Presence Of Lignosulfonate Research Articles

Facile Preparation of MXene Decorated PANI/Lignosulfonate Nanocomposite Film Electrodes for Electrochemical Supercapacitors

AbstractMXenes are a large family of two‐dimensional transition‐metal carbides, nitrides, and carbonitrides with large surface area and metal conductivity. They have not been widely used as electrodes in the field of supercapacitors because of their low specific capacity, poor chemical stability, and tendency towards self‐stacking. Herein, a three‐component nanocomposite film electrode has been successfully achieved, consisting of MXene nanosheets, polyaniline (PANI), and lignosulfonate (LGS). The PANI‐LGS nanocomposite was prepared through the oxidative polymerization of PANI in the presence of LGS, and then MXene decorated PANI/LGS (labeled as MPL) nanocomposite films were facilely self‐assembled via a vacuum‐assisted filtration by using the dispersion. Compared with pure PANI and PANI‐LGS, the MPL nanocomposite film electrode possesses better conductivity, showing a high specific capacitance of 559 F/g at a scan rate of 5 mV/s and a capacity retention rate of 92.2 % after 1000 cycles at a current density of 10 A/g. This study demonstrates that the doping of LGS and MXene can significantly improve the electrochemical performance of PANI‐based composite materials. Thus, the convenient preparation and excellent electrochemical performance of MPL show great potentials in the application of high‐performance electrodes for supercapacitors.

Novel flexible hydrogels based on carboxymethyl guar gum and polyacrylic acid for ultra-highly sensitive and reliable strain and pressure sensors

To realize on stable and real-time monitoring of human activities, novel hydrogels using polyacrylic acid (PAA) and carboxymethyl guar gum (CMGG) were fabricated as wearable and flexible strain or pressure sensors in the presence of lignosulfonate (LS) and Al3+. Based on the co-existence of metal coordination bonds, hydrogen bonds and ionic interaction in this system, the obtained hydrogels exhibited desirable mechanical properties with good self-recovery ability. The hydrogels displayed good self-adhesion behavior and an ultra-high tensile sensitivity (gauge factor (GF) = 24.30), therefore, they could precisely detect human joints movements such as elbow, wrist, and finger bending as well as tiny movements and external stimuli such as swallowing, smile, frown, pulse, speaking, writing, and even the falling of different liquid drops. Additionally, the hydrogels showed excellent self-healing ability with the healing efficiency as high as 100 % after 30 h. Most importantly, the healed hydrogel could perform the same sensing performance as before. Based on these distinguished characteristics, this hydrogel represents great potentials in wearable and flexible sensors for long-term and stable health monitoring application.

Synthesis of Lignosulfonate based Nanocarriers for the Delivery of Agrochemicals

Aims: The study's objective is to develop lignosulfonate-based nanocarriers as a UV protectant for agrochemical delivery
 Place and Duration of Study: Department of Nano Science & Technology, Tamil Nadu Agricultural University, Coimbatore. The research was carried out between March 2021 and January 2022.
 Methodology: We demonstrate a straightforward approach for the solvent – anti-solvent conversion of lignosulfonate macromolecules from black liquor derived from the paper pulping industry to nanocarriers. Due to the amphiphilic nature of lignin, nanoparticles are generated by self-assembly. To create lignin nanoparticles, a drop-by-drop solvent exchange approach has been used. The lignosulfonate solution was prepared using solvents such as ethanol and tetrahydrofuran, and then water was added as an antisolvent, resulting in the creation of nanoparticles by self-assembly. The hydrophobic portion of lignin creates the particle's core, while the hydrophilic hydroxyl groups form the particle's shell. The size and stability of nanoparticles were determined using dynamic light scattering, and the form and size of the systems were imaged using scanning electron microscopy. The functional groups of the nanoparticles were determined using Fourier transform infrared spectroscopy.
 Results: Solvent tetrahydrofuran generated uniform and spherical lignosulfonate nanoparticles than the solvent ethanol employed in the solvent exchange procedure. When ethanol and cetyl trimethyl ammonium bromide were used as solvent and surfactant, respectively, the size of lignosulfonate nanoparticles was smaller (270±31.9nm). However, the stability of nanocarrier systems was unaffected by the solvent used, with polydispersity index values of 0.435±0.003 and 0.401±0.028 for tetrahydrofuran and ethanol solvents, respectively. The existence of a distinctive peak at 526 and 609 cm-1 in the infrared spectrum corresponding to sulfonic stretching indicated the presence of lignosulfonate in the carrier systems.
 Conclusion: Lignosulfonate-based nanocarrier systems were developed using the solvent exchange method. However, the nanocarrier systems are to be validated to assess the bioefficacy of active molecules.

