A facile method to fabricate sustainable bamboo ethanol lignin/carboxymethylcellulose films with efficient anti-ultraviolet and insulation properties.

Given the environmental concerns related to the non-degradability of conventional petroleum-based polymer films, the synthesis of biodegradable films utilizing natural polymers derived from biomass has emerged as a promising alternative, garnering significant attention in recent research endeavors. This research introduced an environmentally friendly and efficient method, utilizing extract liquid from the green ethanol pulping process as the solvent to completely dissolve carboxymethylcellulose into the film-forming liquid, and employing the solution pouring technique to successfully fabricate bamboo ethanol lignin/carboxymethylcellulose films (LCF). The findings revealed that the lignin content significantly influenced the LCF, endowing them with tunable mechanical properties, effective UV-blocking, and thermal insulation capabilities. With a lignin addition of 3.75 %, LCF-3.75 exhibited enhanced mechanical properties, characterized by a tensile strength of 19.4 MPa, along with superior UV-blocking efficiency, blocking 100 % of UVB and 99.81 % of UVA rays. Furthermore, relative to LCF-0, LCF-3.75 had been shown to possess enhanced hydrophobicity and thermal stability, culminating in the development of the composite films that showcased exceptional thermal insulation properties and biodegradability. The films not only harbored extensive application prospects as an anti-ultraviolet and heat-insulating glass films but also represented a potential avenue for the efficient utilization of lignin, thereby contributing to sustainable development.

Synthesis of lignin-based resin and fabrication of sustainable transparent wood based on bio-recycling concept.

Transparent wood (TW) has attracted much attention in the field of energy saving building structural materials because of its high light transmittance, good thermal insulation performance and good toughness. However, the polymeric resins used in the present study to impregnate lignin-based wood templates are usually derived from petroleum-based chemical resources, which pose a fatal threat to human beings both in terms of consuming large amounts of resources and causing environmental pollution problems. It is therefore important to develop alternatives to petroleum-derived chemicals in renewable natural resources. Here, we report a green and sustainable TW production process based on the bio-recycling concept. Lignin-based sustainable resin (LSR) was prepared from waste lignin produced during delignification by polymerization of guaiacol. At the same time, according to FT-IR and NMR data analysis combined with previous studies, the synthesis mechanism of LSR was proposed, and this result provided a reference for bio-based resins made from biomass materials. The prepared lignin-based sustainable transparent wood (LSTW) has good light transmittance and good dimensional stability. In addition, the LSTW also shows good thermal insulation and indoor temperature regulation capabilities compared with the common glass.

Ball-milling as effective and economical process for biodiesel production under Kraft lignin activated carbon stabilized potassium carbonate.

Biodiesel is a typical renewable energy and the previous transesterification processes for biodiesel production mainly focus on thermocatalytic methods. In this paper, the ball-milling process was investigated into the biodiesel production under Kraft lignin activated carbon stabilized K2CO3. Biodiesel yield increased to 66 % after only 5 min and reached 100 % within 25 min under optimal ball-milling conditions (0.5 g of the catalyst; methanol/oil molar ratio 18:1; 195 g of ball-mill beads; 1400 rpm; 25 °C). The power demand between the thermocatalytic method and the ball-milling method was also compared. Based on the computation, the ball-milling method has lower power demand than the traditional method (38 vs 201 kWh·mol-1). Therefore, the ball-milling method is an effective and economical process for biodiesel production.

Insecticidal characteristics and mechanism of a promising natural insecticide against saw-toothed grain beetle.

The prevention of grain storage pests is a universal concern all over the world. It is in high demand to explore novel, safe and green insecticidal techniques to address such concerns. In this work, both raw and calcined diatomite were used as a natural insecticide to remove common grain storage pests with improved lethal effect on the saw-toothed grain beetle. Interestingly, the raw diatomite showed higher insecticidal efficiency than the calcined diatomite, and its associated insecticidal properties and preparation conditions were also optimized through orthogonal tests. The optimal conditions for processing the raw diatomite insecticide were identified as follows: the diatomite dust was 500 mesh (A 3), the temperature was 25 °C (B 1), the relative humidity was 65% (C 2), the diatomite dosage was 20 g m-2 (D 2), the influence factor order was C ≥ D > A > B. The observation of surface morphology indicated that the raw diatomite had a complete, multi hole surface morphology and good adsorption performance, whereas the structure of the calcined diatomite was uncomplete with collapsed pores, resulting in poor adsorption performance. The special pore structure and excellent adsorption capacity of diatomite make the stored grain pests lose water to lethal effect. Acute toxicity and long-term toxicity tests in mice showed that diatomite has no harmful effects on mammals. The findings from our work led to a green and effective approach in producing a highly efficient and safe storage grain insecticide.

