Raw Cellulose Research Articles

A structural investigation on the interactions of cotton fabric cellulose with olive oil and water

The cotton fabric consists of cellulose arranged in a complex structure with multiple levels of organization at different length scales. Understanding this structure and its interactions with water and oil is essential for developing efficient and environmentally friendly methods of cotton washing. In this study, the structure of raw cotton fabric cellulose and the effects of water and oil were examined across a broad range of length scales using spatially resolved synchrotron small-angle X-ray scattering (SAXS) and auxiliary techniques.Water was observed to penetrate the cotton fabric and interact across nearly all length scales. Although a certain amount of the material was not affected by water as seen by intact distance between microfibrils, fractal analysis of the scattering data indicated a loosening of the microfibril arrangement after contact with water. This process was hindered if the material had been pre-treated with oil and was not seen after subsequent washing with water or surfactant solution. Analyzing spatially resolved SAXS data using a bi-sinusoidal model and 2D maps of the oil-to-cotton ratio facilitates understanding the structure of the material and its interactions with oil on the molecular, nano and macrolevels.

The effects of chemical treatment parameters on the yield of bamboo fibers extracted

Nitric Acid and Hydrogen Peroxide (NCHP) treatment offers an efficient method for extracting lignocellulosic fibers from bamboo in a single bath. This procedure effectively removes lignin and hemicellulose, facilitating the separation of bamboo fibers while gradually breaking down inter-microfibrils and interlamellar layers in the cell wall. This study focuses on assessing the yield of lignocellulosic fibers extracted under various chemical treatment parameters and characterizing these fibers. Utilizing crushed and air-dried bamboo as raw material, cellulose, lignin, and hemicellulose content was analyzed. Characterization involved Fourier Transform Infrared (FTIR) Spectroscopy, providing insights into the chemical properties of the extracted lignocellulosic fibers. The FTIR spectra revealed the preservation and reinforcement of cellulose functional groups, confirming the effectiveness of the NCHP treatment. Control over treatment yield was achieved by manipulating temperature, concentration, and time. Optimal conditions were identified: 3.2 mol/L nitric acid, 60 mmol/g hydrogen peroxide, 50°C, and 72 hours, resulting in a maximum fiber yield of 76%. The findings indicate that higher temperatures, prolonged treatment times, and appropriate concentrations significantly enhance fiber extraction. Specifically, the optimal conditions led to an improved yield and better preservation of cellulose content compared to untreated bamboo. The study demonstrates that the NCHP treatment is a robust and effective method for producing high-quality lignocellulosic fibers from bamboo, with potential applications in sustainable materials. In conclusion, the NCHP treatment provides a scalable and efficient approach to extracting lignocellulosic fibers, offering significant improvements in yield and chemical composition. This process has promising implications for industrial applications, particularly in the development of sustainable materials and biocomposites

Water-induced controllable deswelling strategy enabled rapid fabrication of transparent cellulose film for plastics replacement

Plastic pollution has posed significant impacts on the ecosystem. While biodegradable transparent cellulose films are considered ideal alternatives, they still grapple with issues of high energy consumption and low production efficiency. In this study, we proposed a water-induced fiber deswelling strategy to expedite the fabrication of transparent cellulose films from wood pulp. Raw cellulose fibers were firstly disintegrated into micro-sized fibers via cold alkali swelling and mild mechanical blending. Subsequently, water was introduced to govern the swelling and aggregation behavior of these treated cellulose fibers, reducing their water retention and facilitating the rapid preparation of cellulose films. By regulating the amount of water added, cellulose film can be prepared within 1 min using vacuum filtration. Furthermore, the resulting film exhibits good wet strength, surpassing most previously reported cellulose-based films, with a wet strength exceeding 30 MPa and a wet strength retention of up to 65.7 %. With these advantageous features, the cellulose film was demonstrated for packaging and fruits preservation, showing a great potential to replace conventional plastics in the packaging applications. In addition, the life cycle environmental impacts of 1.0 kg cellulose film production (cradle-to-gate system boundary) were 12.63 kg CO2-eq, 0.04 kg SO2-eq, and 397 MJ energy use.

