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[Display omitted] The presence of ions in a solution is anticipated to induce distinct effects on macromolecules. Consequently, the tuning of adsorption and mass transfer of lignin molecules can be achieved by incorporating ions with chaotropic or kosmotropic characteristics. This study examines the adsorption and mass transfer behavior of lignin molecules across model cellulose membranes in presence of ions from the Hofmeister series. Experimental investigations encompassed the use of diffusion cells to quantify lignin's mass transfer through the membranes, and quartz crystal microbalance with dissipation (QCM-D) monitoring was used for adsorption studies. Notably, at high ion concentrations, the mass transport rate of lignin was observed to be lower in the presence of highly hydrated (kosmotropic) sulfate ions, conforming to the Hofmeister series. Intriguingly, this relationship was not apparent at lower ion concentrations. Furthermore, QCM-D experiments indicated that lignin displayed higher adsorption onto the cellulose surface when exposed to less hydrated (chaotropic) nitrate anions. This behavior can be rationalized by considering the system's increased entropy gain, facilitated by the release of adsorbed ions and water molecules from the cellulose surface upon lignin adsorption. This study highlights the complexity of ion-specific effects on mass transfer and adsorption processes and their dependency on ion concentrations. [ABSTRACT FROM AUTHOR]

Low-cost production of nanocellulose from diverse lignocellulosic feedstocks has become an important topic for developing sustainable nanomaterials. The available feedstocks include both woody and nonwoody plants, where the latter are relatively underutilized. Interestingly, the porous structure and low lignin content in most non-woody plants, such as agricultural residues and natural fibers, also makes them ideal sources for lower energy nanocellulose production using simpler methods than those required to process woody plants. To enhance the goal of circularity, this review first provides an overview of the nanocellulose conversion from cellulose and then comprehensively discusses the use of non-woody feedstocks for nanocellulose production. Specifically, the availability of suitable non-woody feedstocks and the use of low-cost processes for pulping and cellulose oxidation treatments, including alkaline, solvent pulping, and nitrogen-oxidation treatments, are discussed. The information in this review can lead to new opportunities to achieve greater sustainability in biobased economies. Additionally, demonstrations of nanocellulose-based water purification technologies using agricultural residues derived remediation materials are highlighted at the end of this review. [ABSTRACT FROM AUTHOR]

Monosaccharides such as L-arabinose (Ara) and D-tagatose (derived from D-galactose, Gal) are low-calorie sweeteners associated with improved glycaemic and insulin control compared to disaccharides such as sucrose. However, alternative sources and better sugar-sugar separation methods are needed to improve the sustainability and economics of their production. Here, these sugars were obtained from purified and ultrafiltered compression screw pressate (CSP) of thermo-mechanical pulping of softwood (Pinus radiata) and orange peels (OPs). Basubstituted zeolite X (BaX) molecular sieves showed superior separation performance of Ara from other sugars compared to conventional Ca-form ion exchange resin. To facilitate subsequent separation of sugars, OP hydrolysates were fermented to leave just Ara and Gal, while OP pectin was hydrolysed to generate a Gal-rich mixture. Overall, BaX has good potential for separating Ara from Ara-rich hydrolysates containing several different sugars. It is also suited for separating Ara and another monosaccharide such as Gal or Xyl in the absence of other sugars. [ABSTRACT FROM AUTHOR]

European paper mills are currently facing the question of whether recovered paper, their main raw material, will be available in sufficient quantities and an acceptable quality in the future. An alternative to recovered paper or wood fiber is the use of agricultural residues such as wheat straw. Sodium carbonate-based straw pulping processes have the advantage of not requiring recausticizing for chemical recovery, which reduces investment and operating costs. With the addition of oxygen, delignification can be significantly improved to provide pulps suitable for bleaching. This study compares the pulping of wheat straw using sodium carbonate, sodium carbonate + oxygen, and sodium carbonate + sodium hydroxide + oxygen. Pulping parameters such as temperature, retention time, and chemical charge were varied, and their influence on pulp properties was studied. The use of sodium carbonate alone produced pulps with high yields of up to 72% and comparably high burst and compressive strength. The addition of oxygen and small amounts of sodium hydroxide produced pulps with a high initial brightness of 42 %ISO and a low kappa number (18), still at high pulp yields of 62%. These pulps were two-stage bleached to achieve brightness levels of up to 73 %ISO. [ABSTRACT FROM AUTHOR]

