobilized on the PVA microspheres. The optimum pH and temperature coupling conditions for the immobilized laccase were determined to be 3.3 and 30 °C, respectively. Residual activity was also investigated by soaking the immobilized laccase in organic solvents at different concentrations, proving it chemically stable. Immobilized laccase exhibited good storage stability at 4 °C. The enzyme biosensor showed good performance in 2,2-azinobis(3-ethylthiazoline-6-sulfonate) and bisphenol A, with concentration ranges of 2 to 8 mM and 0.05 to 0.25 mM, respectively. Therefore, PVA microspheres may have high potential as support for enzyme thermistor applications.     

Enzymatic hydrolysis of mercerized and unmercerized sisal pulp

Enzymatic saccharification of sisal cellulosic pulp has been investigated. Brazil leads global production of lignocellulosic sisal fiber, which has high cellulose content, an important property for producing glucose via saccharification. Hence, sisal pulp can be a good alternative for use in biorefineries. Prior to enzymatic hydrolysis, the starting pulp [85 ± 2% α-cellulose, 15 ± 2% hemicelluloses, 1.2 ± 2% insoluble lignin, viscometric average molar mass (MMvis) 19,357 ± 590 g mol^?1, crystallinity index (CI) 74%] was pretreated with alkaline aqueous solution (mercerization, 20 g of pulp L^?1, 20% NaOH, 50 °C). The changes in the properties of the cellulosic pulp during this pretreatment were analyzed [α-cellulose content, MMvis, CI, pulp fiber dimensions, and scanning electron microscopy (SEM)]. The unmercerized and mercerized (97.4 ± 2% α-cellulose, 2.6 ± 2% hemicelluloses, 0.3 ± 0.1% insoluble lignin, MMvis 94,618 ± 300 g mol^?1, CI 68%) pulps were subjected to enzymatic hydrolysis (48 h, commercial cellulase enzymes, 0.5 mL g^?1 pulp); during the reactions, aliquots consisting of unreacted pulp and liquor were withdrawn from the medium at certain times and characterized (unreacted pulp: MMvis, CI, fiber dimensions, SEM; liquor: high-performance liquid chromatography). The changes in pulp properties observed during mercerization facilitated access of enzymes to cellulose chains, and the yield of the hydrolysis reaction increased from 50.2 (unmercerized pulp) to 89.0% (mercerized pulp). These initial results for enzymatic hydrolysis of sisal pulp indicate that it represents a good alternative biomass for bioethanol production.     

Residual lignin inhibits thermal degradation of cellulosic fiber sheets

The market for cellulosic fiber based food packaging applications is growing together with the importance of improving the thermal durability of these fibers. To shed light on this, we investigated the role of residual lignin in pulp on the thermal stability of refined pulp sheets. The unbleached, oxygen delignified, and fully bleached pulp sheets were studied after four separate refining degrees. Comparison by Gurley air resistance, Bendtsen porosity, and the oxygen transmission rate tests showed that lignin containing sheets had better air and oxygen barrier properties than fully bleached sheets. Sheet density and light scattering coefficient measurements further confirmed that the lignin containing pulps underwent more intense fibrillation upon refining that changed the barrier properties of the sheets. Thermal treatments (at 225 °C, 20 and 60 min, in water vapor atmospheres of 1 and 75 v/v %) were applied to determine the thermal durability of the sheets. The results revealed that the residual lignin in pulps improved the thermal stability of the pulp sheets in the hot humid conditions. This effect was systematically studied by tensile strength, brightness, and light absorption coefficient measurements. The intrinsic viscosity results support the findings and suggest that lignin is able to hinder the thermal degradation of pulp polysaccharides. In spite of the fact that lignin is known to enhance the thermal yellowing of paper, no significant discoloration of the pulp sheets containing residual lignin was observed in the hot humid conditions (75 v/v %). Our results support the idea of lignin strengthening the thermal durability of paper.     

