Synthesis of Humin-based Carbon Quantum Dots and Luminescent Properties

The unique properties of carbon quantum dots(CQDs) make them promising materials in many fields. Herein, we present a facile method for the preparation of photo-luminescent CQDs using humins as the carbon precursor for the purpose of providing a high value-added solution for this "biomass conversion process waste". The structure of the CQDs was analyzed, and the effects of reaction temperature and time on the CQDs' fluorescence were investigated. The results showed that humins were effectively carbonized during the reaction. The fluorescence intensity of humin-based CQDs initially increased with reaction temperature and time, and subsequently decreased beyond 200℃ and 4 h. Polyaromatic structures and hydrophilic groups such as O—H, C—O, —COOH and C==O groups exist in the CQDs. The huminbased CQDs have the dimension of 3～7 nm with an average size of about 5.5 nm. The highest emission intensity of blue/cyan fluorescence light at 440 nm is achieved on the excitation with UV light at the wavelength of 330 nm.     

Structure Elucidation of Hydroxypropyl Cellulose Homogenously Prepared from NaOH/Urea Aqueous Solution

Hydroxypropyl celluloses (HPC) were homogenously synthesized by the reaction of cellulose with propylene oxide in NaOH/urea aqueous solution.Water-soluble HPC with molar degree of substitution (MSNMR) in the range of 0.52～ 0.78 was prepared from microcrystalline cellulose,cotton linters,and spruce sulfite pulp.The structure of the HPC samples was characterized by means of FT-IR,NMR,gas chromatography (GC),and size exclusion chromatography (SEC) analyses.Three types of cellulose samples with different molecular weights were found to dissolve well in the NaOH/urea solvent with no obvious differences in reactivity and regioselectivity.The relative reactivity of hydroxyl groups in the glycosyl unit was in the following order:O-6 ＞ O-2 ＞O-3.In addition,the results of the study indicated that the tandem reaction during hydroxypropylation could be ignored.     

Preparation and Applications of Soybean Residue CNF Films

In this study, soybean residues were treated with HCl and soybean residue cellulose was extracted, which was used to prepare cellulose nanofiber (CNF) using the high-pressure homogenization method. The maximum yield of CNF, the reaction temperature, reaction time, and HCl concentration were optimized. The optimum HCl concentration for acid treatment was 6%, the reaction time was 60 min, the reaction temperature was 80℃, and the maximum yield of soybean residue cellulose was 78.8%. The different CNF films were then prepared; the color, mechanical property, and light transmittance of the CNF films were studied. Compared to the properties of the CNF film prepared with the soybean residue cellulose by high-pressure homogenization 15 times (HGT-15 film), the mechanical properties of the CNF film with soybean residue cellulose by decolorizing treatment decreased, but the light transmittance increased. The film prepared by adding HGT-15 CNF to whey protein was investigated for its mechanical property, light transmittance, and solubility. Unlike the pure whey protein film, addition of 2.0% CNF to the whey protein enhanced the mechanical property and water vapor transmission rate (WVT) of the film. With the increase in CNF content, the solubility of the whey protein film decreased, and then stabilized.     

Heterogeneous Reactions between Starch and AKD under Solvent-free Conditions

Oxidized starch powder and cationic starch solution were reacted with alkyl ketene dimer(AKD) under heterogeneous conditions at 70℃ for 12 h.The AKD molecules reacted with starch hydroxyl groups to form β-keto ester linkages under the above conditions.The reaction products were separated into CHCl_3-soluble and CHCl_3-insoluble fractions.FT-IR spectroscopy,SEM,Xray diffraction,and TG-DTA analyses of the CHCl_3-insoluble fraction indicated that β-keto ester substituents were introduced to hydroxyl groups on the starch surfaces.The results indicated that hydrogen bonds between the starch molecules were disrupted under heterogeneous conditions upon heating.The activity and accessibility of hydroxyl groups were enhanced,as a result of which β-keto ester bonds were produced between AKD and starch.Based on these results,we speculate that the β-keto esters which existed in the sheets sized by AKD emulsions were generated by the reaction between AKD and starch.     

