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1.
Food Chem ; 454: 139698, 2024 Oct 01.
Article in English | MEDLINE | ID: mdl-38795617

ABSTRACT

Enzymatic browning and microbial growth are two natural phenomena that occur when fruits and vegetables are exposed to abnormal conditions, i.e., temperatures in the range of 12-22 °C, leading to their spoilage. Controlling the temperatures during the supply chain aims to optimize the product's shelf life. Irreversible thermochromic beads were fabricated using a simple extrusion technique containing fatty acid, lecithin, and anthocyanin solution-alginate. The pigmentation durability was adjusted based on electrostatic interactions, as evidenced by the reduction in dye leaching in the case of the produced bead at pH = 6 to less than 0.007 after 45 min. Characterization shows that the chosen combination of fatty acids and the quinonoid molecule is useful for producing thermochromic beads, with a color change at 12 °C-22 °C, from blue to purple. Using the prepared thermochromic beads in the supply chain of fresh-cut salad and brussels sprouts showed a great result for monitoring their freshness after 21 ± 1 min.


Subject(s)
Fatty Acids , Flavonoids , Food Packaging , Lecithins , Lecithins/chemistry , Fatty Acids/chemistry , Food Packaging/instrumentation , Flavonoids/chemistry , Vegetables/chemistry , Fruit/chemistry , Temperature
2.
Int J Biol Macromol ; 260(Pt 2): 129389, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38232882

ABSTRACT

Herein, a new hybrid magnetic core@shell biocomposite was prepared based on an alginate-bentonite core and a chitosan shell layer (mAB@Cs) where magnetic Fe3O4 NPs (50.7 nm) were in-situ generated on the surface via a simple non-thermal co-precipitation approach. The biocomposite has a high ability to magnetically separate and remove organic (ciprofloxacin (CPX)) and seven toxic inorganic (Cu2+, Cd2+, Co2+, Ni2+, Pb2+, Zn2+, and Hg2+) contaminants from simulated wastewater. Experimental results showed a CPX monolayer chemisorption with a Langmuir maximum adsorption capacity of 264.7 mg/g, maintained effectiveness up to the fifth cycle, and high removal rates of heavy metals ranging from 74.89 % to 99.86 % corresponding to adsorption capacities ranging from 12 to 20 mg/g. For a more accurate evaluation, the biocomposite was tested on a real urban wastewater sample (RWW) and it has manifested a noteworthy efficiency in removing a mixture of inorganic pollutants in terms of potassium K+ and orthophosphate phosphorous P-PO43-, and organic matter in terms of biological oxygen demand (BOD) and chemical oxygen demand (COD) with 46 %, 90 %, 84 %, and 64 % removal efficiencies, respectively. On top of this, a high inactivation rate of E. coli of the order of 96 % was recorded, making the prepared magnetic biocomposite adept for the simultaneous removal of emergent wastewater pollutants, from organic, inorganic, to pathogen microorganisms.


Subject(s)
Chitosan , Environmental Pollutants , Metals, Heavy , Water Pollutants, Chemical , Wastewater , Chitosan/chemistry , Alginates , Escherichia coli , Metals, Heavy/chemistry , Adsorption , Magnetic Phenomena , Water Pollutants, Chemical/chemistry , Kinetics , Hydrogen-Ion Concentration
3.
Int J Biol Macromol ; 254(Pt 2): 127867, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37935294

