Production of Nanocellulose from Pineapple Leaf Fibers via High-Shear Homogenization and Ultrasonication

Nanocellulose reinforced polyvinyl alcohol-based bio-nanocomposite films: improved mechanical, UV-light barrier, and thermal properties

This study reported the development and characterisation of bio-nanocomposite films based on the polyvinyl alcohol (PVA) reinforced with cellulose nanofibres (CNFs) of different concentrations (1-5 wt%), isolated from pineapple leaf fibre via high-shear homogenisation and ultrasonication. The PVA film and bio-nanocomposite were prepared using a solution casting method. The PVA film and bio-nanocomposite samples were characterized using FE-SEM, XRD, FTIR spectroscopy, UV-vis spectroscopy in transmission mode, TGA, and DTG. Mechanical properties (tensile strength and strain at break) were also determined and statistical analysis was applied as well. With the incorporation of CNFs, the mechanical properties of the bio-nanocomposite were found to be significant (p ≤ 0.05), particularly the 4 wt% CNF bio-nanocomposite showed optimum properties. The tensile strength, CI, and thermal stability of this film were 28.9 MPa (increased by 28.2%), 78.7% (increased by 5.2%), and 341.8 °C (increased by 1.6%), respectively, compared to the pure PVA film. These characteristics imply that the bio-nanocomposite film has prospects as a promising material for biopackaging.

Micromorphology reformation of regenerated cellulose nanofibers from corn (Zea Mays) stalk pith in urea solution with high-speed shear induced

Nanocellulose is a kind of renewable natural polymer material with high specific surface area, high crystallinity, and strong mechanical properties. RC nanofibers (RCNFs) have attracted an increasing attention in various applications due to their high aspect ratio and good flexibility. Herein, a novel and facile strategy for RCNFs preparation with high-speed shear induced in urea solution through "bottom-up" approach was proposed in this work. Results indicated that the average diameter and yield of RCNF was approach to 136.67 nm and 53.3 %, respectively. Meanwhile, due to the regular orientation RC chains and arrangement micro-morphology, RCNFs exhibited high crystallinity, strong mechanical properties, stable thermal degradation performance, and excellent UV resistance. In this study, a novel regeneration process with high-speed shear induced was developed to produce RCNFs with excellent properties. This study paved a strategy for future low-energy production of nanofibers and high value-added conversion applications of agricultural waste.

Nanocellulose-Based Hybrid Scaffolds for Skin and Bone Tissue Engineering: A 10-Year Overview

Cellulose, the most abundant polymer on Earth, has been widely utilized in its nanoform due to its excellent properties, finding applications across various scientific fields. As the demand for nanocellulose continues to rise and its ease of use becomes apparent, there has been a significant increase in research publications centered on this biomaterial. Nanocellulose, in its different forms, has shown tremendous promise as a tissue engineered scaffold for regeneration and repair. Particularly, nanocellulose-based composites and scaffolds have emerged as highly demanding materials for both soft and hard tissue engineering. Medical practitioners have traditionally relied on collagen and its analogue, gelatin, for treating tissue damage. However, the limited mechanical strength of these biopolymers restricts their direct use in various applications. This issue can be overcome by making hybrids of these biopolymers with nanocellulose. This review presents a comprehensive analysis of the recent and most relevant publications focusing on hybrid composites of collagen and gelatin with a specific emphasis on their combination with nanocellulose. While bone and skin tissue engineering represents two areas where a majority of researchers are concentrating their efforts, this review highlights the use of nanocellulose-based hybrids in these contexts.

Fabrication of chitin-glucan nanofibers: Insights into mushroom pretreatment and subsequent acidic deep eutectic solvent-based esterification

Mushrooms contain chitin-glucan complex (CGC), a natural copolymer of chitin and glucan, and nanofibrillation enhances its applicability. Here, a novel method was used to fabricate chitin-glucan nanofibers (CGNFs) from white button mushrooms. The first stage was to pretreat the raw mushroom using hot water and alkali to remove water-soluble glucans and alkali-soluble proteins, respectively, producing a CGC amenable to nanofibrillation. The second stage was nanofibrillation via esterification using acidic deep eutectic solvents (DESs) and subsequent ultrasonication. Five choline chloride-based DESs containing mono- or dicarboxylic acid were tested for the CGC esterification. DESs with strong dicarboxylic acids expedited nanofibrillation by homogeneously dispersing the solid CGC, swelling CGC fibrils, and facilitating acidity-dependent esterification leading to steric and electrostatic repulsions. One CGNF, namely CGNF_CCMnA, was characterized: it contained chitin and glucan at an approximate ratio of 8:2 and exhibited desirable properties as nanomaterials, including small diameter (11 nm) and high colloidal (zeta potential < -30 mV above pH 5.8) and thermal stability (Tm, 315 °C). CGNF_CCMnA was tested for the adsorption to methylene blue, revealing a maximum adsorption capacity of 82.58 mg/g. The proposed approach is an efficient and readily applicable method to fabricate various mushroom-derived safe CGNFs and to produce related nanomaterials.

Current advances of nanocellulose application in biomedical field

Nanocellulose (NC) is a natural fiber that can be extracted in fibrils or crystals form from different natural sources, including plants, bacteria, and algae. In recent years, nanocellulose has emerged as a sustainable biomaterial for various medicinal applications including drug delivery systems, wound healing, tissue engineering, and antimicrobial treatment due to its biocompatibility, low cytotoxicity, and exceptional water holding capacity for cell immobilization. Many antimicrobial products can be produced due to the chemical functionality of nanocellulose, such disposable antibacterial smart masks for healthcare use. This article discusses comprehensively three types of nanocellulose: cellulose nanocrystals (CNC), cellulose nanofibrils (CNF), and bacterial nanocellulose (BNC) in view of their structural and functional properties, extraction methods, and the distinctive biomedical applications based on the recently published work. On top of that, the biosafety profile and the future perspectives of nanocellulose-based biomaterials have been further discussed in this review.

Influence of kepok banana bunch as new cellulose source on thermal, mechanical, and biodegradability properties of Thai cassava starch/polyvinyl alcohol hybrid-based bioplastic

Bioplastics were developed to overcome environmental problems that are difficult to decompose in the environment. This study analyzes Thai cassava starch-based bioplastics' tensile strength, biodegradability, moisture absorption, and thermal stability. This study used Thai cassava starch and polyvinyl alcohol (PVA) as matrices, whereas Kepok banana bunch cellulose was employed as a filler. The ratios between starch and cellulose are 10:0 (S1), 9:1 (S2), 8:2 (S3), 7:3 (S4), and 6:4 (S5), while PVA was set constant. The tensile test showed the S4 sample's highest tensile strength of 6.26 MPa, a strain of 3.85%, and a modulus of elasticity of 166 MPa. After 15 days, the maximum soil degradation rate in the S1 sample was 27.9%. The lowest moisture absorption was found in the S5 sample at 8.43%. The highest thermal stability was observed in S4 (316.8°C). This result was significant in reducing the production of plastic waste for environmental remediation.

