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Deep eutectic solvents (DESs) are a potentially high-value lignin extraction methodology. DESs prepared from choline chloride (ChCl) and three hydrogen-bond donors (HBD)-lactic acid (Lac), glycerol, and urea-were evaluated for isolation of willow ( Salix matsudana cv. Zhuliu ) lignin. DESs types, mole ratio of ChCl to HBD, extraction temperature, and time on the fractionated DES-lignin yield demonstrated that the optimal DES-lignin yield (91.8 wt % based on the initial lignin in willow) with high purity of 94.5% can be reached at a ChCl-to-Lac molar ratio of 1:10, extraction temperature of 120 °C, and time of 12 h. Fourier transform infrared spectroscopy (FT-IR) , 13 C-NMR, and 31 P-NMR showed that willow lignin extracted by ChCl-Lac was mainly composed of syringyl and guaiacyl units. Serendipitously, a majority of the glucan in willow was preserved after ChCl-Lac treatment., Competing Interests: The authors declare no conflict of interest.

Lignins are used often in formulations involving proteins but little is known about the surface interactions between these important biomacromolecules. In this work, we investigate the interactions at the solid-liquid interface of lignin with the two main proteins in soy, glycinin (11S) and β-conglycinin (7S). The extent of adsorption of 11S and 7S onto lignin films and the degree of hydration of the interfacial layers is quantified via Quartz crystal microgravimetry (QCM) and surface plasmon resonance (SPR). Solution ionic strength and protein denaturation (2-mercaptoethanol and urea) critically affect the adsorption process as protein molecules undergo conformational changes and their hydrophobic or hydrophilic amino acid residues interact with the surrounding medium. In general, the adsorption of the undenatured proteins onto lignin is more extensive compared to that of the denatured biomolecules and a large amount of water is coupled to the adsorbed molecules. The reduction in water contact angle after protein adsorption (by ~40° and 35° for undenatured 11S and 7S, respectively) is explained by strong nonspecific interactions between soy proteins and lignin.

As a major component in plant cell walls, lignin is an important factor in numerous industrial processes, especially in wood saccharification and fermentation to biofuels. The ability to chemically differentiate and spatially locate lignins in wood cell structures provides an important contribution to the effort to improve these processes. The spatial distribution of the syringyl (S) and guaiacyl (G) lignins, both over larger regions and within a single cell wall, on poplar ( Populus trichocarpa ) wood cross-sections was determined via time-of-flight secondary ion mass spectrometry (ToF-SIMS). This is the first time that direct chemically specific mass spectrometric mapping has been employed to elucidate the spatial distribution of S and G lignins. In agreement with results obtained by UV microscopy, ToF-SIMS images clearly show that the guaiacyl lignin is predominantly located in the vessel cell walls of poplar wood while syringyl lignin is mainly located in the fiber cell walls. The G/S ratio in vessel cell walls was determined to be approximately twice that found in fiber cell walls. A combination of Bi ToF-SIMS spectral image acquisition and C(60) sputtering provided the ability to attain the combination of spatial resolution and signal-to-noise necessary to determine the distribution of S and G lignins in a single cell wall. By this technique, it was possible to demonstrate that more guaiacyl lignin is located in the middle lamella layer and more syringyl lignin is located in the inner cell wall area.

Many studies of lignins in solution invoke association and aggregation phenomena to explain their solution behavior (e.g., reprecipitation onto pulp fibers, condensation, etc.). Following their colloidal (apparent) molecular weights in solution as a function of time allows us to explore observable dissociation phenomena. These measurements were carried out using multiple angle laser light scattering (MALLS) photometry in the static mode. The challenges and opportunities of measuring the specific refractive index increment (dn/dC) of lignin solutions and determining the kinetics of the dissociation process were thus investigated. Hardwood and softwood representative lignins were isolated, and method for their full dissolution in THF was further developed, which then lead to accurate dn/dC values being obtained as a function of time. When coupled to additional work using light scattering static measurements and Zimm plots for the same solutions, this effort offers insight into the aggregation and ensuing dissociative events that operate within the lignin macromolecules.

