Waste Liquor Research Articles

Preservative Effect on Canned Mackerel (Scomber colias) Lipids by Addition of Octopus (Octopus vulgaris) Cooking Liquor in the Packaging Medium.

The preservative properties of waste liquor obtained from octopus (Octopus vulgaris) cooking were investigated. Three different concentrations (high, medium, and low) of octopus cooking liquor (OCL) were included, respectively, in the aqueous packaging medium employed for mackerel (Scomber colias) canning. As a result, the canning process led to an increase (p < 0.05) of lipid content, lipid oxidation (development of fluorescent compounds and thiobarbituric acid reactive substances, TBARS), lipid hydrolysis (formation of free fatty acids, FFA) and ω3/ω6 ratio in fish muscle. In all canned samples, primary (peroxides) and secondary (TBARS) levels of lipid oxidation were low. Remarkably, the presence in the packaging medium of the high and medium OCL concentrations led to lower (p < 0.05) lipid oxidation development (fluorescent compound and TBARS detection, respectively). Furthermore, an increasing OCL presence led to an average decrease of peroxide and FFA content and to an average increase of the polyene index (PI). All OCL-packaged muscle showed lower average values of saturated fatty acids and ω3/ω6 ratio and higher average values of PI and monounsaturated fatty acid presence. This study provides a first approach to novel and beneficial use of the present marine waste to inhibit lipid damage of commercial canned fish.

Optimal performance of electrodialysis process for the recovery of acid wastes in wastewater: Practicing circular economy in aluminum finishing industry

This work aimed to apply electrodialysis (ED) for the recovery of diluted sulfuric acid (H2SO4) waste liquor generated at rinsing baths in the aluminum anodizing industry. A bench-scale ED process was used to recover acid and water from diluted waste acid liquors in the aluminum anodizing process. The optimal conditions and parameters defined in bench-scale studies were utilized to treat a real industrial acid solution. A bench-scale ED system was run continuously with a connected rinse water line of aluminum plating to concentrate diluted sulfuric acid for recovery. Industrial-scale studies confirmed that the produced concentrated acid and water solutions were of sufficient quality to be reused during the aluminum anodizing process. Besides, diluate characteristics allowed it to be reused as rinse water and reduced the effluent volume sent to the wastewater treatment plant by 90%. Electrodialysis treatment provided a near-zero pollutant discharge. Closed cycle water and acid usage loop were achieved for the aluminum galvanic process, which lessens the environmental and economic impacts of the process. Overall, electrodialysis presented a promising option for the aluminum industry.

Adaptation of Saccharomyces cerevisiae in a concentrated spent sulphite liquor waste stream for increased inhibitor resistance.

The fermentation of spent sulphite liquor (SSL) from the pulping of hardwoods is limited by the combination of xylose, the primary fermentable sugar and high concentrations of microbial inhibitors that decrease the yeast fermentation ability. The inhibitor resistance phenotypes of xylose-capable Saccharomyces cerevisiae strains were therefore enhanced by combining rational engineering for multi-inhibitor tolerance, with adaptation in concentrated hardwood SSL as selective pressure. The adapted strains were assessed in fermentations with 60-80% v/v concentrated SSL under industrially relevant fermentation conditions. During adaptation, strains produced ethanol concentrations between 11.0 and 15.4 g/L in the range of that reported in literature. The adapted TFA40 and TP50 strains displayed enhanced inhibitor resistance phenotypes and were able to ferment xylose-rich SSL at pH below 5, exhibiting improved ethanol yields relative to the reference strain. Using yeast extract and peptone as nitrogen source in concentrated SSL fermentations further improved ethanol yields. However, strains exhibited a trade-off between resistance and ethanol productivity, indicating a carbon/energy cost for the expression of this inhibitor tolerance phenotype. KEY POINTS : • Achieved fermentation of xylose-rich hardwood spent sulphite liquor at pH below 5.0 • Adaptation of xylose-capable S. cerevisiae in concentrated spent sulphite liquor • Adapted strains exhibited enhanced inhibitor resistance phenotypes.

