Uniform rod and spherical nanocrystalline celluloses from hydrolysis of industrial pepper waste (Piper nigrum L.) using organic acid and inorganic acid

A sustainable one-step approach for the functionalized cellulose nanocrystal production using recyclable organic acids: Exploring structure-property dynamics

The study presents a cutting-edge, sustainable approach for the high-yield production (59-62 %) of carboxyl-functionalized cellulose nanocrystals (CNCs) with impressive aspect ratio (20.65 ± 0.74 nm), high crystallinity (77-81 %), outstanding thermal stability (290 °C-343 °C) and varying degrees of functionalization. This innovative method harnesses the synergistic power of mild organic acid hydrolysis (10 %) and steam explosion, employing eco-friendly acids such as acetic, citric, malic, tartaric, and oxalic. These acids drive efficient esterification, as evidenced by zeta potential values (-16 mV to -34 mV) and the presence of ester carbonyl peaks in IR spectroscopy (1730 cm-1). This functionalization enhances the CNCs' colloidal stability by anchoring carboxyl functionalities, which serve as reactive sites for subsequent modifications to tune their hydrophilic or hydrophobic properties -making them versatile candidates for next-generation applications in packaging, biomedical technologies, and edible coatings. Additionally, the successful recovery of the organic acids further enhances the sustainability of this process. Rooted in the principles of green chemistry, this process ensures atom economy, reduced hazardous chemicals, and valorization of Elettaria cardamomum agromass, offering a transformative step towards a circular economy.

Selective separation of poplar hemicellulose and simultaneous enrichment of soluble xylose in the hydrolysate by itaconic acid pretreatment

Organic-acid pretreatments designed to efficiently separate hemicellulose and preserve high-value soluble monosaccharides in hydrolysates have become a significant research focus. In this study, the efficiency of the catalytic degradation of a lignocellulosic model using itaconic acid (IA) was evaluated. The exceptional selectivity of IA for xylan degradation was confirmed. The separation yield of poplar fractions was assessed after IA pretreatment. The yield of xylose was 81.91 % under the optimal conditions (IA concentration: 5.0 wt%, 160 °C, 60 min). The hydrolysate contained up to 12.10 g/L xylose, exceeding that obtained with formic acid and levulinic acid pretreatments. The simultaneous separation of hemicellulose and protection of soluble sugars was achieved. The high crystallinity index (66.69 %) of the residual solid (RS) confirmed the effective protection of cellulose by IA pretreatment. Additionally, the lignin in the RS contained 53.45 % β-O-4 and 1.21 mmol/g phenolic hydroxyl. This suggests that the IA-pretreated lignin retains more active functional groups, which are advantageous for subsequent conversion and utilization. These findings offer a novel approach for efficient hemicellulose separation and the effective protection of soluble xylose during organic-acid pretreatment.

Biogenic, sustainable cellulose nanocrystals for removal of pharmaceuticals from water: a prospective upgradation and value addition of Grewia Optiva fiber

Biogenic, sustainable adsorbents in general and more specifically from cellulosic origin are in demand for enabling cost-effective and environmentally friendly wastewater treatment. A novel carbonaceous, highly crystalline, mesoporous cellulose-nanocrystal (GOF@n-CL) was extracted from Grewia Optiva fiber (GOF) via 40 % H2SO4 hydrolysis and successfully applied for adsorptive removal of some pharmaceuticals (Diclofenac, Ciprofloxacin, Tetracycline, Ofloxacin, Norflox-TZ) from wastewater. While 13C NMR and FTIR spectral data confirmed the sanctity of cellulosic structure, XRD revealed cellulose-I structure having high crystallinity of 77.4 % in the fabricated GOF@n-CL. TEM analysis revealed a networked porous structure due to agglomeration of nearly spherical shaped GOF@n-CL with SAED confirming its poly-crystalline nature. Batch studies showed 96 % tetracycline (TTC) removals by GOF@n-CL and isotherm studies reflected its binding affinity was onto the heterogeneous surface. Physisorption binding mechanism via the involvement of pore diffusion, hydrogen bonding and electrostatic interactions was indicated from kinetics and from FTIR studies. The efficacy of the GOF@n-CL was further demonstrated by high removals of ciprofloxacin (81 %), diclofenac (46 %), ofloxacin (78 %) (under single adsorbate system) and of norflox-TZ (norfloxacin-48 %; trinidazole-35 %; dual adsorbate system). The promising results have suggested a pathway for upgradation of GOF to value added water-based biogenic and sustainable adsorbents.

