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Sulfonation degree is an important structural parameter of lignosulfonates which affect their water solubility, surface activity, and dispersing performance. Presently, the methods for determining sulfonation degree include elemental analysis and potentiometric titration; they have some shortcomings such as complex purification process, high equipment requirements, and time-consuming. Hence, a simple and rapid method to determine the sulfonation degree of lignosulfonates was proposed based on the electrostatic interaction between cationic surfactant (hexadecyl trimethyl ammonium bromide (CTAB)) and anionic lignosulfonates. CTAB was added and co-precipitated with lignosulfonates and then the ultraviolet absorbance of the supernatant was determined. The sulfonation degree of lignosulfonates was calculated according to the titration curve of the supernatant absorbance to the amount of CTAB. This method is applicable to lignosulfonates recovered from acid pulping as well as sulfonation products of alkali lignin. Because of the easy operation process and no purification process for lignosulfonates, this method was simple and rapid when compared to existing methods for sulfonation degree determination of lignosulfonates. [ABSTRACT FROM AUTHOR]

Two pretreatment methods to overcome recalcitrance of lignocelluloses, sulfite pretreatment (SPORL) and dilute acid (DA), were conducted to pretreat softwood masson pine and hardwood eucalyptus for enzymatic hydrolysis. In the presence of corresponding pre-hydrolysates, adding moderate cetyltrimethylammonium bromide (CTAB) could enhance the enzymatic hydrolysis of the SPORL-pretreated substrates, but had no enhancement for the DA-pretreated substrates. The results showed that sodium lignosulfonate (SL) in pre-hydrolysates and CTAB together had a strong enhancement on the enzymatic hydrolysis of lignocelluloses. The compound of commercial lignosulfonate SXSL and CTAB (SXSL-CTAB) could enhance the substrate enzymatic digestibility (SED) of SPORL-pretreated masson pine from 27.1% to 71.0%, and that of DA-pretreated eucalyptus from 37.6% to 67.9%. The mechanism that CTAB increased the adsorption of SL on lignin to form more effective steric hindrance and reduced the non-productive adsorption of cellulase on lignin by neutralizing the negative charge of SL was proposed. [ABSTRACT FROM AUTHOR]

Using a simple method, we developed a new family of alkyl sulfonic acid modified lignosulfonate (ASLSs) with simultaneously improved sulfonation degrees and molecular weights via one step. Direct sulfonation occurred on both phenolic and alcoholic hydroxyl groups of alkali lignin raw material with 1,4-butylenesulfone used as sulfonation agent. A sulfonation degree of 3.86 mmol/g had been achieved which presents as one of the highest sulfonation degrees among those of reported LSs, to date.1H-NMR and Fourier transform infrared spectroscopy measurements confirmed the efficient sulfonation. Furthermore, the dispersion properties were investigated in low-rank coal-water slurry (CWS). ASLS3 showed better viscosity-reduction effect than naphthalene sulfonate formaldehyde condensate (FDN) in CWS with dosages from 0.6% to 1.0 wt%. ASLS3 had the similar sulfonation degree with FDN; however, the large steric hindrance, soft long alkyl chain-C4H8-SO3H, and their efficient anchoring effect of ASLSs contributed to their improved dispersion properties. [ABSTRACT FROM PUBLISHER]

Compared with traditional approaches using synthetic amphiphilic block copolymers, alkyl chain cross-linked lignosulfonate (ASL) with high molecular weight (Mw) from black liquor was synthesized and characterized by GPC, functional group content, FTIR, and ¹H-NMR measurement, and then used as water soluble amphiphilic biopolymer to prepare polymersomes via solution self-assembly. DLS illustrated the solution assembly behavior. The hollow nature of nanospheres was revealed by TEM. Moreover, the element analysis and XPS results revealed the hollow sphere structure with a hydrophilic core and a hydrophobic shell. It facilitated the efficient encapsulation of pesticide carbendazim into the hollow sphere via electrostatic interaction, which was investigated by SEM, TEM, elemental analysis and XPS. In our study, ASLs with different Mw from 20 kDa to 200 kDa all could exhibit the similar self-assembly behavior, which suggests that the hollow spheres and the encapsulation experiment were easily duplicated from ASL polymers without structure dependence. Furthermore, the dispersion properties of ASL in the carbendazim suspension concentrate (SC) system were also investigated, which showed that SC with ASL exhibited better dispersion property and rheological performance than that of NSF and commercial LS. Preparation and application of polymersomes via self-assembly from modified-lignin from black liquor provide a promising and effective scaffold which can be conveniently obtained from cheap and renewable bioresource. [ABSTRACT FROM AUTHOR]