Strength and post-freeze-thaw behavior of a marl soil modified by lignosulfonate and polypropylene fiber: An environmentally friendly approach

Lignosulfonate is one of the by-products in the paper and pulp industry that is widely produced around the world and its improper disposal or storage can pose irreparable risks to human health and the environment. Sustainable reuse of this industrial waste as a stabilizing agent not only provides a novel approach in the construction industry, but also prevents the loss of natural resources. In this study, an environmentally friendly strategy involving lignosulfonate as a binder along with the polypropylene (PP) fiber as a reinforcing material was adopted to enhance the characteristics of marl soils from detrimental impacts of freeze-thaw (F-T) cycles. To this end, the pure marl specimens were improved by various contents of lignosulfonate and polypropylene fiber solely and simultaneously and cured for different time intervals. The variables assessed in this study were lignosulfonate content, polypropylene fiber content, curing period as well as the number of F-T cycles. The results showed that the greatest improvement was observed in the samples containing 1.5% lignosulfonate and 0.6% PP fibers, showing the least amplitude of fluctuations in MR reduction upon the F-T cycles. Moreover, freeze-thaw weathering transformed the stress-strain pattern of the samples from strain-softening to hardening behavior as well as increased the ductility behavior. It was observed that the simultaneous application of lignosulfonate and PP fibers led to the complete bonding of soil particles and the formation of interlocking zones around the fiber strands, leading to stronger particle bonding. The results of the Fourier transform infrared (FTIR) test also verified the formation of ionic bonds owing to the inclusion of lignosulfonate in the marl soil and the presence of lignosulfonate in the distance between the mineral layers of the soil. Overall, the reuse of lignosulfonate as a non-traditional alternative to marl soil modification can play an effective role in enhancing the durability and mechanical characteristics as well as sustainable development.

Lignosulfonate properties and reaction conditions enhance precipitation and affect ensuing quality of proteins from green biomass juice for monogastric animal feed

This is the first study investigating the effects of lignosulfonate (LS) properties and reaction conditions on the precipitation of proteins from green biomass juice for producing monogastric animal feed. Both the improvement in the protein precipitation yield and the resulting impact on the quality of the protein pellets were investigated with new methods and approaches. High molecular weight (MW) LS gave the highest precipitation yield, 21–33% higher than traditional heat and isoelectric methods. Electrostatic interaction between LS and soluble proteins was observed to be higher in high MW LS than others, and likely improved the precipitation. A response surface design experiment showed that pH was more important than LS concentration for precipitation. The optimum conditions predicted by the model improved precipitation by up to 61% compared to traditional methods. Using high MW LS at near optimum conditions resulted in more LS being retained in the pellet, with a final LS content of up to 60 g/kg dry matter (DM). The improved precipitation yield came at the expense of lower crude protein (CP) content of the pellet. Despite reduced pellet protein purity, the total CP recovery from the juice was improved by up to 800 g/kg DM. The in vitro protein digestibility (IVPD) and amino acid composition were not significantly affected by the presence of LS. Using high MW LS at optimum reaction conditions can significantly improve protein precipitation yield from green biomass juice without compromising digestibility. However, finding the compromise between yield and protein purity is necessary to improve feasibility.