Adsorption and inactivation behavior of horseradish peroxidase on cellulosic fiber surfaces

The physical immobilization behavior of horseradish peroxidase (HRP) on cellulosic fiber surfaces was characterized using adsorption and inactivation isotherms measured by the depletion method followed by fitting of Langmuir’s and Freundlich’s models to the experimental data. The adsorption and inactivation behavior of simpler and relatively non-porous high and low crystalline cellulosic substrates (microcrystalline cellulose and regenerated cellulose) as well as more complex and porous cellulosic pulp fibers (bleached kraft softwood fibers) were investigated. The effect of the sorbent surface energy on HRP adsorption was demonstrated by increasing the hydrophobicity of the cellulosic fibers using an internal sizing agent. The influence of the fiber surface charge density on HRP adsorption was studied via modification of the cellulosic fibers using TEMPO (2,2,6,6-tetramethyl-1-piperidiniloxy radical)-mediated oxidation methods. Results showed that hydrophobic interactions had a much larger effect on HRP adsorption than electrostatic interactions. More hydrophobic fiber surfaces (lower polar surface energy) result in larger enzyme-fiber binding affinity constants and higher binding heterogeneity. It was also found that oxidation of the cellulosic fiber substrate reduces enzyme adsorption affinity but significantly increases the loading capacity per unit weight of the surface.     

Reinforced absorbent material: a cellulosic composite of TEMPO-oxidized MFC and CTMP fibres

This research aims to develop new materials based on renewable resources that can fulfill the functions necessary in the absorption core of a disposable diaper. Absorbent foam was recently produced from softwood kraft pulp by TEMPO oxidation, disintegration and freeze drying. In this study, the TEMPO-oxidized MFC was mixed with pulp fibres, thus forming a cellulosic composite, in an attempt to improve the mechanical stability of the freeze-dried absorbent material. The fibres were added in different amounts and the freeze-dried materials were evaluated for their absorption and retention properties. The results of this study suggest that the composite material has a better mechanical stability than the absorbent foam without fibres. It was shown that using spruce CTMP fibres in the composite resulted in better absorption and retention capacities than in a composite with softwood kraft pulp fibres. The higher stiffness of the CTMP fibres is a probable explanation for this difference. For the composite material with CTMP fibres, liquid porosimetry showed that pore size distribution was more or less retained when put under load. Furthermore, it was seen that the retention properties reached a maximum around 85 % CTMP fibres and 15 % TEMPO-oxidized MFC. In the centrifuge retention test, the retention of the TEMPO-oxidized MFC in the composite material reached about the same capacity as conventional superabsorbent polymers.     

Purification of cellulosic pulp by hot water extraction

Hot water extraction (HWE) of pulp in a flow-through reactor was evaluated as a method to purify paper-grade pulps. About 50–80 % of the xylan and up to 50 % of the lignin in unbleached birch Kraft pulp was extracted by the HWE without losses in cellulose yield. The residual xylan content in the extracted pulps was predominantly too high for dissolving-grade applications, but some of the pulps with a xylan content of 5–7 % might still be suitable as rayon-grade pulps. Increasing extraction temperature lowered the xylan content at which cellulose yield started to decrease. Furthermore, at any given xylan content, increasing extraction temperature resulted in cellulosic pulp with higher degree of polymerization. The extracted xylan was recovered almost quantitatively as xylo-oligosaccharides. The results suggest that HWEs at elevated temperatures may be applied to purify cellulosic pulps, preferably containing a low xylan content, and to recover the extracted sugars.     

Preparation, characterization of carboxylated bamboo fibers and their adsorption for lead(II) ions in aqueous solution

The present study was conducted to develop a simple and versatile method to prepare carboxylated bamboo fibers which can be applied as potential bio-adsorbent for metal ions removal due to the high content of carboxyl groups. The chemical modification of bamboo fibers with citric acid (CA) was carried out by friendly semi-dry oven method. The resulting products with carboxyl group content between 1.99 and 4.13 mmol/g were accessible by changing ultrasonic pretreatment time, reaction temperature, reaction time and the amounts of catalyst and citric acid in order to minimize cross-linking reaction and thereby maximize carboxyl groups content. The characterization of the resulting products confirmed that carboxyl groups were successfully grafted onto surface of bamboo fibers. Moreover, the carboxylated bamboo fibers could be applied as bio-adsorbent for the removal of lead(II) ions from aqueous solution. Results showed that the adsorption capacity of Pd²⁺ could reach 127.1 mg/g for carboxylated bamboo fibers with 4.13 mmol/g carboxyl group content prepared under the ultrasonic pretreatment for 20 min at the CA/bamboo fibers weight ratio of 4.0 in the catalyst amount of 30 wt% at 120 °C for 90 min and the carboxylated bamboo fibers exhibited highly efficient regeneration with no significant loss of adsorption capacity of lead ion after five repeated adsorption/desorption cycles.     