Research on Resin Used for Impregnating Polyimide Fiber Paper-Based Composite Materials.

In this paper, a resin with high adhesion, easy curing, good flexibility, and high temperature resistance was prepared from polyimide fiber paper. First, in order to improve the toughness and curability of impregnating resin, epoxy resin was modified by addition of vinyl silicone resin. Subsequently, ternary resin with high temperature stability was obtained by polyimide resin addition. Among the investigated conditions, the optimal additive amount of vinyl silicone resin and polyimide resin was 30% and 5%, respectively. The prepared ternary resin has better toughness, crosslinking degree, high temperature stability (5% mass loss at 339.2 °C) and no obvious glass transition at high temperature. Finally, the polyimide fiber paper-based composite material was impregnated with modified epoxy resin and ternary resin, respectively. The results shows that the paper-based composite material impregnated with modified epoxy resin has a better fiber bonding degree, a smooth surface, and contact angle could reach up to 148.71°. Meanwhile, the paper-based composite material impregnated with ternary resin has good high temperature resistance, and the tensile index of the paper-based composite material could reach up to 35.1 N·m/g at 200 °C.

Adsorption and Release Kinetics, Equilibrium, and Thermodynamic Studies of Hymexazol onto Diatomite.

Pesticide sustained-release agents have advantages of low toxicity, high efficiency, and long duration. However, the sustained-release effects were not ideal, such as short release time and low release rate. The physical and chemical properties of diatomite are high stability, high porosity, and good sustained-release and controlled-release abilities. A series of diatomite-based pesticide sustained-release agents were prepared by adsorbing hymexazol onto diatomite. Kinetics, equilibrium, and thermodynamic studies for adsorption were carried out as well. It was found that the modified diatomite has a better adsorption effect for hymexazol, and the adsorption rate reached 16.64%. The equilibrium data followed with the Langmuir isotherm model, and the adsorption process was an endothermic process. Release results showed that the diatomite-based pesticide has a significant sustained-release effect. The sustained-release time reached more than 25 days, and the maximum release rate was above 70%. The experimental data was fitted into the Ritger-Peppas equation, and it was found that the release was controlled by the Fick diffusion mechanism. This confirmed the applicability of the modified diatomite as an efficient adsorption carrier for pesticide release.

A rapid and quantitative method for assessing the whiteness of whitened lignin based on an in-depth analysis of reported methods.

The modification of lignin to a lighter color has been a concern in lignin valorization. In the previous reports on lignin color reduction, the methods of assessing the whiteness of lignin varied from each other, due to the absence of a universal method for characterizing the lightness/darkness of dark samples. In this paper, the reported methods for assessing the whiteness of lignin were analyzed, including "comparison of absorbance curve", "absorbance at specific wavelength", "ISO or TAPPI brightness" and "photograph observation". Our study revealed that various defects existed in these methods. In light of the Munsell color system, we herein proposed a quantitative method for evaluating the whiteness of lignin, based on the finding that the sum of the reflectance of samples with the same Munsell value (whiteness) are substantially equal. A model for converting the reflectance of lignin to Munsell value was established, and the effectiveness of the model was verified and discussed. The standard deviation of the model ranges from 0.23-1.10. The applicability of the method to liquid was also discussed in the paper. Moreover, because the model was derived from the Munsell color system, it can also be applied to characterize other medium to dark-colored objects besides lignin.

Investigation on the production of formic and acetic acids from lignin by ethanol organosolv treatment at mild conditions.

Cellulose and hemicellulose are usually considered the sources of formic and acetic acids that are obtained during ethanol pulping process, while our research reveals that lignin is another critical source of acids in the process. In this research, the sample lignin was purified and treated under ethanol pulping conditions and the factors that influence the yields of acids including: ethanol ratio (0-100%), residence time (30-210 min), reaction temperature (150-200 °C) and the effect of residual oxygen in the vessel, were tested separately. The yields of acids were identified using UPLC, the volatile products were characterized by GC-MS and the residual lignin was characterized by 13C NMR. The results indicated that the residual oxygen in the reaction vessel acted as an oxidant and the maximum yields of formic and acetic acid are 5.5% and 4.8% (g/g-lignin) from reed and aspen lignin, respectively. For understanding mechanism of the reaction, six lignin model compounds (LMCs) were treated and analyzed in the same reaction conditions; the subsequent results showed that both formic and acetic acid could be detected for all the LMCs tested. On the bases of the experimental results, the reaction pathways have been proposed and discussed.

Immobilizing Laccase on Different Species Wood Biochar to Remove the Chlorinated Biphenyl in Wastewater.