Синтез коллоидного серебра с использованием лигносульфонатов

Colloidal silver solutions can be used as catalysts for carrying out various chemical transformations of organic substances and solving the problems of disposal of toxic compounds, as well as antibacterial agents for combating pathogenic microflora, in the manufacture of lubricants and light-absorbing materials, coatings, sensors, conductive pastes, and high-performance electrode materials. The research purpose is to study the synthesis of colloidal silver using a solution of technical lignosulfonates (LST) as a stabilizer. Colloidal silver was synthesized as a result of the reduction-oxidation (redox) reaction of Ag(I) cations with glucose at 100 °C in the presence of lignosulfonates. The reaction was carried out in an alkaline medium, which is provided by the addition of ammonia water. Electronic spectroscopy was used to control the synthesis of colloidal silver. After the reaction, the solution turned dark brown and an intense absorption band with a maximum at 400 nm appeared on the electron spectra. The effects of reagent consumption and synthesis duration were studied. It was found that the optimal reagent consumption in the colloidal silver synthesis is as follows: 2.5–5 g glucose / g Ag, 0.3–1 g LST / g Ag, and 3–5 g NH3 / g Ag. The synthesis duration is 2–5 min. The resulting colloidal silver solution is stable for several months. Partial stratification without precipitation is observed during the solution storage. It is shown experimentally that the stratification is followed by a redistribution of colloidal silver particles. Electron spectroscopy confirmed the absence of colloidal silver particles in the upper layer. The reaction kinetics has been studied in experiments carried out under thermostatically controlled conditions at temperatures from 50 to 100 °C. The kinetic dependence is described by a first-order equation at the initial stage of the reaction, the duration of which depends on the temperature. The duration of the active part of the kinetic curves is 15–90 % of the total reaction time. The logarithm of the rate constant on the active section was proved to depend linearly on the reverse thermodynamic temperature (pair correlation coefficient is 0.9887). The activation energy was 47 kJ/mol. For citation: Plakhin V.A., Khabarov Yu.G., Veshnyakov V.A. Synthesis of Colloidal Silver Using Lignosulfonates. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 184–195. DOI: 10.37482/0536-1036-2021-6-184-195

Behavior of Indium during the Pressure Leaching of a Zinc Concentrate in the Presence of Lignosulfonate

Behavior of Indium during the Pressure Leaching of a Zinc Concentrate in the Presence of Lignosulfonate

Physicochemical Regularities of the Pressure Leaching of a Zinc Sulfide Concentrate in the Presence of Lignosulfonate

Physicochemical Regularities of the Pressure Leaching of a Zinc Sulfide Concentrate in the Presence of Lignosulfonate

Physical and chemical regularities of zinc sulfide concentrate pressure leaching in the presence of lignosulfonate

The study covers physical and chemical regularities of zinc sulfide concentrate oxygen pressure leaching in sulfuric acid. The effect of lignosulfonate concentration (CLSN = 0.2÷0.8 g/dm3), leaching time (τ = 20÷120 min), temperature (T = 393÷423 K), and oxygen partial pressure (РО2= 0.3÷0.7 MPa) on the degree of zinc and iron extraction into the solution and on the cake grain-size distribution was established. It was shown that lignosulfonate additive intensifies zinc and iron extraction into the solution. Maximum extraction of zinc and iron was 89 and 37 %, respectively, for 120 min of leaching at CLSN = 0.6÷0.8 g/dm3. The differential rate law with respect to lignosulfonate was 0.3 for sphalerite, and 0.9 for iron sulfides. A controversial influence of rising temperature on the process under investigation was found. Temperature elevation from 413 to 423 K leads to a decrease in zinc extraction by 3–4 % due to the formation of sulfur-sulfide aggregates over 150 μm in size. The calculated values of apparent activation energy (Еа) of sphalerite and iron sulfide leaching in the presence of lignosulfonate were 30 and 45 kJ/mole, respectively. It was found out that an increase in oxygen partial pressure from 0.3 to 0.5 MPa has a positive influence on leaching and increases extraction of zinc and iron by 22 and 27 %, respectively. However, an increase in oxygen partial pressure up to 0.7 MPa in the presence of lignosulfonate after 40 min of leaching led to a decrease in leaching rate, possibly as a result of lignosulfonate destruction. It was found that differential rate laws with respect to oxygen are 1.2 for sphalerite and 2.5 for iron sulfides.