New application of nano NaY zeolite in acrylic polymer pretanning agent

Modified nano NaY zeolite was used as pretanning agent additive in leather industry for the first time in order to decrease the chromium content in leather waste liquor and enhance the mechanical properties of leather. The synthetic nano NaY zeolite with the particle size of 70 nm was modified by silane coupling agent with carbon-carbon double bond, and then a series of MY/PMAA nanocomposites with different MY amounts were prepared by in-situ polymerization method. After then, these MY/PMAA samples were used as the pretanning agents to tan the pickled goat skin. The introduction of nano NaY zeolite was beneficial to improve the physical mechanical properties and sensory properties of the leather, and the chromium content in the waste liquor was also reduced effectively. It provides a new strategy for the development of chrome-less tanning agent and expands the new application of zeolite in leather industry. Nano NaY zeolite is used as pretanning additive agent in leather industry for the first time in order to decrease the chromium content in leather liquor and enhance the mechanical properties of tanned leather. • Nano NaY zeolite was introduced as pretanning additive agent in leather industry . • MY/PMAA pretanning agent enhanced physical properties of leather and decreased effectively the Cr content in the tanning liquor.

Анализ мицеллообразования и адсорбционных слоев бинарных смесей компонентов сульфатного мыла

Currently, the main trend of the pulp and paper industry development is bio-refining. It is based on integrated and deep processing of wood raw materials to obtain products with higher value added and reduced amount of waste. One of the high priority tasks of bio-refining is improvement of technology of by-product (sulphate soap) extraction from spent liquor with an increase in the yield and quality of the resulting product and a decrease in the level of environmental pollution. The complexity and energy intensity of sulphate soap extraction from spent liquor depends on many factors, including the species used for wood cooking, composition of extractives, the method of wood preparation for delignification, etc. Sulphate soap is a multicomponent emulsion with a predominant content of resin and fatty acids, small amount of unsaponifiable substances and an admixture of lignin, which is mainly extracted from waste liquior by settling. The low degree of its extraction is associated with the absence of systematical data on the mutual influence of the sulphate soap components. In this work, the patterns of intermolecular interaction of the individual components of the by-product (sulphate soap) are found. For this purposes the critical concentration of micelle formation (CCM) and surface tension depression of surface-active sodium oleate and sodium abietate and their mixtures of varying compositions were determined by the methods of tensiometry and conductometry. A detailed analysis of its mixed micelles and adsorption layers was carried out using the Rubin–Rosen pseudophase model. The interaction mechanisms of components in mixtures are explained. The impact on the composition of micelles and adsorption layers of the more surface-active sodium oleate was detected in mixed solutions. A maximum synergistic effect of micelle formation was observed in mixtures with a predominant content of sodium abietate. Analysis of experimental data and the result of sulphate soap modeling allow substantiating the complexity of its extraction from waste liquor after wood cooking with the presence of hardwood over 30 %, which is explained by the reduced content of resin acids in black liquor. For citation: Yakubova O.S., Demiantseva E.Yu., Smit R.A., Dubovy V.K. Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 196–205. DOI: 10.37482/0536-1036-2021-6-196-205

Stabilizing MXene by Hydration Chemistry in Aqueous Solution

AbstractMXenes attract interest in diverse fields but suffer from fast structural degradation by attacking of dissolved oxygen and water molecules in aqueous solution. This drawback hinders the long‐term storage, applications and understanding of the chemical nature of MXenes. Herein, we report a cost‐effective and environmentally sustainable way for long‐term storage of MXenes in aqueous solution by hydration chemistry of nontoxic inorganic salts. The attacking of MXene by free water and dissolved oxygen molecules is inhibited by decreasing the water activity, which simultaneously lowers the dissolved oxygen concentration, of saline solution. As a result, the storage life of MXene can be prolonged to up to 400 days at ambient conditions without loss of intrinsic surface chemistry and bulk carrier properties. Over 90 % of salt protectant can be recycled by simply evaporating the final waste liquor after fully extracting the MXene to minimize the waste discharge and processing cost. This work offers a commercializable approach with high cost‐effectiveness, processing sustainability and environmental benefit for extending the shelf life of MXenes.