Despite evidence that lignin associates under both aqueous and organic media, the magnitude and nature of the underlying driving forces are still a matter of discussion. The present paper addresses this issue by examining both solution properties and size exclusion behaviour of lignins isolated from five different species of softwoods, as well as from the angiosperms Eucalyptus globulus and wheat straw. This investigation has used the recently described protocol for isolating enzymatic mild acidolysis lignin (EMAL), which offers lignin samples highly representative of the overall lignin present in the wood cell wall. The molecular weight distributions of these EMALs were found to be dependent upon the wood species from which they were isolated and upon the incubation conditions used prior to size exclusion chromatography. While the chromatograms of EMALs isolated from softwoods displayed a bimodal behaviour, the elution profiles of EMAL from E. globulus and straw were nearly unimodal. A marked tendency to dissociate prevailed under incubation at room temperature for all examined species with the exception of the straw lignin preparation; furthermore, lignin solutions incubated at 4 degrees C showed an associative behaviour manifested by an increase in the weight and number average molecular weights for some species. The extent of such association/dissociation, as well as the time needed for the process to reach completion, was also found to depend upon the wood species, i.e. lignins from softwoods were found to associate/dissociate to a greater extent than lignins from E. globulus and straw. The origin of such effects within the lignin structure is also discussed.

Milled wood lignin (MWL), cellulolytic enzyme lignin (CEL), and enzymatic mild acidolysis lignin (EMAL) were isolated from different wood species and characterized by various techniques. The EMAL protocol offered gravimetric lignin yields 2-5 times greater than those of the corresponding MWL and CEL. The purities of the EMALs were 3.75-10.6% higher than those of their corresponding CELs, depending upon the wood species from which they were isolated. Molecular weight analyses showed that the EMAL protocol isolates lignin fractions that are not accessed by the other procedures evaluated, while 31P NMR spectroscopy revealed that MWL is more condensed and bears more phenolic hydroxyl groups than EMAL and CEL. The yields and purities of EMAL, MWL, and CEL from hardwood were greater than those obtained for the examined softwoods. Structural details obtained by DFRC (derivatization followed by reductive cleavage)/31P NMR revealed different contents of condensed and uncondensed beta-O-aryl ether structures, dibenzodioxocins, and condensed and uncondensed phenolic hydroxyl and carboxylic acid groups within lignins isolated from different wood species.

The recently developed protocol for isolating enzymatic mild acidolysis lignins (EMAL) coupled with the novel combination of derivatization followed by reductive cleavage (DFRC) and quantitative (31)P NMR spectroscopy were used to better understand the lignin isolation process from wood. The EMAL protocol is shown to offer access at lignin samples that are more representative of the overall lignin present in milled wood. The combination of DFRC/(31)P NMR provided a detailed picture on the effects of the isolation conditions on the lignin structure. More specifically, we have used vibratory and ball milling as the two methods of wood pulverization and have compared their effects on the lignin structures and molecular weights. Vibratory-milling conditions cause substantial lignin depolymerization. Lignin depolymerization occurs via the cleavage of uncondensed beta-aryl ether linkages, while condensed beta-aryl ethers and dibenzodioxocins were found to be resistant to such mechanical action. Condensation and side chain oxidations were induced mechanochemically under vibratory-milling conditions as evidenced by the increased amounts of condensed phenolic hydroxyl and carboxylic acid groups. Alternatively, the mild mechanical treatment offered by ball milling was found not to affect the isolated lignin macromolecular structure. However, the overall lignin yields were found to be compromised when the mechanical action was less intense, necessitating longer milling times under ball-milling conditions. As compared to other lignin preparations isolated from the same batch of milled wood, the yield of EMAL was about four times greater than the corresponding milled wood lignin (MWL) and about two times greater as compared to cellulolytic enzyme lignin (CEL). Molecular weight distribution analyses also pointed out that the EMAL protocol allows the isolation of lignin fractions that are not accessed by any other lignin isolation procedures.