Removal of Cr(VI) from Wastewater Using Acrylonitrile Grafted Cellulose Extracted from Sugarcane Bagasse.

A highly efficient low-cost adsorbent was prepared using raw and chemically modified cellulose isolated from sugarcane bagasse for decontamination of Cr(VI) from wastewater. First, cellulose pulp was isolated from sugarcane bagasse by subjecting it to acid hydrolysis, alkaline hydrolysis and bleaching with sodium chlorate (NaClO3). Then, the bleached cellulose pulp was chemically modified with acrylonitrile monomer in the presence Fenton's reagent (Fe+2/H2O2) to carry out grafting of acrylonitrile onto cellulose by atom transfer radical polymerization. The developed adsorbent (acrylonitrile grafted cellulose) was analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Both raw cellulose and acrylonitrile grafted cellulose were used for chromium removal from wastewater. The effects of metal ion concentration, pH, adsorbent dose and time were studied, and their values were optimized. The optimum conditions for the adsorption of Cr(VI) onto raw and chemically modified cellulose were: metal ion concentration: 50 ppm, adsorbent dose: 1 g, pH: 6, and time: 60 min. The maximum efficiencies of 73% and 94% and adsorption capacities of 125.95 mg/g and 267.93 mg/g were achieved for raw and acrylonitrile grafted cellulose, respectively. High removal efficiency was achieved, owing to high surface area of 79.92 m2/g and functional active binding cites on grafted cellulose. Isotherm and kinetics studies show that the experimental data were fully fitted by the Freundlich isotherm model and pseudo first-order model. The adsorbent (acrylonitrile grafted cellulose) was regenerated using three different types of regenerating reagents and reused thirty times, and there was negligible decrease (19%) in removal efficiency after using it for 30 times. Hence, it is anticipated that acrylonitrile could be utilized as potential candidate material for commercial scale Cr(VI) removal from wastewater.

Extraction and characterization of a new natural cellulosic fiber from the Habara Plant Stem (HF) as potential reinforcement for polymer composites

In this present work, characterize the chemical, physical, thermal and Morphological behaviour of raw and alkali-treated (NaOH 5 %,10 % & 15 %) new natural cellulose Habara plant stem fiber (HF). From the chemical analysis, the 10 % alkali-treated HF obtained cellulose (67.9 %), hemicellulose (12.7 %), lignin (11.8 %) wax (0.18 %), moisture (2.44 %) and Ash (1.21 %). Fourier Transform Infrared Spectroscopy Analysis, alkali treatment effectively eliminates hemicellulose and lignin from the surfaces of natural fiber, as seen changes in the FTIR peaks at 1730, 1480, and 1140 cm−1.The X-ray analysis results indicate that, there is crystalline cellulose present, with a crystallinity level of 43.87 %, and that the other components are amorphous. In addition, the thermal stability of lignocellulosic fiber up to 230 °C was observed, and the degradation steps of each major component could be identified. The 10 % alkali-treated HF provides tensile strength of 790.9 MPa, with an elongation at break of about 3.41 %. The Scanning Electron Microscope analysis showcased the morphological changes on the fiber fractured surface, diameter variation, and impurities, etc. The Atomic Force Microscopy was used to determine the surface roughness characteristics of the HF, which confirmed the possible reinforcement in the structure of the polymer matrix composite structure.

Preparation of polypyrrole-functionalized recycled cotton fiber as a renewable and eco-friendly cellulose-based adsorbent for water decolorization: Comprehensive batch and fixed-bed column study