Formic-oxalic synergy unlocks bamboo nanocellulose with high-thermal-stability and superior dispersion

Nanocellulose is among the most promising sustainable materials, with the potential to replace petroleum-based counterparts. However, its application process is often hindered by challenges related to reduced thermal stability and dispersibility. We firstly devised a novel strategy for preparing bamboo cellulose nanocrystals (CNCs) via the synergistic catalysis of formic acid and oxalic acid. Meanwhile, we conducted a comparative study on the thermal and dispersion stabilities of bamboo nanocellulose prepared by multiple methods, including mechanical, sulfuric acid, formic acid, oxalic acid and citric acid ones. The initial decomposition temperature of CNC prepared by this new method can reach 308.1 °C, and the maximum thermal decomposition temperature can reach 344.1 °C. The findings demonstrate that the high thermal stability of bamboo nanocellulose is primarily attributed to the ester groups grafted onto the cellulose-OH groups. Furthermore, the simultaneous introduction of carboxyl groups makes the CNCs exhibit an exceptional zeta potential of -43.87 mV, indicating excellent dispersion stability. The study underscores the critical role of surface ester group content in determining the thermal property of nanocellulose. Overall, the development of high-performance nanocellulose has been developed, contributing to the expanded application of nanocellulose in bio-based composites.

Nanocellulose synthesis via synergistic application of solid acid and cellulase

Nanocellulose stands out in numerous applications due to its excellent properties. Yet, achieving its preparation in a cost-effective, efficient, and environmentally benign manner remains challenging. This study introduces a green synthesis approach by employing a non-polluting solid acid, combined with a cellulase enzyme, for nanocellulose production. We explored the impact of varying the addition sequence of solid acid and cellulase on nanocellulose yield. Experimental results showed that under optimal cellulase hydrolysis conditions, solid acid hydrolysis yielded 41.3 % nanocellulose, whereas cellulase hydrolysis resulted in a 27.1 % yield. In co-treatment experiments, with the following process steps: 1) sequential hydrolysis with solid acid, followed by cellulose (SA-E); 2) simultaneous hydrolysis with solid acid and cellulase (SA + E); 3) cellulase followed by solid acid hydrolysis (E-SA). the nanocellulose yields were: 73.37 %, 70.43 %, and 57.21 %, respectively. These results proved a synergistic effect between solid acid and cellulase in both SA-E and SA + E scenarios. In addition, the synergistic mechanism between solid acid and cellulase was proposed. This approach presents a highly promising strategy for achieving high yields of nanocellulose.

Nanocrystalline cellulose from Calophyllum inophyllum shells waste by adjusting organic acid hydrolysis and optimization of reaction parameters using response surface methodology

Biodiesel production from Calophyllum inophyllum oil in Indonesia produces significant biomass waste, including seed shells. This study explores the conversion of the seed shell of Calophyllum inophyllum into nanocrystalline cellulose (NCC) via consecutive alkalization, bleaching and hydrolysis using various organic acids. Scanning electron microscopy (SEM) analysis showed a reduction in the diameter of cellulose fibers from 21.7 μm to 9.6 μm after alkalinization and bleaching. The hydrolysis process using several organic acids was optimized to produce thermally stable nanocellulose while maintaining its crystallinity. The diameter of the resulting nanofibrous cellulose was 20.53 nm for citric acid, 21.69 nm for maleic acid, and 22.06 nm for formic acid hydrolysis. In particular, lactic acid-derived NCC (NCC-LA) showed the highest crystallinity of 64.22 % with an average diameter of ~13.69 nm. Optimization of hydrolysis parameters using Response Surface Methodology (RSM) suggested 74.79 % crystallinity could be achieved with 6.01 M lactic acid following 3.46 h of hydrolysis at 91.12 °C.