Thermoplastic starch (TPS) bioplastic, the green solution for single-use petroleum plastic food packaging - A review

Plastic throughout the years is now one of the biggest world commodities and also the largest pollution to have an environmental impact, accumulating in landfills and also leaching into water systems and oceans. Especially with the shift to single-use disposable plastic, evermore positions plastics as the number one novel entity that pollutes the earth. This shift is also consistent in the food packaging industry. Managing plastic waste is still an issue at large, while the process of pyrolysis incineration still requires an obscene amount of energy that also does not resolve the problems with its environmental impact, the cost of mechanical-chemical degradation even outweighs the cost of producing the materials, and biodegradation process is a very slow and long process. Converting to bioplastics is one of the potential solutions to the global plastic issue. This review covers the potentials, limitations, challenges, progress and advancements of bioplastics, especially thermoplastic starch (starch-based bioplastic) in their efforts to replace petroleum plastics in food packaging and smart food packaging, especially for single-use (disposable) food packaging.

High yield production of nanocrystalline cellulose from corn cob through a chemical-mechanical treatment under mild conditions

Agricultural biomass waste such as corn cob is available in large quantities and can be used as renewable materials for various applications. Corn cob was converted into nanocrystalline cellulose by using mild sulfuric acid concentrations (30 % w/v) at low temperature (50 °C) and a relatively shorter time extraction (30 min) combined with mechanical treatment using a conventional high-speed blender. NCC from cellulose and α-cellulose from corn cobs have been successfully isolated with relatively high yields and crystallinities of 50.07-65.33 % and 65.5-69.9 %, respectively. Scanning electron microscopy (SEM) evaluated the morphological variation and dimension from corn cob fiber (CF), delignification fiber (DF), cellulose, and α-cellulose, which shows that each pretreatment stage causes a decrease in fiber diameter from 16.56 to 5.48 μm. Transmission electron microscopy (TEM) images confirmed the nano-scale dimension with fiber diameters ranging between 9.35 nm and 6.51 nm. Thermogravimetric analysis shows that NCC has relatively high thermal stability ranging from 429 to 437 °C. Thus, this characteristic of NCC has the potential to be applied as a reinforcing agent in various fields of polymer composites. Finally, this study presents a method for isolating NCC from corncob waste using a conventional high-speed blender in a mild condition process with a relatively low cost, environmentally friendly pathway, and high yield that was still preserved.

An efficient approach to extract nanocrystalline cellulose from sisal fibers: Structural, morphological, thermal and antibacterial analysis

Nanocellulose has been proposed by many researchers as a suitable bio-reinforcement material for the development of sustainable bio-nanocomposites in advanced applications due to its excellent properties. Conventional techniques for extracting nanocellulose from plant biomass are time-consuming and involve chemical wastage. This study aims to extract nanocellulose using simple processes with minimal consumption of chemicals in a minimum time. In the present work, cellulose nanocrystalline has been extracted from sisal fibers efficiently by chemical treatment assisted with steam explosion and mechanical grinding. The morphology of extracted sisal cellulose nanocrystalline (CNC-S) was analyzed by FESEM, whereas the DLS, TEM and AFM confirmed its nanosize. The average aspect ratio and zeta potential (ζ) of CNC-S were measured as 7.4 and -14.3 mV, respectively. The XRD analysis indicated that the crystallinity of the fibers considerably improved from 48.74 % for untreated fibers (UT-S) to 74.28 % for CNC-S. The chemical structure of the fibers was changed as hemicellulose and lignin were found to be eliminated after the chemical treatment which FTIR confirmed. From TGA-DTG results, it was observed that CNC-S has good thermal stability. It was also noticed that CNC-S did not show any antibacterial properties against E. coli and S. aureus due to the complete removal of lignin. This study suggests that the present extraction process can be considered as an efficient process to convert fibers into high performance nanocellulose to be used as potential reinforcing material in advanced applications.

Integrated Biobased Processes for Nanocellulose Preparation from Rice Straw Cellulose

High-potential nanomaterials were derived from rice straw using the integrated biobased processes of enzymatic hydrolysis with green organic acid hydrolysis assisted with ultrasonication pretreatment. The optimization condition of nanocellulose preparation by enzymatic hydrolysis via central composite design (CCD) achieved a maximum nanocellulose content of 32.37 ± 0.47% using a cellulase concentration of 107.06 U/mL and 0.13% (w/w) of rice straw cellulose. The ultrasonication-assisted pretreatment prior to enzymatic hydrolysis improved nanocellulose preparation to 52.28 ± 1.55%. Integration with oxalic acid hydrolysis increased the nanocellulose content to 64.99 ± 0.16%. Granular nanocellulose was obtained and consisted of a 105–825 nm nanosize with a zeta potential value of −34.5 mV, and nanocellulose suspension showed high stability without aggregation. In addition, the remaining rice straw cellulose after oxalic acid was microcrystalline nanocellulose. All prepared nanocellulose represented a functional group as original cellulose but had a low crystallinity index (CrI) of 15.68% that could be classified as amorphous nanocellulose. Based on their characteristics, all nanocellose could be further applied in food, cosmetics, and pharmaceuticals. Moreover, the results indicated that the rice straw could be an alternative non-edible cellulose source for preparing potential nanocellulose via a controlled hydrolysis process.

Nanocellulose: An amazing nanomaterial with diverse applications in food science

Recently, nanocellulose has gained growing interests in food science due to its many advantages including its broad resource of raw materials, renewability, interface stability, high surface area, mechanical strength, prebiotic characteristics, surface chemistry versatility and easy modification. Since then, this review summarized the sources, morphology, and structure characteristics of nanocellulose. Meanwhile, the mechanical, chemical, and combined treatment methods for the preparation of nanocellulose with desired properties were elaborated. Furthermore, the application of nanocellulose in Pickering emulsions, reinforced food packaging, functional food ingredient, food-grade hydrogels, and biosensors were emphasized. Finally, the safety, challenges, and future perspectives of nanocellulose were discussed. This work provided key developments and effective benefits of nanocellulose for future research opportunities in food.