Effect of the molecular structure of lignosulfonate-based polyoxyethylene ether (LS-PEG) on the enzymatic hydrolysis of Avicel and corn stover was investigated. With the increase of PEG contents and M w of LS-PEG, glucose yield of corn stover increased from 16.7% to 51.9%. When LS-PEG was compounded with cationic surfactant cetyltrimethylammonium bromide (CTAB), the enhancement of glucose yield of corn stover was further increased from 45.3% to 62.8%. Sulfonic group of LS-PEG preferentially interacted with quaternary ammonium group of CTAB by the electrostatic attraction to form a similar non-ionic surfactant CTAB-LS-PEG. CTAB-LS-PEG showed electrically neutral and more hydrophobic, and blocked more nonproductive adsorption of cellulase on the lignin. Therefore, CTAB-LS-PEG enhanced enzymatic hydrolysis efficiency of lignocelluloses more significantly. The understanding developed in this study can help to develop potential approaches and strategies for effective application of lignosulfonate to improve bioconversion of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

A light-colored hydroxypropyl sulfonated alkali lignin (HSAL) was synthesized based on pine alkali lignin (AL) by grafted-sulfonation and crosslinking reaction processes. The reactions were evaluated by gel-permeation chromatography (GPC), infrared (IR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The sulfonic group content and the molecular weight ( M w) of HSAL significantly increased, while the phenolic hydroxyl groups diminished by around 80% compared to AL. The color of HSAL turned to light yellow compared to the dark brown color of AL, that is, it stained less the fiber. The dispersity, heat stability, and dye uptake of dye bath with HSAL was significantly improved compared to sodium lignosulfonate, sulfomethylated AL, and dispersants of the naphthalene series. [ABSTRACT FROM AUTHOR]

The process sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) has been the focus of this study. Pilot-scale (50 kg) pretreatment of wood chips of lodgepole pine ( Pinus contorta Douglas ex Loudon) killed by mountain pine beetle ( Dendroctonus ponderosae Hopkins) were conducted at 165°C with a dilute sulfite solution of pH 2 for bioconversion to ethanol and lignosulfonate (LS). The pretreatment duration was optimized in laboratory bench scale experiments with a certain severity based on a combined hydrolysis factor (CHF). The sodium bisulfite loading was 8% and the liquor to wood ratio 3. The pretreated solids were disk milled together with the spent liquid and the resultant slurry with a 25% solids content was directly (without detoxification) submitted to a simultaneous enzymatic saccharification and fermentation (SSF) with Saccharomyces cerevisiae YRH400 at cellulase loading of 35 ml kg-1 of untreated wood. At solids loading of 20%, the alcohol yield was 288 l t-1 wood (with a final concentration of 52.2 g l-1), which corresponds to a 72.0% theoretical yield based on total glucan, mannan, and xylan. The LS from SPORL was highly sulfonated and its molecular weight was lower than that of a purified commercial softwood LS, and therefore it has a high potential as a directly marketable co-product. [ABSTRACT FROM AUTHOR]