Efficient cellulose dissolution and derivatization enabled by oxalic/sulfuric acid for high-performance cellulose films as food packaging

The performance of cellulose-based materials is highly dependent on the choice of solvent systems. Exceptionally, cellulose dissolution and derivatization by efficient solvent have been considered as a key factor for large-scale industrial applications of cellulose. However, cellulose dissolution and derivatization often requires harsh reaction conditions, high energy consumption, and complex solubilizing, resulting in environmental impacts and low practical value. Here we address these limitations by using a low-temperature oxalic acid/sulfuric acid solvent to enable cellulose dissolution and derivatization for high-performance cellulose films. The dissolution and derivatization mechanism of the mixed acid is studied, demonstrating that cellulose is firstly socked by oxalic acid, then more hydrogen bonds ionized by sulfuric acid break cellulose chain, and finally the esterification reaction between oxalic acid and cellulose is catalyzed by sulfuric acid. Solutions containing 8 %-10 % cellulose are obtained and can be stored for a long time at -18 °C without significant degradation. Moreover, the cellulose film exhibits a higher tensile strength of up to 66.1 MPa, thermal stability, and degree of polymerization compared to that fabricated by sulfuric acid. These unique advantages provide new paths to utilize renewable resources for alternative food packaging materials at an industrial scale.

Improvement in Noodle Quality and Changes in Microstructure and Disulfide Bond Content through the Addition of Pepper Straw Ash Leachate

Every year, a significant amount of pepper stalks are wasted due to low utilization. The ash produced from pepper stalks contains a significant amount of alkaline salts, which are food additives that can enhance the quality of noodles. Therefore, utilizing natural pepper straw ash to improve the quality of noodles shows promising development prospects. In this study, pepper straw ash leachate (PSAL) was extracted and added to noodles. The quality of the noodles gradually improved with the addition of PSAL, with the best effect observed at a concentration of 18% (PSAL mass/flour mass). This addition resulted in a 57.8% increase in noodle hardness, a 55.43% increase in chewiness, a 19.41% rise in water absorption rate, and a 13.28% increase in disulfide bond content. These alterations rendered the noodles more resilient during cooking, reducing their tendency to soften and thus enhancing chewiness and palatability. Incorporating PSAL also reduced cooking loss by 57.79%. Free sulfhydryl groups decreased by 5.1%, and scanning electron microscopy revealed a denser gluten network structure in the noodles, with more complete starch wrapping. This study significantly enhanced noodle quality and provided a new pathway for the application of pepper straw resources in the food industry.

Biomass-derived cellulose nanocrystals modified nZVI for enhanced tetrabromobisphenol A (TBBPA) removal

Nano zero-valent iron (nZVI) is an advanced environmental functional material for the degradation of tetrabromobisphenol A (TBBPA). However, high surface energy, self-agglomeration and low electron selectivity limit degradation rate and complete debromination of bare nZVI. Herein, we presented biomass-derived cellulose nanocrystals (CNC) modified nZVI (CNC/nZVI) for enhanced TBBPA removal. The effects of raw material (straw, filter paper and cotton), process (time, type and concentration of acid hydrolysis) and synthesis methods (in-situ and ex-situ) on fabrication of CNC/nZVI were systematically evaluated based on TBBPA removal performance. The optimized CNC-S/nZVI(in) was prepared via in-situ liquid-phase reduction using straw as raw material of CNC and processing through 44 % H2SO4 for 165 min. Characterizations illustrated nZVI was anchored to the active sites at CNC interface through electrostatic interactions, hydrogen bonds and FeO coordinations. The batch experiments showed 0.5 g/L CNC-S/nZVI(in) achieved 96.5 % removal efficiency at pH = 7 for 10 mg/L initial TBBPA. The enhanced TBBPA dehalogenation by CNC-S/nZVI(in), involving in initial adsorption, reduction process and partial detachment of debrominated products, were possibly attributed to elevated pre-adsorption capacity and high-efficiency delivery of electrons synergistically. This study indicated that fine-tuned fabrication of CNC/nZVI could potentially be a promising alternative for remediation of TBBPA-contaminated aquatic environments.