Pineapple Agro-Industrial Biomass to Produce Biomedical Applications in a Circular Economy Context in Costa Rica

Pineapple is a highly demanded fruit in international markets due to its unique appearance and flavor, high fiber content, vitamins, folic acid, and minerals. It makes pineapple production and processing a significant source of income for producing countries, such as Costa Rica. This review collects bibliographic information dating back to the beginnings of pineapple production in Costa Rica to the state of the market today. It details the impacts of its production chain and proposes a biorefinery as a solution to environmental problems. Besides the potentiality of new sustainable markets to contribute to the post-COVID-19 economy in Costa Rica is highlighted. The general characteristics of pineapple by-products -cellulose, hemicellulose, lignin, and other high-value products like bromelain y saponin- are described, as well as the primary processes for their ex-traction via biorefinery and main applications in the medical field. Finally, a brief description of the main works in the literature involving modeling and simulation studies of pineapple by-products properties is included.

The Encapsulation of Bioactive Plant Extracts into the Cellulose Microfiber Isolated from G. optiva Species for Biomedical Applications

Agricultural waste-based cellulose fibers have gained significant interest for a myriad of applications. Grewia optiva (G. optiva), a plant species, has been widely used for feeding animals, and the small branches' bark is used for making rope. Herein, we have extracted cellulose fibers from the bark of G. optiva species via chemical treatments (including an alkaline treatment and bleaching). The gravimetric analysis revealed that the bark of G. Optiva contains cellulose (63.13%), hemicellulose (13.52%), lignin (15.13%), and wax (2.8%). Cellulose microfibre (CMF) has been synthesized from raw fibre via chemical treatment methods. The obtained cellulose fibers were crosslinked and employed as the matrix to encapsulate the bioactive plant extracts derived from the root of Catharanthus roseus (C. roseus). The microscopic images, XRD, FTIR, and antibacterial/antioxidant activity confirmed the encapsulation of natural extracts in the cellulose microfiber. The microscopic images revealed that the encapsulation of the natural extracts slightly increased the fiber's diameter. The XRD pattern showed that the extracted cellulose microfiber had an average crystalline size of 2.53 nm with a crystalline index of 30.4% compared to the crystalline size of 2.49 nm with a crystalline index of 27.99% for the plant extract incorporated membrane. The water uptake efficiency of the synthesized membrane increased up to 250%. The antimicrobial activity of the composite (the CMF-E membrane) was studied via the zone inhibition against gram-positive and gram-negative bacteria, and the result indicated high antibacterial activity. This work highlighted G. optiva-derived cellulose microfiber as an optimum substrate for antimicrobial scaffolds. In addition, this paper first reports the antimicrobial/antioxidant behavior of the composite membrane of the C. roseus extract blended in the G. optiva microfiber. This work revealed the potential applications of CMF-E membranes for wound healing scaffolds.

Ultrasonic cavitation: An effective cleaner and greener intensification technology in the extraction and surface modification of nanocellulose

With rising consumer demand for natural products, a greener and cleaner technology, i.e., ultrasound-assisted extraction, has received immense attention given its effective and rapid isolation for nanocellulose compared to conventional methods. Nevertheless, the application of ultrasound on a commercial scale is limited due to the challenges associated with process optimization, high energy requirement, difficulty in equipment design and process scale-up, safety and regulatory issues. This review aims to narrow the research gap by placing the current research activities into perspectives and highlighting the diversified applications, significant roles, and potentials of ultrasound to ease future developments. In recent years, enhancements have been reported with ultrasound assistance, including a reduction in extraction duration, minimization of the reliance on harmful chemicals, and, most importantly, improved yield and properties of nanocellulose. An extensive review of the strengths and weaknesses of ultrasound-assisted treatments has also been considered. Essentially, the cavitation phenomena enhance the extraction efficiency through an increased mass transfer rate between the substrate and solvent due to the implosion of microbubbles. Optimization of process parameters such as ultrasonic intensity, duration, and frequency have indicated their significance for improved efficiency.

Nanocellulose-Based Nanocomposites for Sustainable Applications: A Review

Nanocellulose has emerged in recent years as one of the most notable green materials available due to its numerous appealing factors, including its non-toxic nature, biodegradability, high aspect ratio, superior mechanical capabilities, remarkable optical properties, anisotropic shape, high mechanical strength, excellent biocompatibility and tailorable surface chemistry. It is proving to be a promising material in a range of applications pertinent to the material engineering to biomedical applications. In this review, recent advances in the preparation, modification, and emerging application of nanocellulose, especially cellulose nanocrystals (CNCs), are described and discussed based on the analysis of the latest investigations. This review presents an overview of general concepts in nanocellulose-based nanocomposites for sustainable applications. Beginning with a brief introduction of cellulose, nanocellulose sources, structural characteristics and the extraction process for those new to the area, we go on to more in-depth content. Following that, the research on techniques used to modify the surface properties of nanocellulose by functionalizing surface hydroxyl groups to impart desirable hydrophilic-hydrophobic balance, as well as their characteristics and functionalization strategies, were explained. The usage of nanocellulose in nanocomposites in versatile fields, as well as novel and foreseen markets of nanocellulose products, are also discussed. Finally, the difficulties, challenges and prospects of materials based on nanocellulose are then discussed in the last section for readers searching for future high-end eco-friendly functional materials.

Biomass conversion of agricultural waste residues for different applications: a comprehensive review

Agricultural waste residues (agro-waste) are the source of carbohydrates that generally go in vain or remain unused despite their interesting morphological, chemical, and mechanical properties. With rapid urbanization, there is a need to valorize this waste due to limited non-renewable resources. Utilizing agro-waste also prevents the problems like burning and inefficient disposal that otherwise lead to immense pollution worldwide. In addition, conversion of biomass to value-added products like earthen cups, weaving baskets, and bricks is equally beneficial for the rural population as it provides secondary income, creates jobs, and improves rural people's lifestyles. This review paper will discuss an overview of different applications utilizing agro-waste residues. In particular, agro-wastes used as construction material, bio-fertilizers, pulp and paper products, packaging products, tableware, heating applications, biocomposites, nano-cellulosic materials, soil stabilizers, bioplastics, fire-retardant additive, dye removal, and biofuels will be summarized. Finally, several commercially available agro-waste products will also be discussed, emphasizing the circular economy.