The solution behavior and molecular conformation of sodium lignosulfonates (NaLS) in saline solution has been studied by means of static and dynamic light scattering (LSstat and LSdyn). Results show that the salt content must be larger to eliminate the slow mode in LSdyn analysis of NaLS than that of the theory, and this discrepancy can only be explained by a modified microgel model. The higher salt amount is needed for the formation of a strong ionic gradient field between surface and the inner part of NaLS, which forces counter ions to penetrate into the inner part of NaLS to screen the small amount of charges. The NaLS single molecular shape can be described by an oblate spheroid based on the absolute molecular weight Mw and diffusion coefficients D. The best fitting result is semiaxis a=1.6 nm and axial ratio r=3.5, D=5.73×10-7 cm2 s-1, and the corresponding Mw=1.7×105 g mol-1. [ABSTRACT FROM AUTHOR]

Three purified sodium lignosulfonates (SLs) with different molecular weights were prepared by ultrafiltration. The structural characteristics of SL and their effects on the properties of dye were investigated. When the molecular weight is increased, the chroma, purity, and the content of guaiacyl of SL increases, whereas the phenolic hydroxyl, carboxyl, and sulfonic groups in SL decrease, the dispersibility, heat stability properties, and dyeing rate of SL on dye improve, and the fiber staining of SL weakens at high concentration. The fraction of SL with the cutoff molecular weight above 2.5 kDa has the weakest reduction effect on dyestuffs. [ABSTRACT FROM AUTHOR]

Concentrated sodium lignosulfonate (NaLS) solutions have wide industrial applications. Therefore, the viscoelastic properties of NaLS in concentrations of 55%-63% have been investigated between 5°C and 55°C by means of a dynamic rheological technique, namely, the oscillatory rheological experiments were conducted in a rheometer in the small amplitude oscillatory mode. All solutions showed 'shear-thinning' behavior over frequency. The complex viscosity ( η*) increased and the loss tangent (tanδ) decreased with increasing concentrations. Both the storage modulus ( G′) and the loss modulus ( G″) increased with increasing frequencies and concentrations. The change in viscoelastic behavior was probably caused by stronger aggregation effects. However, the effects of temperature on the viscoelastic properties are more complex. For 60% NaLS, G′, G″, and η* decreased, but tanδ increased with increasing temperatures. When the temperature exceeded 20°C, G′, G″, and η* increased, but tanδ decreased, and the relaxation times were increased as a function of temperature. The change in viscoelasticity as a function of temperature may also be related to intermolecular aggregation and the swelling of aggregates. The conductivity experiments indicated that the formation of a greater strength of network structures at higher levels of concentrations between 55% and 63% and temperatures between 20°C and 55°C was probably responsible for elasticity enhancement. [ABSTRACT FROM AUTHOR]

Sodium lignosulfonate (NaLS) was dissolved in saline solutions, and the dissolving process was examined by a combination of static and dynamic light scattering. When NaLS was dissolved in 1.2 mol l-1 NaCl solution for 24 h and filtered through a 0.45 μm syringe filter, only a fast relaxation mode was observed, which was attributed to the co-diffusion of NaLS molecular ions and counterions. When the concentration of NaCl was below 1.2 mol l-1 or the dissolving time was <24 h, an additional slow relaxation mode (SRM) appeared due to hindered motions of electrostatically interacting chains. Without filtering or filtering followed by rising temperature to 38°C, SRM appeared due to aggregation, which occurred at a position similar to that caused by electrostatic interaction. For poly(sodium styrenesulfonate) (NaPSS) and modified bamboo lignin derivate with open polyelectrolyte structures, 0.1 mol l-1 NaCl was enough to inhibit the electrostatic interaction. For NaLS with a closed polyelectrolyte structure, the SRM could not be removed until the concentration of NaCl reached 1.2 mol l-1. Above observations give insights for the first time into the relationship between the SRM caused by electrostatically interacting chains and the diffusion mode due to NaLS aggregation, and the influence of the closed polyelectrolyte structure on the SRM. [ABSTRACT FROM AUTHOR]