Cotton fiber is a low-cost material made from renewable and eco-friendly cellulose and can be used for various applications. However, raw cellulose has a low capacity for capturing pollutants. In this study, recycled cotton fiber was modified with polypyrrole through a chemical oxidative polymerization approach to enhance its implementation and suitability for removing reactive orange 5 (RO5) and reactive yellow 15 (RY15) from aqueous solutions. The cotton/polypyrrole (cotton/ppy) was characterized using SEM, EDS FTIR, and XRD techniques. These analyses indicated that polypyrrole was successfully coated on the cotton fiber. The optimal conditions for maximizing adsorption efficiency, including contact time, concentration of dye, adsorbent dosage, pH levels, and temperature, were determined. RO5 and RY15 eliminations are enhanced in the acidic environment (pH=2, contact time (RO5: 120 min, RY15: 90 min, adsorbent dosage: 200 mg, dye concentration (RO5: 20 mg/L, RY15: 40 mg/L)). The best fit for the adsorption procedure of RO5 and RY15 is the Temkin isotherm model, which indicates a chemisorption process delivers viable mechanism for the adsorption of RO5 (R2 =0.992) and RY15 (R2 = 0.987). Moreover, pseudo-first-order is the leading kinetic model for both RO5 (R2 = 0.999) and RY15 (R2 = 0.995). Furthermore, the study of the fixed-bed column was carried out, showing that the service volume decreased as the flow rate increased. The removal efficiency for RO5 and RY15 exceeded 80% even after using cotton/ppy adsorbent eight times. Therefore, the sustainable polypyrrole-functionalized recycled cotton fiber adsorbent is an excellent choice to eliminate dye effluents.

A Green Nanocatalyst for Fatty Acid Methyl Ester Conversion from Waste Cooking Oil

This study used a novel combination of cellulose nanocrystals (CNCs) and calcium oxide (CaO) nanocomposite (CaO/CNCs) for the production of biodiesel from waste cooking oil. The filter paper was used as a raw cellulose source to produce the CNCs from the acid hydrolysis of cellulose with sulfuric acid. The as-synthesized CaO/CNC nanocomposite is recyclable and environmentally friendly and was characterized using Fourier transform infrared spectroscopy, energy dispersive X-ray, scanning electron microscopy, and X-ray diffraction. The optimum process parameters investigated are a 20:1 methanol-to-oil molar ratio, 3-weight percent catalyst concentration, 60 °C temperature, and 90 min of reaction time. Under the optimum conditions, a biodiesel yield of 84% was obtained. The CaO/CNC nanocomposite achieved five times reusability, indicating its effectiveness and reusability in the transesterification reaction. The synthesized biodiesel chemical composition was examined using FTIR, GCMS, 1H-NMR, and 13C-NMR, and its properties, including specific gravity, color, flash point, cloud point, pour point, viscosity, sulfur content, sediments, water content, total acid number, cetane number, and corrosion test, were ascertained using ASTM standard practices. The outcomes were determined to fulfill global biodiesel standards (ASTM 951, 6751). Five successive transesterification processes were used to test the regeneration of the catalyst; the first three showed no distinct change, while the fifth cycle showed a reduction of up to 79%. The innovative composite CaO/CNC and used cooking oil are stable, affordable, and extremely successful for long-term biodiesel generation.

Petroleum-contaminated soil bioremediation and microbial community succession induced by application of co-pyrolysis biochar amendment: An investigation of performances and mechanisms

This study aimed to remediate petroleum-contaminated soil using co-pyrolysis biochar derived from rice husk and cellulose. Rice husk and cellulose were mixed in various weight ratios (0:1, 1:0, 1:1, 1:3 and 3:1) and pyrolyzed under 500 °C. These biochar variants were labeled as R0C1, R1C0, R1C1, R1C3 and R3C1, respectively. Notably, the specific surface area and carbon content of the co- pyrolysis biochar increased, potentially promoting the growth and colonization of soil microorganisms. On the 60th day, the microbial control group achieved a 46.69% removal of pollutants, while the addition of R0C1, R1C0, R1C3, R1C1 and R3C1 resulted in removals of 70.56%, 67.01%, 67.62%, 68.74% and 67.30%, respectively. In contrast, the highest efficiency observed in the abiotic treatment group was only 24.12%. This suggested that the removal of petroleum pollutants was an outcome of the collaborative influence of co-pyrolysis biochar and soil microorganisms. Furthermore, the abundance of Proteobacteria, renowned for its petroleum degradation capability, obviously increased in the treatment group with the addition of co-pyrolysis biochar. This demonstrated that co-pyrolysis biochar could notably stimulate the growth of functionally associated microorganisms. This research confirmed the promising application of co-pyrolysis biochar in the remediation of petroleum-contaminated soil.

