Sulfuric Acid Hydrolysis Research Articles

Correlation between preparation techniques and frictional properties of cellulose nanocrystals as additives in water-based lubricants

To explore the tribological characteristics of cellulose nanocrystals derived through various preparation techniques when utilized as additives in water-based lubricants, two types of cellulose nanocrystals (S-CNC and C-CNC) were chosen. These were produced via sulfuric acid hydrolysis and oxidation methods. The morphology and structural features were assessed through techniques such as Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), laser confocal Raman spectroscopy, elemental analysis, scanning electron microscopy (SEM), and laser particle size analysis. According to thermogravimetric analysis (TGA), the thermal stability of S-CNC is slightly superior to that of C-CNC. S-CNC exhibits liquid crystallinity when the concentration exceeds 0.5 %, whereas C-CNC does not display liquid crystallinity at any concentration tested. Further investigation was conducted on the frictional properties of the two types of CNCs using a UMT reciprocating friction tester. The results indicate that both types of CNC exhibit significant friction reduction properties at various additive concentrations, provided the addition does not exceed w=1 %. When below their respective liquid crystalline phase concentrations, the friction reduction performance of S-CNC is slightly inferior to that of C-CNC; however, when above the liquid crystalline phase concentration, the friction reduction performance of S-CNC surpasses that of C-CNC. The addition of w=0.5 % S-CNC leads to a relative reduction of 63.4 % in the friction coefficient compared to the base system. Analysis of the steel plate surface contact angle and post-wear surface suggests that the lubrication mechanism of CNC involves the adsorption of polar functional groups such as hydroxyl or carboxyl groups from the CNC structure onto the friction pair surface, forming a lubricating protective film to varying degrees. Additionally, the liquid crystalline structure of S-CNC facilitates the formation of an ordered lubricating film, further enhancing the frictional properties. These findings provide valuable insights into the application of nanocellulose crystals as lubricant additives.

Sulfuric acid solvolysis of cellulose in a butanol-1/benzene mixture for isolating cellulose nanocrystals

The absence of a universal method for isolating cellulose nanocrystals (CNCs) has prompted researchers to explore alternative approaches to traditional sulfuric acid hydrolysis. In this study, the authors continue their previous research by investigating CNC synthesis through cellulose solvolysis in an alcoholic environment. The CNCs were successfully obtained utilizing controlled sulfuric acid solvolysis of sulfate cellulose in a butanol-1/benzene mixture. The highest CNC yield (over 60 %) was achieved at strictly controlled acid-to-benzene ratios in a butanol-1/benzene/sulfuric acid reaction mixture, with a significant reduction in the optimal acid concentration. The study also analyzes the physicochemical properties of the isolated CNCs. No surface alkylation of the synthesized CNCs was observed during the cellulose solvolysis in the butanol-1/benzene mixture. Besides, the properties of these CNCs closely resembled those obtained through traditional sulfuric acid hydrolysis. The paper also discusses the potential mechanism of cellulose solvolysis in the process of CNC production.

Sustainable biofuels from corncobs: optimization of microwave pretreatment for enhanced fermentable sugar yield

Microwave-Assisted Alkali (MAA) pretreatment of corncob biomass was optimized for maximum fermentable sugar yield using dilute sulfuric acid hydrolysis. A Central Composite Design (CCD) investigated the effects of microwave power (450–9000 W), NaOH concentration (1.5 to 4.5% wt./v), and irradiation time (10–20 min) on lignin removal. The optimal MAA pretreatment conditions were found to be 691.73 W, 3.4% NaOH, and 15.5 min, resulting in the selective removal of 73.36% lignin with high retention of cellulose (71.69%) and hemicellulose (22.14%). Characterization techniques (FTIR, SEM, XRD, TGA) confirmed substantial changes in surface morphology, functional groups, crystallinity, and thermal stability of the pretreated corncobs. Dilute sulfuric acid hydrolysis (0.5–2.5%, 110130 °C, 3060 min) of the optimized sample yielded a maximum reducing sugar output of 537.42 mg/g, achieved at 0.534% H2SO4, 122.3 °C, for 58 min. Optimizing Microwave-Assisted Alkali pretreatment process for corncobs could boost biofuel production efficiency, sustainably utilize agricultural waste, and advance a more sustainable energy landscape.