Etherification of Alkali-pretreated Sugarcane Bagasse Cellulose in Tetrahydrofuran

Sugarcane bagasse (SCB) is an important by-product in the sugar industry. It is a source of cellulose fibers or cellulose for paper mills and textiles factories. In this study, SCB was ethyl etherified in tetrahydrofuran (THF) after alkali pretreatment. The alkali concentration for the pre-treatment, the ratio of ethyl bromide (EtBr) to dried SCB in the reaction, reaction time, and temperature were investigated for the etherification of SCB. The ethoxyl content and characterization of the product were determined using headspace gas chromatography (HS-GC), Fourier Transform Infrared (FT-IR) and ¹³C-NMR spectroscopy, respectively. It was found that SCB was well-etherified with EtBr in alkali-THF. Upon ethylation of SCB, the ethoxyl content of the product was high when the alkali concentration and the ratio of EtBr to dried SCB were controlled from 50% to 75% and 4:1 (V/w) to 6:1 (V/w), respectively. The reaction occurred optimally when the temperature was controlled below 110℃; above this temperature, the degree of etherification decreased. The thermal stability of ethylated SCB was higher than that of SCB but slightly lower than that of commercial ethyl cellulose. Ethylated SCB has the potential to form composites with many materials because it is soluble in a wide variety of solvents.     

Biodegradation Behavior of Starch in Simulated White Water System of Old Corrugated Cardboard Pulping Process

Considering the serious barriers/issues induced by the accumulated starch generated in white water system of old corrugated cardboard(OCC) pulping process, large amounts of accumulated starch in white water would be decomposed by microorganisms and could not be utilized, thereby resulting in severe resource wastage and environmental pollution. This study mainly explored the effects of biodegradation/hydrolysis conditions of the two types of starch substrates(native starch and enzymatically(α-amy...     

The Prevention and Elimination of Insects in Storage of wheat Grains by Gamma Irradiation

This article deals with radiation sensitivity and lethal dose on the main cereal insects such as:Oryzaephilus Surinamensis Linnaeus(OSL),Sitophilus Oryzae Linnaeus(SOL),Rhizopertha Dominica Fabricius(RDF)and Tribolium Castaneum Herbst(TCH)in China.The experiments showed that there was a difference in radiation sensitivity.Among four insects species,OSL had the least tolerance;the second was RDF;the next was SOL and TCH had the biggest tolerance.After radiation with 0,15KGY-0.3KGY all OSL were dead in 2 weeks,all SOL and RDF dead in 3 weeks and all TCH dead in 4 weeks.All eggs could not be incubated with 0.1KGY radiation dose and adults insects had no bearing ability with 0.1 KGY radiation.There was no negative effect on germination potential and germination percentage of wheat with less than 1.0 KGY radiation.The article deals with bioeffect and lethal dose on OSL,SOL,RDF and TCH by ^60Co gamma ray radiation and with wheat germination potential and germination percentage.The economical and reasonable conditions are found for the development of science and technology and to provide the basis for the commercial operation.     

淀粉-脂肪酸改性高岭土的制备及其在包装纸上的应用

To improve the bondability between clay filler and lignocellulosic fiber,Kaolin clay particles were modified using a starch-fatty acid complex method.The coating efficiency of starch on clay particle surfaces was investigated by measuring the dissolved starch in the supernatant.The experimental results indicated that more than 98%of the applied starch was precipitated onto the surface of the filler,and the resulting starch-fatty acid-clay composites had relatively good resistance against moderate shear force.The morphology,particle size,andζpotential of the starch modified filler were also determined with scanning electron microscopy,Malvern particle size analyzer,and Malvern Zetasizer,respectively.An aqueous slurry of linerboard pulp containing 5～15wt%modified fillers was used for handsheet preparation,and the effects of the addition of modified filler on the paper properties were studied.At a dosage of 10%of the modified filler(based on filler), the retention of the filler was higher than 75%.The strength properties of paper with starch modified fillers were improved by approximately 15%when compared against those of paper with unmodified fillers.     

New Process for Extracting Oil and Starch from Tea Seeds

A new process for extracting oil and starch from tea seed was introduced. The new process included one special link compared with all of the processes used now for tea seed oil and starch production. The link was static fermentation by which oil bodies and starch were separated naturally from tea seeds. By the process, tea seed oil and starch which were in conformity with government standards about edible oil and starch were successfully produced with 16% and 8% of production rate, respectively. The new process has many advantages, such as more simple equipments, lower production cost and whole natural products, etc..     