Multifunctional applications of cellulose/sodium alginate aerogel material: Antibacterial, adsorption, and heat insulation

In this work, cellulose aerogel (CellA) was synthesized from raw cellulose derived from coconut peat and sodium alginate wherein zinc ion played as the binder agent. The investigation focused on the alternation of cellulose to sodium alginate ratio, which caused differentiation in characteristic aspects, mechanical strength, and antibacterial capability. Among them, the corresponding ratio of 10:1 (CellA-10 sample) was found to be the optimal one thanks to the prosperous bactericidal properties against both Gram-positive and Gram-negative bacterial strains. Besides, the fabricated material also possessed relatively applicable heat insulation of 0.064 W/m.K. Upon the surface modification with stearic acid, the material exhibited better hydrophobicity via the water contacting angle of 113o whilst its adsorption capacity towards organic liquids reaching up to 17 g/g. Conclusively, the obtained results suggest the highly promising synthesized CellA material in environmental remediation and antibacterial or heat insulation sectors.

Triple-effect new generation drying technique

This paper introduces the triple-effect new generation drying technique that is defined as simultaneously swirling flow-fluidized bed-infrared drying process. It aims to perform the conceptual design of this innovative drying technology, and to experimentally investigate the drying behavior of green tea leaves by applying such a technique, and to develop the drying curve equations of the products in terms of the mathematical modeling, and to perform the quality analysis of the dried products. For these purposes, drying experiments were conducted for 100 W, 250 W, 500 W, 750 W and 1000 W infrared powers, and the parameters such as dimensionless moisture ratio, moisture content, mass shrinkage ratio, drying rate were calculated. Using the thin layer drying curve equations, mathematical modeling was performed by the assumption of thin layer since tea leaves perform swirling flow by forming thin layers in the annular form during drying. 13 evaluation criteria were considered for selection of the best model describing the thin layer drying curve of the product. Quality analysis was performed, considering the quality parameters such as water extract, total ash, total polyphenols, caffeine and raw cellulose of the dried green tea samples. As a result, it is determined that the best suitable infrared power is 500 W and the best thin layer drying model is Aghbashlo et al. model for the process, and the highest value of water extract is obtained to be 44.04% at 500 W in the process. Thus, it is expected that this study will contribute to the researchers, investors and policy makers for improvement and development of tea drying technologies in tea industry.

Aerenchyma tissue of Juncus effusus L.: a novel resource for sustainable natural cellulose foams

The demand for sustainable, low-cost, and high-performance natural cellulose foams with isotropic structures has increased greatly due to growing environmental awareness. However, the synthesis of current cellulose foams/aerogels requires substantial amounts of energy and chemicals, mainly due to the challenges posed by the poor solubility and processability of raw cellulose derived from biomass resources. Consequently, these challenges further highlight the advantages offered by the direct utilization of natural cellulose foams, considering their economic and environmental benefits. Previous studies on natural cellulose foams have predominantly focused on specific plant components such as phloem, xylem, vascular vessels, fruits, and seeds. In this study, we present an overlooked alternative: the aerenchyma tissue of aquatic or wetland plants. Specifically, we investigated on Juncus effusus L. (JE), a commonly found problematic wetland weed that is known for its high reproductive ability, causing a reduction in annual forage yield. The aerenchyma tissue of JE was discovered to possess a well-developed 3D interconnected hierarchical structure, exhibiting remarkable properties as a natural lignocellulosic foam. These properties include exceptional compressibility, hydrophobicity (water contact angle: 147°), lightweights (density: 0.017 g/cm3), and high porosity (98%). Through this study, we have introduced a novel natural cellulose foam and explored the utilization of biomass derived from wetland weed wastes.