Prospective life cycle assessment: Identifying the most promising methods for sustainable cellulose nanocrystal production

Concerted endeavors are presently in progress to discern eco-friendlier methods for cellulose nanocrystals (CNC) production, negating the conventional reliance on hazardous concentrated sulfuric acids. Despite the proliferation of methods purported to be environmentally sound, their assertions often lack rigorous scrutiny, relying on theoretical postulations. This study presents the first prospective glimpse into their environmental performance utilizing a life cycle assessment (LCA) methodology from cradle-to-gate. The results transpired that many of the vaunted environmentally-friendly methods resulted in higher environmental loads compared to the traditional method, due to lower conversion rates and higher reaction energy demand. Notably, only specific methods demonstrate lower endpoint impact scores, including deep eutectic solvent extraction (−48 %), ammonium persulfate-assisted oxidation (−62 %), sulfuric acid hydrolysis in glycerol medium (−56 %), and enzymatic hydrolysis (−40 %). Their primary green attributes associate with the utilization of solvents carrying lower climate impact and toxicity level. The reaction stage carries the heaviest burden due to the increased energy required to counteract modest reactivities of the milder solvents. As mitigation strategies, heat integration and by-product recovery for energy generation were explored, resulting in emission reductions of 11–26 % and 41–68 %, respectively, across the proven eco-friendlier methods. This study comprehensively validated a roster of genuinely green candidates, offering a more sustainable prospect than traditional methods and paving the way for large-scale green CNC production.

Effectiveness of Jute Cellulose Nanocrystal Reinforcement into Biodegradable Packaging “Sonali Bags®”

In an age marked by environmental consciousness, “Sonali Bags®” have emerged as promising substitutes for single-use plastic bags, invented in Bangladesh. It is a jute cellulose-based, totally biodegradable, compostable, recyclable, and environment-friendly biopolymer. However, certain physical limitations have hindered its widespread consumer appeal. To address these challenges, this study pioneers the integration of Jute Cellulose Nano-crystals (JCNC) into Sonali bags, with the objective of enhancing their physical properties. JCNC, obtained through a meticulous 64% concentrate sulfuric acid hydrolysis process, has been reinforced with Sonali Bags at varying loadings (0, 0.1, 0.2, 0.3, and 0.4 wt%). The SEM analysis showed spherical cellulose nanocrystals with high crystallinity and distinctive tear-like features on the nanoparticle's surface. Furthermore, the SEM micrographs depicted that JCNC loading up to 0.2% helped reduce the pore formation of bio-composite. Moreover, the thermal properties increased significantly, and tensile strength increased by approximately 37% MPa after reinforcing JCNC with Sonali Bag. The water-resistant capacity of 0.2% CNC reinforced film was about 30% better than other compositions. The JCNC-reinforced composite materials were found to moderate the degradation rate, contributing to the prolonged sustainability of these biodegradable solutions.

High Yield Synthesis of Cellulose Nanocrystals From Avicel by Mechano‐Enzymatic Approach

AbstractCellulose nanocrystals are an important class of bio‐based crystalline nanostructures, finding application in several technological fields, including paper and textile coating, biocomposite engineering, biocatalysts immobilization, etc. This study explores enzymatic hydrolysis of Avicel, using endoglucanase from Aspergillus niger, to find an environmentally friendly method to extract cellulose nanocrystals from cellulose sources. Enzymatic hydrolysis has the advantage of reduced energy consumption and higher environmental friendliness compared to acid hydrolysis. In this work, we report for the first time very high nanocrystals yield by combining mechanical pretreatment of the cellulose starting material with a ball miller and endoglucanase hydrolysis, as a result of an extensive optimization of reaction conditions. In particular, a ball milling pretreatment carried out for 50 minutes at 3 Hz, allowed to isolate enzymatic CNCs with 76 % yield and with crystallinity as high as 75 %. The materials were characterized by X‐Ray diffractometry, attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy, dynamic light scattering, zeta potential and field emission scanning electron microscopy (FE‐SEM). Their characteristics were compared with the properties of sulfated CNCs, prepared from Avicel by sulfuric acid hydrolysis. Our results are technologically relevant, as they contribute to the accessibility and sustainability of CNCs for a wide range of applications in various industries.

