Rational Biomimetic Construction of Lignin-based Carbon Nanozyme for Identification of Uric Acid in Human Urine

Nanozymes have made remarkable progress in the field of sensing assays by replacing native enzyme functions. However, it is still a challenge to rationally design active centers from molecular structure to enhance the catalytic performance and develop low-cost nanozymes. In this work, guided by the catalytic site of horseradish peroxidase (HRP), iron source and histidine were coupled to the main chain of aminated sodium lignosulfonate (SL) through the self-assembly biomimetic strategy to construct His-SL-Fe with peroxidase activity. The inherent functional groups and basic framework of aminated SL provide a robust environment and promote the formation of active sites. His-SL-Fe shows excellent robustness over multiple test cycles and has a strong affinity for the substrate compared to HRP. His-SL-Fe had been effectively integrated in the sensing system for catalytic detection of uric acid (UA) to achieve accurate recognition of UA in the range of 0.5-100 μM with the limit of detection as low as 0.18 μM. The recovery of human urine samples is in the range of 96.8%-106.1 % and the error is within 4 %. This work not only provides a new approach for the directed design of high-performance nanozymes, but also demonstrates promising ideas for the refined application of biomass resources.

Sodium lignosulfonate/graphene composites for efficient desalination by incorporating CoS to control pore size

The phenomenon of overlapping double layers due to micropores inhibits capacitive deionization performance, which is improved by increasing the pore size. In this study, a novel ternary composite electrode (sodium lignosulfonate/reduced graphene oxide/cobalt sulfide, LGC) was designed using a two-step hydrothermal method. CoS with high pseudocapacitance modifies sodium lignosulfonate and graphene connected by hydrogen bonding, benefiting from the constitutive steric structure. The electrochemical performance was significantly enhanced, and the desalination capacity substantially improved. The LGC electrode specific capacitance was as high as 354.47 F g-1 at a 1 A g-1 current density. The desalination capacity of the capacitive deionization device comprising LGC and activated carbon in 1 M NaCl electrolyte reached 28.04 mg g-1 at an operating condition of 1.2 V, 7 mL min-1. Additionally, the LGC electrodes degraded naturally post the experiment by simply removing the CoS, suggesting that the LGC composites are promising material for capacitive deionization electrodes.

Biodegradable and multifunctional black mulch film decorated with darkened lignin induced by iron ions for "green" agriculture

High-value utilization of bleached lignin has been widely used in different fields, whereas the investigation on darkened lignin in composite materials was often ignored. In this work, a sort of eco-friendly and structurally robust sodium carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA)/sodium lignosulfonate (SLS) black composite mulch film was elaborately designed. The chelation and redox reaction effect between Fe ions and SLS lead to the formation of a more quinones structure on lignin, darkening both lignin and the mulch films. The chelation effect between Fe ions and biopolymer formed three-dimensional structures, which can be used as sacrifice bonds to dissipate energy and improve the mechanical properties of the composite films. In particular, the maximum elongation at break and toughness increased from 48.4 % and 1141 kJ/m3 for the CMC/PVA film to 210.9 % and 1426 kJ/m3 for the optimized CMC/PVA/SLS/Fe black mulch film, respectively. In addition, the optimized black mulch film also possesses good soil water retention, thermal preservation effect, controlled urea release, and well biodegradability. This work offered a novel strategy for designing eco-friendly black mulch with reinforced mechanical strength, slow-release urea, soil moisture retention, and heat preservation performances.

Crystallization-induced formation of two-dimensional carbon nanosheets derived from sodium lignosulfonate for fast lithium storage