ABSTRACT

In order to enhance the removal of cadmium from phosphoric acid, it is imperative to explore novel resources that may be utilized for the development of highly effective and environmentally sustainable adsorbents. Cellulose beads are composed of naturally occurring polysaccharide fibers and find extensive utilization across several industrial sectors and applications. Within this framework, this research paper presents a green and simple method for producing porous cellulose beads using date palm fibers as the preferred raw material. The innovation lies in immersing the obtained cellulose beads in a Polyvinyl fluoride (PVDF)/N,N-dimethylformamide (DMF) suspension as a coating polymer with different concentrations (2.5, 5, 10 %) to maintain their stability in an acidic environment. The surface of cellulose/PVDF beads were subjected to multiple characterizations like Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), size distribution then pH stability confirming that the coating has been perfectly achieved and conserved well the shape of the beads. The coated cellulose/PVDF-2.5 % underwent evaluation by the process of batch adsorption experiments while different parameters were varied including contact time (5, 10, 20, 30, 60, 90 min), temperature (25, 35, 45 and 55 °C), and adsorbent mass (20, 40, 60, 80 and 100 mg). The obtained ICP data showed that the adsorption rate of Cd (II) from phosphoric acid medium decreased while increasing both temperature from 25 to 55 °C and contact time from 5 to 90 min while adding more adsorbent dosage from 20 to 100 mg enhanced the removal percentage. The cellulose/PVDF-2.5 % was more effective with an adsorption capacity equal to 3.4998 mg/g at optimal conditions including 25 °C as the temperature after 5 min as contact time and by adding a mass 100 mg of the biosorbent while the pH = 2 of the solution is maintained the same. The examined material's adsorption processes proved to be exothermic and non-spontaneous, and it proved that the pseudo-second-order model provided the best match for the cellulose/PVDF-2.5 % beads kinetics data. Furthermore, the cellulose beads exhibited exceptional reusability for up to four repeated cycles without undergoing desorption. The present study offers a viable approach for producing environmentally sustainable biomass-derived adsorbents. Additionally, the study validates the potential of cellulose/PVDF beads as an intriguing material for phosphoric acid decadmiation.


Subject(s)
Cadmium , Water Pollutants, Chemical , Cellulose , Water Pollutants, Chemical/chemistry , Porosity , Adsorption , Kinetics , Hydrogen-Ion Concentration , Spectroscopy, Fourier Transform Infrared
4.
Int J Biol Macromol ; 259(Pt 1): 128893, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38159693

ABSTRACT

In this study, a novel mechanical process was used to produce cellulose beads (CB). These beads were then doped with cobalt ferrite nanoparticles (CoFe2O4 NPs) to serve as catalysts for the degradation of rhodamine B (RhB) through peroxymonosulfate (PMS) activation. The physical and chemical properties of CoFe2O4 and CoFe2O4@CB catalysts were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) combined with energy dispersive X-ray spectrometer (EDX), scanning transmission electron microscopy (STEM) techniques, and thermogravimetric analysis (TGA). To optimize RhB degradation efficiency, Response Surface Methodology (RSM) was employed, utilizing the Box-Behnken design (BBD). Under the optimized conditions of a catalyst dosage of 0.40 g/L, PMS dosage of 0.98 mM, RhB concentration of 40 mg/L, pH of 5.27, and reaction time of 60 min, a remarkable degradation efficiency of 98.51 % was achieved at a temperature of 25 °C. In quenching experiments, 1O2, SO4•-, and HO• species are produced in the CoFe2O4@CB/PMS system, with 1O2, and SO4•- species dominating RhB degradation. Remarkably, the new CoFe2O4@CB catalyst has demonstrated exceptional stability and reusability, validated by recycling tests (up to 78 % of RhB degradation efficiency after a 5-cycle experiment) and subsequent characterizations (FTIR, SEM, and EDX) emphasizing unchanged bands, uniform distribution, and consistent composition after reuse cycles. These results demonstrate the effectiveness of mechanically produced CoFe2O4@CB catalysts for advanced oxidation processes (AOPs), with promising applications in wastewater treatment.


Subject(s)
Cellulose , Nanoparticles , Peroxides , Spectroscopy, Fourier Transform Infrared , Nanoparticles/chemistry , Rhodamines
5.
RSC Adv ; 13(47): 33294-33304, 2023 Nov 07.
Article in English | MEDLINE | ID: mdl-37964908