The surface and total charge density of industrially manufactured hardwood and softwood grade kraft lignocellulosic fibers can mainly be attributed to carboxylic acid functionalities as determined from topochemical adsorption of a cationic polymer (methyl glycol chitosan) and the use of conductometric titration. These charge density measurement methods have led to a powerful and accurate photometric method for the quantitative analysis of surface charge. The method is based on directly monitoring the iodide ion, the counterion of the chitosan polymer, which is released upon electroneutralization between a chitosan cationic site and an anionic site at the fiber surface, thereby directly providing the concentration of surface charge. The stoichiometry for the chitosan adsorption onto the fiber surfaces is unity despite pulp types and adsorption quantity of cationic polymer. Given the high charge density of the chitosan molecule and the determined physical charge density limitations for its distribution onto the surface of pulps, a new and heretofore unused concept referred to as the subsurface was posited to adequately describe the surface charge determination after the adsorption of cationic polymer on the fibers. More specifically, within the subsurface of the suspended fibers in solution, carboxylates (COO-) were neutralized by the cationic sites of chitosan. The COO- sites in the subsurface can electrically attract positive sites of the cationic polymer, resulting in the complete release of counterions. To account for the charge density measurements, the charge measurement of the fibers includes not only nominal topochemical surface charges but also charges below this surface (subsurface)., (Copyright 2004 Elsevier Inc.)

Magnetic lignin-based adsorbent (MLA) was successfully fabricated to remove methyl orange dye from aqueous solution. The synthesized MLA was characterized by means of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). In the process of adsorption, influence factors and recycling performance were considered, and the adsorption mechanisms such as isotherm and kinetics were investigated. The result showed that the equilibrium data was consisted with the Langmuir model with a maximum adsorption capacity of 85.0 mg/g. The adsorption kinetics followed a pseudo-secondorder model. Based the adsorption performance, MLA showed good recyclability. Therefore, these results demonstrate that MLA could offer a great potential as an efficient and reusable adsorbent in the wastewater treatments. [ABSTRACT FROM AUTHOR]

Lignin is a by-product of the pulp and paper industry that can be precipitated by acidification from black liquor as a potential feedstock for valuable green materials. Precipitation and quantification of lignin from softwood black liquors have been documented and commercialized with well-established methods; however, applying those methods to the precipitation of lignin from hardwood black liquors has produced low lignin yields. A need to understand the main differences between hardwood and softwood lignin precipitation prompted the current investigation. Multiple black liquor samples from sweetgum and pine pulping were obtained at different times of standard kraft cooks. Two lignin fractions were precipitated from each of these black liquors, one at pH 9.5 and one at pH 2.5. Detailed lignin and carbohydrate material balances were performed around each of the sample sets, starting with the wood and ending with precipitated lignin fractions. For all conditions tested, the amount and purity of pine lignin precipitated were superior to sweetgum lignin. The maximum recovery for sweetgum lignin was 69.7%, while for pine lignin, it was 90.9%. [ABSTRACT FROM AUTHOR]

Hydrogels from alkali lignin were prepared and shown to display unique swelling. Variable lignin contents (6.25%, 10.00%, 12.50%, and 14.29%) were successfully grafted with both N,N'-methylenebisacrylamide (MBA) and acrylamide (AM). Ionic liquids such as 1-ethyl-3-methylimidazolium acetate ([Emim]Ac) were used to avoid harsh, unfriendly solvents. All materials were characterized using X-ray diffraction (XRD) FT-IR spectroscopy, scanning electron microscope (SEM), thermogravimetric analysis (TGA), and swellability. The swelling behaviors of the hydrogels were noticeably influenced by their lignin content. The degree of equilibrium swelling (the maximum swelling degree) decreased with increasing content of lignin. The highest swelling degree (1,650%) was obtained at 6.25 wt% lignin. Kinetics revealed that the swelling behaviors of hydrogels were well-fitted by the Schott model. [ABSTRACT FROM AUTHOR]