Synthesis of Keratin Nanoparticles Extracted from Human Hair through Hydrolysis with Concentrated Sulfuric Acid: Characterization and Cytotoxicity.

Human hair, composed primarily of keratin, represents a sustainable waste material suitable for various applications. Synthesizing keratin nanoparticles (KNPs) from human hair for biomedical uses is particularly attractive due to their biocompatibility. In this study, keratin was extracted from human hair using concentrated sulfuric acid as the hydrolysis agent for the first time. This process yielded KNPs in both the supernatant (KNPs-S) and precipitate (KNPs-P) phases. Characterization involved scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Zeta potential analysis, X-ray diffraction (XRD), and thermogravimetric analysis (TG). KNPs-S and KNPs-P exhibited average diameters of 72 ± 5 nm and 27 ± 5 nm, respectively. The hydrolysis process induced a structural rearrangement favoring β-sheet structures over α-helices in the KNPs. These nanoparticles demonstrated negative Zeta potentials across the pH spectrum. KNPs-S showed higher cytotoxicity (CC50 = 176.67 µg/mL) and hemolytic activity, likely due to their smaller size compared to KNPs-P (CC50 = 246.21 µg/mL), particularly at concentrations of 500 and 1000 µg/mL. In contrast, KNPs-P did not exhibit hemolytic activity within the tested concentration range of 32.5 to 1000 µg/mL. Both KNPs demonstrated cytocompatibility with fibroblast cells in a dose-dependent manner. Compared to other methods reported in the literature and despite requiring careful washing and neutralization steps, sulfuric acid hydrolysis proved effective, rapid, and feasible for producing cytocompatible KNPs (biomaterials) in single-step synthesis.

Efficient preparation of cellulose nanocrystals and regulation of cholesteric liquid crystals for advanced anti‐counterfeiting

AbstractCellulose nanocrystals (CNCs) can self‐assemble to form cholesteric liquid crystal, which make it one of the most promising optical materials at present. CNCs can be produced by sulfuric acid hydrolysis. It is found that hydrolysis conditions influence the existing form of reaction components and their reaction activities, which leads to different reaction routes and mechanisms under varied reaction conditions, with CNCs of varied quality produced. High‐quality CNC with more uniform particle size could be prepared at a critical acid concentration of 64 wt%, which was used to study the formation process of CNC liquid crystal and the structure regulation of cholesteric liquid crystal. By adjusting the drying temperature and adding a small molecule of water‐soluble chitosan (WSC) can well regulate cholesteric liquid crystal and change the pitch of a film, and the reflection wavelength can be redshifted, thus enriching texture patterns and creating distinctive color. Suitable addition of WSC can enhance the multi‐domain effect during liquid crystal formation process and finally creates more colorful film with fine texture. The rich and tunable liquid crystal characteristics endowed by WSC addition is irreplicable and artistic, which helps to realize the great potential application of the composite film in advanced anti‐counterfeiting.

Investigating Cellulose Nanocrystal and Polyvinyl Alcohol Composite Film in Moisture Sensing Application

This study focused on utilizing cellulose nanocrystal (CNC)–polyvinyl alcohol (PVA) composite in optical sensor applications to detect high humidity conditions and determine water concentration in ethanol. We focused on the composite’s effectiveness in moisture absorption to demonstrate visual color change. We demonstrated that the different molecular weights of PVA significantly affect CNC’s chiral nematic structure and moisture absorption capability. PVA with molecular weight 88 k–97 k exhibited the disintegration of its chiral nematic structure at 30 wt%, whereas low molecular weight PVA (n~1750) showed no structural disintegration even at 100 wt% concentration when analyzed through UV-Vis spectroscopy. Further, the thermal crosslinking of the CNC-PVA composite showed no significant loss of moisture sensitivity for all molecular weights of the PVA. We observed that the addition of PVA to the sulfated CNC obtained from sulfuric acid hydrolysis did not facilitate moisture absorption significantly. A CNC-PVA sensor was developed which can detect high humidity with 2 h. of exposure time. 2,2,6,6-tetramethylpiperidin-1-piperidinyloxy oxidized CNC (TEMPO-CNC) having carboxylic functionality was also used to prepare the CNC-PVA composite films for comparing the effect of functional groups on moisture sensitivity. Finally, we demonstrated a facile method for utilizing the composite as an optical sensor to detect water concentration in ethanol efficiently; thus, it can be used in polar organic solvent dehydration applications.