Sodium lignosulfonate, an abundant natural resource, is regarded as an ideal precursor for the synthesis of hard carbon. The development of high-performance, low-cost and sustainable anode materials is a significant challenge facing lithium-ion batteries (LIBs). The modulation of morphology and defect structure during thermal transformation is crucial to improve Li+ storage behavior. Synthesized using sodium lignosulfonate as a precursor, two-dimensional carbon nanosheets with a high density of defects were produced. The synergistic influence of ice templates and KCl was leveraged, where the ice prevented clumping of potassium chloride during drying, and the latter served as a skeletal support during pyrolysis. This resulted in the formation of an interconnected two-dimensional nanosheet structure through the combined action of both templates. The optimized sample has a charging capacity of 712.4 mA h g-1 at 0.1 A g-1, which is contributed by the slope region. After 200 cycles at 0.2 A g-1, the specific charge capacity remains 514.4 mA h g-1, and a high specific charge capacity of 333.8 mA h g-1 after 800 cycles at 2 A g-1. The proposed investigation offers a promising approach for developing high-performance, low-cost carbon-based anode materials that could be used in advanced lithium-ion batteries.

Insights into the physico-chemical and biological characterization of sodium lignosulfonate - silver nanosystems designed for wound management

Chronic wounds represent one of the complications that might occur from the disruption of wound healing process. Recently, there has been a rise in interest in employing nanotechnology to develop novel strategies for accelerating wound healing. The aim of the present study was to use a green synthesis method to obtain AgNPs/NaLS systems useful for wounds management and perform an in-depth investigation of their behavior during and post-synthesis as well as of their biological properties. The colloids obtained from silver nanoparticles (AgNPs) and commercial sodium lignosulfonate (NaLS) in a single-pot aqueous procedure have been fully characterized by UV-Vis, FT-IR, DLS, TEM, XRD, and XPS to evaluate the synthesis efficiency and to provide new insights in the process of AgNPs formation and NaLS behavior in aqueous solutions. The effects of various concentrations of NaLS (0-16 mg/mL) and AgNO3 (0-20 mM) and of two different temperatures on AgNPs formation have been analyzed. Although the room temperature is feasible for AgNPs synthesis, the short mixing at 70 °C significantly increases the speed of nanoparticle formation and storage stability. In all experimental conditions AgNPs of 20-40 nm in size have been obtained. The antimicrobial activity assessed quantitatively on clinical and reference bacterial strains, both in suspension and biofilm growth state, revealed a broad antimicrobial spectrum, the most intensive inhibitory effect being noticed against Pseudomonas aeruginosa and Escherichia coli strains. The AgNP/NaLS enhanced the NO extracellular release, potentially contributing to the microbicidal and anti-adherence activity by protein oxidation. Both AgNP/NaLS and NaLS were non-hemolytic (hemolytic index<5%, 2.26 ± 0.13% hemolysis) and biocompatible (102.17 ± 3.43 % HaCaT cells viability). The presence of AgNPs increased the antioxidative activity and induced a significant cytotoxicity on non-melanoma skin cancer cells (62.86 ± 8.27% Cal-27 cells viability). Taken together, all these features suggest the multivalent potential of these colloids for the development of novel strategies for wound management, acting by preventing infection-associated complications and supporting the tissue regeneration.

Influence of bio-coupling agent on interfacial interlocking compatibility and toughness of ultrafine bamboo charcoal/polylactic acid composite film

Applications for polylactic acid (PLA) are significantly impacted by its poor mechanical properties and lack of thermal stability. The goal of this work is to bridge the gap of poor compatibility among the components and enhance their interface interlocking capability to improve the toughness and thermal stability. Ultrafine bamboo charcoal (UFBC) was treated through deep eutectic solvent (DES) method to deposit sodium lignosulfonate (LS) on its surface. LS was used with PLA as a bio-coupling agent to create an eco-friendly PLA composite film with a wide range of characteristics. Benefiting from the penetration of PLA to the internal pores in UFBC, the resultant L-UFBC/PLA film has a good mechanical interlocking structure. Ls can increase the compatibility and strengthen the interface interlocking capability through DES method, which greatly improves the mechanical properties of the system. In comparison to pure PLA one, the elongation at break was 136.24 % greater, and the crystallinity (Xc) increased from 1.09 % to 3.33 %. Furthermore, the thermal stability of the system was also improved, and the residual at 600 °C rose by 4.83 %. These characteristics offer the prepared L-UFBC/PLA film a wide range of potential applications in the packaging, medical, agricultural, and other sectors.