Coal–water slurry (CWS) is a new type of oil-replaceable liquid fuel with low pollution. The cost of CWS preparation will be greatly reduced if low-rank coal is used as the preparation material. In this work, chemical modification was used to prepare the modified sodium lignosulfonate (SL-M) hyper-dispersant, having larger molecular weight and more sulfonic groups than sodium lignosulfonate (SL), which was widely used for preparation of CWS from low-rank Shenhua coal due to its rich source and lower price. Effects of preparation conditions and molecular structure of SL-M on rheological properties of CWS were studied by using Haak rheometer. Results showed that the CWS transfered from viscous fluid to swelling fluid when the coal particle size decreased. The consistency coefficient of CWS decreased with the increase of additive dosage. The rheological properties of CWS became much better with the addition of the stabilizer, sodium carboxymethyl cellulose (CMC), compared with that of CWS without CMC. The prepared CWS changed from yield viscous fluid into yield swelling fluid with the increase of the molecular weight of SL-M. The rheological index was lower than 1 when the sulfonic group content was low, then it was increased with the increase of the sulfonic group content. [ABSTRACT FROM AUTHOR]

Single molecules of sodium lignosulfonate (NaLS) were prepared and their aggregation behavior was studied as a function of temperature. The molecular dispersity of the NaLS solutions were confirmed by dynamic light scattering (DLS), and the aggregation behavior was studied by DLS and static light scattering (SLS), fluorescence spectrometry (FS), and atomic force microscopy (AFM). It was demonstrated that NaLS molecules started to aggregate above a critical temperature and the aggregation behavior was related to their spherical microgel conformation and hydrophobic interaction. During the DLS measurement, when NaLS was dissolved in 1.2 mol·l-1 NaCl aqueous solution and then filtered with 0.45 μm syringe filter, the slow-mode diffusion (smD) corresponded to the polyelectrolyte effect and the original aggregates disappeared and the fast-mode diffusion (fmD) corresponded to the monomolecular NaLS (not yet aggregated) in the solution. When the temperature of the NaLS solution was raised to 38°C, the disappeared smD in DLS analysis appeared again, indicating that NaLS molecules started to form new aggregates. Due to the aggregation at 38°C, molecular weight ( Mw) obtained from the SLS had a sharp increase, intensity ratio (I1/I3) of pyrene in FS suddenly decreased, and the adsorption of NaLS on a solid substrate and the corresponding roughness of the surface increased significantly. [ABSTRACT FROM AUTHOR]

The effects of lignosulfonate (LS) on enzymatic saccharification of pure cellulose were studied. Four fractions of LS with different molecular weight (MW) prepared by ultrafiltration of a commercial LS were applied at different loadings to enzymatic hydrolysis of Whatman paper under different pH. Using LS fractions with low MW and high degree of sulfonation can enhance enzymatic cellulose saccharification despite LS can bind to cellulase nonproductively. The enhancing effect varies with LS properties, its loading, and hydrolysis pH. Inhibitive effect on cellulose saccharification was also observed using LS with large MW and low degree of sulfonation. The concept of 'LS-cellulase aggregate stabilized and enhanced cellulase binding' was proposed to explain the observed enhancement of cellulose saccharification. The concept was demonstrated by the linear correlation between the measured amount of bound cellulase and saccharification efficiency with and without LS of different MW in a range of pH. [ABSTRACT FROM AUTHOR]

Lignosulfonates(LSs), by-products from chemical pulping processes, are low-value products with limited dispersion properties. The ability of commercially available horseradish peroxidase (HRP) to polymerize LS macromolecules and improve the dispersion properties of LSs was investigated. The polymerization of LSs proceeded efficiently under mild reaction conditions in an aqueous solution with HRP/H 2O 2. Gel permeation chromatography showed a significant increase in weight-average molecular weight ( Mw) of sulfonated kraft lignin and sodium lignosulfonate (NaLS) by 8.5-fold and 4.7-fold, respectively. The mechanism of polymerization was investigated by elemental analysis, surface charge measurement, headspace gas chromatography, infrared spectroscopy (IR), and hydrogen nuclear magnetic resonance spectrometry ( 1H-NMR). The functional group measurements indicated that HRP incubation did not reduce the sulfonic group content. However, it decreased the phenolic and methoxyl group contents. As the phenolic group content decreased, Mw increased as a power function. The polymerization was proposed to involve the random coupling of phenoxy radical intermediates. The radicals coupled with each other to form different inter-unit linkages, most of which were the β-O-4’ type, as the 1H-NMR spectra indicated. Moreover, the HRP/H 2O 2 incubation induced a significant improvement in the adsorption and dispersion properties of LSs. Therefore, the HRP/H 2O 2 incubation is a promising approach for industrial applications of LSs. [ABSTRACT FROM AUTHOR]