The stepwise pyrolysis of technical lignin with and without a catalyst was investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Lignin was first pyrolyzed at 260 or 360 °C, and then the residue was subsequently pyrolyzed at 650 °C. It was found that stepwise pyrolysis of lignin concentrated the phenolic compounds in lignin-derived bio-oil. In a stepwise 260 to 650 °C process, the maximum total phenolic compounds were 86.2%. Among the phenolic compounds, guaiacol-type and phenol-type phenolic compounds were predominant. Further addition of a catalyst (HZSM-5) in the stepwise pyrolysis process enhanced control over the product distribution through conversion of phenolic compounds into aromatic hydrocarbon products. The aromatic hydrocarbons achieved the highest yield of 30.4% in the catalytic stepwise 260 to 650 °C process. [ABSTRACT FROM AUTHOR]

Fractionation of lignocellulosic components is a prerequisite for maximizing valorization of plant biomass in an integrated biorefinery. In this study, microwave-assisted H2O2-NaOH extraction was developed for fractionation of Pennisetum sinese Roxb. (P. sinese), a highly productive energy crop. Different reaction conditions including solid-liquid ratio, NaOH concentration, H2O2 concentration, temperature, and time were tested for their effects on P. sinese fractionation. The cellulose, hemicellulose, and lignin obtained under optimal fractionation conditions were characterized by Fourier transform infrared spectrometry (FT-IR) and nuclear magnetic resonance (NMR). The optimal fractionation conditions were a solid-liquid ratio of 1:25 using 0.5% H2O2 and 4% NaOH at 75 °C for 4 h, which gave cellulose, hemicellulose, and lignin yields of 42.8%, 21.9%, and 15.2%, respectively. FT-IR and NMR analyses of the fractionated components clearly confirmed their structural integrity and representation. The work demonstrates the potential of the alternative approach for efficient fractionation of lignocellulosic biomass components for further valorization. [ABSTRACT FROM AUTHOR]

The components of the effluent from the chemical pretreatment of poplar alkaline peroxide mechanical pulp (APMP) were analyz ed in this study. The main dissolved organics were low-molecular weight (LMW) lignin, oligosaccharides, and monosaccharides. The lignin and sugar concentrations in the effluent obtained using different chemical pretreatment conditions and chemical dosages were analyz ed using ultraviolet (UV) spectroscopy. This analysis provided a theoretical basis for the subseq uent treatment and utiliz ation of APMP effluent. The experimental results showed that the dosages of NaO H, H2O2, and Na2SiO3 in the chemical pretreatment process affected the lignin and sugar concentrations in the effluent and that different chemicals had differing degrees of influence. The degree of influence exhibited the following order: NaOH>H2O2> Na2SiO3. More specifically, the dosages of NaO H and H2O2 had stronger influences on the lignin and sugar concentrations than that of Na2SiO3. Indeed, the Na2SiO3 dosage hardly affected the lignin and sugar concentrations in the effluent, but Na2SiO3 could stabiliz e the chemical pretreatment system and improve the reactive efficiency of NaOH and H2O2. The pretreatment temperature and time also affected the organic components, and the influence of the temperature was stronger than that of time. [ABSTRACT FROM AUTHOR]

The use of supercritical water for the decomposition of lignin and evaluation of its influence on lignin decomposition and conversion to various products was the thrust of the current study. Poplar alkali lignin (AL), corncob-to-xylitol residue lignin (XRL), and cornstalk-to-ethanol residue lignin (ERL) were the lignin species studied because they constitute the main residual lignins available in the biomass refinery industry. The lignins were characterized by elementary analysis, Fourier transform infrared spectrometry (FT-IR), phosphorus nuclear magnetic resonance (31P-NMR), and X-ray diffraction (XRD), and their hydrothermal depolymerization products were analyzed by gas chromatography-mass spectrometer (GC-MS). The results showed that the residual lignin is a potential source for valuable aromatics. The XRL had the best total phenolics yield, 140 mg/g, while AL had the lowest, 90 mg/g. The maximum yields of phenol (28.94 mg/g) and 4-ethylphenol (36.21 mg/g) were obtained from XRL depolymerization at 375 °C for 30 min, and the optimal yields of guaiacol (14.34 mg/g) and 2,6-dimethoxyphenol (15.67 mg/g) were achieved by AL at 375 °C for 30 min. The information here provides some insights toward developing selective biorefinery methods for lignin-to-organic products conversion processes. [ABSTRACT FROM AUTHOR]