Preparation and characterization of hexadecyl trimethyl ammonium bromide (HDTMA-Br)-modified cellulose nanocrystals (CNCs) derived from South African waste agricultural residue (Corncobs)

To address the challenges associated with waste management in South Africa, agro-waste products such as corncobs can be valorized into value-added materials like cellulose nanocrystals (CNCs), thus paving the way for the circular economy. This study investigated the extraction of CNCs from South African waste corncobs through mixed acid hydrolysis using a mixture of sulfuric acid and oxalic acid dihydrate in a mass ratio of 1:5. For the first time, CNCs obtained from South African waste corncobs were functionalized using hexadecyl trimethyl ammonium bromide (HDTMA-Br) to enhance their usability in a variety of applications. Characterization techniques such as: Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infra-red (FTIR) spectroscopy, X-ray Diffraction (XRD), and Thermogravimetric analysis (TGA), were used to examine the surface morphology, surface functional groups, crystallinity, and thermal degradation of the isolated and the functionalized CNCs, respectively. SEM images revealed that the waste corncobs were successfully pre-treated due to the fibrous structure and individual particles observed. The TEM image of the prepared CNCs showed needle-shaped nanoparticles with an average diameter of 40 ± 1.11 nm, 178.5 ± 2.3 nm long, and 20.8 ± 1.7 nm wide. According to the XRD pattern, a strong peak showed at2Θ = 22.4(degree) was considered for the determination of the crystallinity of raw cellulose and that of the CNCs. About 64.5% and 78.9% crystallinity were obtained from the raw cellulose and the extracted CNCs, respectively, with approximately 55.25% yield. FTIR spectra of the functionalized CNCs showed the attachment of new functional groups, methyl, and methylene groups, onto the fCNCs’ surface. Furthermore, TGA analysis indicated that functionalized CNCs were more thermally stable compared to non-functionalized CNCs. These findings showed successful isolation and modification of CNCs from South African waste corncobs for their prospective use in wide-ranging applications.

Influence of Different Treatments on the Structure and Conversion of Silicon Species in Rice Straw to Tetraethyl Orthosilicate (TEOS).

The production of tetraethyl orthosilicate (TEOS) from biomass provides a new way for TEOS production and biomass valorization. In this study, rice straw was treated using different fractionation methods, and the content, state, and reactivity of Si in the treated samples were investigated. It was found that acid treatment and ethanol extraction kept most Si in the biomass, while alkali treatment caused significant Si loss. Si was mainly present in the SiOx , Si-O-C, and Si-O-Si states in the surface of raw rice straw, cellulose and Klason lignin. The results showed that the Si-O-Si state in rice straw was beneficial for the formation of TEOS. The removal of lipids from rice straw facilitated the production of TEOS, giving the highest TEOS yield of 76.2 %. In contrast, the production of TEOS from other samples became difficult; the simultaneous conversion of the three organic components of rice straw also facilitated the production of TEOS.

SUSTAINABILITY IN THE PRINT AND PACKAGING INDUSTRY

In the printing and packaging industry, sustainability is defined as manufacture and practices that reflect responsibility for the environment and resources to meet the needs and expectations of future generations. In this article, raw material management, cellulose resources, industrial forests, ecological and renewable alternative fiber resources were examined in the framework of the sustainability of the printing and packaging industry. The recycling of printed materials and packaging and the effects of paper-ink types and product design in this recycling have been discussed. The effect of separation and processing at the source on the efficiency of paper recycling, economy and ecology was emphasized. The greenhouse gas emissions of solvents used in inks and cleaners, the impact on climate change, water footprint and carbon footprint issues were examined. Suggestions have been made on environmental sustainability in the printing industry, what needs to be done for a competitive production, successful optimization, minimization of waste, use of existing possibilities, recycling and evaluation of alternatives and use of clean energy.