Biochars produced from two different wood species over a microwave assisted pyrolysis process were used as novel and green-based supports for immobilizing enzyme, laccase in particular. The results obtained from FT-IR, SEM and BET measurements indicated that Maple biochar with honeycomb structure has higher surface area and pore volume than Spruce biochar; and there exist O-H, C-H, C=O and C=C groups in biochars for potential chemical modification. The best laccase immobilization conditions identified from an orthogonal experiment were pH = 3, laccase concentration 16 g/L and contact time 8 h. Under such conditions, the high immobilization yield (64.2%) and amount (11.14 mg/g) of laccase on Maple biochar were achieved, leading to the significantly improved thermal stability of laccase. Moreover, the immobilized laccase is reusable and enhanced the enzymatic degradation of 4-hydroxy-3,5-dichlorobiphenyl (71.4% yield), thus creating a promising and novel type of adsorbent in the removal of polychlorinated biphenyls from wastewater.

Immobilizing Laccase on Modified Cellulose/CF Beads to Degrade Chlorinated Biphenyl in Wastewater.

Novel modified cellulose/cellulose fibril (CF) beads (MCCBs) loaded with laccase were prepared to degrade polychlorinated biphenyls (PCBs) in wastewater. The proper porous structure in MCCBs was achieved by introducing nano CaCO3 (as a pore forming agent) in cellulose/CF (CCBs) beads during the preparation process. Cellulose/CF composite beads were modified by maleic anhydride to introduce carboxyl groups. Laccase was immobilized on the MCCBs through electrostatic adsorption and covalent bonding. The effects of pH, laccase concentration and contact time on immobilization yields and recovered activity were investigated. The best conditions were pH 4, concentration 16 g/L and contact time 3 h. The immobilized laccase under these conditions showed a good performance in thermal and operational stability. The laccase immobilized on MCCB beads can remove 85% of 20 mg/L 4-hydroxy-3,5-dichlorobiphenyl (HO-DiCB) in wastewater. The results demonstrated that MCCBs, as a new type of green-based support, are very promising in material immobilizing laccase. This technology may be of potential advantage for the removal of polychlorinated biphenyls in wastewater from an environmental point of view.

Effect of Feedstock Concentration on Biogas Production by Inoculating Rumen Microorganisms in Biomass Solid Waste.

A methane production system with continuous stirred-tank reactor, rumen liquid as inoculate microorganisms, and paper mill excess sludge (PES) as feedstock was studied. The work mainly focused on revealing the effect of feedstock concentration on the biogas production, which was seldom reported previously for the current system. The optimal fermentation conditions were found as follows: pH = 7, T = 39 ± 1 °C, sludge retention time is 20 days, sludge with total solids (TS) are 1, 2, 3.5, 5, 10, and 13% in weight. Daily gas yields were measured, and biogas compositions were analyzed by gas chromatograph. Under such conditions, the optimum input TS was 10 wt%, and the biogas yield and volume gas productivity were 280.2 mL/g·TS and 1188.4 mL L-1·d-1, respectively. The proportions of CH4 and CO2 in the biogas were 65.1 and 34.2%. The CH4 yield reached 182.7 mL/g VS (volatile suspended solid), which was higher than previously reported values. The findings of this work have a significant effect on promoting the application of digesting PES by rumen microorganisms and further identified the technical parameter.

[Rapid Method for Determination of Furfural and 5-Hydroxymethyl Furfural of Ethanol-Water Hydrolysate of Biomass with UV Spectroscopy].

The soluble lignin and furan compounds in hydrolysate of lignocellulose biomass have absorbed peaks and inter-superimpose in UV spectroscopy. Therefore, this paper developed a method for the determination of furfural and 5-hydroxymethyl furfural in ethanol-water refining liquors of lignocellulose biomass based on UV spectroscopy. The study showed that there is a good and linear relationship between maximum absorption (λmax) and the concentration percent of 5-HMF (W(5-HMF)) of M, the regression coefficient up to 0.998 4 (R(2)=0.998 4). Furthermore, a better linear relationship was also observed between the concentration of mixture (cM) and absorptivity (A) when the W(5-HMF) was constant, the R(2) of 0.998 6～1.000 0 and reproducibility are desirable. The contents of F and 5-HMF could be calculated accurately according to the perfect liner relationship of A and c(M), λ(max) and W(5-HMF), and the relative deviation of F and 5-HMF of 5.6% and 3.7%, recovery of 89%～96%, RSD of 0.21%～0.85%, respectively. Overall, The simple rapid and precise method in this paper can be applied to the determination of the F and 5-HMF in the hydrolysate of ethanol-water refining lignocellulose biomass.