Stabilizing MXene by Hydration Chemistry in Aqueous Solution.

MXenes attract interest in diverse fields but suffer from fast structural degradation by attacking of dissolved oxygen and water molecules in aqueous solution. This drawback hinders the long-term storage, applications and understanding of the chemical nature of MXenes. Herein, we report a cost-effective and environmentally sustainable way for long-term storage of MXenes in aqueous solution by hydration chemistry of nontoxic inorganic salts. The attacking of MXene by free water and dissolved oxygen molecules is inhibited by decreasing the water activity, which simultaneously lowers the dissolved oxygen concentration, of saline solution. As a result, the storage life of MXene can be prolonged to up to 400 days at ambient conditions without loss of intrinsic surface chemistry and bulk carrier properties. Over 90 % of salt protectant can be recycled by simply evaporating the final waste liquor after fully extracting the MXene to minimize the waste discharge and processing cost. This work offers a commercializable approach with high cost-effectiveness, processing sustainability and environmental benefit for extending the shelf life of MXenes.

Recycling the steel pickling waste liquor to produce a low-cost material for immobilization of heavy metal(loid)s

This work aims to demonstrate the practicability of employing Iron (Fe)-manganese (Mn) binary oxide (FMBO) synthesized from pickling wastewater to immobilize arsenic (As(V)) and antimony (Sb(V)). Visual MINTEQ software was used to simulate the speciation of As(V) and Sb(V) under different pH values. The adsorption performance of FMBO for Sb(V) and As(V) were examined by batch experiments, the pH impact, sorption kinetics, sorption isotherms and the reuse of the adsorbent were investigated. The pH impact results demonstrated that the absorption capacity decreased dramatically as the pH value increased, the maximum adsorption capacities As(V) and Sb(V) were obtained at pH value of 4 as 95.24 and 147.1 mg/g, respectively. The kinetic results indicated that the pseudo-second order model could fit the kinetic data of Sb(V) and As(V) well. Equilibrium studies displayed that the adsorption of Sb(V) and As(V) on FMBO could be appropriately described by Freundlich model. Results of the binary adsorption indicated that Sb(V) exhibited ∼ 5% improvement for As(V) when the initial Sb(V) content raised from 0 to 500 mg/L, while As(V) showed a significant hindrance for Sb(V) adsorption. Moreover, utilization of FMBO could also effectively reduce the TCLP extractable and easy mobile As and Sb in contaminated soil, thus reducing their bioavailability. In view of the advantages of cost-effective, eco-friendly and excellent sorption performance, the steel pickling waste liquor-derived FMBO could be regarded as a promising amendment for remediating As and Sb contamination in environment. • A new low-cost adsorbent (FMBO) was prepared from steel pickling waste liquor. • FMBO exhibited an excellent performance for sorption of As(V) and Sb(V). • The existence of Sb(V) favor As(V) sorption, while As(V) showed opposite effect on Sb(V). • The FMBO could also effectively reduce the bioavailability of soil As and Sb.

Comparative study on washing effects of different washing agents and conditions on heavy metal contaminated soil

The soil washing technology of heavy metals in soil has the prospect of practical application. In this study, we screening out the best washing conditions for remediation of heavy metal contaminated soil and the conclusions are verified by pilot-scale field tests. Compared with citric acid (CA) and ethylene diamine teraacetic acid disodium salt (EDTA), Iron-based compounds (IC) has highest removal rate of heavy metals in soil. Heavy metals are mainly concentrated in soil with small particle size. Comprehensive cost consideration, the best washing concentration is 0.06 mol·L−1, the best solid liquid ratio is 1:5 and the best washing time is 30 min. CaO can precipitate heavy metals in washing waste liquor by increasing the pH of heavy metals in washing waste liquor, and the best precipitation time is 30 min considering the comprehensive cost. The results of pilot scale experiments show that the IC washing technology was shown to be an effective approach to rapidly reduce the Pb, Zn and As in contaminated soil.