Monocomponent Biosorption of Copper Ions (II) onto Nanocrystalline Cellulose from Coconut Husk Fibers

Introduction: Nanocrystalline cellulose (NCC) is one of the most suitable cellulose derivatives for the treatment of wastewater. Various agricultural wastes have been used for the extraction of NCC. Coconut wastes have been widely studied as potential adsorbents for the removal of pollutants, including dyes and heavy metals. Methods: In this work, nanocrystalline cellulose (NCC) was successfully isolated from coconut husk fibers through alkaline pretreatment accompanied by sulfuric acid hydrolysis. Then, the ability of NCC to adsorb Cu2+ from aqueous solution in batch studies was investigated. Results: Results indicated that the optimal hydrolysis parameters were achieved at 50° C for 45 min with 64% sulfuric acid to extract NCC as rod-like particles with diameters between 4-10 nm. The potential of NCC as a biosorbent to remove copper ions (Cu2+) from aqueous solution was investigated in terms of batch mode and maximum adsorption capacity (qm) of 79.491 mg/g of Cu2+. The adsorption efficiency of Cu2+ions increased with an increase in the adsorbent dosage, decreased with an increase in the initial concentration of contaminant, and increased with the contact time. Under optimal conditions, adsorption kinetic followed a pseudo-second-order kinetic model and the adsorption isotherm fitted most closely with the Langmuir model. Conclusion: According to a literature review, NCC from coconut husk fibers has not been used for the adsorption of heavy metals, mainly copper ions. This study shows that NCC from coconut husk fibers can be used as a low-cost and environmentally friendly adsorbent for the removal of Cu2+ from aqueous solutions.

Production of Nanocellulose from Sugarcane Bagasse and Development of Nanocellulose Conjugated with Polylysine for Fumonisin B1 Toxicity Absorption.

The present study aimed to extract nanocellulose (NC) from sugarcane bagasse agricultural waste through a chemical method (sulfuric acid hydrolysis and ultrasonication). Subsequently, the nanocellulose product was conjugated with polylysine (NC-PL) and assessed for its efficacy in reducing the toxicity of Fumonisin B1 (FB1), a mycotoxin produced by fungi commonly found in corn, wheat, and other grains. Experimental results confirmed the successful conjugation of NC and PL, as evidenced by FTIR peaks at 1635 and 1625 cm-1 indicating amide I and amide II vibrations in polylysine (PL). SEM analysis revealed a larger size due to PL coating, consistent with DLS results showing the increased size and positive charge (38.0 mV) on the NC-PL surface. Moreover, the effect of FB1 adsorption by NC and NC-PL was evaluated at various concentrations (0-200,000 μg/mL). NC-PL demonstrated the ability to adsorb FB1 at concentrations of 2000, 20,000, and 200,000 μg/mL, with adsorption efficiencies of 94.4-100%. Human hepatocellular carcinoma (HepG2) cells were utilized to assess NC and NC-PL cytotoxic effects. This result is a preliminary step towards standardizing results for future studies on their application as novel FB1 binders in food, food packaging, and functional feeds.

Obtaining cellulose nanocrystals by acid hydrolysis procedure; and their use as reinforcement in polylactide biocomposites