Lignosulfonates in Crude Oil Processing: Interactions with Asphaltenes at the Oil/Water Interface and Screening of Potential Applications.

The goal of this article is to test the potential application of lignosulfonates (LSs) in crude oil production and processing. Three LS samples of varying hydrophobicity and average molecular weight were considered. First, the interfacial tension between brine and xylene and interfacial dilational rheology properties of LS samples were measured. It was found that the most surface-active LS sample has the lowest molecular weight in agreement with the results from the literature. In the presence of asphaltenes, all three LS samples were able to compete with asphaltenes, the most polar crude oil component, at the interface and form mixed LS–asphaltene interfaces. However, only the most surface-active LS sample among the three tested could fully desorb asphaltenes at the highest tested LS concentration (500 ppm). Second, three possible applications were screened. LSs were tested to prevent the formation of w/o crude oil emulsions or to break these. However, the opposite effect was observed, that is, stabilization of water-in-crude oil emulsions. The potential application of LS in produced water (PW) clarification was furthermore considered. The kinetics of PW clarification was found unaffected by the presence of LS, even at very high concentrations (1000 ppm). Finally, the potential of LS for enhanced oil recovery was assessed. The LS flood changed the surface wettability toward water wetness for one of the samples, yet LS injection did not recover additional oil beyond brine recovery. It was concluded that LS has interesting properties, such as the potential to compete with crude oil indigenous components at the oil/water interface. The stabilization action of LS was dominant over any destabilization effect, which led to the conclusion that LSs are more efficient for stabilizing emulsions rather than destabilizing.

Study into the effect of sodium lignosulfonate, anionic surfactants and their mixtures on the rate of copper ion cementation by zinc

The article focuses on the effect of sodium lignosulfonate (LS), anionic surfactants (sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate (SDBS)), and their mixtures on the rate of copper cementation by zinc. The results obtained demonstrate a decrease in copper cementation rate with the increasing LS and SDBS concentrations. There was also excessive zinc consumption for copper ion cementation noted due to LS and SDBS anion adsorption on positively charged zinc cathodic areas of the cementing agent and the precipitate. This led to a decrease in the rate of copper particle nucleation, energy consumption for forming new copper nucleation centers, and conditions for hydrogen overpotential reduction. In addition, rising temperature led to a decrease in zinc consumption in the presence of LS. Surfactants under investigation may be ranked by the negative impact on copper ion cementation in an ascending order as follows: SDS < SDBS < LS. LS + SDS mixture testing showed its irregular effect on copper cementation rate at test temperatures. Experiments with LS and SDBS mixtures demonstrated a linear decrease in copper ion cementation rate with increasing SDBS concentration and simultaneously rising zinc consumption. Due to the negative impact of investigated reagents discovered, we proposed a method for removing organic impurities from solutions using multilayered aluminosilicates modified by cationic surfactants. The results obtained indicate the high effectiveness of organic impurity removal from solutions providing for a 50 % increase in cementation rate in the presence of LS + SDBS mixture together with a decrease in zinc consumption.

Lignosulfonate, anionic surfactants and their mixtures influence on water solutions surface tension and zinc concentrate pressure leaching

The formation of elemental sulfur during sulfide concentrate pressure leaching leads to the appearance of sulfur-sulfide granules, which significantly reduces zinc dissolution rate. The solution for this problem was the use of surfactants, which prevents the negative effect of molten sulfur, avoiding the granule formation during leaching. Lignosulfonates (waste from the woodworking industry) are most often used as reagents for sulfide concentrate pressure leaching. Influence of individual and mixtures of surfactants on surface tension of aqueous solutions, zinc extraction and size-grade distribution of cakes after sulfide zinc concentrate pressure leaching. Surface tension of aqueous solutions was analyzed by stalagmometric method. Leaching was performed in titanium autoclave in presence of lignosulfonate, sodium dodecylbenzenesulfonate and sodium dodecylsulfate. Solutions after leaching were analyzed on zinc by atomic absorption spectroscopy. Size-grade analysis of cakes after leaching was carried out by laser diffraction particle size analyzer. In this work, synergetic influence was observed of anionic surfactants and lignosulfonate on decreasing of aqueous solutions surface tension. The best results were obtained when LS-SDBS mixture was used, namely in the range of sodium dodecylbenzenesulfonate concentrations 400-600 mg / l. Usage of combined surfactants allowed to achieve high rates of zinc extraction and optimal particle size of cakes after leaching. At Ls and SDBS using zinc extraction was increased from 77,2 % up to 82,8 %, with the bulk of the cake (96,7%) having a particle size of -150 μm. Combined surfactants usage (lignosulfonate and sodium dodecylbenzenesulfonate) can be recommended for applying at pressure leaching of sulfide zinc concentrates.