Element Migration Behaviors During the Reduction of Vanadium Slag for Iron‐Removal and Vanadium‐Enrichment

The lengthy production procedures of FeV alloy from vanadium slag (VS) presently may cause high production costs and hazardous leaching liquor waste containing toxic V5+ and Cr6+ ions. A two‐step direct reduction technology is considered a short and environmental‐friendly process to solve the aforementioned problems. Solar grade silicon cutting slurry waste (SoG‐Siw) containing Si and SiC is regarded as an effective reductant to achieve comprehensive resource utilization and control reductant cost. The element migration behaviors during the reduction process are clarified from phase transitions and microcosmic features. The results showed that 78.7 wt% of Fe and 38.6 wt% of Cr migrated from slag to the metal phase with a mass ratio of pretreated SoG‐Siw (Si‐SiCmixt) to VS (S/V) of 0.15 after soaking at 1823 K for 60 min. The content of V2O3 is enriched from 12.14 to 16.13 wt%. The mass ratio of V to Fe increased from 0.28 to 1.40, satisfying the composition goal of the production of FeV60 alloy (50–65 wt% V). With an increase of S/V to 0.20, 4.6 wt% of V migrated from slag to the metal phase, causing the loss of vanadium. The reduction path is FeO → Fe2TiO4 → (Mn, Fe)(V, Cr)2O4 → (V, Cr)2O3.

Biosorption of nickel, cobalt, zinc and copper ions by Serratia marcescens strain 16 in mono and multimetallic systems

The metallurgical industry is one of the main sources of heavy metal pollution, which represents a severe threat to life. Metals can be removed from aqueous solutions by using microbial biomasses. This paper analyses the heavy metal biosorption capacity of Serratia marcescens strain 16 in single and multimetallic systems. The results obtained show that Co(II), Ni(II) and Zn(II) biosorption in monometallic systems is two to three times higher than in the presence of bi-metallic and multimetallic solutions. Fourier transform infrared spectroscopy confirmed that carbonyl, carboxyl and hydroxyl were the main functional groups, as well as the amide bands I and II involved in metal uptake, which are present in external structures of the bacterial cell. The results obtained demonstrated the viability of S. marcescens strain 16 as a biosorbent for the design of eco-friendly technologies for the treatment of waste liquor.

Characteristics of calcium lignin from pulping waste liquor and application for the treatment middle-stage wastewater of paper making

ABSTRACT In order to obtain a lignin-based adsorbent with low cost, simple operation and no further modification, a calcium lignin adsorbent was prepared from chemical mechanical pulping (CMP) waste liquor by directly calcification from lime. The calcium lignin was characterized by BET, SEM, TEM, FT-IR and solid-state NMR analyses. The results showed that the molecular structure of the calcium lignin particles did not change when compared to sodium lignin, the formation mechanism of calcium lignin was revealed. The initial COD and lignin contents of CMP waste liquid were 54858 mg/L and 24.39 g/L, the conversion rate of lignin can reach 71.36% when was deal with lime. Thus, most of the lignin resources in the waste liquid were recovered. The middle-stage wastewater (MSWW) of pulping and papermaking was dealt with calcium lignin, the COD removal rate was up to 85.83%. The adsorption isotherms and kinetics were well fitted by the Langmuir model and pseudo-second-order kinetic model, respectively. Lime was regenerated from the used calcium lignin with high-temperature calcination, the conversion rate of calcium ions can reach 83.56%. Overall, the calcium lignin prepared by the one-step method exhibited great potential for effectively removing COD from middle-stage wastewater.