Nanocrystalline cellulose derived from spruce wood: Influence of process parameters

The cellulose nanocrystals (CNCs) were produced from spruce wood using less hazardous and toxic reagents with understanding of influence of process parameters on CNCs properties. This study employed acetosolv pulping followed by alkaline-peroxide bleaching, eliminating highly reactive chemicals such as Na-chlorites and Na-sulfite for cellulose pulp extraction from spruce wood. Cellulose pulp yield of 41.5 ± 0.7 wt% of dry wood was obtained from pulping followed by bleaching treatment. Cellulose pulp was hydrolyzed with 59.0-65.0 wt% sulfuric acid followed by ultrasonic treatment to produce CNCs. CNCs yield of 8.0 ± 3.2 wt% of dry wood was obtained at 65 wt% acid concentration and yield of 25.1 ± 0.7 wt% at 62 wt% acid concentration. The optimization of acid hydrolysis and ultrasonic treatment resulted in CNCs with high aspect ratios (length/width) up to 48.1. It was demonstrated that higher acid concentration requires lower intensity of ultrasonic treatment for CNCs dispersion, and that higher intensity could enhance aspect ratio without impacting the crystallinity index. However, ultrasonic treatment for longer than 5 min led to destruction of the whisker morphology of CNCs. The extracted CNCs possess high crystallinity index of 80.8 ± 1.7 %, low residual hemicellulose (<2.0 %) and lignin (<0.7 %), and high-char content of 26.7 wt% from thermal degradation.

Experimental Investigation of Effect of Fiber Length on Mechanical, Wear, and Morphological Behavior of Silane-Treated Pineapple Leaf Fiber Reinforced Polymer Composites

The development of the best properties in polyester composite from pineapple leaf fiber (PALF) as a reinforcing material is a subject of interest. The properties of PALF are reliant upon fiber length, wherein technical difficulties in production of long fibers and processing for better characteristics in polyester composites possess inherent challenges. The PALFs are subjected to silane treatment for altering fiber properties. This research attempts to analyze the impact of silane-treated PALF with varying fiber lengths (5, 10, 15, 20, and 25 mm) on the performance of natural fiber composites (NFC) properties. Open mold and hand lay-up techniques were employed to develop the polyester composites. The prepared PALF-based polyester composites were examined for different properties (impact, flexural, tensile strength, and wear rate). Coefficient of friction and wear studies are performed on the prepared composites subjected to different loads (10, 20, and 30 N) via a pin on disc test rig. Polymer composite fracture surfaces were analyzed to observe the interfacial bonding between fibers and matrix via scanning electron microscopy (SEM). SEM results showed that the application of silane treatment resulted in better surface topography (fiber length of 5–10 mm showed smooth surface resulted in crack proliferation possessing low fracture toughness of 15–32 MPa; whereas a 15–20 mm fiber length resulted in better fiber–matrix bonding, improving the fracture toughness from 42–55 MPa) as a result of change in chemical structure in PALF. The 20 mm length of PALF resulted in better properties (flexural, tensile, impact, and wear resistance) which are attributed to fiber–matrix interfacial bonding. These properties ensure the developed polymer composites can be applied to walls, building insulation, and artificial ceilings.

Optimization of Hemp Bast Microfiber Production Using Response Surface Modelling

Non-wood biomass is particularly attractive as a cellulose source because of the lower lignin content. However, optimal cellulose extraction conditions are required as lignin content varies between plant sources. Further, the use of organic acids in place of harsh mineral acids is of interest in “greening” the cellulose production process. This study sought to establish optimum parameters for the extraction of cellulose microfibers (CMFs) from hemp (Cannabis sativa) biomass, using maleic and formic acids. Hemp fibers were pre-treated in NaOH (4 wt%) and aqueous chlorite in acetate buffer before ultrasonic treatment to break down bundles. The CMFs produced were compared with those generated from sulfuric acid hydrolysis. Response surface methodology (RSM) was used to determine combinations of three processing conditions, including acid concentration (45–64%), hydrolysis time (30–90 min), and temperature (45–65 °C). A central composite design (RSM-CCD) model with 21 experimental runs was optimized using MODDE 13.1 software. The model suitably described the data (R2 = 0.99; R2adj = 0.96). Microfibers with an average width of 6.91 µm, crystallinity range 40–75%, and good thermal stability were produced. Crystallinity was influenced by all three factors. The optimal crystallinity predicted by the model was 83.21%, which could be achieved using formic acid 62 wt% formic acid, 36 min hydrolysis time, and 47 °C hydrolysis temperature. These conditions resulted in a crystallinity degree of 82%. These data suggest formic acid can be used as an alternative to sulfuric acid for synthesis of cellulose microfibers from biodegradable hemp waste fibers.

Effect of oxalic acid and sulphuric acid hydrolysis on the preparation and properties of pineapple pomace derived cellulose nanofibers and nanopapers

Nanocellulose is the "green magnet" which attracts a wide spectrum of industries towards it due to its availability, biodegradability, and possible smart applications. For the first time, pineapple pomace was being explored as an economic precursor for cellulose nanofibers. Nanofiber isolation was accomplished using a chemo-mechanical method and solution casting was adopted for the development of nanopapers. Moreover, the study examines the structural, optical, crystalline, dimensional, and thermal features of nanofibers isolated using different acid hydrolysis (oxalic acid and sulphuric acid) methods. Fourier-transform infra-red spectroscopy, ¹³C solid-state nuclear magnetic resonance spectroscopy, and X-ray diffraction analysis indicated the presence of type I cellulose. The transmittance, crystallinity index, and thermal stability of PPNFS (sulphuric acid treated fiber) were greater than PPNFO (oxalic acid treated fiber). The transmission electron microscopy and dynamic light scattering analysis confirmed the nanodimension of PPNFO and PPNFS. While comparing the optical and mechanical properties of nanopapers, PPNFS outperforms PPNFO. The tensile strength of the prepared nanopapers (64 MPa (PPNFO) and 68 MPa (PPNFS)) was found to be high compared to similar works reported in the literature. The prepared nanopaper is proposed to be used for food packaging applications.

Whey Protein Isolate Nanofibers Prepared by Subcritical Water Stabilized High Internal Phase Pickering Emulsion to Deliver Curcumin

This study aimed to design a Pickering emulsion (PE) stabilized by whey protein isolate nanofibers (WPINs) prepared with subcritical water (SW) to encapsulate and prevent curcumin (Cur) degradation. Cur-loaded WPINs–SW stabilized PE (WPINs–SW–PE) and hydrothermally prepared WPINs stabilized PE (WPINs–H–PE) were characterized using the particle size, zeta potential, Congo Red, CD, and TEM. The results indicated that WPINs–SW–PE and WPINs–H–PE showed regular spherical shapes with average lengths of 26.88 ± 1.11 μm and 175.99 ± 2.31 μm, and zeta potential values were −38.00 ± 1.00 mV and −34.60 ± 2.03 mV, respectively. The encapsulation efficiencies of WPINs–SW–PE and WPINs–H–PE for Cur were 96.72 ± 1.05% and 94.07 ± 2.35%. The bio-accessibility of Cur of WPINs–SW–PE and WPINs–H–PE were 57.52 ± 1.24% and 21.94 ± 2.09%. In addition, WPINs–SW–PE had a better loading effect and antioxidant activities compared with WPINs–H–PE. SW could be a potential processing method to prepare a PE, laying the foundation for the subsequent production of functional foods.