Mulch from lignocellulose as agricultural plastic alternative for sustained-release of photosensitive pesticide

Extensively used agricultural mulch fabricated from nonbiodegradable polyolefin plastic causes tremendous environmental pollution. In this work, a paper-based mulch, composed of the cellulose fiber networks incorporated with Emamectin benzoate (EB)@sodium lignosulfonate (SL), has been developed with facile papermaking/coating methods. The spherical microcapsule loaded with pesticide EB has a desirable core-shell structure for better protection and sustained release of photosensitive EB. The loading rate and encapsulation efficiency reached 78.5 % and 52.3 %, respectively. Furthermore, microcapsules exhibited excellent slow-release behavior and resistance to photolysis. Natural carnauba wax was coated on the surface of the paper-based mulch to form a hydrophobic layer and increase the physical intertwinement of fibers in the mulch, thereby exhibiting superior performance, such as enhanced tensile strength, excellent hydrophobicity, high air permeability, and high light transmittance at reasonable level. Moreover, unlike conventional polyethylene mulch film, the functionalized paper-based mulch almost completely biodegraded after 75 days in the soil. Thus, multifunctional, eco-friendly mulch from lignocellulose is an innovative approach to obtaining the sustained release of agrochemicals, and it provides an excellent alternative to conventional agricultural plastic mulch.

Preparation and characterization of polyvinyl alcohol/sodium lignosulfonate/black rice anthocyanin extract agricultural film for monitoring soil pH

This study focuses on the formulation of polyvinyl alcohol (PVA)-based films with pH-sensitive properties and ultraviolet (UV) resistance by incorporating sodium lignosulfonate (LS) and varying concentrations of black rice anthocyanin extract (BRE) into PVA matrix. The films were characterized through Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), tensile test, water vapor permeability (WVP), and ultraviolet-visible (UV-vis) spectroscopy. The results indicated that BRE and LS effectively formed strong hydrogen bonds with PVA, leading to reduced film crystallinity, improved mechanical properties, and lowered WVP as the BRE content increased. The addition of LS and BRE improved the UV resistance of the films, and BRE imparted films with excellent pH-sensitive properties. Among the film variants, the PVA/LS/BRE film containing 1 wt% BRE exhibited excellent mechanical performance, boasting an elongation at a break of 360.66 % and a strength of 35.68 MPa. Additionally, soil pH visualization holds significant potential within agriculture. In this study, the PVA/LS/BRE film containing 2 wt% BRE exhibited minimum UV transparency (0.9 %) and displayed the most distinct color response across varying pH environments. Therefore, the PVA/LS/BRE film containing 2 wt% BRE excelled in both UV resistance and pH sensitivity, positioning it as the most suitable material for the development of agricultural films integrated with soil pH monitoring capabilities.

Engineering a hierarchical reduced graphene oxide and lignosulfonate derived carbon framework supported tin dioxide nanocomposite for lithium-ion storage

Tin dioxide (SnO2) is widely recognized as a high-performance anode material for lithium-ion batteries. To simultaneously achieve satisfactory electrochemical performances and lower manufacturing costs, engineering nano-sized SnO2 and further immobilizing SnO2 with supportive carbon frameworks via eco-friendly and cost-effective approaches are challenging tasks. In this work, biomass sodium lignosulfonate (LS-Na), stannous chloride (SnCl2) and a small amount of few-layered graphene oxide (GO) are employed as raw materials to engineer a hierarchical carbon framework supported SnO2 nanocomposite. The spontaneous chelation reaction between LS-Na and SnCl2 under mild hydrothermal condition generates the corresponding SnCl2@LS sample with a uniform distribution of Sn2+ in the LS domains, and the SnCl2@LS sample is further dispersed by GO sheets via a redox coprecipitation reaction. After a thermal treatment, the SnCl2@LS@GO sample is converted to the final SnO2/LSC/RGO sample with an improved microstructure. The SnO2/LSC/RGO nanocomposite exhibits excellent lithium-ion storage performances with a high specific capacity of 938.3 mAh/g after 600 cycles at 1000 mA g-1 in half-cells and 517.1 mAh/g after 50 cycles at 200 mA g-1 in full-cells. This work provides a potential strategy of engineering biomass derived high-performance electrode materials for rechargeable batteries.