In the article, the dynamic surface tension of sodium lignosulfonate (SL) aqueous solutions are investigated using an axisymmetric drop shape analysis-profile method. The data are analyzed by the Langmuir, Frumkin, modified Frumkin, and modified Flory-Huggins equations. The results indicate that the Langmuir model's results with two adjustable parameters are comparable to that of other models with three or four adjustable parameters. Based on the simplicity of simulation, the Langmuir adsorption equation is used to correlate the dynamic adsorption processing. The aggregation between SL molecules and the variation of adsorption configuration are proposed to interpret the results of dynamic surface tension. [ABSTRACT FROM AUTHOR]

The adsorption behavior and dispersion efficiency of sodium lignosulfonate (NaLS) on Al2O3 particles at different pH values were investigated by UV-Vis spectroscopy, zeta potential measurement, X-ray photoelectron spectroscopy, and viscosity measurements. The effects of the additives urea, Na2SO4, and NaCl were tested. At low pH values, NaLS adsorbed on the Al2O3 particles in the form of aggregates and at high pH values as separated single molecules. At pH 3-11, the adsorption was not affected through addition of urea, ruling out hydrogen bond as a controlling factor. By adding Na2SO4 and NaCl, the main driving force was the synergistic effect of the electrostatic interaction and the metal cation-π interaction at pHIEP (IEP, isoelectric point), whereas the metal cation-π interaction was dominant at pH>pHIEP. The dispersing mechanism was mainly attributed to the steric hindrance (at pHIEP) and the electrostatic repulsive force (at pH>pHIEP) owing to the differences in the aggregation state of the adsorbed molecules. [ABSTRACT FROM AUTHOR]

The problems related to the determination of the absolute molecular weight ( Mw) of sodium lignosulfonate (NaLS) are the focus of the present work. Four narrow-dispersed NaLS fractions were collected by filtration, ultrafiltration, and gel permeation chromatography (GPC), and their Mw measured by laser light scattering (LLS Mw) was compared with that obtained by GPC (GPC Mw). The LLS Mw values were much larger than GPC Mw, and this Mw difference increased with increasing Mw of NaLS. This finding confirms the known polyelectrolyte and aggregation effects of NaLS. The deviation is also partly due to the conformation differences between the GPC standard (sodium polystyrene sulfonate) and the NaLS molecules. The effects of polyelectrolytes and NaLS aggregates could be inhibited by adding enough NaCl salt in the NaLS solution and filtering the NaLS/NaCl solution through a syringe filter. As a result, the slow mode in dynamic LLS measurement disappeared. By this approach, the absolute LLS Mw values were only slightly larger than that determined by GPC due to the conformation differences between the GPC standard and the NaLS molecules. [ABSTRACT FROM AUTHOR]

The ability of commercial laccase for improvement of the physicochemical properties of sodium lignosulfonate (NaLS) without any mediator has been investigated. Surface tension, adsorption characteristics, rheological behaviors and fluidity of cement pastes were in focus. Gel permeation chromatography (GPC) shows an initial decrease and then an extensive increase of molecular weight (MW) of NaLS after incubation with laccase. Parallel to MW decrement, the content of phenolic groups is increasing, while an MW increment has the opposite effect. The UV-Vis spectra and the zeta potential of NaLS do not indicate further modification of the substitution pattern on the aromatic ring. The surface tension of NaLS and the adsorbed amount of NaLS on MgO particles is elevated after laccase treatment. The electrostatic attraction between MgO particles and NaLS is the main driving force during this adsorption process. The dispersion efficiency of laccase modified NaLS on the MgO slurry and cement paste is improved. [ABSTRACT FROM AUTHOR]