Influence of lignosulfonic acids on the formation of magnetoactive compound in the redox reaction of iron(II) with chromate-anion

Chromium and its compounds are widely used in various industries. Wastewater from industrial enterprises using chromium compounds are subject to complete disposal at treatment facilities. The possibility of synthesizing a magnetoactive compound by oxidizing part of Fe(II) cations with chromate-anions in the presence of lignosulfonates was investigated. The magnetic activity was measured on Gouy balance, magnetic characteristics were determined by the magnetic granulometry method. It has been shown that the interaction of Fe(II) cations with chromate-anions passes with the formation of an water soluble intermediate without redox transformations at pH 3.4. Using method of the isomolar series, it was determined that the ratio of chromate-ions and Fe(II) cations in the intermediate is 1:2.33. The intermediate solution is stable for a long time. Synthesized magnetoactive compound samples are ferrimagnets. The use of lignosulfonate and the synthesis with heating can achieve a higher magnetic activity of magnetoactive compound. The optimal lignosulfonate consumption is 0.7 g/g Fe.

Lignosulfonate/APP IFR and its flame retardancy in lignosulfonate-based rigid polyurethane foams

Lignin containing substantial aromatic rings and high content of carbon has been employed as carbonizing agent to investigate the flame retardancy in the lignin/ammonium polyphosphate (APP) intumescent flame retardant (IFR) system. In addition, owing to the abundant phenolic and aliphatic hydroxyl groups, lignosulfonate, which is considered as a renewable aromatic macropolyols, substituted part of diethylene glycol (DEG) and copolymerized with isocyanate to produce lignosulfonate-based rigid polyurethane (LRPU) foams. Thermal stability was characterized by thermogravimetric analysis (TGA), and flame retardancy was investigated by limiting oxygen index (LOI) and cone calorimetry testing (CCT). Lignosulfonate increases thermal stability of LRPU foams and LRPU containing 15 wt% of lignosulfonate based on DEG (L15RPU) give rise to the best thermal stability. When 15% of lignosulfonate incorporated in the LRPU, reduced the heat release rate (HRR) and total heat release (THR) value 21 kW/m2 and 13 MJ/m2, respectively, and postponed 96 s time-to-peak carbon monoxide production than that of pure DEG rigid polyurethane (RPU) foam, the LOI values increased progressively with lignosulfonate content increasing. These results showed that lignosulfonate polyol may substitute polyol to produce lignosulfonate-based RPU foam and the presence of lignosulfonate could improve the flame retardancy. The mass loss gradually decreases with increasing APP addition, and the highest char yield was obtained from LRPU5 foam which at the lignosulfonate-to-APP ratio is 1:5. At the lignosulfonate-to-APP ratio of 1:5, the LOI value increased over 30%, and the HRR value reduced and the time-to-peak HRR postponed significantly. In addition, LRPU5 foams give rise to the lowest effect heat combustion (EHC) value, less smoke, and carbon monoxide (CO) production. Lignosulfonate acts as carbonizing agent in the lignosulfonate/APP IFR system, and the best fire retardancy is obtained at 1:5 of lignosulfonate-to–APP ratio.

One-step synthesis of a magnetoactive compound

The synthesis of stable silver-containing aqueous solution with magnetoactive particles (26–90 nm) based on the redox reaction of Fe ii cations with diammine silver( i ) hydroxide in the presence of lignosulfonate and tetraethylammonium hydroxide has been developed.