Enhancing cellulosic digestibility of wheat straw by adding sodium lignosulfonate and sodium hydroxide to hydrothermal pretreatment

Surfactant-assisted pretreatment has been widely reported to improve the enzymatic hydrolysis of lignocellulose by promoting removal of xylan and lignin. Hence, this work innovatively proposed the use of sodium lignosulfonate (SL) as an additive of alkaline pretreatment (AP), and evaluated its influence on the cellulosic digestibility of wheat straw (WS). The results displayed that the maximum of 72-h cellulosic digestibility could reach 83.5% as 15 g/L SL was introduced to the AP process (SAP), while the cellulosic digestibility of hydrothermal and alkaline pretreated WS was only 63.6% and 70.2%, respectively. These increments were subsequently attributed to the improvement of 6.5% xylan and 26.8% lignin accelerated by SAP, resulting in positive changes in structural characteristics such as accessibility, specific surface area, and cellulosic crystalline structure. The utilization of lignin-based surfactants in pretreatment has realized the economic feasibility of lignocellulosic biorefining and broadened the application prospect of surfactants.

Insights into S-doped iron-based carbonaceous nanocomposites with enhanced activation of persulfate for rapid degradation of organic pollutant

In the work, S-doped iron-based carbon nanocomposites (Fe-S@CN) for activating persulfate (PS) were prepared by calcining iron-loaded sodium lignosulfonate. The characterization revealed that the main substances of Fe-S@CN were FeS and Fe₃C, which were distributed on porous carbon nanosheets in rod-like morphology. In the Fe-S@CN/PS system, carbamazepine could be completely removed within 30 min, and the relative contribution of hydroxyl radicals (OH·), sulfate radicals (SO4·-) and total singlet oxygen (¹O₂) and superoxide radicals (O2·-) for carbamazepine removal were approximated as 8.7%, 19.2% and 72.1%, respectively. Electron paramagnetic resonance spectroscopy demonstrated that S doping promoted the formation of various active species. Compared with the catalyst without S doping, Fe-S@CN exhibited higher activation performance (1.48-fold) for PS due to the enhanced electron transfer rate and facilitated Fe²⁺/Fe³⁺ cycle. Density functional theory calculations showed that S doping promoted the binding between the catalyst and PS, and enhanced the overall internal electron density of the catalyst. Fe-S@CN exhibited excellent catalytic performance over a wide pH range (3.0-11.0). The active sites of Fe-S@CN used in the cycling experiments was also largely recovered after thermal regeneration. Overall, this study shows for the first time the impact of SLS as an S dopant on enhanced PS activation.

Sodium lignosulfonate causes cell membrane perturbation in the human fungal pathogen Candida albicans

Underestimating fungal infections led to a gap in the development of antifungal medication. However, rising rates of morbidity and mortality with fungal infection have revealed an alarming rise in antifungal resistance also. Due to the eukaryotic properties of fungi and the close evolutionary similarity between fungal cells and human hosts, therapeutic targeting of Candida infections is troublesome, along with the development of resistance. The discovery of new antifungals is so far behind schedule that the antifungal pipeline is nearly empty. Previously, we have reported the activity and susceptibility of Sodium lignosulfonate (LIG) against C. albicans. In this work, we have established the mechanistic actions of LIG's activity. We performed flow cytometric analysis for membrane integrity, ergosterol binding assay, crystal violet assay, and membrane leakage assay to analyze quantitatively that the C. albicans membrane is being disrupted in response to LIG. Electron microscopic analysis with SEM and TEM confirmed changes in Candida cellular morphology and membrane perturbation respectively. These findings indicated that LIG causes cell membrane damage in C. albicans. This knowledge about LIG's mechanism of action against C. albicans could be used to explore it further as a lead antifungal molecule to develop it as a potent candidate for antifungal therapeutics in the future.