An enzymatic mild acidic hydrolysis was used to separate and purify residual lignin from alkaline peroxide mechanical pulp (APMP). Using the optimum conditions for the laccase treatment (pH 4.5, temperature 50℃, lignin consistency of 1%, a reaction time of 60 min, and a laccase dosage of 8 µ/g), oven-dried lignin was treated with laccase and in a laccase mediator system (LMS) to explore the mechanism for laccase and the LMS modification of APMP. The changes of functional groups in lignin were analyzed using nuclear magnetic resonance (31P-NMR and 13C-NMR). The molecular weight distributions of the lignin samples were confirmed by gel permeation chromatography (GPC). The 31P-NMR and 13C-NMR spectra revealed that the lignin structure changed significantly with the laccase and the LMS treatments. Meanwhile, GPC demonstrated that laccase without a mediator could lead to the polymerization of lignin, while the LMS could degrade the lignin. Hence, it was concluded that laccase is an attractive enzyme for lignin modification. [ABSTRACT FROM AUTHOR]

A new fast-growing wood raw material, willow (Salix matsudana cv. Zhuliu), was subjected to pulping to identify the structure of its lignin. Thus, the black liquor lignin (AL) and enzymatic mild acidolysis lignin (EMAL) were prepared, and their molecular structure and molecular weight of the isolated lignin polymers were comprehensively investigated by Fourier transform infrared spectroscopy (FT-IR), two-dimensional nuclear magnetic resonance (2D-NMR HSQC), 13C nuclear magnetic resonance (13C-NMR), and gel permeation chromatography (GPC). The NMR results showed that syringyl (S) unit was the predominant structural monomeric unit in willow lignin, as opposed to guaiacyl (G) and phydroxyphenyl (H) units. The S/G ratio for the EMAL was found to be 2.02, whereas that for the AL was 0.94. The lignin in the black liquor (AL) fraction was modified during pulping, as shown by its reduced molecular weight. The two isolated lignin polymers, EMAL and AL showed low weight-average molecular weight: 4127 g/mol and 3522.5 g/mol, and in addition they exhibited low polydispersity index (Mw/Mn < 2.0). [ABSTRACT FROM AUTHOR]

The oxidative degradation of eucalyptus kraft lignin as a function of an oxygen-enriched ionic liquid (IL) medium was investigated as part of a fundamental study to examine its capacity to degrade lignin into a suite of potentially valuable by-products relative to a standard sodium hydroxide solution (control). The variables of temperature, oxygen pressure, reaction time, and catalyst on the aromatic monomer products were controlled, whereas it was found that the yields of various aromatic monomer products were significantly improved when ionic liquid was used as the solvent instead of sodium hydroxide solution. These yields increased more substantially when a mixture of ionic liquid and sodium hydroxide was exploited as the reaction solvent. A quantity of 105.3 mg/g aromatic monomer products can be obtained at a temperature of 150°C, reaction time of two hours, and oxygen pressure of 6 MPa using CuO as the catalyst. In addition to the formation of aromatic monomer products, there were a number of other fascinating functional group and chemical linkage changes observed in the lignin macromolecule within the IL-based reaction system. [ABSTRACT FROM PUBLISHER]

Presents a study which explained how chlorine dioxide alters lignin during delignification. Purpose of chemical pulp bleaching; Feature of unbleached residual lignin; Characterization of delignification residual lignin.