ABSTRACT

Hemp is known for its swift growth and remarkable sustainability, requiring significantly less water, an adaptable cultivation to a wide range of climates when compared to other fibers sources, making it a practical and environmentally friendly choice for packaging materials. The current research seeks to extract cellulose nanocrystals (CNCs) from hemp fibers using alkali treatment followed by acid hydrolysis and assess their reinforcing capacity in polyvinyl alcohol (PVA) and chitosan (CS) films. AFM analysis confirmed the existence of elongated, uniquely nanosized CNC fibers. The length of the isolated CNCs was approximately 277.76 ± 61 nm, diameter was 6.38 ± 1.27 nm and its aspect ratio was 44.69 ± 11.08. The FTIR and SEM analysis indicated the successful removal of non-cellulosic compounds. Furthermore, the study explored the impact of adding CNCs at varying weight percentages (0, 0.5, 1, 2.5, and 5 wt%) as a strengthening agent on the chemical composition, structure, tensile characteristics, transparency, and water solubility of the bionanocomposite films. Adding CNCs to the CS/PVA film, up to 5 wt%, resulted in an improvement in both the Young's modulus and tensile strength of the bionanocomposite film, which are measured at (412.46 ± 10.49 MPa) and (18.60 ± 3.42 MPa), respectively, in contrast to the control films with values of (202.32 ± 22.50 MPa) and (13.72 ± 2.61 MPa), respectively. The scanning electron microscopy (SEM) images reveal the creation of a CS/PVA/CNC film that appears smooth, with no signs of clumping or clustering. The blending and introduction of CNCs have yielded transparent and biodegradable CS/PVA films. This incorporation has led to a reduction in the gas transmission rate (from 7.013 to 4.159 cm3 (m2 day·0.1 MPa))-1, a decrease in transparency (from 90.23% to 82.47%), and a lowered water solubility (from 48% to 33%). This study is the inaugural effort to propose the utilization of hemp-derived CNC as a strengthening component in the development of mechanically robust and transparent CS/PVA-CNC bio-nanocomposite films, holding substantial potential for application in the field of food packaging.

6.
Water Sci Technol ; 88(2): 408-429, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37522442

ABSTRACT

As the population continues to grow, the preservation of the world's water resources is becoming a serious challenge. The seawater desalination process is considered a sustainable option for the future. The two most common technologies used in desalination are reverse osmosis (RO) and membrane distillation (MD). However, membrane fouling caused by the accumulation of contaminants on the membrane surface is an emerging and growing problem. A pre-treatment stage is required to reach optimal efficiency during the desalination process since this stage is crucial for a successful desalination process. In this regard, the development of new material-based composite membranes has the potential to upgrade the anti-fouling features of RO membranes thereby enhancing desalination efficiency due to their high permeability, hydrophilicity, selectivity mechanical strength, thermal stability, and anti-bacterial properties. The objective of this review is to present various techniques for seawater pre-treatment. The results of the use of several membrane types and methods of modification have also been discussed. The performance of composite membranes for seawater pre-treatment is defined and the future perspectives have been highlighted.


Subject(s)
Membranes, Artificial , Water Purification , Osmosis , Water Purification/methods , Seawater , Permeability
7.
Int J Biol Macromol ; 242(Pt 3): 125077, 2023 Jul 01.
Article in English | MEDLINE | ID: mdl-37236555

ABSTRACT

Biobased packaging is an essential parameter in the pharmaceutical industry. In the present work, bio-composites consisting of high-density polyethylene (HDPE) as a matrix and lignin recovered from argan nut shells as filler were developed to investigate their potential use as packaging materials for vitamin C drugs. The lignin was extracted via alkali and klason processes, and the effects of the extraction method as well as the lignin content on the thermal, morphological, mechanical, and rheological properties of the produced composites, as well as their application for vitamin C packaging, were investigated. Among all the prepared packaging materials, the one with desirable results in pH, color stability, hardness, and mechanical characteristics was based on alkali lignin. It achieved its highest Young's modulus enhancement, 10.12 %, at 10 % alkali lignin loading, while the highest yield strain enhancement (4.65 %) was obtained with 2 % loading. When compared to neat HDPE and HDPE/klason lignin packaging materials, vitamin C solutions packed with this composite showed a lower oxidation rate, attributed to the extremely low pH variation and high color stability of the material, which decreased the rate of vitamin C degradation. According to these findings, HDPE/alkali lignin composite is a promising vitamin C syrup packaging material.


Subject(s)
Lignin , Polyethylene , Polyethylene/chemistry , Lignin/chemistry , Ascorbic Acid , Vitamins , Product Packaging
8.
Environ Sci Pollut Res Int ; 30(25): 67720-67729, 2023 May.
Article in English | MEDLINE | ID: mdl-37115451