Preparation of in-situ nitrogen-doped lignin-based porous carbon and its efficient adsorption of chloramphenicol in water

Porous carbon is an excellent absorbent for pollutants in water. Here, we report a breakthrough in performance of porous carbon based on lignin prepared using sodium lignosulfonate (SLS), potassium carbonate and melamine as precursor, activator and nitrogen source, respectively. A series of characterization tests confirmed that in-situ nitrogen doping greatly enhanced porous structure, resulting in a specific surface area of 2567.9 m² g^-1 and total pore volume of 1.499 cm³ g^-1, which is nearly twice that of non-nitrogen-doped porous carbon. Moreover, adsorption experiments revealed that at 303 K, the saturated adsorption capacity of chloramphenicol was as high as 713.7 mg g^-1, corresponding to an improvement of 33.7%. Further, the prepared porous carbon exhibited a strong anti-interference against metal ions and humic acid. The adsorption process was confirmed to be an endothermic reaction dominated by physical adsorption, indicating that an increase in temperature is conducive to adsorption. The results of this study show that nitrogen-doped lignin-based porous carbon prepared by in-situ doping is a promising material to significantly alleviate water pollution owing to its low cost, excellent pore structure and good adsorption properties.

Preparation of uniform lignosulfonate-based colloidal spheres for UV-absorbing thermoplastics

Lignosulfonate-based colloidal spheres were prepared from sodium lignosulfonate and cetyltrimethylammonium bromide (NaLS/CTAB) complex through electrostatic and hydrophobic self-assembly. Due to the stronger hydrophobicity and UV-blocking performance, NaLS/CTAB colloids were easier to be blended with HDPE than lignosulfonate, and therefore applied to UV-absorbing thermoplastics. Results showed NaLS/CTAB colloidal spheres had a particle size of 160 nm with a polydispersity index of 0.081. NaLS/CTAB molecules started to form spheres at critical water content of 64 vol% when the initial concentration of NaLS/CTAB in EtOH was 0.5 mg/cm³ and the obtaining of colloids was completed at a water content of 90 vol%. The size and polydispersity of spheres were well controlled by adjusting initial concentrations of NaLS/CTAB in EtOH. Since NaLS/CTAB colloidal spheres retained phenylpropane units and phenolic hydroxyl groups of NaLS, NaLS/CTAB/HDPE composites displayed excellent UV-absorbing properties. Meanwhile, the mechanical property of NaLS/CTAB/HDPE composites was also superior to that of frequently-used CaCO₃/HDPE materials in industry, reaching the requirement of industrial uses. However, too high additions would result in the increased agglomeration of NaLS/CTAB spheres in HDPE, and thus the deteriorated mechanical property. Additionally, the added spheres played a role of "ball", which caused the decreased viscosity, improved flowability and processability of composites.

Synthesis of a functional biomass lignin-based hydrogel with high swelling and adsorption capability towards Acid Red 73

In this study, sodium lignosulfonate (LS) was used as raw material. Acrylamide (AM) and acryloxyethyltrimethylammonium chloride (DAC) were grafted onto LS through the free radical graft copolymerisation to synthesise a functional biomass terpolymer lignin-based hydrogel adsorbent (LAD). The effects of different factors on the LAD adsorption of Acid Red (AR 73) were investigated through the static adsorption method. LAD adsorbed AR 73 (C0=100mg·L-1) for 2 h to reach equilibrium, and the equilibrium adsorption capacity and removal rate were 47.59 mg·g-1 and 95.18%, respectively. The prepared LAD hydrogel swelling ratio for 2 h was 25 g·g-1, and the water loss rate in ethanol solvent in 120 min was 93.51%. The adsorption of AR 73 by LAD was consistent with the Langmuir isotherm adsorption model. This adsorption was a single-molecule adsorption with a maximum adsorption capacity of 409.84 mg·g-1. The adsorption was a process of spontaneous heat release and entropy reduction. The adsorption kinetic was in accordance with the pseudo-second-order model, and the adsorption activation energy was 2.501 kJ·moL-1. Moreover, the mechanism of adsorption was electrostatic attraction, and comprehensive effects of physical, and chemical adsorption and hydrogen bond. The LAD hydrogel adsorbent has a remarkable adsorption effect on AR 73, and can be used as an efficient and recyclable biomass adsorbent for the treatment of anionic dye wastewater.