The co-editors of BioResources note the completion of our first ten years. We think that the journal can be judged as a success based on having achieved an impact factor of about 1.4 each year since 2009 and having reached a publication rate of about 700 articles per year. We strive to be a "people's journal" serving scientists, students, and society. We plan to continue emphasizing editorial pieces and review articles, which supplement our main service of publishing peer-reviewed articles dealing with the science of lignocellulosic materials, chemicals, and their uses. We also support undergraduate scholarship in our academic department, including tuition payment, opportunities for pre-editing work, and support for undergraduates to attend conferences, etc. [ABSTRACT FROM AUTHOR]

Purity, morphology, and structural characterization of synthesized deep eutectic solvent (DES)-lignins (D6h, D9h, D12h, D18h, D24h) extracted from willow (Salix matsudana cv. Zhuliu) after treatment with a 1:10 molar ratio of choline chloride and lactic acid at 120 °C for 6, 9, 12, 18, and 24 h were carried out. The purity of DES-lignin was ~95.4%. The proportion of hydrogen (H) in DES-lignin samples increased from 4.22% to 6.90% with lignin extraction time. The DES-lignin samples had low number/weight average molecular weights (1348.1/1806.7 to 920.2/1042.5 g/mol, from D6h to D24h) and low particle sizes (702–400 nm). Atomic force microscopy (AFM) analysis demonstrated that DES-lignin nanoparticles had smooth surfaces and diameters of 200–420 nm. Syringyl (S) units were dominant, and total phenolic hydroxyl content and total hydroxyl content reached their highest values of 2.05 and 3.42 mmol·g−1 in D12h and D6h, respectively. β-Aryl ether (β-O-4) linkages were eliminated during DES treatment. [ABSTRACT FROM AUTHOR]

Nanofibers were produced by electrospinning aqueous alkaline solutions containing different mass ratios of soy protein and lignin in the presence of poly(ethylene glycol) coadjutant, all of which presented shear thinning behavior. SEM revealed that the addition of polyethylene oxide as a coadjutant indeed facilitated the formation of defect-free fibers whose diameter increased with lignin concentration, in the range between ≈ 124 and ≈ 400 nm. Favorable interactions between lignin and soy protein were identified from data provided by differential scanning calorimetry. In addition, an increased hydrogen bonding and the loss of secondary structure of the proteins as the lignin concentration increased were observed from the disappearance of amide II (∼1500 cm −1 ) and III (∼1400–1200 cm −1 ) bands and a red shift of amide I band in the FT-IR spectrum. The unfolding of the protein contributed to a better interaction with lignin macromolecules, which further improved the electrospinning process. It is concluded that mixtures of lignin and soy proteins, two major renewable resources with interesting chemical features, are suitable for the development of composite sub-micron fibers. [ABSTRACT FROM AUTHOR]

Lignin was isolated from a spruce bleached chemithermomechanical pulp (BCTMP) with a mild acid hydrolysis and acetylated. Nonacetylated and acetylated lignins were impregnated onto cellulosic testsheets and photolyzed by two different light sources. Optical reflective studies indicated that the irradiated lignin underwent a two-phase photodiscoloration process with the acetylated lignin exhibiting reduced color formation. To examine the chemical processes initiated by irradiation, the photolyzed nonacetylated and acetylated lignins were extracted from the cellulosic testsheets and analyzed by using nuclear magnetic resonance (NMR). The results indicated that the photobehavior of the acetylated lignin exhibited substantially decreased reactivity during the light irradiation. The extent of lignin acetylation prior to photolysis was shown to be a very important parameter in controlling the overall photoreactivity of the acetylated materials. Aliphatic hydroxyl groups in lignin were observed to extensively degrade during photolysis, whereas the amounts of C5 condensed phenolics, guaiacyl phenolics, acids, and p-hydroxyphenyl increased. [Copyright &y& Elsevier]