In the first step of this study, purpose was to obtain and characterize cellulose nanocrystal (CNC) particles by applying sulfuric acid hydrolysis method to the starting material of microcrystalline cellulose (MCC) fibrils. After obtaining CNC particles via acid hydrolysis procedure, various analyses (SEM, DLS, FTIR, XRD, TGA) conducted revealed that average size of round shaped CNC particles was 38 nm with −30.4 mV Zeta potential value. They had monoclinic Cellulose-I crystal structure with Crystallinity Index of 80.6% and Crystallite Size of 3.39 nm. Their maximum thermal degradation temperature was 307°C with 23 wt% residue at 800°C. In the second step, the main aim was to investigate contribution of these obtained CNC particles when they were used as nano-reinforcement in polylactide (PLA) matrix biocomposites produced by industrially compatible melt mixing and shaping techniques. Mechanical tests revealed that when only 1 wt% CNC particles were incorporated into PLA matrix, increases in flexural strength and modulus were 29% and 51%; while increases in K IC and G IC fracture toughness values were 42% and 105%, respectively. Because, high degree of hydroxyl groups and presence of sulfate half-ester groups on the surfaces of CNC particles improved the interfacial interactions between the matrix and nano-reinforcement phase, leading to efficiency in strengthening and toughening mechanisms.

Two-response surface design optimization of carboxylated CNCs with super high thermal stability and dye removal capability

Discharging wastewater from industrial dyeing and printing processes poses a significant environmental threat, necessitating green and efficient adsorbents. Cellulose nanocrystals (CNCs) have emerged as a promising option for dye adsorbing. However, the industrial production and commercialization of CNCs still faced low yield, time-consuming, and uneco-friendly. In this study, we proposed a facile hydrochloric/maleic acid (HCl/C4H4O4) hydrolysis method to synthesize carboxylated CNCs using Box-Behnken design and dual response surface design, which can systematically investigate the effect of experimental factors (temperature, time and HCl/C4H4O volume ratio) on the final products. The rod-liked carboxylated CNCs gave the highest yield of 90.50 %, maximum carboxyl content of 1.29 mmol/g, and efficient dye removal ratio of 91.5 %. Furthermore, compared to CNCs obtained by commonly sulfuric acid hydrolysis way (CNCs-S) with a Tmax of 242.6 °C, the CNCs extracted at 5 h exhibited significantly improved thermal stability with Tmax reaching 351.2 °C. The enriched carboxyl content and excellent thermal stability show potential wastewater treatment applications under harsh conditions.

Isolation and Characterization of Spherical Cellulose Nanocrystals Extracted from the Higher Cellulose Yield of the Jenfokie Plant: Morphological, Structural, and Thermal Properties.

Scholars are looking for solutions to substitute hazardous substances in manufacturing nanocellulose from bio-sources to preserve the world's growing environmental consciousness. During the past decade, there has been a notable increase in the use of cellulose nanocrystals (CNCs) in modern science and nanotechnology advancements because of their abundance, biocompatibility, biodegradability, renewability, and superior mechanical properties. Spherical cellulose nanocrystals (J-CNCs) were successfully synthesized from Jenfokie micro-cellulose (J-MC) via sulfuric acid hydrolysis in this study. The yield (up to 58.6%) and specific surface area (up to 99.64 m2/g) of J-CNCs were measured. A field emission gun-scanning electron microscope (FEG-SEM) was used to assess the morphology of the J-MC and J-CNC samples. The spherical shape nanoparticles with a mean nano-size of 34 nm for J-CNCs were characterized using a transmission electron microscope (TEM). X-ray diffraction (XRD) was used to determine the crystallinity index and crystallinity size of J-CNCs, up to 98.4% and 6.13 nm, respectively. The chemical composition was determined using a Fourier transform infrared (FT-IR) spectroscope. Thermal characterization of thermogravimetry analysis (TGA), derivative thermogravimetry (DTG), and differential thermal analysis (DTA) was conducted to identify the thermal stability and cellulose pyrolysis behavior of both J-MC and J-CNC samples. The thermal analysis of J-CNC indicated lower thermal stability than J-MC. It was noted that J-CNC showed higher levels of crystallinity and larger crystallite sizes than J-MC, indicating a successful digestion and an improvement of the main crystalline structure of cellulose. The X-ray diffraction spectra and TEM images were utilized to establish that the nanocrystals' size was suitable. The novelty of this work is the synthesis of spherical nanocellulose with better properties, chosen with a rich source of cellulose from an affordable new plant (studied for the first time) by stepwise water-retted extraction, continuing from our previous study.