Fast one-step preparation of porous carbon with hierarchical oxygen-enriched structure from waste lignin for chloramphenicol removal

This work explored the use of porous carbon (PC) materials converted from waste lignin as raw materials for the removal of chloramphenicol (CAP) in water. The PC with controllable pores was prepared through a facile, cost-effective one-step method. The physical and chemical properties of the material were characterized by BET, SEM, FT-IR, and XRD, and the best conditions for preparation were selected based on the results of adsorption experiments. The PC, which was prepared at reaction temperature of 800 °C and the K₂CO₃/sodium lignosulfonate mass ratio of 4, namely PC-800-4, had a high specific surface area (1305.5 m² g^-1) and pore volume (0.758 cm³ g^-1). At a lower initial concentration of CAP (C₀ = 120 mg L^-1), the maximum adsorption capacity of this adsorbent was 534.0 mg g^-1 at 303 K. In addition, PC-800-4 maintained good adsorption performance in a wide pH range and strongly resisted the interference of ions and humic acid. The results showed that the adsorption removal CAP was based on physical adsorption and chemical adsorption as a process supplement. The advantages of wide sources, high efficiency and speed, wide application, and rich oxygen-containing functional groups made the adsorbent have great application potential for removal chloramphenicol from water.

Stabilizing zinc deposition with sodium lignosulfonate as an electrolyte additive to improve the life span of aqueous zinc-ion batteries

Thanks to high safety and low cost, rechargeable zinc-ion batteries (RZIBs) have become a promising candidate for grid-scale energy storage systems. However, zinc anodes suffer from severe dendrite growth and irreversible side reactions, leading to poor cyclability of RZIBs. In this work, low-cost sodium lignosulfonate (SL) is utilized as the electrolyte additive to solve this problem. The added amount of SL is optimized to be 0.02%, which enables the Zn//α-MnO₂ battery to deliver a large capacity of 146 mAh g^-1 after 1000 cycles at 1 A g^-1, corresponding to a high capacity retention of 83.5%. The Zn//Zn symmetric cell with the modified electrolyte also shows excellent cyclability even under a commercial level of areal specific capacity (4 mAh cm^-2). Overall, the results of this study confirm that the SL additive can improve the ionic conductivity of electrolyte, restrict the two-dimensional planar diffusion of Zn²⁺ ions at the electrode/electrolyte interface, lower the nucleation overpotential of Zn²⁺ ions, prevent side reactions, and inhibit the corrosion of Zn metal. Therefore, the dendrite growth and byproduct formation can be effectively suppressed. This study provides new insights into protecting metal electrodes of electrochemical energy storage devices.

Preparation and characterization of an eco-friendly dust suppression and sand-fixation liquid mulching film

An eco-friendly dust suppression and sand-fixation liquid mulching film was prepared via a facile secondary spraying process in this work. Water polyurethane (WPU) was blended with dissolved humic acid (HA) firstly, and then the blend solutions (HWPU) were sprayed on the surface of cationic starch (CS) / sodium lignosulfonate (LS) film to synthesize the liquid mulching film (CLS-HWPU). The effects of liquid mulching film composition on mechanical properties in dry and wet states were investigated. The results showed that the optimal composition of liquid mulching film was: 3% (CS), 0.9 % (LS), 1.5 % (glycerol), 2% (HA), and 30 % (WPU). The CLS-HWPU liquid mulching films were characterized in terms of light transmittance, degradation performance test, contact angle test, scanning electron microscopy (SEM), total reflectance-Fourier transform infrared spectrometer (ATR-FTIR), thermo gravimetric analysis (TGA), and erosion resistance test. The results indicated that the CLS-HWPU film had good UV resistance, thermal stability, anti-erosion, and biodegradation. The CLS-HWPU film meets the demand of dust suppression and sand-fixation in dusty areas and desertification environments, which opens a new application field for liquid mulching film with high safety and environmental protection.