Co-Delivery of Doxycycline and Hydroxychloroquine Using CdTe-Labeled Solid Lipid Nanoparticles for Treatment of Acute and Chronic Brucellosis

Brucellosis is a systemic disease in both acute and chronic forms which can affect any organ or tissue in the body. One of the biggest issues in treating this disease is its relapse. In this study, a complete treatment of brucellosis was evaluated using enhanced performance of doxycycline and hydroxychloroquine drugs by using solid lipid nanoparticles (SLN) conjugated cadmium-telluride quantum dots. The double emulsion method was used to prepare SLN and cadmium-telluride quantum dots. The physicochemical properties of NPs were determined. The effect of nanoparticle-loaded antibiotics against Brucella melitensis was determined by well diffusion, minimum inhibitory concentration (MIC), cell culture, and animal studies. The means of particle size, PDI, zeta potential, drugs loading, and encapsulation efficiency were 214 ± 25 nm, 0.385 ± 0.022, −18.7 ± 2.3 mV, 17.7 ± 1.5%, and 94.15 ± 2.6%, respectively. The results of FTIR and DSC showed that no chemical reaction occurred between the components of the NPs. The effect of free drug and NPs on bacteria was the same by well diffusion and MIC method. Drug-loaded NPs significantly reduced the number of CFUs in the cell line and acute and chronic brucellosis compared to the free drug. In conclusion, the synthesized nanoparticles were safe and green. With the slow release of the drug (100 h), the accumulation of the drug at the bacterial site increases and causes a greater effect on the B. melitensis and improves the disease of brucellosis. The use of synthesized nanodrugs in this study had promising therapeutic results.

An Innovative Preparation, Characterization, and Optimization of Nanocellulose Fibers (NCF) Using Ultrasonic Waves

Recently, environmental and ecological concerns have become a major issue owing to the shortage of resources, high cost, and so forth. In my research, I present an innovative, environmentally friendly, and economical way to prepare nanocellulose from grass wastes with a sodium hypochlorite (NaClO) solution of different concentrations (1−6% mol) at different times 10−80 min, washed with distilled water, and treated with ultrasonic waves. The optimum yield of the isolated cellulose was 95%, 90%, and 87% NaClO at 25 °C for 20 min and with NaOH and H2SO4 at 25 °C with 5% M, respectively. The obtained samples were characterized by dynamic light scattering (DLS), Fourier-transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD). The effect of test temperature and reaction times on the crystallinity index (IC) of GNFC with different treated mediums was carried out and investigated. The IC was analyzed using the diffraction pattern and computed according to the Segal empirical method (method A), and the sum of the area under the crystalline adjusted peaks (method B) and their values proved that the effect of temperature is prominent. In both methods, GNFC/H2SO4 had the highest value followed by GNFC/NaOH, GNFC/NaClO and real sample nano fiber cellulose (RSNFC). The infrared spectral features showed no distinct changes of the four cellulose specimens at different conditions. The particle size distribution data proved that low acid concentration hydrolysis was not sufficient to obtain nano-sized cellulose particles. The Zeta potential was higher in accordance with (GNFC/H2SO4 > GNFC/NaOH > GNFC/NaClO), indicating the acid higher effect.

Recent advancement in isolation, processing, characterization and applications of emerging nanocellulose: A review

The emergence of nanocellulose from various natural resources as a promising nanomaterial has been gaining interest for a wide range application. Nanocellulose serves as an excellent candidate since it contributes numerous superior properties and functionalities. In this review, details of the three main nanocellulose categorised: cellulose nanocrystal (CNC), cellulose nanofibril (CNF), and bacterial nanocellulose (BNC) have been described. We focused on the preparation and isolation techniques to produce nanocellulose including alkaline pre-treatment, acid hydrolysis, TEMPO-mediated oxidation, and enzymatic hydrolysis. The surface modification of nanocellulose through esterification, silylation, amidation, phosphorylation, and carboxymethylation to improve the diverse applications has also been reviewed. Some invigorating perspectives on the applications, challenges, and future directions on the relevant issues regarding nanocellulose are also presented.

Investigating the Processing Potential of Ethiopian Agricultural Residue Enset/Ensete ventricosum for Biobutanol Production

The Enset plant is a potential food source for about 20 million Ethiopians. A massive amount of residual byproduct is discarded from traditional Ethiopian Enset food processing. This study shows a compositional analysis of Enset biomass and its use for biobutanol production. The Enset biomass was pretreated with 2% (w/v) NaOH or 2% (v/v) H₂SO₄ and subjected to enzymatic hydrolysis. The enzymatic hydrolysates were then fermented anaerobically by C. saccharoperbutylacetonicum DSM 14923. The majority of Enset biomass waste samples contained 36–67% cellulose, 16–20% hemicelluloses, and less than 6.8% lignin. In all alkali-pretreated Enset biomass samples, the enzyme converted 80–90% of the biomass to glucose within 24 h, while it took 60 h to convert 48–80% of the acid-pretreated Enset biomass. In addition, the alkali pretreatment method released more glucose than the acid pretreatment in all Enset biomass samples. After 72 h of ABE fermentation, 2.8 g/L acetone, 9.9 g/L butanol, and 1.6 g/L ethanol were produced from mixed Enset waste hydrolysate pretreated with alkali, achieving an ABE yield of 0.32 g/g and productivity of 0.2 g × L⁻¹ × h⁻¹, showing the first value of butanol produced from Enset biomass in the literature.

Highly antimicrobial and strong cellulose-based biocomposite film prepared with bacterial cellulose powders, Uncaria gambir, and ultrasonication treatment

This work characterized bacterial cellulose (BC)/Uncaria gambir (G) biocomposite film prepared with ultrasonication treatment. Films were prepared from BC powder suspensions in distilled water without and with various loadings (0.05 g, 0.1 g, 0.2 g, 2 g) of G powder then treated using an ultrasonic probe at 1000 W for one hour. The results revealed that the ultrasonication treatment of the suspension greatly increased tensile strength (TS), elongation at break (EB), and toughness (TN) of a BC film by 3097%, 644%, and 32,600%, respectively, compared to non-sonicated BC film. After adding 0.05 g G into the sonicated BC powder suspension, TS, EB, and TN of the biocomposite film were improved to 105.6 MPa, 14.3%, and 8.7 MJ/m³, respectively. The addition of the G increased in antimicrobial activity of the film. This study indicates that biocomposite film is potentially useful for nanopaper production with good antimicrobial and high tensile properties.