Utilization and Standardization of Fermented Maize Waste Liquor as a Coagulant for Tofu Production and Its Effect on Tofu Quality

Coagulation of soymilk is the most important step in the production of tofu. Industrially, CaCl2, CaSO4, MgSO4 and MgCl2 are many of the different types of coagulants. Effluent from pap produced from maize is a local coagulant used; however, this has not been standardized. This study therefore aimed at standardizing fermented maize waste liquor (FMWL) as a local coagulant for tofu production. FMWL at ratios of 600 ml, 550 ml, 500 ml, 450 ml to 1000 ml soybean milk was used to prepare tofu and compared with tofu coagulated with lemon juice. The result revealed that the tofu coagulated with 550 ml of FMWL exhibited higher fat (47.78%) while tofu coagulated with 600 mls of FMWL had significantly (p&lt;0.05) higher protein (31.75%). On the other hand, sample coagulated with 500 mls FMWL had significantly (p&lt;0.05) higher crude fibre content. Soymilk coagulated with 400ml of FMWL exhibited significantly (p&lt;0.05) higher contents of magnesium (75.42 mg/100g) and calcium (46.32 mg/100g) and iron (15.85 mg/100g) while the sample coagulated with lemon juice (control) had higher potassium content (201.17 mg/100g) The sensory evaluation result revealed that the control sample was highly acceptable to the panelists and this was followed closely with the sample coagulated with 550mls of FMWL. Hence, FMWL when utilized at a level of 550 mls will yield soybean curd that is acceptable and comparable to soybean curd coagulated with lemon juice. The use of FMWL will serve as an alternative, cheap and natural coagulant for soybean curd preparation at household and commercial levels.

Synergistic effect of water-ethanol-formic acid for the depolymerization of industrial waste (black liquor) lignin to phenolic monomers

In this study, synergistic effect of a mixture solvent of water-ethanol-formic acid was investigated for the depolymerization of concentrated acid hydrolysis lignin (CAHL, isolated from industrial black liquor waste; source: pine wood) to produce phenolic monomers. The effects of solvent ratios, reaction temperature and time on CAHL depolymerization and the distribution of products were also explored. The highest bio-oil yield of 64.24 wt% containing 23.02 wt% monomers was obtained at 330 °C for 2 h with a water-ethanol-formic acid ratio of 1:1:0.4. Ethanol played an important role in increasing the solubility of CAHL and partly suppressing the repolymerization of reactive intermediates, while formic acid enhanced lignin depolymerization through an acid-catalyzed reaction and efficaciously preventing the repolymerization of unstable intermediates generated. Among the different monomers, 4-propylguaiacol (5.51 wt%), 4-methylguaiacol (3.43 wt%), catechol (3.02 wt%), 4-ethylguaiacol (2.73 wt%) and phenol (2.11 wt%) were identified as the major compounds in phenol-rich bio-oils. The MALDI-TOF MS spectra revealed that the oligomers present in the bio-oil were composed of dimers and trace amounts of trimer type compounds. Meanwhile, GPC results showed that CAHL (Mw = ~2156 g/mol) was efficiently depolymerized into lower molecular weight (Mw = 887 g/mol) compounds.The process parameters, such as water/ethanol ratio, FA-to-water/ethanol ratio, reaction temperature and time were also optimized using a central composite rotatable design (CCRD) in response surface methodology (RSM). ANOVA results showed that reaction temperature and time had highly significant effect (ρ < 0.05) on the yield of bio-oil. The depolymerization approach and outcomes of this study suggest that this method is efficient for pulp and paper industry waste management and production of value-added chemicals.