Identification of SNPs Associated with Grain Quality Traits in Spring Barley Collection Grown in Southeastern Kazakhstan

Barley (Hordeum vulgare L.) is an important cereal crop with high genome plasticity that is cultivated in all climatic zones. Traditionally, barley grain is used for animal feed, malting, brewing, and food production. Depending on the end-use product, there are individual requirements for the quality traits of barley grain, particularly for raw starch and protein contents. This study evaluates a collection of 406 two-rowed spring barley accessions, comprising cultivars and lines from the USA, Kazakhstan, Europe, and Africa, based on five grain quality traits (the contents of raw starch, protein, cellulose, and lipids, and grain test weight) over two years. The results of population structure analysis demonstrate the significant impact of geographical origin on the formation of subclusters in the studied population. It was also found that the environment significantly affects grain quality traits. Heat and drought stresses, particularly during grain filling, led to higher protein and lower starch contents. A genome-wide association study (GWAS) using a multiple-locus mixed linear model (MLMM) allowed for the identification of 26 significant quantitative trait loci (QTLs) for the five studied grain quality traits. Among them, 17 QTLs were found to be positioned close to known genes and previously reported QTLs for grain quality in the scientific literature. Most of the identified candidate genes were dehydration stress and flowering genes, confirming that exposure to heat and drought stresses during grain filling may lead to dramatic changes in grain quality traits, including lower starch and higher protein contents. Nine QTLs were presumably novel and could be used for gene mining and breeding activities, including marker-assisted selection to improve grain quality parameters.

Effects of a Cellulose Aerogel Template on the Preparation and Adsorption Properties of Coal Gangue-Based Multistage Porous ZSM-5.

In this study, a ZSM-5/CLCA molecular sieve was prepared by the hydrothermal method using coal gangue as the raw material and cellulose aerogel (CLCA) as the green templating agent, which not only reduces the cost of traditional molecular preparation but also improves the comprehensive resource utilization rate of coal gangue. Through a series of characterization methods (XRD, SEM, FT-IR, TEM, TG, and BET), the crystal form, morphology, and specific surface area of the prepared sample were tested and analyzed. The performance of the adsorption process of malachite green (MG) solution was analyzed by adsorption kinetics and adsorption isotherm. The results show that the synthesized zeolite molecular sieve and the commercial zeolite molecular sieve are highly consistent. At a crystallization time of 16 h, a crystallization temperature of 180 °C, and an additive amount of cellulose aerogel of 0.6 g, the adsorption capacity of ZSM-5/CLCA for MG was up to 136.5 mg/g, much higher than that of commercially available ZSM-5. This provides an idea for the green preparation of gangue-based zeolite molecular sieves to remove organic pollutants from water. Moreover, the process of adsorbing MG on the multistage porous molecular sieve, which is spontaneous, conforms to the pseudo-second-order kinetic equation and Langmuir isothermal adsorption model.

Cellulose esterification with carboxylic acid in deep eutectic solvent pretreatment inhibits enzymatic hydrolysis

Avicel cellulose was pretreated using two commonly used carboxylic acid-based deep eutectic solvents, i.e., choline chloride-lactic acid and choline chloride-formic acid. The pretreatment process resulted in the formation of cellulose esters with lactic acid and formic acid, which was confirmed by infrared and nuclear magnetic resonance spectra. Surprisingly, the esterified cellulose led to a significant decrease in the 48-h enzymatic glucose yield (≥75%) compared to raw Avicel cellulose. Analysis of changes in cellulose properties caused by pretreatment, including crystallinity, degree of polymerization, particle size and cellulose accessibility, contradicted the observed decline in enzymatic cellulose hydrolysis. However, removing the ester groups through saponification largely recovered the reduction in cellulose conversion. The decreased enzymatic cellulose hydrolysis by esterification may be attributed to changes in the interaction between cellulose-binding domain of cellulase and cellulose. These findings provide valuable insights into improving the saccharification of lignocellulosic biomass pretreated by carboxylic acid-based DESs.