Xylan enriched viscose fibers

In this study, a new xylan enriched viscose fiber was developed. A high molecular weight xylan with a degree of polymerization of 150–200 was added during a late stage of the viscose production process. The xylan deriving from a cold caustic extraction (CCE) of an eucalypt paper pulp was introduced to the process after xanthation and thus neither objected to any degradation conditions during alkalization nor to the xanthation step. About 90 % of the added xylan was transferred to the final fiber. A xylan content of up to 7.5 % was achieved. Fiber properties like strength showed a comparable level to the reference fibers while the water retention value was clearly raised due to the higher content of hemicelluloses. The hemicellulose distribution over the fiber cross section was investigated by enzymatic peeling. Even though a segregation of the different polysaccharides was observed, the goal of a good blending of CCE-xylan into cellulosic fibers with new interesting features was achieved.     

Nanofibrillated cellulose/nanographite composite films

Though research into nanofibrillated cellulose (NFC) has recently increased, few studies have considered co-utilising NFC and nanographite (NG) in composite films, and, it has, however been a challenge to use high-yield pulp fibres (mechanical pulps) to produce this nanofibrillar material. It is worth noting that there is a significant difference between chemical pulp fibres and high-yield pulp fibres, as the former is composed mainly of cellulose and has a yield of approximately 50 % while the latter is consist of cellulose, hemicellulose and lignin, and has a yield of approximately 90 %. NFC was produced by combining TEMPO (2,2,6,6-tetramethypiperidine-1-oxyl)-mediated oxidation with the mechanical shearing of chemi-thermomechanical pulp (CTMP) and sulphite pulp (SP); the NG was produced by mechanically exfoliating graphite. The different NaClO dosages in the TEMPO system differently oxidised the fibres, altering their fibrillation efficiency. NFC–NG films were produced by casting in a Petri dish. We examine the effect of NG on the sheet-resistance and mechanical properties of NFC films. Addition of 10 wt% NG to 90 wt% NFC of sample CC2 (5 mmol NaClO CTMP-NFC homogenised for 60 min) improved the sheet resistance, i.e. from that of an insulating pure NFC film to 180 Ω/sq. Further addition of 20 (CC3) and 25 wt% (CC4) of NG to 80 and 75 wt% respectively, lowered the sheet resistance to 17 and 9 Ω/sq, respectively. For the mechanical properties, we found that adding 10 wt% NG to 90 wt% NFC of sample HH2 (5 mmol NaClO SP-NFC homogenised for 60 min) improved the tensile index by 28 %, tensile stiffness index by 20 %, and peak load by 28 %. The film’s surface morphology was visualised using scanning electron microscopy, revealing the fibrillated structure of NFC and NG. This methodology yields NFC–NG films that are mechanically stable, bendable, and flexible.     

Fiber properties of eucalyptus kraft pulp with different carboxyl group contents

Fiber properties (fiber swelling ability, crystal structure of cellulose, fiber surface morphology, and etc.) of eucalyptus kraft pulp with different contents of carboxyl group in Na-form were studied. There was a direct proportional relationship between water retention value and carboxyl content of pulp. When the carboxyl content increased from 35.6 to 315.7 mmol/kg, tensile index and burst index increased by 56.1 and 117.8 %, respectively, and crystallinity of cellulose decreased by 11.8 %. Environmental scanning electron microscope showed that more fibrillation was observed on the carboxymethylated fiber surface, compared with the control sample. The results from Fourier transform infrared spectra analysis suggested that the relative intensity of the band at 1,633/cm was increased after carboxymethylation treatment, which showed that the carboxyl content increased. The increase in the carboxyl content not only could increase the fiber strength properties, but also could increase the recycling times of the fiber.     

Alkaline steeping of dissolving pulp. Part I: cellulose degradation kinetics

The production of cellulosic man made fibres by the viscose process has been known for more than 120 years now, but still some aspects are not sufficiently understood in detail. The carbohydrates in the pulp are exposed to varying conditions during the manufacturing process. In the first production step of steeping, the strong alkaline treatment leads to undesirable loss reactions of the cellulose. In this study, a comprehensive kinetic model was developed for process simulation of cellulose degradation for the fist time comprising primary and secondary peeling, stopping and alkaline hydrolysis. A total chlorine free bleached beech sulfite pulp was treated with 18 % sodium hydroxide at 40, 50 and 60 °C for time periods up to 80 h. The corresponding reaction rates, activation energies and frequency factors for all reaction steps were calculated. The peeling-off reaction was of great significance for the cellulose yield loss, due to a contribution of the secondary peeling after random chain scission. The moderate decrease of the intrinsic viscosity and the changes in molar mass distribution indicated the validity of the assumption. Further, a reduction of the carbonyl and an increase of the carboxyl groups in the cellulose were observed due to the formation of the stable metasaccharinic acid at the reducing ends of the molecules. The fibre morphology was investigated by SEM measurements. Already short alkaline treatment times favored the dissolution of fibril fragments from the fibre surface leading to a smooth fibre surface.     