A rational design of the intrinsic lattice structure of catalysts is vitally important to address catalytic performance. Herein is reported a top-down synthesis for the fabrication of a bifunctional metallic catalyst. First, palladium nanocubes with (100) lattices planes were synthesized through a shape-control strategy; next, the as-synthesized Pd/Co-ZIF was used as a template for in - situ phase reconstruction by a spontaneous phase transformation process in the presence of H 4 SiW under solvothermal conditions. Ultimately, formation of 3D hierarchical flower-like bimetallic nitride nanosheets (SiW 12 @Pd/Co-ZIF-NS) were generated because of this process. The SiW 12 @Pd/Co-ZIF-NS catalyst not only displays excellent catalytic transfer hydrogenolysis for C-O bond cleavage of lignin dimeric substrates, but also maintains superior recycling durability due to an encapsulation phenomenon preventing aggregation. Finally, the resulting nanocomposites exhibit superior activity and good size selectivity toward catalytic transfer hydrogenolysis of the actual lignin substrates to produce a significant amount of low-molecular-weight aromatic compounds. [Display omitted] • A multifunctional catalyst composed of ultrathin nanosheets (SiW 12 @Pd/Co-ZIF-NS) was fabricated. • Using silicotungstic acid as precursor for the first time. • The as-prepared catalyst has unique architecture, rich N, O vacancies, and good cooperation among the active components. • The remarkable CTH activity toward lignin valorization was obtained with nearly full conversion under mild conditions. [ABSTRACT FROM AUTHOR]

Lignosulfonate- g -acrylic acid (LS- g -AA) hydrogels that possess superabsorbent capacity were synthesized by grafting acrylic acid (AA) on the backbone of lignosulfonate (LS) in the presence of N , N ′-methylene- bis -acrylamide (MBA) as initiated by laccase/ t -BHP(tert-butyl hydroperoxide). Specifically, the carboxylic acid groups introduced by grafting acrylic acid, significantly enhanced the absorption capacity of LS- g -AA hydrogels. In this case, methylene blue (MB) was the representative dye substrate to study absorption dynamics. It was found that the equilibrium absorption of MB reached 2013 mg·g − 1 while pH, absorption time, and initial MB concentration affected the overall absorption capacity. The absorption isotherms and kinetics obeyed standard Freundlich and pseudo-2nd-order models, respectively. Furthermore, preliminary desorption experiments were conducted in weak acid solution and showed that ~ 50% of the original MB could be removed over one rinse cycle. [ABSTRACT FROM AUTHOR]

• Modified lignin cargo carrier. • Lignin nanoparticles. • Folic acid host. • Drug delivery. Two fractions of kraft lignin of low and high molecular weight were reacted with cholesteryl chloroformate (Chol.Cl) to produce a modified lignin that demonstrated very high hydrophobicity. Surprisingly, both fractions displayed discernible melting points as opposed to the starting lignin. The suspension in water also gave rise to nanoparticles that displayed sizes in the range of 200−500 nm that were shown to satisfactorily load and release folic acid, a representative hydrophobic molecule, within the context of drug delivery. [ABSTRACT FROM AUTHOR]

Acetylation of wood is an age‐old chemical platform known to improve its chemical and physical properties in direct correlation with the degree of acetylation. However, as of yet, no systematic study has been undertaken to probe the selectivity of acetylation of wood. A fundamental understanding of the molecular basis for acetylation of the constituent biopolymers, viz., holocellulose, and lignin for tropical hardwood, an emerging building material, is therefore undertaken. Wood samples are treated with acetic anhydride at 120 °C over a wide range of time periods. The degrees of acetylation and acetyl content of the tropical hardwood are measured to reveal that the acetyl content in which the hydroxyl groups of wood correspond to an increment in weight percent gain as confirmed by FT‐IR for individual wood biopolymers and whole wood. However, surprisingly, 31P‐NMR establishes the order of reactivity for the hydroxyl groups as lignin > hemicelluloses > whole wood in direct opposition to their proportions in wood, but in correlation to their direct accessibilities and reactivities. [ABSTRACT FROM AUTHOR]