The hydrophilicity of lignocellulosic biomass hinders the application of a high concentration slurry for supercritical water gasification, thereby reducing the gasification efficiency and energy self-sufficiency. A pretreatment method of alkaline pulping with KOH and NaOH was proposed to achieve the high feed concentration for continuous reactor and macromolecular simplification for barrier reduction of conversion. In this study, bark as an example of lignocellulosic biomass, whose 30 wt% and 40 wt% slurries with favorable rheology and stability, was prepared by alkaline pulping successfully. The minimum alkali consumption of NaOH and KOH pulping for 30 wt% and 40 wt% were 11%–14%, 16%–20%, and 16%–21%, 23%–28%, respectively. The most economical conditions were 180 °C and 24% KOH addition. All slurries prepared by NaOH and KOH at 180 and 200 °C could satisfy the industrial standard of coal-water slurry, and only 3–5 times higher than water viscosity. The bark macromolecules were restructured due to the hydrolysis of cellulose and lignin by breaking down the hydrogen bond and ether bond with trivial hydrocarbon matrix loss. The scattered crystal growth facilitated the uniform premixing of bark and water. Meanwhile, a surface particle charges potential increase leading to a heightened repulsive force by alkaline pulping furtherly enhanced the premixing effect. Additionally, metal ions could be deposited onto the bark surface during alkaline pulping. The chemical modification leading by alkaline pulping achieved the premixing of feedstock and water to form bark slurry. The conversion barrier was decreased to fulfill the ordered conversion, and 95.66% gasification efficiency for 40 wt% bark slurry was displayed at 600 °C with a preheated water of 6. Phenolic compounds and hydrocarbons were the most dominant components in liquid products. Polycyclic aromatic hydrocarbons in liquid products were detected at 620 °C with a preheated water of 4. The functional groups of organic matter in the slurry were significantly converted into the gas phase, and lattice oxygen was produced in the solid product. The alkali recovery was 65% at the optimal gasification condition, and achieved the maximum of 80% at 580 °C. The successful completion of this research affirms the dominance of the pulping-alkali recovery-gasification method for expanding the application of SCWG of lignocellulosic biomass in large engineering projects. Alkaline pulping was employed to modify the physiochemical properties. Metal ion loading, slurry preparation, and structural simplification reduced conversion barrier, which catalyzes the ordered conversion in the supercritical water gasification. [Display omitted] • The excellent pulping of KOH was present compared with NaOH. • Chemical modification of alkaline pulping reshaped the bark macromolecular. • Alkaline pulping was a new catalytic route for the H 2 production. • 40 wt% bark slurry achieved the ordered conversion in supercritical water at 600 °C. • The proper process of lignocellulosic biomass in supercritical water was proposed. [ABSTRACT FROM AUTHOR]

Production of dissolving pulp from wood for cellulose-based fibers is challenged by so-called lipophilic wood extractives (LWEs), causing serious quality issues. We investigated the application of three lipolytic enzymes—lipase, sterol esterase, cutinase—to achieve resource-friendly reduction of LWE components, such as sterol esters (SEs) and triglycerides (TGs), in beech brown stock pulp resulting from an acidic magnesium sulfite process. A mixture-process design based on a Kowalski–Cornell–Vining model was used to determine effective combinations of enzymes at different pH values (6–9), enzyme quantities (100–1000 ppm), and water qualities (process water from hot caustic extraction and softened fresh water). The hydrolysis performance was maintained on varying levels across the pH range due to the distinct optima of the enzymes. Lipase showed the highest activity against TG with −85 % (pH 7.5, process water, 550 ppm). No significant reduction of SEs was observed under simulated process conditions for any of the enzymes. Interestingly, process water led to a significant increase in TG hydrolysis of all enzymes with an additional conversion of about −10 % to −40 %. Looking closer, we discovered a pH buffering effect that stabilized the lipase reaction in process water, while a decrease in pH explained the poorer performance in softened fresh water. Implementing a new processing stage for pitch control comes with expenditure and operating costs. This study showed, that reusing process water instead of fresh water does not only enhance the performance of the used enzyme, but saves also water and stabilizing chemicals. [Display omitted] • Pros and cons of KCV mixture-process design for optimization of enzyme cocktails. • PH enzyme optima shift for pulp-containing systems determined using a KCV model. • Enzyme mixtures broaden the applicable pH range compared to single enzymes. • Buffering effect of fatty acids in process water enhances enzyme activity. [ABSTRACT FROM AUTHOR]