Co-adsorption and competitive adsorption of sulfamethoxazole by carboxyl-rich functionalized corn stalk cellulose in the presence of heavy metals

Diethylenetriamine pentaacetic acid (DTPA) functionalized modified corn stalk cellulose (DCS) was successfully prepared and applied to the adsorption of sulfamethoxazole (SMZ) wastewater in the presence of copper (Cu). Compared with the raw corn stalk cellulose (RCS), DCS has the characteristics of more hydrophilic groups, larger contact space and lower steric hindrance. The adsorption amount for Cu and SMZ in binary system were 4.41 mg/g and 29.7 mg/g, respectively. Additionally, DCS has good pH buffering capability, resistance to potentially interfering ions (NaCl and HA) and great regeneration performance after 5 cycles. More importantly, the experimental results demonstrated competitive adsorption and complexation synergy occurred between Cu, SMZ and DCS. Cu inhibited the adsorption of SMZ while SMZ promoted the adsorption of Cu, which was attributed to the fact that SMZ provided additional adsorption sites or complexation reduced the surface charge of Cu. Based on this situation, density functional theory (DFT) calculations were carried out for the further explanation of adsorption mechanism. The molecular electrostatic potential maps showed that DCS possessed more SMZ adsorption sites than Cu, and the adsorbed Cu or SMZ on DCS would provide additional adsorption sites. The equilibrium configurations and binding energy indicated that the competitive adsorption, bridge effect adsorption and co-adsorption would occur simultaneously. The total electron density and differential charge confirmed that SMZ was more likely to overlap electron clouds and transfer electrons with DCS, while the adsorption process of Cu was conformed the complexation adsorption dynamic equilibrium. This paper provided a new perspective on the co-adsorption and competitive adsorption processes by multisystem experiments and abundant DFT calculations and indicated the good adsorption performance of DCS on SMZ in the presence of Cu.

The transformations of cellulose after concentrated sulfuric acid treatment and its impact on the enzymatic saccharification

BackgroundThe dense structure of cellulose lowers its reactivity and hinders its applications. Concentrated sulfuric acid is an ideal solvent to dissolve cellulose and thus has been used widely to treat cellulose. However, the changes of cellulose after reaction with concentrated sulfuric acid at near-limit S/L ratio and its effect on enzymatic saccharification still need further investigation.ResultsIn this study, the interactions between cellulose (Avicel) and 72% sulfuric acid at very low acid loading conditions of 1:2 to 1:3 (S/L ratio) were studied for the enhanced production of glucose. The Avicel gradually transformed from cellulose I structure to cellulose II structure during the sulfuric acid treatment. Other physicochemical characteristics of Avicel also changed dramatically, such as the degree of polymerization, particle size, crystallinity index, and surface morphology. After acid treatment, both the yield and productivity of glucose from cellulose increased significantly under a very low enzyme loading of 5 FPU/g-cellulose. The glucose yields for raw cellulose and acid-treated (30 min) were 57% and 85%, respectively.ConclusionLow loadings of concentrated sulfuric acid were proven to be effective to break the recalcitrance of cellulose for enzymatic saccharification. A positive correlation between cellulose CrI and glucose yield was found for concentrated sulfuric acid-treated cellulose, which was opposite to previous reports. Cellulose II content was found to be an important factor that affects the conversion of cellulose to glucose.

Facile Preparation of Cellulose Aerogels with Controllable Pore Structure.

Cellulose aerogels are the latest generation of aerogels and have also received extensive attention due to their renewable and biocompatible properties. Herein, cellulose aerogel was facilely prepared by using NaOH/urea solution as solvent, raising the temperature to control gelation and drying wet gel sequentially. With NaOH/urea solution as solvent, the cellulose concentration has an important impact on the micromorphology of cellulose aerogels, while the aging time rarely affects the micromorphology. The appropriate solvent and drying method allow the formation of different cellulose crystalline structures. Different from the Cellulose Ⅰ crystalline structure of raw cellulose powder, the cellulose phase of as-prepared cellulose aerogels belongs to the Cellulose Ⅱ crystalline structure, and to some extent the pyrolysis temperature is also lower than that of raw cellulose powder. The resultant cellulose aerogel prepared by using NaOH/urea solution as solvent and freeze-drying has a uniform macroporous structure with a macropore size of 1~3 µm.