Magnetic biochar derived from rice straw and stainless steel pickling waste liquor for highly efficient adsorption of crystal violet

Reducing the preparation cost of magnetic biochar is necessary for its large-scale application as an adsorbent. In this study, stainless steel pickling waste liquor and rice straw were successfully applied to synthesize of magnetic biochar (SPWL-MBC). Several iron oxides adhered on the biochar matrix, mainly Fe3O4, Fe2O3 and FeO. SPWL-MBC exhibited superparamagnetism, and its specific surface area was 274.29 m2/g. The material was able to adsorb a model contaminant, crystal violet (CV), with a maximum adsorption capacity of approximately 111.48 mg/g. Adsorption mechanism analysis showed that iron oxides, π-π interaction, hydrogen bonding and electrostatic interaction were responsible for the adsorption of CV. The CV adsorption efficiency of SPWL-MBC remained 71.91% after three adsorption-regeneration cycles. These outcomes illustrate that the magnetic biochar prepared from stainless steel pickling waste liquor can effectively remove CV from wastewater.

Can lignin be transformed into agrochemicals? Recent advances in the agricultural applications of lignin

With the increased use of agro-chemicals in the last two decades it has become crucial to find alternative chemicals that are less harmful to the environment and humankind. One such alternative is lignin which is abundant both in agricultural waste and black liquor from the pulp and paper industry. In recent years, research and development of lignin-based agro-chemicals has gained traction and demand, as well as its use popularized. Lignin can be transformed into agrochemicals such as fertilizers, pesticide, soil improver and plant growth regulator. This paper presents the various potential ways in which recovered lignin may be reused in agriculture. There exists a continued need for research, development, improvement and innovation in the ways in which it is used, so that along with reducing the dependence on conventionally available, harmful and potentially toxic agro-chemicals, a valuable resource will not be lost. Continued research in to mapping lignin structure, development of bioengineering techniques for unifying various lignin structures and cooperation between relevant sectors to promote and incentivize the recovery and reuse of lignin for lignocellulosic waste are key to this issue. By doing so, a major element of air, land and water pollution can be eliminated and an important resource recovered.

Dispose waste liquor of fresh biomass of a hyperaccumulator Sedum plumbizincicola in phytoextraction process

Sedum plumbizincicola has been widely employed to remove cadmium (Cd) and zinc (Zn) from contaminated soils and harvested biomass is used to recover valuable metals. While chopping and compacting are efficient methods to rapidly reduce the volume and moisture of fresh biomass, the resulting waste liquor containing metals needs treatment. Two types of contaminated soils were cropped with S. plumbizincicola and top-dressed with this liquor to study metals migration in soil profile and their uptake by plants. There were three treatments: planting and adding liquor (PL), planting without liquor (P) and adding liquor without planting (L). The results showed that Cd and Zn from liquor were mainly retained at top soil 0–10 cm under L treatment. Compared with L treatment, soil Cd and Zn under PL treatment decreased significantly in soil profile due to the extraction of S. plumbizincicola. Moreover, the amount of Cd and Zn extracted by plants was greater than that applied in soils. The metal removal rate by S. plumbizincicola in acid clay loam soil was higher than that in neutral sandy soil. To sum up, metal retaining in soil and uptake by S. plumbizincicola can be used to treat waste liquor from its fresh biomass. Novelty Statement Rapid and efficient treatment of harvested fresh biomass is still a challenge although phytoextraction using hyperaccumulator Sedum plumbizincicola has been widely employed. Chopping and compacting fresh biomass are efficient methods for rapid dehydration, however, a large amount of waste liquor that contains of Cd and Zn is produced and needs treatment. In the present study, a simple and low-cost method was tested to dispose the liquor, i. e. irrigating it onto the surface of contaminated soils where grown S. plumbizincicola. It was found that Cd and Zn applied in soils from liquor were mainly retained at top 0–10 cm soil depth where S. plumbizincicola root system was widespread, and the amount of Cd and Zn extracted by plants was greater than that applied in soils. Therefore, it is technically feasible to dispose the waste liquor dewatering from fresh biomass of S. plumbizincicola in its phytoextraction process. This study is helpful for the rapid, efficient and low-cost treatment of harvested fresh biomass in the large-scale application of phytoremediation.