Isolation and characterization of cellulose nanofibers from Agave gigantea by chemical-mechanical treatment

Nanocellulose is a renewable and biocompatible nanomaterial that evokes much interest because of its versatility in various applications. This study reports the production of nanocellulose from Agave gigantea (AG) fiber using the chemical-ultrafine grinding treatment. Chemical treatment (alkalization and bleaching) removed non-cellulose components (hemicellulose and lignin), while ultrafine grinding reduced the size of cellulose microfibrils into nanocellulose. From the observation of Transmission Electron Microscopy, the average diameter of nanocellulose was 4.07 nm. The effect of chemical-ultrafine grinding on the morphology and properties of AG fiber was identified using chemical composition, Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared, and Thermogravimetric Analysis. The bleaching treatment increased the crystal index by 48.3% compared to raw AG fiber, along with an increase in the cellulose content of 20.4%. The ultrafine grinding process caused a decrease in the crystal content of the AG fiber. The crystal index affected the thermal stability of the AG fiber. The TGA results showed that AG fiber treated with bleaching showed the highest thermal stability compared to AG fiber without treatment. The FTIR analysis showed that the presence of CH vibrations from the ether in the fiber. After chemical treatment, the peaks at 1605 and 1243 cm-1 disappeared, indicating the loss of lignin and hemicellulose functional groups in AG fiber. As a result, nanocellulose derived from AG fiber can be applied as reinforcement in environmentally friendly polymer biocomposites.

Nanocellulose, a versatile platform: From the delivery of active molecules to tissue engineering applications

Nanocellulose, a biopolymer, has received wide attention from researchers owing to its superior physicochemical properties, such as high mechanical strength, low density, biodegradability, and biocompatibility. Nanocellulose can be extracted from wide range of sources, including plants, bacteria, and algae. Depending on the extraction process and dimensions (diameter and length), they are categorized into three main types: cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial nanocellulose (BNC). CNCs are a highly crystalline and needle-like structure, whereas CNFs have both amorphous and crystalline regions in their network. BNC is the purest form of nanocellulose. The nanocellulose properties can be tuned by chemical functionalization, which increases its applicability in biomedical applications. This review highlights the fabrication of different surface-modified nanocellulose to deliver active molecules, such as drugs, proteins, and plasmids. Nanocellulose-mediated delivery of active molecules is profoundly affected by its topographical structure and the interaction between the loaded molecules and nanocellulose. The applications of nanocellulose and its composites in tissue engineering have been discussed. Finally, the review is concluded with further opportunities and challenges in nanocellulose-mediated delivery of active molecules.

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

Conversion of lignocellulosic biowastes from agricultural industry into nanocrystalline cellulose provides pathway to reduce environmental pollution while enhancing the economic value of biowastes. Nanocellulose (NCC) with uniform morphology was isolated from pepper (Piper nigrum L.) stalk waste (PW) using acid hydrolysis method. The role of inorganic acids (sulfuric acid, hydrochloric acid, phosphoric acid), organic acids (oxalic acid, citric acid, acetic acid) and variation of sonication times were investigated on the physicochemical characteristics, self-assembled structure, crystallinity, particle size, zeta potential and thermal stability of the isolated nanocellulose. Hydrolysis using inorganic acids transformed cellulose from PW into a spherical shaped NCC at ~33-67 nm of average diameter. Meanwhile hydrolysis in organic acids produced rod-shaped NCC at 210-321 nm in length. This study highlighted the role of acidity strength for organic acid and inorganic acid in controlling the level of hydrogen bond dissociation and the dissolution of amorphous fragments, which consequently directing the morphology and the physicochemical properties of NCCs.

Thermoplastic starch nanocomposites using cellulose-rich Chrysopogon zizanioides nanofibers

Green thermoplastic starch (TPS) nanocomposite films aided by cellulose nanofibers (CNFs) from Chrysopogon zizanioides roots were developed and characterized. When compared to other lignocellulosic fibers, Chrysopogon zizanioides roots revealed exceptionally high cellulose content (~48%). CNFs were separated using an environmentally friendly acid isolation technique that included three stages: (i) alkali treatment; (ii) bleaching; and (iii) mild acid hydrolysis using oxalic acid in an autoclave. Following that, green nanocomposite films were made from potato starch using the solution casting process, by which we used glycerol (30 wt%) to make thermoplastic starch. Then, cellulose nanofibers in different concentrations (0, 1, 2, 3, 4 wt%) were added to the thermoplastic starch matrix. The isolated CNFs had diameters in the range of 17-27 nm. Besides, these nanostructures presented a very high crystallinity index (~65%), thereby enhanced the thermal stability. TPS/CNF green nanocomposites containing 3 wt% CNFs had exceptional tensile strength (~161%), tensile modulus (~167%), thermal stability, and crystallinity. As a result, nanocomposite films made of starch and cellulose nanofibers (3 wt%) extracted from Chrysopogon zizanioides roots would be alternatives for sustainable packaging. It can be concluded that Chrysopogon zizanioides roots have high potential for polymer industry.

Micro- and nanocelluloses from non-wood waste sources; processes and use in industrial applications

In addition to renewability and abundance, nanocellulose materials have tremendous (and variable) properties for different applications, ranging from bulk applications, such as paper and packaging reinforcement, to emerging high added-value applications, such as substrates for optoelectronics. Lignocellulosic biomass from agricultural and industrial waste sources is readily available and shows great promise as an inexpensive and sustainable raw material for nanocellulose production. However, the understanding of the potential of using non-wood based biowaste sources is not established and systematic comparisons of versatile agricultural and industrial waste sources can elucidate this complex topic. Here we present an overview of the most studied and most promising sources from agro-industrial waste, the processes to convert them into nanocellulose, some of the established and emerging applications, and discuss the advancements that are still needed for large-scale production. Sugarcane bagasse and oil palm empty fruit bunch have been the most researched waste-based sources for nanocellulose production and demonstrate the most promise due to availability and access. Industrial sources seem to have advantages over agricultural sources in collectability and ease of access. This work gives insight on the potential and the challenges of nanocellulose production from waste sources and discusses how the criteria set for nanocellulose materials in different applications can be met, thus opening new routes for circular economy.