Evaluating the reinforcing potential of enzymatic cellulose nanocrystals in polypropylene nanocomposite

Cellulose nanocrystals (CNCs) produced through enzymatic hydrolysis exhibit physicochemical properties that make them attractive as eco-friendly reinforcing agents in polymer composites. However, the extent of their efficacy within a polymeric matrix is yet to be fully established. This study investigated the reinforcing capabilities of enzymatic CNC (approximately 3 nm in diameter) isolated from bleached eucalyptus Kraft pulp (BEKP), focusing on its application in polypropylene (PP) nanocomposites produced by injection molding. The study compared the performance of this enzymatic CNC (1–5 % wt) with PP composites reinforced with micro-sized cellulose fibers (BEKP at 10–30 % wt, approximately 13 μm) and additionally with commercial CNC produced by sulfuric acid hydrolysis. Despite enzymatic CNC experiencing agglomeration during spray-drying, leading to an average diameter increase to 3 μm, it still significantly increased the crystallization and glass transition temperature of the PP matrix. However, this agglomeration likely hindered the improvement of the mechanical properties within the nanocomposites. The results also showed that enzymatic CNC provided higher thermal stability at lower reinforcement levels compared to BEKP, but this came with a reduction in stiffness, posing a significant consideration in composite design. The addition of a coupling agent greatly enhanced the dispersion of reinforcements and the interfacial adhesion within the matrix, contributing to the enhanced performance of the composite properties. Additionally, enzymatic CNC demonstrated potential for superior reinforcement efficacy compared to commercially available CNC produced by sulfuric acid hydrolysis. In conclusion, enzymatic CNC exhibited a promising role as nano-reinforcement for thermoplastic polymer nanocomposites, exhibiting higher thermal properties at lower reinforcing loads than traditional micro-sized fiber reinforcements. The absence of sulfur, coupled with its higher thermal stability and sustainable potential, positions enzymatic CNC as a particularly favorable choice for applications involving direct contact with food, cosmetics, pharmaceuticals, and biomedical materials.

The Effect of Acid Hydrolysis on the Pickering Emulsifying Capacity of Tartary Buckwheat Flour.

The effect of sulfuric acid hydrolysis on the Pickering emulsifying capacity of Tartary buckwheat flour (TBF) rich in starch was evaluated for the first time. The results indicate that the sulfuric acid concentration and hydrolysis time had a significant impact on the Pickering emulsifying capacity of acid-hydrolyzed Tartary buckwheat flour (HTBF). A low sulfuric acid concentration (1-2 mol/L) could reduce the particle size of HTBF, but it also decreased the Pickering emulsifying ability. At a sulfuric acid concentration of 3 mol/L, appropriate treatment time (2 and 3 days) led to particle aggregation but significantly improved wettability, thereby resulting in a rapid enhancement in emulsifying capacity. Under these conditions, the obtained HTBF (HTBF-D2-C3 and HTBF-D3-C3) could stabilize medium-chain triglyceride (MCT)-based Pickering high-internal-phase emulsions (HIPEs) with an oil-phase volume fraction of 80% at the addition amounts (c) of ≥1.0% and ≥1.5%, respectively. Its performance was significantly superior to that of TBF (c ≥ 2.0%). Furthermore, at the same addition amount, the droplet size of HIPEs constructed by HTBF-D3-C3 was smaller than that of HTBF-D2-C3, and its gel strength and microrheological performance were also superior to those of HTBF-D2-C3, which was attributed to the higher wettability of HTBF-D3-C3. The findings of this study can facilitate the in-depth application of Tartary buckwheat and provide references for the development of novel Pickering emulsifiers.

Influence of acid hydrolysis on the degree of polymerization of cellulose from colored cotton substrates

This study investigated the influence of sulfuric acid hydrolysis on the cellulosic fibers and films’ degree of polymerization (DP). Cotton textile residues (dyed and white) and hydrophilic cotton were used as the raw material. The films were formed by the dissolution of fibers in ionic liquid and regeneration in water. Results showed that dyed cotton residues required hydrolysis at 0.5 M sulfuric acid for 30 min to achieve complete dissolution during viscosimetry assay. Due to different dyeing processes and chemical compositions, the color of the fibers influences the DP. Undyed samples submitted to hydrolysis had DP around 60% lower than samples without pretreatment. This effect was not observed when comparing films with and without hydrolysis, because the depolymerization occurs in the dissolution and regeneration step. This study expands the applicability of viscometry to colored substrates, serving as a starting point for future research on the impact of process parameters and dyes on cellulose polymerization.