ZrB system by self-propagating

emperature synthesis (SHS) technique, and the effect of particle size of Zr powder on the SHS reaction in ZrB system was studied. The phase constituent of SHS product was investigated by X-ray diffraction analysis, a     

Mechanism Analysis of Stiffness Improvement by Waterborne Epoxy Resin Surface Sizing Agent

Low-basis-weight paper lacks normal strength and stiffness.Waterborne epoxy resin could be employed with oxidized starch to improve paper stiffness through surface sizing.In this study,the mechanism of enhancing stiffness by adding waterborne epoxy resin was fully investigated.The results indicated that through surface sizing with epoxy resin,the paper thickness was preserved,whereas the elastic modulus increased significantly and the epoxy resin had positive impact on single fiber strength.A rigid resin layer and interpenetrating polymer network formed on the surface and in the inner layer of the paper,respectively.The formed resin layer and interpenetrating polymer network strongly supported the paper,leading to the improvement of the elastic modulus and stiffness.The stiffness improvement through surface sizing was mainly due to the formation of a fibrous composite layer and penetration of the sizing agent into the inner layers of the paper.The better the combination between fiber and sizing agent,the higher were the elastic modulus and the stiffness of the whole paper.     

Homogeneous Synthesis and Characteri-zation of Quaternized Cellulose Derivatives in NaOH-urea Aqueous Solutions

Quaternized cellulose( QC) derivatives were synthesized by reacting cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride( CHPTAC) in an aqueous solution of Na OH-urea. The chemical structures and physical properties of the obtained QC derivatives were characterized using nitrogen content analysis,Fourier transform infrared spectroscopy( FT-IR),~1H-nuclear magnetic resonance(1H-NMR),X-ray diffraction( XRD),and thermal gravity analysis( TGA). The FT-IR and ~1H-NMR results confirmed the successful introduction of cationic quaternary ammonium groups into the main chain of cellulose. A series of QC derivatives with the degree of substitution( DS) values ranging from 0. 33 to 0. 80 were derived by adjusting the molar ratio of CHPTAC to anhydroglucose unit( AGU) of cellulose,concentration of cellulose in the Na OH-urea solution,as well as reaction temperature and time. According to the DS values of the QC derivatives,the optimized synthetic conditions were as follows: 25℃ reaction temperature,3% cellulose in Na OH-urea solution,the molar ratio of etherification agent to glycosidic cellulose of 15∶ 1,and 12 h reaction time. The TGA and XRD results revealed that the crystalline structure was destroyed during etherification,and the thermal stability of the QC derivatives was lower than that of cellulose.     

Improvement of solubility and Emulsifying Properties of Soy Protein Isolates by Glucose Conjugotion

Soy Protein Isolate(SPI)was modified with glucose(G-) through the amino-carbonyl reaction (Maillard Reaction).Solubility and emulsifying properties of the modified proteins were investigated.G-SPI conjugate was highly soluble at wide pH while untreated SPI was hardly soluble especially at pH4-PH6.Solubility of modified SPI showed the resistance to heat treatment and high ionic concentration.Emulsifying activity and emulsion stability of G-SPI conjugate was much higher than those of native SPI were.Comparing with some commercial emulsifiers,the G-SPI conjugate showed as good or better emulsifying properties in high salt concentration and in neutral pH.SDS-PAGE was also used to confirm the formation of G-SPI conjugate.     

Study on the structure and properties of modified silk with ultraviolet absorbent北大核心CSCD