Structural characterization of microcrystalline and nanocrystalline cellulose from Ananas comosus L. leaves: Cytocompatibility and molecular docking studies

The present study focused on the preparation of microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) from pineapple (Ananas comosus L.) leaves using chemical treatments followed by acid hydrolysis. Pineapple leaves could be used in medical applications such as drug delivery carriers. Advanced spectroscopy techniques such as Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the physical, chemical, and morphological features of the isolated MCC and NCC; the results indicated the needle-shaped form of nanostructures with good purity and high crystallinity index of 75.00 and 76.38%, respectively. In addition, inhibition of the treated MRC-5 cells with all the samples revealed that the percentage of cell viability was less than 30%, which is an interesting finding given their role in the cytotoxicity effect of MCC and NCC. It appears that MCC and NCC derived from pineapple leaves have lower toxicity. As a result, the developed MCC and NCC can be used in pharmaceutical applications as a novel drug delivery system. Molecular docking was performed to understand the non-bonding interaction of cellulose with human acid-beta-glucosidase (β-Glc) (PDB: 1OGS). The docking result shows that cellulose unit docked within the active pocket of the enzyme by forming hydrogen bonds against ASN19, THR21, and VAL17 with distances of 2.18, 1.93, and 2.92 Å, respectively, with binding energy (−5.0 kcal/mol) resulting in close interaction of cellulose unit with the receptor.

Mechanical and Structural Characterization of Pineapple Leaf Fiber

Evidence-based research had shown that elevated alkali treatment of pineapple leaf fiber (PALF) compromised the mechanical properties of the fiber. In this work, PALF was subjected to differential alkali concentrations: 1, 3, 6, and 9% wt/wt to study the influence on the mechanical and crystal properties of the fiber. The crystalline and mechanical properties of untreated and alkali-treated PALF samples were investigated by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and tensile testing analysis. The XRD results indicated that crystal properties of the fibers were modified with 6% wt/wt alkali-treated PALF recording the highest crystallinity and crystallite size of 76% and 24 nm, respectively. The FTIR spectra suggested that all alkali-treated PALF samples underwent lignin and hemicellulose removal to varying degrees. An increase in the crystalline properties improved the mechanical properties of the PALF treated with alkali at 6% wt/wt, which has the highest tensile strength (1620 MPa). Although the elevated alkali treatment resulted in decreased mechanical properties of PALF, crystallinity generally increased. The findings revealed that the mechanical properties of PALF not only improve with increasing crystallinity and crystallite size, but are also dependent on the intermediate bond between adjacent cellulose chains.

A review of nanocellulose as a new material towards environmental sustainability

Synthetic polymers, commonly referred to as plastics, are anthropogenic contaminants that adversely affect the natural ecosystems. The continuous disposal of long lifespan plastics has resulted in the accumulation of plastic waste, leading to significant pollution of both marine and terrestrial habitats. Scientific pursuit to seek environment-friendly materials from renewable resources has focused on cellulose, the primary reinforcement component of the cell wall of plants, as it is the most abundantly available biopolymer on earth. This paper provides an overview on the current state of science on nanocellulose research; highlighting its extraction procedures from lignocellulosic biomass. Literature shows that the process used to obtain nanocellulose from lignocellulosic biomass greatly influences its morphology, properties and surface chemistry. The efficacy of chemical methods that use alkali, acid, bleaching agents, ionic liquids, deep eutectic solvent for pre-treatment of biomass is discussed. There has been a continuous endeavour to optimize the pre-treatment protocol as it is specific to lignocellulosic biomass and also depends on factors such as nature of the biomass, process and environmental parameters and economic viability. Nanofibers are primarily isolated through mechanical fibrillation while nanocrystals are predominantly extracted using acid hydrolysis. A concise overview on the ways to improve the yield of nanocellulose from cellulosic biomass is also presented in this review. This work also reviews the techniques used to modify the surface properties of nanocellulose by functionalizing surface hydroxyl groups to impart desirable hydrophilic-hydrophobic balance. An assessment on the emerging application of nanocellulose with an emphasis on development of nanocomposite materials for designing environmentally sustainable products is incorporated. Finally, the status of the industrial production of nanocellulose presented, which indicates that there is a continuously increased demand for cellulose nanomaterials. The demand for cellulose is expected to increase further due to its increasing and broadening applications.

Modification of pineapple leaf fibers with aminosilanes as adsorbents for H2S removal

Pineapple leaves were used as a natural fiber source to prepare various modified microcrystalline cellulose (MCC) samples as sorbents for H₂S sorption. Pineapple leaf fibers were first extracted from pineapple leaves, followed by hydrolyzing to produce MCC before various modifications using primary amine (3-aminopropyltrimethoxysilane, APS), secondary amine (N-methyl-3-aminopropyltrimethoxysilane, MAPS), or tertiary amine (N,N-dimethyl-3-aminopropyltrimethoxysilane, DAPS). The characterization results proved that all the aminosilane groups were successfully grafted onto the MCC. In addition, the thermal stability and the porosity of the modified sorbents were enhanced relative to those of unmodified MCC. The H₂S sorption studies of MCC modified with APS, MAPS, and DAPS at 0, 3, or 5%w/w showed that MCC-MAPS had better H₂S sorption performance than MCC-APS and MCC-DAPS, respectively, when comparing the H₂S sorption performance at the same loading level. The optimum H₂S sorption performance of each aminosilane group was achieved from MCC-APS at 5%, MCC-MAPS at 3%, and MCC-DAPS at 5%. An additional study of H₂S sorption of these three sorbents in the presence of CO₂ showed that MCC-DAPS at 5% was the best sorbent for selective H₂S removal. Our results indicated that MCC modified with the aminosilane groups, especially MAPS, were promising materials for H₂S sorption, with potential application in gas separation.

Effect of Steam and Bleaching Treatment on the Characteristics of Pineapple Leaves Fibre Derived Cellulose

Pineapple leaf fibres (PALF) is one of the abundant residues generated from pineapple plantation. The residues are left on the plantation for nutrient cycling or burning, and this circumstance leads to environmental issues. PALF has high cellulose content among other natural fibres. Cellulose is a reinforcing element that exists as whisker-like microfibrils and has a long-chain structure. In this study, cellulose produced from PALF was treated by steam and chemical treatment. The fibre was treated with steam at 121°C, a pressure of 21 psi for 30 or 60 min. Next, the steam-treated fibre was treated with 5 wt% sodium chlorite (NaClO2) solution with pH adjusted between 4 and 5 for 90 min. The condition was varied with three different temperatures, which were room temperature, 50, and 70°C. Then, the bleached fibre was treated with 5 wt% sodium hydroxide (NaOH) at room temperature for 3 h. After the treatments, the fibre was analysed for its thermal stability, morphology, and chemical composition. Cellulose obtained from the treatment condition of steam for 60 min, bleaching at 70°C, and alkali treatment at room temperature expressed the highest degradation temperature of 276°C at 20% weight loss, percentage of cellulose of 86% and lowest moisture content (8%) compared to others sample. It also had an excellent surface morphology with finest fibril disintegration. It showed longer steam treatment (60 min) degrading more hemicellulose; and bleaching treatment at high temperature (70°C), increasing the rate of oxidative delignification. In conclusion, the suggested treatment provides a simple but efficient method to isolate cellulose that can be used for various types of applications.