Renewable lignin-based surfactant modified layered double hydroxide and its application in polypropylene as flame retardant and smoke suppression

A novel and environmentally friendly lignin-based surfactant sodium lignosulfonate (SLS) modified layered double hydroxide (LDH) flame retardant (LDH-LS) was fabricated via co-precipitation method, and subsequently incorporated into polypropylene (PP) matrix to obtain the PP and LDH-LS composites (PP/LDH-LS) by melt blending method. The XRD, FT-IR and XPS results indicated that SLS had successfully modified LDH by adsorbing on the surface of the LDH nanosheet. The WCA and SEM results revealed that the hydrophobic property of LDH-LS had been evidently improved, and it displayed a more homogeneous dispersion than virgin LDH in the PP matrix. Furthermore, cone calorimetry tests (CCT) illustrated that the peak heat release rate (PHRR), total heat release (THR), and total smoke release (TSR) of PP/LDH-LS composites exhibited declines of 62.9%, 25.1%, and 43.3% compared with those of Neat PP, respectively. Besides, the PP/LDH-LS achieved a LOI value of 29.4% and a UL-94 V-0 rating, whereas the PP/LDH showed only a LOI value of 25.2% and a UL-94 V-2 rating at 20 wt% loading. These improvements of flame retardant properties can be attributed to that the well-dispersed LDH-LS and synergistic flame retardancy between LDH and SLS.

Synthesis of sodium lignosulfonate-guar gum composite hydrogel for the removal of Cu2+ and Co2

As an emerging pollutant treatment material, hydrogel is known for its good adsorption capacity and environmental friendliness. In this study, a composite material of acrylic acid as the polymerization monomer grafted sodium lignosulfonate and guar gum was prepared, which provided a channel for adsorbing metal ions with its abundant active functional groups and porous structure. The optimized synthesized product was applied to the removal of Cu²⁺ and Co²⁺ in a one-component system and a multi-component system, and the maximum ion adsorption capacities obtained were determined to be 709 mg g^-1 of Cu²⁺, 601 mg g^-1 of Co²⁺, respectively. The adsorption kinetics and isotherms were well fitted by the pseudo second-order kinetic model and the Langmuir isotherm, showing that the adsorption of Cu²⁺ and Co²⁺ by the adsorbent belongs to the chemisorption on monolayer. XPS results confirmed the successful adsorption of Cu²⁺ and Co²⁺ by GG/SLS. Surface complexation was proposed to be the main mechanism for GG/SLS adsorbent to remove heavy metal ions. In addition, the use of recycling research showed that the adsorbent has good chemical stability. These results provided valuable information for designing highly efficient adsorbents that can be used as a high-quality wastewater treatment material.

Alkali lignin and sodium lignosulfonate additives promote the formation of humic substances during paper mill sludge composting

Alkali lignin (AL) and sodium lignosulfonate (SLS) are by-products of the papermaking industry and could influence composting processes due to their rich aromatic structures. In this study, the roles of AL and SLS additives in the formation of humic substances (HS) during paper mill sludge composting were investigated. Results showed that HS content and degree of polymerization of the final products in AL (44.42 mg·g^-1 and 0.70, respectively) and SLS (45.87 mg·g^-1 and 1.14, respectively) treatments were appreciably higher than those of the control sample (34.36 mg·g^-1 and 0.67). Excitation-emission matrix-parallel factor coupled with two-dimensional FT-IR correlation spectroscopy analysis suggested that AL and SLS additives could speed the transformation of quinone-like substances by increasing the amounts of low molecular weight lignin depolymerized products, which led to higher HS concentrations. This work provided a way of promoting HS formation and the comprehensive utilization of papermaking wastes.