The silk fiber has an irreplaceable position in textile fibers and related silk fabrics have the advantages of light and airy texture good moisture absorption and breathability comfort in wear etc. It is also widely used in other fields such as the biomedical sector. However silk also has its own limitations poor light resistance and susceptibility to ultraviolet light especially the ultraviolet light of 290-400 nm wavelength in daylight such as under which condition it is prone to yellowing and photodegradation. The yellowing of silk is due to the photo-oxidation of tyrosine and tryptophan in silk protein under the action of ultraviolet light from sunlight and due to the production of yellow substances which affects the whiteness of silk. In addition from the molecular structure of silk most of the amino acids susceptible to UV light are distributed in the amorphous region. As the amorphous region is affected the structure of the crystalline region is also gradually relaxed the local degradation begins and the silk protein macromolecule chain is cleaved which leads to the decrease of the mechanical properties of silk fibers and accelerates the aging of silk fibers and fabrics. Therefore it is necessary to modify the silk products outside the anti-purple line. The current methods used to modify silk are mostly for post finishing modification including coating impregnation and chemical grafting methods but these methods often affect the original color or feel of the fabric and the durability of the modified effect is also poor. The feeding method is a green method to obtain modified silk by spraying mulberry leaves or artificial feed mixed with modifier which is ingested by silkworm and transferred to silk gland. In this study five aminobenzene UV absorbers were used as exogenous additive food for silkworms. The effect of molecular polarity on the transport of modifiers to silk glands was investigated and their effects on silkworm development and silk structural properties were studied. It was found that the aminobenzene UV absorbers were more easily transferred to the central silk gland silk glue and less to the posterior silk gland (fibroin). 4-dimethylaminobenzoic acid was found to be the highest in the posterior silk gland with a content of 3. 27 μg / strip. The cocoon width and cocoon quality of this group were significantly lower than those of the control group and the silk gum content was increased when this group was used as the study object. Compared with the control group the relative content of β-folded structure and crystallinity of the silk in the addition feeding group decreased slightly. The silkworm silk in the feeding group showed a certain UV absorption ability. After 330 h UV irradiation the breaking strength and elongation of the control group decreased by 48. 95% and 43. 52% respectively while those of the feeding group decreased by 42. 03% and 34. 18% respectively. In this paper UV absorbers were added to silkworms to obtain modified silk mainly focusing on the transfer of the modifier to the silk gland and the structural properties of the modified silk only for the most UV absorbers to enter the silk gland of the posterior group of silk. Other properties of the modified silk such as washing resistance have not been studied and some more in-depth studies are required. For instance it needs to be studied in depth for the limited absorption of exogenous additives by silkworms additive food's being not always absorbed by silkworms and transferred to the silk gland and the mechanism of action between the additive food and silk protein after the former's entering the silk gland. © 2022 Authors. All rights reserved.     

Conservation of Leaves of a Medicinal Plant of Western Algeria （Pistacia atlantica）

In our context, and in the goal to valorize the Pistacia atlantica species Desfthat grows spontaneously in Algeria occidental except the coastline, and that is used by the nomadic populations in their daily consumptions, we are thinking about drying its leaves. Here, the biochemical analysis of dried leaves ofPistacia atlantica is determined, the sorption is other ms are of great importance in the food industry, especially in the drying; the sorption isotherms of pistachio leaves were measured by the gravimetric method at three temperatures 40, 50 and 60 ℃. The equilibrium was achieved after eight days for desorption and seven days for adsorption with water activity ranging from 5% to 90%. Only the GAB and Peleg models were found to be the most suitable for describing the sorption curves. The isosteric heat of sorption of Pistacia atlantica leaves decreases with an increase in moisture content and was found to be an exponential function of moisture content for adsorption and desorption. The pistachio leaves could be considered as a rich natural source of valuable nutriments （carbohydrates, proteins and lipids）; lipid fraction is equal to 2.25%; proteins are the second macronutriment that predominates in these sheets： 4.35%; accordingly carbohydrates content was about 25.77%.     

Preparation of Highly Crystalline Microcrystalline Cellulose by Hydrolysis of Cellulose with Phosphotungstic Acid

Phosphotungstic acid(H_3PW_(12)O_(40), HPW), a kind of solid acid, is widely used for hydrolyzing cellulose to prepare microcrystalline cellulose(MCC). MCC is usually used in food, synthetic leather, chemical and pharmaceutical industries. The use of response surface methodology(RSM)can help avoid the random error caused by single factor experimental design,reduce test times and cost, and improve quality. The RSM was used in this study to determine the following optimal process conditions: H~+ molar quantity, 31 mmol/L; reaction temperature, 93℃; reaction time, 2 h; and solid to liquid ratio, 1∶38. Under these conditions, the crystallinity of MCC was77.4%. Thus, the use of RSM allows the preparation of MCC with higher performance and increased crystallinity.     