ABSTRACT

To selectively remove Cr (III) from synthetic phosphoric acid solution, a chelating ion exchanger was developed through Merrifield resin (MHL) functionalization with diethylenetriamine (DETA). The functional moieties of the grafted Merrifield resin were characterized and confirmed by means of Fourier-transform infrared spectroscopy. The morphological changes before and right after functionalization were visualized with Scanning electron microscopy and enhanced amine content was confirmed via energy dispersive X-ray. To assess the effectiveness of the MHL-DETA in the extraction of Cr (III) from a synthetic phosphoric acid solution, batch shaking adsorption tests were conducted through optimizing different factors such as contact time, metal ion concentration and temperature. According to our findings, higher adsorption was achieved when increasing contact time and decreasing metal ion concentration, while temperature variation doesn't affect much the process. The higher sorption yield was found to be 95.88% attained within 120 min at room temperature without varying the solution's pH. Under optimum conditions (120 min, 25 °C and 300 mg. L-1), the total sorption capacity was reported to be 38.35 mg. g-1. The system's adsorption behavior was found to be consistent with the Langmuir isotherm and the pseudo second-order model accurately described the kinetic data. In this view, Merrifield resin functionalized with DETA could be used as a promising adsorbent material for Cr (III) adsorption from synthetic phosphoric acid medium.


Subject(s)
Chromium , Water Pollutants, Chemical , Chromium/chemistry , DEET , Adsorption , Spectroscopy, Fourier Transform Infrared , Kinetics , Hydrogen-Ion Concentration , Water Pollutants, Chemical/chemistry
9.
Int J Biol Macromol ; 234: 123764, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36805509

ABSTRACT

Smart materials based on biomaterials have been shown growing interest by researchers. This paper investigated pH-indicator film with less leaching containing betalain molecule extracted from red prickly pear fixed in the cellulose-alginate blend as a matrix. Herein, the film was manufactured from a blend containing covalently bounded cellulose with betalain via the creation of a Fischer esterification (FE) to solve the leaching problem of dyes in contact with food. The structural, thermal, morphological optical, and mechanical properties and the pH-sensitive properties of films were examined. The FTIR and color analysis confirmed the fisher esterification. The fisher esterification led to a pH-indicator film with less leaching with significant color stability against UV light. The smart film changes colors with the pH values, where it goes from purple at a pH below 10 to yellow color at a pH above 10. All those proprieties with contact angles helped this film to be used as an intelligent film for monitoring salmon spoilage.


Subject(s)
Betalains , Cellulose , Cellulose/chemistry , Alginates , Food Packaging , Coloring Agents/chemistry , Hydrogen-Ion Concentration , Anthocyanins/chemistry
10.
Carbohydr Polym ; 296: 119972, 2022 Nov 15.
Article in English | MEDLINE | ID: mdl-36088011

ABSTRACT

The UV-protection films based on renewable materials extracted from natural sources are being one of the most interesting targets for the packaging industry. In this paper, the UV-protection films were produced based on modified lignin and cellulose nanocrystals, both were extracted from the Argania nutshell. The lignin was extracted via the alkylation process followed by chemical modification using epichlorohydrin. The chemical modification and the in-use temperature range of the films were investigated via FTIR and TGA, where the chemical modification of lignin improves the thermal property which is an essential parameter during the thermo-sealing of food packaging. On the other hand, the CNCs were extracted via acid hydrolysis treatment with the smallest size around 300 nm generating smooth texture of films. Finally, the produced films were shown a maximum absorption of the UV light in the range of 450-200 nm and great results in food packaging.


Subject(s)
Cellulose , Nanoparticles , Cellulose/chemistry , Food Packaging/methods , Life Expectancy , Lignin/chemistry , Nanoparticles/chemistry
11.
Int J Biol Macromol ; 210: 663-668, 2022 Jun 15.
Article in English | MEDLINE | ID: mdl-35513091

ABSTRACT

In this study, encapsulated modified montmorillonite with alginate (MMT-TBZC16/Alg) content and its incorporation into the biopolymer on morphological, mechanical, rheological, and transport properties of bio-based films based on chitosan were analyzed. The spray-drying approach was used to create organo-modified montmorillonite with alginate as a biopolymer. These encapsulating materials were then described and used as reinforcing agents for chitosan in the second step of this investigation to produce new reinforced biofilms with improved performance. This study aimed to study the effect of the addition of encapsulated organo-montmorillonite into the chitosan solution on the mechanical, rheological, and transport properties of the elaborated films. Films reinforced with encapsulated modified montmorillonite were characterized using Fourier transform infrared spectroscopy (FTIR), Water vapor transmission rate (WVTR) as well as mechanical and rheological properties. Adding encapsulated reinforcing agents to chitosan-based films is an option for improving mechanical and water barrier qualities. These results suggest that the developed MMT-TBZC16/Alginate-based chitosan films with higher performances could be used in designing potential packaging films.