Lignosulfonate is a type of macromolecular surfactant widely used as interfacial additive in various industrial fields and it is produced during chemical pulping process. In this paper, we present a new effective method for measurement of the critical aggregation concentration (CAC) of sodium lignosulfonate (SL) in water solution, with which a value of 0.38 g L−1 was obtained. Through the determination of CAC and observation by DLS, the state and dynamics of the formation of the SL micelles were disclosed. The results showed that SL was the state of individual molecules when its mass concentration was less than CAC; the individual SL molecules started to aggregate above CAC and thus micelles formed and grew with increasing SL concentration. The SL solution was quickly frozen and the structures of SL molecules or micelles were observed by ESEM, revealing that the spherical micelles were the main form of SL in the solution. Based on the results, the spherical hollow vesicular structure is proposed as a model of the aggregated micelles of SL in the solution. [ABSTRACT FROM AUTHOR]

Abstract: Lignosulfonate is an anionic surfactant from pulp processing industries. Alcohols are often used as cosurfactants in the application of surfactant. The improvement of straight-chain alcohols with different alkyl chain lengths as cosurfactant on the physicochemical properties of calcium lignosulfonate (CL) aqueous solution has been investigated. The results indicate that small amounts of straight-chain alcohols with longer alkyl chains are helpful in improving the surface activity of CL, especially when the number of carbon atoms in alcohols is 10 or larger. The adsorption amount of CL solutions with additives of longer chain alcohols on TiO2 particles increases greatly, and the zeta potential of TiO2 particles adsorbing CL rises significantly. It can be concluded that there is a cooperative effect of the longer chain alcohols on lignosulfonate to form a tighter adsorption layer at the interface. The steric hindrance increases with the increasing amount of adsorption, and the static repulsive force increases with the increasing zeta potential. Therefore, the effect of CL on the stability of the TiO2 suspension is enhanced dramatically by addition of longer chain alcohols. This understanding can lead to further development in expanding the functionalities of the lignosulfonate through manipulation of the adsorption capacity of CL on solid particles and enhance the dispersive ability of CL on solid suspensions by adding longer straight-chain alcohols. [Copyright &y& Elsevier]

Sodium lignosulfonate (SXSL) and long-chain fatty alcohols (LFAs) could enhance the enzymatic hydrolysis of xylan, and the compound of SXSL and LFAs have synergies on the enzymatic hydrolysis. SXSL shows a strong enhancement in buffer pH range from 4.0 to 6.0. The enhancement increased with the SXSL dosage and the xylanase loading. The cellulose and lignin in corncob substrate could not only adsorb xylanase nonproductively, but also seriously reduce the accessibility of xylanase on xylan to impede the enzymatic hydrolysis of xylan. Cellulase could break the plant cell wall structure of corncob and make additives work better. The xylose yield of corncob at 72 h increased from 59.4% to 73.7% by adding the compound of 5 g/L SXSL and 0.01% (v/v) n -decanol, which was higher than that without cellulase and additives by 30.7%. Meanwhile, the glucose yield at 72 h of corncob increased from 45.8% to 62.3%. [ABSTRACT FROM AUTHOR]

Highlights: [•] A modified lignosulfonate GCL4-1 improves stability of DMM suspension significantly. [•] GCL4-1 fraction with Mw of 10,000–30,000 has strongest dispersive ability. [•] Dispersive ability of GCL4-1 is contributed to sulfonated degree and adsorbed amount. [•] GCL4-1 fraction with largest Mw has strongest adsorption, but may cause flocculation. [ABSTRACT FROM AUTHOR]

Highlights: [•] SL clearly reduced the non-productive adsorption of cellulase on lignin. [•] SL with higher MW had stronger blocking effect on cellulase adsorption on lignin. [•] Linear anionic aromatic polymers strongly blocked cellulase adsorption on lignin. [•] Copolymer of lignin and PEG had stronger enhancement than PEG. [Copyright &y& Elsevier]