Preparation and functionalization of cellulose nanofibers using a naturally occurring acid and their application in stabilizing linseed oil/water Pickering emulsions

Finding efficient and environmental-friendly methods to produce and chemically modify cellulose nanofibers (CNFs) remains a challenge. In this study, lactic acid (LA) treatment followed by microfluidization was employed for the isolation and functionalization of CNFs. Small amounts of HCl (0.01, 0.1, and 0.2 M) were used alongside LA to intensify cellulose hydrolysis. FTIR spectroscopy and solid-state 13C NMR confirmed the successful functionalization of CNFs with lactyl groups during isolation, while SEM, AFM, and rheological tests revealed that the addition of HCl governed the fibers' sizes and morphology. Notably, the treatment with LA and 0.2 M HCl resulted in a more efficient defibrillation, yielding smaller nanofibers sizes (62 nm) as compared to the treatment with LA or HCl alone (90 and 108 nm, respectively). The aqueous suspension of CNFs treated with LA and 0.2 M HCl showed the highest viscosity and storage modulus. LA-modified CNFs were tested as stabilizers for linseed oil/water (50/50 v/v) emulsions. Owing to the lactyl groups grafted on their surface and higher aspect ratio, CNFs produced with 0.1 and 0.2 M HCl led to emulsions with increased stability (a creaming index increase of only 3 % and 1 %, respectively, in 30 days) and smaller droplets sizes of 23.4 ± 1.2 and 35.5 ± 0.5 μm, respectively. The results showed that LA-modified CNFs are promising stabilizers for Pickering emulsions.

Jackfruit peel cellulose nanocrystal - Alginate hydrogel for doripenem adsorption and release study

As a natural raw material to replace synthetic chemicals, cellulose and its derivatives are the most popular choices in the pharmaceutical industry. For drug delivery applications, cellulose is usually used as a cellulose nanocrystal (CNC). CNC-based hydrogels are widely utilized for drug delivery because drug molecules can be encapsulated in their pore-like structures. This study aims to develop CNC hydrogels for the delivery of doripenem antibiotics. CNC was obtained from jackfruit peel extraction, and alginate was used as a network polymer to produce hydrogels. Ionotropic gelation was used in the synthesis of CNC-alginate hydrogel composites. The maximum adsorption of doripenem by CNC was 65.7 mg/g, while the maximum adsorption by CNC-alginate was 98.4 mg/g. One of the most challenging aspects of drug delivery is predicting drug release from a solid matrix using simple and complex mathematical equations. The sigmoidal equation could represent the doripenem release from CNC, while the Ritger-Peppas equation could describe the doripenem release from CNC-Alginate. The biocompatibility testing of CNC and CNC-alginate against a 7F2 cell line indicates that both materials were non-toxic.

Synthesis of tapioca starch/palm oil encapsulated urea-impregnated biochar derived from peppercorn waste as a sustainable controlled-release fertilizer

Nutrient leaching and volatilization cause environmental pollution, thus the pursuit of developing controlled-release fertilizer formulation is necessary. Biochar-based fertilizer exhibits slow-release characteristic, however the nutrient release mechanism needs to be improved. To overcome this limitation, the approach of applying encapsulation technology with biochar-based fertilizer has been implemented in this study. Black peppercorn waste was used to synthesize urea-impregnated biochar (UIB). Central composite design was used to investigate the effects of pyrolysis temperature, residence time and urea:biochar ratio on nitrogen content of UIB. The optimum condition to synthesize UIB was at 400 °C pyrolysis temperature, 120 min residence time and 0.6:1 urea:biochar ratio, which resulted in 16.07% nitrogen content. The tapioca starch/palm oil (PO) biofilm formulated using 8 g of tapioca starch and 0.12 µL of PO was coated on the UIB to produce encapsulated urea-impregnated biochar (EUIB). The UIB and EUIB pellets achieved complete release of nitrogen in water after 90 min and 330 min, respectively. The nutrient release mechanism of UIB and EUIB was best described by the Higuchi model and Korsmeyer-Peppas model, respectively. The improvement of water retention ratio of UIB and EUIB pellets was more significant in sandy-textural soil as compared to clayey-textural soil. The EUIB derived from peppercorn waste has the potential to be utilized as a sustainable controlled-release fertilizer for agriculture.