Preparation of cellulosic fibers with biological activity by immobilization of trypsin on periodate oxidized viscose fibers

In this study, a biologically active fibrous material was designed by immobilizing trypsin on viscose fibers. The viscose yarn was first oxidized with sodium periodate to produce aldehyde groups and then employed as a support for subsequent immobilization of trypsin through bovine serum albumin. The oxidation by sodium periodate caused changes in the chemical and physical properties of the modified yarn samples, which were evaluated by determining the aldehyde group content, fineness and tensile strength of yarn. The viscose fibers oxidized under the most severe conditions (0.4 % NaIO₄, 360 min) exhibited the maximum amount of introduced aldehyde groups (1.284 mmol/g), but also the highest decrease in tensile strength. The trypsin activity was assayed with N-α-benzoyl-DL-arginine p-nitroanilide hydrochloride, whereas the amount of bound trypsin was determined by Bradford method. Trypsin immobilized on oxidized viscose yarn retained 97.3 and 83.8 % of the initial activity over 60 days of storage at 4 and 25 °C, respectively, and remained firmly attached to the carrier. The potential application of obtained bioactive fibers is in the treatment of wounds.     

SEC-MALLS analysis of TEMPO-oxidized celluloses using methylation of carboxyl groups

Two cellouronic acids [sodium (1 → 4)-β-polyglucuronates, CUAs] and one 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized wood cellulose (TOC) became soluble in 8 % lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) after the methylation of C6 carboxyl groups in these samples using trimethylsilyldiazomethane (TMSD). The obtained solutions were diluted to 1 % LiCl/DMAc and subjected to size-exclusion chromatography combined with multi-angle laser-light scattering (SEC-MALLS). Neither depolymerization nor side reactions took place during methylation; this was confirmed by SEC-MALLS and nuclear magnetic resonance analyses, using CUAs as models. The SEC-MALLS analysis of the original wood cellulose and the carboxyl-methylated TOC prepared from it, using 1 % LiCl/N,N-dimethyl-2-imidazolidinone and 1 % LiCl/DMAc, respectively, as eluents, showed that the weight-average degree of polymerization of the original wood cellulose decreased from 3,100 to 2,210 through TEMPO-mediated oxidation. The molecular-mass distributions of the original wood cellulose and the TOC both consisted of one large peak with a small shoulder, indicating that some of the oxidized hemicelluloses remained in the TOC. The combination of methylation of carboxyl groups in polysaccharides using TMSD and subsequent SEC-MALLS analysis using 1 % LiCl/DMAc as an eluent may be applicable not only to TOCs, but also to other polysaccharides with carboxyl groups, for evaluation of their molecular-mass parameters.     

Ionic liquid extraction method for upgrading eucalyptus kraft pulp to high purity dissolving pulp

High purity cellulose from wood is an important raw material for many applications such as cellulosic fibers, films or the manufacture of various cellulose acetate products. Hitherto, multi-step refining processes are needed for an efficient hemicellulose removal, most of them suffering from severe cellulose losses. Recently, a novel method for producing high purity cellulose from bleached paper grade birch kraft pulp was presented. In this so called IONCELL process, hemicelluloses are extracted by an ionic liquid–water mixture and both fractions can be recovered without yield losses or polymer degradation. Herein, it is demonstrated that bleached Eucalyptus urograndis kraft pulp can be refined to high purity acetate grade pulp via the IONCELL process. The hemicellulose content could be reduced from initial 16.6 to 2.4 wt% while persevering the cellulose I crystal form by using an optimized 1-ethyl-3-methylimidazolium dimethylphosphate-water mixture as the extraction medium. The degree of polymerization was then reduced by a sulfuric acid treatment for subsequent acetylation of the pulp, resulting in a final hemicellulose content of 2.2 wt%. When pre-treating the pulp enzymatically with endoxylanase, the final hemicellulose content could be reduced even to 1.7 wt%. For comparison, the eucalyptus kraft pulp was also subjected to cold caustic extraction and the same subsequent acid treatment which led to 3.9 wt% of residual hemicelluloses. The performance in acetylation of all produced pulps was tested and compared to commercial acetate grade pulp. The endoxylanase-IONCELL-treated pulp showed superior properties. Thus, an ecologically and economically efficient alternative for the production of highest value cellulose pulp is presented.