Tunable synthesis of polyethylene polyamine modified lignin and application for efficient adsorption of Fe2+ in super acid system

In this study, a lignin-based adsorbent modified with epichlorohydrin and pentaethylenehexamine (LO-PEHA) was controllably synthesized via epoxidation and Mannich reaction to scavenge ferrous (Fe2+) ions in the super acidic solution. Various kinds of characterization were executed to investigate the structural morphological characteristics of the resulting adsorbent. The well-designed adsorbent showed a rich mesoporous structure with intricate channels. The ferrous ions entrapment by the adsorbent followed the Langmuir model with the maximum adsorption capacity of 862.9 mg/g at dosage of 0.05 g/20 mL under 298 K. And the adsorption kinetics complied with the pseudo-second-order model. The adsorbent possessed substantial adsorption efficiency (qe: 188.9–198.3 mg/g) for ferrous ions with sulfuric acid concentration of 5–250 g/L. It also demonstrated reliable performance with ferrous ions removal of 92.23% in the actual pickling waste liquor, slightly lower than that in the simulated system (99.24%). Furthermore, the mass transfer process of ferrous ions was predicted considerably well under the pore volume diffusion model (PVDM) with the effective pore volume diffusion coefficient of 4.5 × 10−10 m2/s, essentially commanded by the intraparticle resistance. Meaningfully, the tailor-made adsorbent is prospective as an efficient alternative for ferrous ions elimination, inspiring the future development of competent adsorbents for industrial effluent treatment.

One-pot green extraction of high charge density cellulose nanocrystals with high yield for bionanocomposites

The use of lignocellulosic materials for extracting functionalized cellulose nanocrystals (FCNs) in a green and sustainable method under mild conditions is limited owing to the strong hydrogen bonding in cellulose. A facile, green, and high-efficient avenue was developed to produce FCNs with high yield through the mechanochemistry synergetic effect of recyclable p-toluenesulfonic acid (PTSA)-catalyzed deep eutectic solvent (PDES) and microwave- solvothermal (MWS). FCNs with a high charge density of 1.59 e nm−2, a crystallinity of 81%, a better thermostability and dispersibility were obtained at a high yield of 87.6% by the one-step processing. The PDES could be easily recycled, and thus was beneficial to cost reduction and waste liquor treatment. Generated FCNs could be used to develop functional bionanocomposites due to their enhanced effect. When a loading of 1 wt% FCNs was added into gelatin matrix, the tensile strength and Young’s modulus of the bionanocomposites increased 188 and 131%, respectively, suggesting their remarkable stress transfer potential. Thus, the study demonstrates a green and cost-effective approach for the mass production of FCNs, contributing to strong potential in building high-performance bionanocomposites.

Carboxymethylation of polysaccharide isolated from Alkaline Peroxide Mechanical Pulping (APMP) waste liquor and its bioactivity

In recent years, the biological activity of polysaccharides and their derivatives has been widely studied. However, in addition to the natural polysaccharides directly extracted from plants and animals, there are rich polysaccharides in the pulping waste liquor that have not been fully utilized. The extracted polysaccharide from eucalyptus Alkaline Peroxide Mechanical Pulping (APMP) waste liquor was used as a raw material. For the production of carboxymethyl polysaccharide, the effects of temperature (T), the amount of alkali (NaOH) and the amount of etherifying agent (ClCH2COOH) on the degree of substitution (DS) were investigated, the optimal preparation conditions are: reaction time 2 h, temperature 75 °C, and the molar ratio of polysaccharide, NaOH and ClCH2COOH is 1:1:2, the highest DS is 1.47; FT-IR, NMR and GPC were used to characterize the structure and Molecular weight, the results show that the polysaccharide of APMP waste liquor is rich in xylan, and it was proved that the carboxymethyl substitution was successful and the positions of the substituent group were determined. The characterization and biological activity research of xylan polysaccharide (XP) and carboxymethyl xylan polysaccharide (CMXP), such as antioxidation, moisture absorption/retention, bacteriostatic action and cytotoxicity were discussed. CMXP shows better effects compared with XP.