Life cycle assessment of cellulose nanocrystals prepared from crop straw by sequential periodate-chlorite oxidation

Life cycle assessment (LCA) of cellulose nanocrystals (CNC) prepared by sequential periodate-chlorite oxidation (SPCO) remains limited. In this study, the environmental impacts of CNC preparation at lab (LAB) and industrial (IND) scales were assessed based on the eFootprint system and data from the Chinese Life Cycle Database (CLCD). At the LAB scale, the global warming potential (GWP) reached 3410 kg CO2 eq/kg CNC. The contributions of the U2 (pulp making), U3 (periodate oxidation), U5 (concentration), and U6 (freeze-drying) unit processes were 42.9%, 22.8%, 21.3%, and 10.6%, respectively. At the IND scale, the GWP was reduced by one order of magnitude to 141 kg CO2 eq/kg CNC, and most of the other 13 category indicators of environmental impact (acidification, eutrophication, ecotoxicity, human toxicity, etc.) also showed the same trend. The contribution of the unit process U5 exceeded 50% in the 12 environmental impact indicators. The large contribution of U5 was attributable to the extensive use of ethanol. At the industrial scale, the GWP was reduced to 22.7 kg CO2 eq/kg CNC when the periodate was recycled, and an ultrafiltration membrane system was used to concentrate CNC solutions. The environmental impact of CNC prepared by SPCO was lower than that of CNC prepared by sulfuric acid hydrolysis. This study comprehensively assessed the potential environmental impacts of CNC production on an industrial scale and provided valuable data for future industrial-scale production of CNC and for comparison with alternative products.

Cellulose nanocrystals as an innovative superdisintegrant for oral dispersible tablets

Oral Dispersible Tablets (ODTs), designed for rapid disintegration in the oral cavity, offer advantages such as easy administration for diverse populations and faster drug absorption. Microcrystalline cellulose (MCC) has been a traditional choice as a disintegrant, but its limitations have led to increased interest in cellulose nanocrystals (CNCs). This study focuses on obtaining and characterizing CNCs derived from MCC by sulfuric acid hydrolysis, exploring different times and drying methods (lyophilization or spray drying). At a 50 % v/v acid concentration for 60 min at 45 °C it was possible to extract CNC with a 76 % yield. When lyophilized, CNC micrographs showed large aggregates with few isolated particles, while the spray-dried samples were seen as free, elongated particles. The resulting CNCs, with enhanced properties like high hydrophilicity and surface area, are investigated for their impact on ODT formulations. All of them disintegrated faster than 10 s. A comprehensive analysis of ODTs' disintegration mechanism was also undertaken. The drying method dictates the predominant disintegration mechanism, even though this is also influenced by the nanoparticle size. Therefore, the study contributes insights into the potential of CNCs as innovative superdisintegrants, offering a promising path for improving oral drug delivery systems.

Optimization of hydrolysis conditions of alginate based on high performance liquid chromatography

Alginate is the most abundant polysaccharide compound in brown algae, which is widely used in various fields. At present, the determination of the content of alginate is mostly carried out using sulfuric acid and trifluoroacetic acid hydrolysis followed by the determination of the content, but the results are not satisfactory, and there are problems such as low hydrolysis degree and low recovery rate. Therefore, in this study, based on the optimization of high performance liquid chromatographic conditions for pre-column derivatization of 1-phenyl-3-methyl-5-pyrazolone (PMP), the hydrolysis effects of sulfuric acid, trifluoroacetic acid (TFA), oxalic acid, and formic acid were compared and the hydrolysis conditions were optimized. The results showed that formic acid was the best hydrolyzing acid. The optimal hydrolysis conditions were 95 % formic acid at 110 °C for 10 h. The hydrolysis effect was stable, with high recovery and low destruction of monosaccharides, which made it possible to introduce formic acid into the subsequent polysaccharide hydrolysis. The pre-column derivatization high performance liquid chromatography method established in this study was accurate and reliable, and the hydrolysis acid with better effect was screened, which provided a theoretical basis for the subsequent determination of alginate content.