Thisstudy conducted an investigation of the effect of lignosulfonate(LS) on enzymatic saccharification of lignocelluloses. Two commercialLSs and one laboratory sulfonated kraft lignin were applied to Whatmanpaper, dilute acid and SPORL (sulfite pretreatment to overcome recalcitranceof lignocelluloses) pretreated aspen, and kraft alkaline and SPORLpretreated lodgepole pine. All three lignin samples inhibited cellulosesaccharification of Whatman paper, but enhanced the saccharificationof the four lignocellulosic substrates. The level of enhancement wasrelated to the molecular weight and degree of sulfonation of the ligninas well as the substrate lignin structure. When different molecularweight (MW) fractions of one commercial LS (SXP), generated from sulfitepulping of hardwood, were applied to the Whatman paper, the largeMW fraction (SXP1) with the lowest degree of sulfonation inhibitedcellulose saccharification while the intermediate (SXP2) and smallest(SXP3) MW fractions enhanced saccharification. All MW fractions enhancedsaccharification of the four lignocellulosic substrates with maximalenhancement by the smallest MW fraction, SXP3. The enhancement wasmost significant for the kraft lodgepole pine substrate and leastsignificant for the SPORL pretreated lodgepole pine using all threeLS and SXP fractions. The results suggest that LS acts as a surfactantto enhance pure cellullose saccharification. When LS is applied tolignocelluloses, it acts as a surfactant to block bound lignin frombinding cellulase nonproductively leading to enhanced saccharification. [ABSTRACT FROM AUTHOR]

Abstract: Different lignosulfonate (LS) samples were prepared via a three-step method and were characterized by FT-IR, UV, GPC and functional groups measurement. FT-IR and UV spectra confirmed the prepared samples had typical characteristics of lignin materials. GPC and functional groups measurement results indicated the samples had different molecular mass (M w), but same quantities of sulfonic groups (S). The influence of M w of LS on the resulting surface charges of dimethomorph particles via adsorption was further investigated. The results indicated that the adsorption isotherms of LS on dimethomorph surfaces belonged to L-type and the adsorption capacity (q m) increased with increasing M w. However, the non-linear correlation between zeta potentials with the products of S and adsorption amount (SA) indicated SA did not positively improve the surface charges expectedly. Based on the analysis, an adsorption confirmation was proposed allowing prediction of the relation between M w and surface charge efficiency of LS for solid particles. [Copyright &y& Elsevier]

Abstract: As a plasticizer and retarder, calcium lignosulfonate (CL) frequently leads to quick set of Portland cement containing anhydrite. For exploring the cause of this problem, the hydration characteristics of the tricalcium aluminate–anhydrite system in the saturated calcium hydroxide solution with and without CL were researched from two aspects: the compositions of liquid phases and the formations of hydration products. Results show that the CL can promote the formation of ettringite, which induces a significant decrease in sulfate ion concentration at the initial time of hydration. The size of ettringite crystals becomes large in the presence of CL, which seems to be related to a decrease in calcium sulfate saturation ratio. It can be deduced that the quick set in the presence of CL is mainly caused by the accelerated reaction between the tricalcium aluminate and the anhydrite at the initial time of hydration. [Copyright &y& Elsevier]

Abstract: The solution behavior of purified sodium lignosulfonate (PSL) at different pH values were investigated by means of acid–base titration, surface tension, viscosity, fluorescence spectrometry, dynamic light scattering (DLS) and environmental scanning electron microscopy (ESEM) experiments. Fluorescence experiments showed that the critical aggregate concentration (CAC) of PSL was 0.05g/L. DLS results indicated that the average dimension of PSL molecule and PSL aggregate was about 8nm and 80nm, respectively. The surface charge of PSL molecules and the aggregation degree of PSL in solution increased with the increasing of pH due to the ionization of sulfonic and phenolic hydroxyl groups. The size of PSL aggregates and reduced viscosity of PSL solution increased as pH values increased because expansion of the PSL cores. A model for the assembly behavior of PSL was first proposed to explain the influence of pH on the molecular configuration and aggregation behaviors of lignosulfonate in aqueous solutions. [ABSTRACT FROM AUTHOR]