Flexible and transparent composite nanofibre membrane that was fabricated via a "green" electrospinning method for efficient particulate matter 2.5 capture

Air particulate pollution from ever-increasing industrialization poses an enormous threat to public health. Thus, the development of a green air filter with high efficiency and performance is of urgent necessity. In this study, we introduce a new effective air filtration membrane that can be used for outdoor protection. The air filter's composite nanofibre materials were prepared from polyvinyl alcohol (PVA)-sodium lignosulfonate (LS) via a "green" electrospinning method and thermal crosslinking. The addition of LS helped increase the PM_2.5 removal efficiency compared to that of a pure PVA nanofibre membrane. The pressure drops of the electrospun PVA-LS membranes exceeded those of the pristine PVA air filter. The remarkable air filtration performance was maintained even after 10 cycles of circulation filtration. In addition, the PVA-LS composite nanofibre membrane exhibited excellent mechanical properties and transparency due to the introduction of LS. This study provides new insight into the design and development of high-performance and high-visibility green filter media, which include personal protection and building screens.

Exploring why sodium lignosulfonate influenced enzymatic hydrolysis efficiency of cellulose from the perspective of substrate-enzyme adsorption

BACKGROUND

Cellulase adsorbed on cellulose is productive and helpful to produce reducing sugars in enzymatic hydrolysis of lignocellulose; however, cellulase adsorbed on lignin is non-productive. Increasing productive adsorption of cellulase on cellulose would be beneficial in improving enzymatic hydrolysis. Adding lignin that was more hydrophilic in hydrolysis system could increase productive adsorption and promote hydrolysis. However, the effect mechanism is still worth exploring further. In this study, lignosulfonate (LS), a type of hydrophilic lignin, was used to study its effect on cellulosic hydrolysis.

RESULTS

The effect of LS on the enzymatic hydrolysis of pure cellulose (Avicel) and lignocellulose [dilute acid (DA) treated sugarcane bagasse (SCB)] was investigated by analyzing enzymatic hydrolysis efficiency, productive and non-productive cellulase adsorptions, zeta potential and particle size distribution of substrates. The result showed that after adding LS, the productive cellulase adsorption on Avicel reduced. Adding LS to Avicel suspension could form the Avicel-LS complexes. The particles were charged more negatively and the average particle size was smaller than Avicel before adding LS. In addition, adding LS to cellulase solution formed the LS-cellulase complexes. For DA-SCB, adding LS decreased the non-productive cellulase adsorption on DA-SCB from 3.92 to 2.99 mg/g lignin and increased the productive adsorption of cellulase on DA-SCB from 2.00 to 3.44 mg/g cellulose. Besides, the addition of LS promoted the formation of LS-lignin complexes and LS-cellulase complexes, and the complexes had more negative charges and smaller average sizes than DA-SCB lignin and cellulase particles before adding LS.

CONCLUSIONS

In this study, LS inhibited Avicel's hydrolysis, but enhanced DA-SCB's hydrolysis. This stemmed from the fact that LS could bind cellulase and Avicel, and occupied the binding sites of cellulase and Avicel. Thus, a decreased productive adsorption of cellulase on Avicel arose. Regarding DA-SCB, adding LS, which enhanced hydrolysis efficiency of DA-SCB, increased the electrostatic repulsion between DA-SCB lignin and cellulase, and therefore, decreased non-productive adsorption of cellulase on DA-SCB lignin and enhanced productive adsorption of cellulase on DA-SCB cellulose.

Renewable Lignosulfonate-Assisted Synthesis of Hierarchical Nanoflake-Array-Flower ZnO Nanomaterials in Mixed Solvents and Their Photocatalytic Performance

With the assistance of sodium lignosulfonate, hierarchical nanoflake-array-flower nanostructure of ZnO has been fabricated by a facile precipitation method in mixed solvents. The sodium lignosulfonate amount used in our synthetic route is able to fine-tune ZnO morphology and an abundance of pores have been observed in the nanoflake-array-flower ZnO, which result in specific surface area reaching as high as 82.9 m(2) · g(-1). The synthesized ZnO exhibits superior photocatalytic activity even under low-power UV illumination (6 W). It is conjectured that both nanoflake-array structure and plenty of pores embedded in ZnO flakes may provide scaffold microenvironments to enhance photocatalytic activity. Additionally, this catalyst can be used repeatedly without a significant loss in photocatalytic activity. The low-cost, simple synthetic approach as well as high photocatalytic and recycling efficiency of our ZnO nanomaterials allows for application to treat wastewater containing organic pollutants in an effective way.