Predicting the standardized ileal protein digestibility of processed soybean meal and rapeseed meal in growing pigs using two in vitro methods1

A study was conducted to compare protein digestibility of processed ingredients using 2 in vitro methods with known standardized ileal digestibility of CP (SIDCP) measured in growing pigs. The SIDCP in soybean meal (SBM), rapeseed meal (RSM), and both ingredients retoasted in the presence of lignosulfonate, resulting in processed SBM (pSBM) and processed RSM (pRSM), was determined in a trial with growing pigs surgically fitted with a steered ileocecal valve cannula. Toasting in the presence of lignosulfonate was performed to induce protein damage. Initial pH and degree of hydrolysis after 10 min (DH10) and 120 min (DH120) were determined using the pH-STAT method. Hydrolysis was performed using trypsin, chymotrypsin, and peptidase at pH 8. Size-exclusion profiles of the resulting peptides after hydrolysis were also determined. Crude protein digestibility was determined using a 2-step enzymatic method, with pepsin at pH 2 and pancreatin at pH 6.8. The SIDCP in SBM, pSBM, RSM, and pRSM were 83.9, 71.6, 74.9, and 64.6%, respectively. Initial pH of ingredient solutions measured at constant N concentration was 6.9, 5.9, 6.1, and 5.5, respectively, and was highly positively correlated to SIDCP (r = 0.99, P A study was conducted to compare protein digestibility of processed ingredients using 2 in vitro methods with known standardized ileal digestibility of CP (SIDCP) measured in growing pigs. The SIDCP in soybean meal (SBM), rapeseed meal (RSM), and both ingredients retoasted in the presence of lignosulfonate, resulting in processed SBM (pSBM) and processed RSM (pRSM), was determined in a trial with growing pigs surgically fitted with a steered ileocecal valve cannula. Toasting in the presence of lignosulfonate was performed to induce protein damage. Initial pH and degree of hydrolysis after 10 min (DH10) and 120 min (DH120) were determined using the pH-STAT method. Hydrolysis was performed using trypsin, chymotrypsin, and peptidase at pH 8. Size-exclusion profiles of the resulting peptides after hydrolysis were also determined. Crude protein digestibility was determined using a 2-step enzymatic method, with pepsin at pH 2 and pancreatin at pH 6.8. The SIDCP in SBM, pSBM, RSM, and pRSM were 83.9, 71.6, 74.9, and 64.6%, respectively. Initial pH of ingredient solutions measured at constant N concentration was 6.9, 5.9, 6.1, and 5.5, respectively, and was highly positively correlated to SIDCP (r = 0.99, P

Processing of soybean meal and 00-rapeseed meal reduces protein digestibility and pig growth performance but does not affect nitrogen solubilization along the small intestine.

An experiment was conducted to determine the effects of processing of soybean meal (SBM) and 00-rapeseed meal (RSM) on N solubilization in chyme, CP digestibility along the small intestine, metabolic load as determined by organ weight, body composition, and growth performance in growing pigs. The SBM and RSM were processed by secondary toasting (at 95°C for 30 min) in the presence of lignosulfonate, resulting in processed SBM (pSBM) and processed RSM (pRSM) as a model for overprocessed protein sources. Fifty-four growing pigs were each fed 1 of the 6 experimental diets. Four of the diets contained SBM, pSBM, RSM, or pRSM as the sole protein source. The remaining 2 experimental diets contained pSBM or pRSM and were supplemented with crystalline AA to the same standardized ileal digestible AA levels as the SBM or RSM diet. Pigs were slaughtered at 40 kg, and organ weights were recorded. The organs plus blood and empty carcass were analyzed for CP content. The small intestine was divided into 3 segments, and chyme samples were taken from the last meter of each segment. Chyme of the SBM, pSBM, RSM, and pRSM diets was centrifuged to separate the soluble and insoluble fractions, and N content was determined in the latter. The amount of insoluble N as a fraction of N in chyme at each small intestinal segment was not affected by processing. Diet type, comprising effects of processing and supplementing crystalline AA, affected ( < 0.05) the G:F and standardized ileal digestibility (SID) of CP. Processing reduced G:F from 0.56 to 0.38 for SBM and 0.49 to 0.40 for RSM, whereas supplementing crystalline AA increased G:F to the level of the SBM and RSM diets. Processing reduced the SID of CP from 87.2% to 69.2% for SBM and 71.0% to 52.2% for RSM. Diet type affected ( < 0.05) the CP content in the empty body, with processing reducing this content from 170 to 144 g/kg empty BW for SBM and 157 to 149 g/kg empty BW for RSM and supplementing crystalline AA restoring this content. Processing reduced ( < 0.05) the weight of several organs, and supplementing crystalline AA restored organ weight. In conclusion, processing increased the amount of N in the chyme, reduced organ weight, body CP content, and G:F. These effects were caused by a reduction in available AA as supplementing crystalline AA restored organ weight, body CP content, and G:F.