Preparation and Characterization of Natural Bamboo Fiber

In this study,natural bamboo fiber was prepared combining chemical pretreatment with mechanical disc refining,opening,and carding.An orthogonal experiment was designed based on four factors and three levels;thereafter,the manufacturing process was optimized.The length,diameter,tensile strength,and elastic modulus of the bamboo fiber were determined,and the crystallinity and morphology of the fiber were analyzed using X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results showed that the optimum parameters for the chemical pretreatment were a cooking temperature of 130℃,heating time of 2 h,NaOH dosage of 2%,and Na2SO3 dosage of 10%.The cooking yield of bamboo chips was 89.5%,and the carding yield of natural bamboo fiber was 43.0% under the optimum conditions.The length,diameter,tensile strength,and elastic modulus of the obtained fiber were 36.71 mm,0.285 mm,407 MPa,and 27.7 GPa,respectively.XRD analysis and SEM observations showed that the technology used in this study can produce bright and compact natural bamboo fibers with high crystallinity.     

Analysis of purple red color on the traditional Daur embroidered pouch北大核心CSCD

Twenty five pieces of embroidered pouches collected from Molidawa Daur National Museum in Inner Mongolia were analyzed. Among them, eight embroidered pouches which might be dyed with vegetable dyes were chosen. Sixteen purplish red colors were selected for the recovery experiment. The range of L∗, a∗, b∗ and c∗ value of colors were obtained through positioning and comparative study. The feasible dyes were confirmed to be sappanwood and safflower. The dyeing process was as follows: direct dyeing with sappanwood, pre, mordant dyeing, and post, mordant dyeing. The results showed that a variety of purple, red colors were obtained by adjusting the dye concentration, the mordant types and the pH value. One color could be recovered by direct dyeing with sappanwood, while eight colors could be recovered by pre, mordant dyeing. Seven colors could be recovered by safflower dyeing. The color difference to the collected colors was less than four which reached the purpose of recovery research. © 2018 China Silk Association. All rights reserved.     

Ultrasound-assisted Biodiesel Production from Waste Cooking Oil at Room Temperature

Waste cooking oil (WCO) is considered to be a promising alternative for vegetable oils that have been traditionally used for biodiesel production. In this study, WCO with a fairly high free fatty acid content was transesterified into biodiesel in a one-step procedureat room temperature (25℃ ) under ultrasound irradiation and in the presence of potassium hydroxide (KOH) as catalysts. Response surface methodology (RSM) was used to investigate the effects of the methanol/oil molar ratio, reaction time, and catalyst loading on the fatty acid methyl ester (FAME) yield and the biodiesel yield. The optimal reaction conditions for the production of WCO biodiesel were found to be a methanol/oil molar ratio of 8.6:1, a reaction time of 25 min, and a catalyst loading of 2.43 wt%. Under these optimal settings, the FAME and biodiesel yields were 96.4% and 92.7%, respectively. The properties of the resultant WCO biodiesel, including kinetic viscosity, acid number, water content, and flash point, were measured according to ASTM D6751 standards. The obtained results provide useful information for the large-scale production of WCO biodiesel.     

Natural Rosin-based Phosphate Diester Surfactant Assisted One-step Synthesis of 3D Flowerlike β-Ni(OH)2/g-Ni(OH)2 Composite Nano-microspheres

Self-assembled uniform 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres with hollow interiors were successfully synthesized via a facile aqueous-ethanol mixed solvothermal method, using nickel sulfate as a precursor, urea as a precipitant, and dehydroabietic based phosphate diester sodium (DDPDS) as a surfactant. The prepared 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres were tested as supercapacitors in a two-electrode cell with 6 mol/L KOH electrolyte. In addition, the influence of DDPDS concentration on the morphology and size of 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres was studied at 180℃. X-ray diffraction (XRD), scanning electron microscopy (SEM), BET (Brunauer, Emmett and Teller) techniques, and equity default swap (EDS) were used to characterize the structure, morphology, and size of the as-prepared samples. Moreover, a possible formation mechanism of the 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂composite nano-microspheres was proposed based on the effects of DDPDS concentration and reaction time. The surfactant micelles were used as soft templates to induce the self-assembly of nanosheets. The crystallinity of the 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres improved with the increase of DDPDS concentration, and the morphology and size of synthetic nano-microspheres could be controlled.