Cellulose nanocrystalline from biomass wastes: An overview of extraction, functionalization and applications in drug delivery

Cellulose nanocrystals (CNC) have been extensively used in various fields due to their renewability, excellent biocompatibility, large specific surface area, and high tensile strength. Most biomass wastes contain significant amounts of cellulose, which forms the basis of CNC. Biomass wastes are generally made up of agricultural waste, and forest residues, etc. CNC can be produced from biomass wastes by removing the non-cellulosic components through acid hydrolysis, enzymatic hydrolysis, oxidation hydrolysis, and other mechanical methods. However, biomass wastes are generally disposed of or burned in a random manner, resulting in adverse environmental consequences. Hence, using biomass wastes to develop CNC-based carrier materials is an effective strategy to promote the high value-added application of biomass wastes. This review summarizes the advantages of CNC applications, the extraction process, and recent advances in CNC-based composites, such as aerogels, hydrogels, films, and metal complexes. Furthermore, the drug release characteristics of CNC-based material are discussed in detail. Additionally, we discuss some gaps in our understanding of the current state of knowledge and potential future directions of CNC-based materials.

Emerging Food Packaging Applications of Cellulose Nanocomposites: A Review

Cellulose is the most abundant biopolymer on Earth, which is synthesized by plants, bacteria, and animals, with source-dependent properties. Cellulose containing β-1,4-linked D-glucoses further assembles into hierarchical structures in microfibrils, which can be processed to nanocellulose with length or width in the nanoscale after a variety of pretreatments including enzymatic hydrolysis, TEMPO-oxidation, and carboxymethylation. Nanocellulose can be mainly categorized into cellulose nanocrystal (CNC) produced by acid hydrolysis, cellulose nanofibrils (CNF) prepared by refining, homogenization, microfluidization, sonification, ball milling, and the aqueous counter collision (ACC) method, and bacterial cellulose (BC) biosynthesized by the Acetobacter species. Due to nontoxicity, good biodegradability and biocompatibility, high aspect ratio, low thermal expansion coefficient, excellent mechanical strength, and unique optical properties, nanocellulose is utilized to develop various cellulose nanocomposites through solution casting, Layer-by-Layer (LBL) assembly, extrusion, coating, gel-forming, spray drying, electrostatic spinning, adsorption, nanoemulsion, and other techniques, and has been widely used as food packaging material with excellent barrier and mechanical properties, antibacterial activity, and stimuli-responsive performance to improve the food quality and shelf life. Under the driving force of the increasing green food packaging market, nanocellulose production has gradually developed from lab-scale to pilot- or even industrial-scale, mainly in Europe, Africa, and Asia, though developing cost-effective preparation techniques and precisely tuning the physicochemical properties are key to the commercialization. We expect this review to summarise the recent literature in the nanocellulose-based food packaging field and provide the readers with the state-of-the-art of this research area.

Investigation of the Structural, Thermal, and Physicochemical Properties of Nanocelluloses Extracted From Bamboo Shoot Processing Byproducts

Nanocellulose has gained increasing interest due to its excellent properties and great potential as a functional component or carrier in food and pharmaceutical industries. This study investigated the structural, thermal, and physicochemical properties of nanofibrillated cellulose (NFC) and nanocrystalline cellulose (CNC) extracted from bamboo shoot (Leleba oldhami Nakal) processing byproducts. NFCs were prepared through low concentration acid hydrolysis combined with ultrasonic treatment. CNCs were further isolated from NFCs using sulfuric acid hydrolysis treatment. TEM images showed that NFC and CNC exhibited typical long-chain and needle-like structures, respectively. CNC suspension was stable due to its zeta potential of -34.3 ± 1.23 mV. As expected, both NFC and CNC displayed high crystallinity indexes of 68.51 and 78.87%, and FTIR analysis confirmed the successful removal of lignin and hemicellulose during the treatments. However, the thermogravimetric analysis indicated that sulfuric acid hydrolysis decreased the thermal stability of CNCs. The improved physicochemical properties of NFC and CNC suggested their potential in various applications.