Functionalization of organically modified silica with gold nanoparticles in the presence of lignosulfonate

It is shown that lignosulfonate (LS) can be used as an effective reducing agent for gold ions and simultaneously as a stabilizing agent for gold nanoparticles (AuNPs). When organically modified silica is introduced to the reaction mixture, most of the AuNPs grow on the surface of the silica due to hydrophobic interactions between LS and organic layers covering the solid particles. It was also found that the structure of the organic layer is crucial for the effective deposition of gold nanoparticles onto silica spheres in terms of particle size and gold content in the final SiO2-LS-AuNPs composites. Due to the hydrophobicity of the modified silica it was necessary to carry out the modification in mixed organic/aqueous solvent. The polarity of the organic co-solvent was found to have an effect on the size of the deposited Au-NPs and their quantity. The physical appearance of the obtained hybrids was analyzed by colorimetry, and their structure and composition were evaluated using transmission electron microscopy (TEM). Additionally dispersive and thermal properties were examined by dynamic light scattering (DLS) and thermogravimetry (TG), respectively. The obtained multifunctional hybrid materials exhibits remarkable catalytic activity for the reduction of C.I. Basic Blue 9 (Methylene Blue) by borohydride.

Conferring antioxidant capacity to cellulose based materials by using enzymatically-modified products

A new, industrially feasible method for conferring cellulosic substrates antioxidant properties by using enzymatic products was developed. The method allows cellulose surfaces such as those of paper sheets to be conferred antioxidant capacity by using a functionalization solution (FS) obtained from an enzymatic reaction. Various laccases and different phenolic compounds (PhCs) potentially possessing antioxidant action were used to prepare the FS. Antioxidant capacity was assessed by using UV spectrophotometry to monitor the inhibition of ABTS radical cation (ABTS·+) in the presence of antioxidants. Based on the results, enzymatic modification of the phenolic compound in the FS increases the bonding strength of its components to cellulosic materials. Evidences on the grafting of the FS onto the cellulosic sheets, and changes in the chemical structure of the resulting oxidized form of PhCs were assessed by using ATR–FTIR. The level of antioxidant capacity achieved depends on the enzyme type, the chemical structure of the compounds in FS, and the presence of lignosulfonates in it. The potential of the proposed method for conferring antioxidant properties to cellulose-based materials by surface application of a product obtained from an enzymatic reaction is demonstrated here for the first time.

Antioxidant Effect on the Growth And Formation of Lipids in the Fungus Lentinus tigrinus Growing on Medium with Lignosulfonate

The addition of an antioxidant (2-ethyl-6-methyl-3-hydroxypyridine hydrochloride) to a culture of the fungus Lentinus tigrinus growing on a medium with lignosulfonate inhibited growth and changed the composition of cell phospholipids. The ratio of lipid messengers also changed, the phosphatidic acid level decreased, and the content of phosphatidylinositol dramatically increased. The substitution of lignosulfonate with glucose and the addition of an antioxidant increased the biomass yield of L. tigrinus, as well as that of another fungus, Cunninghamella japonica, which was incapable of biodegrading the biopolymer. The obtained results indicate the specificity of growth processes in the presence of lignosulfonate and confirm the role of free radical oxidation reactions in the biodegradation of this biopolymer by L. tigrinus.