Minimizing Organic Waste Generated by Pineapple Crown: A Simple Process to Obtain Cellulose for the Preparation of Recyclable Containers

In this study, cellulose was obtained from the residues of pineapple crown by means of simple acid pretreatment and subsequent alkaline treatment. The pretreatment consisted of washing, drying, and chopping with high shear at pH = 5 under heating. The content of cellulose, hemicellulose, and lignin in the pineapple crown was determined by chemical methods. The cellulose obtained was compared with commercial cellulose by Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis, and X-ray diffraction (XDR). Thus, from the obtained fiber cellulose, a food container was prepared, and its physical-mechanical properties were determined. Then, after alkali treatment, the purity of cellulose was 84.7% from the pineapple crown (56.0%) and was compared with commercial cellulose (95%). FTIR results confirmed the removal of the non-cellulosic compounds after alkali treatment. The maximum pyrolysis temperature increased to 356 °C, higher than the original fiber (322 °C), indicating greater thermal stability after chemical treatment. Furthermore, the crystallinity increased to 68% with respect to the original fiber (27%). The physical properties of the container showed a decrease in the parameters in wet 95% RH, as expected, thus facilitating its reuse. These results indicate that the pineapple crown cellulose can be obtained with significant purity, from a single chemical treatment. In addition, this polymorphous cellulose can be used to make ecofriendly reusable food containers.

Structural, Morphological and Thermal Properties of Cellulose Nanofibers from Napier fiber (Pennisetum purpureum)

The purpose of the study is to investigate the utilisation of Napier fiber (Pennisetum purpureum) as a source for the fabrication of cellulose nanofibers (CNF). In this study, cellulose nanofibers (CNF) from Napier fiber were isolated via ball-milling assisted by acid hydrolysis. Acid hydrolysis with different molarities (1.0, 3.8 and 5.6 M) was performed efficiently facilitate cellulose fiber size reduction. The resulting CNFs were characterised through Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), particle size analyser (PSA), field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The FTIR results demonstrated that there were no obvious changes observed between the spectra of the CNFs with different molarities of acid hydrolysis. With 5.6 M acid hydrolysis, the XRD analysis displayed the highest degree of CNF crystallinity at 70.67%. In a thermal analysis by TGA and DTG, cellulose nanofiber with 5.6 M acid hydrolysis tended to produce cellulose nanofibers with higher thermal stability. As evidenced by the structural morphologies, a fibrous network nanostructure was obtained under TEM and AFM analysis, while a compact structure was observed under FESEM analysis. In conclusion, the isolated CNFs from Napier-derived cellulose are expected to yield potential to be used as a suitable source for nanocomposite production in various applications, including pharmaceutical, food packaging and biomedical fields.

Effect of heat treatment on thermal resistance, transparency and antimicrobial activity of sonicated ginger cellulose film

Transparent film with high thermal resistance and antimicrobial properties has many applications in the food packaging industry particularly packaging for reheatable food. This work investigates the effects of heat treatment on the thermal resistance, stability of transparency and antimicrobial activity of transparent cellulose film. The film from ginger nanocellulose fibers was prepared with chemicals and ultrasonication. The dried film was heated at 150 °C for 30, 60, 90, or 120 min. The unheated and sonicated film had the lowest crystallinity index and the lowest thermal properties. After heating, the film became brownish-yellow resulting from thermal oxidation. The reheated film had higher thermal resistance than unheated film. Heating led to further relaxation of cellulose network evidenced by shifting of the XRD peak positions toward lower values. The antimicrobial activity decreased due to heating. Average opacity value increases after short heating durations. It was relatively stable for further heating.

Antimicrobial Imperata cylindrica paper coated with anionic nanocellulose crosslinked with cationic ions

Recently, the interest in active packaging utilization has increased with population growth, food demand and new consumer trend like food delivery services. This new system, however, requires the use of additives to extend the food product quality and safety as well as in maintaining the shelf-life. This study was to prepare the antimicrobial paper from I. cylindrica coated anionic nanocellulose crosslinked cationic to create a system with the ability to actively control microbe growth in the packaging materials. The process involved pulping of I. cylindrica using semi-chemical and soda chemical method. The antimicrobial paper was prepared by printing the pulp suspension in 60 g/m² grammage in mold followed by the spray of anionic nanocellulose and subsequent soaking of the paper in cationic solution. The results showed the I. cylindrica paper coated anionic nanocellulose crosslinked with H⁺ and Al³⁺ cations were successfully produced. The paper produced was also observed to have antimicrobial activity against Gram-negative of E. coli and S. typhi as well as Gram-positive of S. aureus and B. subtilis bacteria. Furthermore, the best coating method was found on antimicrobial paper coated anionic nanocellulose crosslinked Al³⁺ as evidenced by smoother and compact surface structure.

Enhanced adsorption of Cr(VI), Ni(II) ions from aqueous solution using modified Eichhornia crassipes and Lemna minor

The environment is seriously affected by the release of hazardous heavy metals from the industries. The transformation of aquatic weeds into valuable nanosorbent has been considered as effective and efficient material in the wastewater treatment process. The aim of the study is to analyze the potential of nano-EC and nano-LM for the removal of chromium(VI) and nickel(II) ions. The characteristics of nanosorbent were analyzed using Fourier transform infrared spectroscopy (FTIR), Brunauer Emmett-Teller analysis (BET), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and thermo gravimetric analysis (TGA), respectively. Adsorptive performance of nanosorbent was studied with respect to pH, contact time, nano adsorbent dosage, and metal ion concentration. The maximum monolayer adsorption capacity of Cr(VI) and Ni(II) with respect to nano-EC was found to be 79.04 mgg^-1 and 85.09 mgg^-1, respectively. Adsorption isotherm and kinetic studies were performed and it was reported that adsorption isotherm follows Langmuir model with regression coefficient R² > 0.9 for nano-EC and nano-LM respectively. The pseudo-second order model was found to fit well with experimental data. Experimental results suggested that nano-EC can be considered as a suitable nanosorbent for the removal of Cr(VI) and Ni(II) ions from effluents.