Subject(s)
Chitosan , Food Packaging , Alginates/chemistry , Bentonite/chemistry , Chitosan/chemistry , Clay , Spray Drying
12.
RSC Adv ; 12(14): 8536-8546, 2022 Mar 15.
Article in English | MEDLINE | ID: mdl-35424799

ABSTRACT

In general, during the papermaking process or the production of cellulosic materials for food-packaging applications, lignin and other amorphous components are usually removed via the pulping and multilevel bleaching process to entirely separate them from the fiber. The aim of this work was to study the positive effect that can impart the residual lignin remaining in the alkali-treated fiber surface over bleached fibers to produce an alternative food-packaging cellulosic paper. Herein, cellulosic papers based on alkali-treated and bleached fibers obtained from the Alfa plant were successfully prepared using a compression process. The as-obtained papers were coated by crosslinked starch using a solvent-casting method to improve their mechanical and surface properties. The morphological and contact angle results showed that the residual lignin in the alkali-treated cellulosic papers strongly increased the interfacial adhesion by making the structure denser and more compact, resulting in an improved water resistance property over the bleached ones. On the other hand, it also promoted char formation, slowing down the burning process, resulting in better flame resistance. Additionally, the mechanical properties demonstrated that the presence of lignin contributed to the material rigidity improvement without compromising its flexibility (folding endurance). The as-developed cellulosic papers coated with crosslinked starch could be used for the production of high-quality materials for food-packaging applications using conventional industrial processes.

13.
Int J Biol Macromol ; 200: 182-192, 2022 Mar 01.
Article in English | MEDLINE | ID: mdl-34995656

ABSTRACT

Enormous interest in using marine biomass as a sustainable resource for water treatment has been manifested over the past few decades. Herein, the objective was to investigate the possible use of green macroalgae (Codium tomentosum) for cellulose-based foam production through a versatile and convenient process. Macroporous cellulose monolith was prepared from cellulose hydrogel using freeze-drying process, resulting in a mechanically rigid monolith with a high swelling ratio. The as-produced spongy-like porous cellulosic material was used as bio-sorbent for wastewater treatment, particularly for removing methylene blue (MB) dye from concentrated aqueous solution. The adsorption capacity of MB was subsequently studied, and the effect of adsorption process parameters was determined in a controlled batch system. From the kinetic studies, it was found that the adsorption equilibrium was reached within 660 min. Furthermore, the analysis of the adsorption kinetics reveals that the data could be fitted by a pseudo-second order model, while the adsorption isotherm could be described by Langmuir isotherm model. The maximum adsorption capacity was found to be 454 mg/g. The findings suggested that the produced cellulose monolith could be used as a sustainable adsorbent for water treatment.


Subject(s)
Cellulose
14.
Environ Sci Pollut Res Int ; 28(33): 44638-44666, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34212334

ABSTRACT

For many decades, titanium dioxide (TiO2) semiconductor has been extensively applied in several environmental applications due to its higher photocatalytic performances toward different organic pollutants, pharmaceutical compounds, and bacteria. However, its shortfall response to visible light, and the expeditious recombination rate of the photogenerated electron-hole pairs, hampers its utilization. Doping TiO2 semiconductor with silver nanoparticles is a sound strategy to (1) extend its photocatalytic activity to visible light, (2) prevent the electron/holes pairs recombination due to the formation of the Schottky barrier at the interfaces with TiO2 that act as an electron-trapping center, and (3) enhance its bactericide performances. This review focuses on the recent progress on silver-doped titanium dioxide (Ag/TiO2)-based photocatalysts. It addresses a wide range of Ag/TiO2 synthesis techniques, their physicochemical properties and discusses thoroughly the important role of silver (Ag) nanoparticles in enhancing the removal capacity and antibacterial performances of the Ag/TiO2 photocatalysts.


Subject(s)
Metal Nanoparticles , Silver , Anti-Bacterial Agents/pharmacology , Catalysis , Light , Titanium
15.
Int J Biol Macromol ; 184: 981-989, 2021 Aug 01.
Article in English | MEDLINE | ID: mdl-34197851

ABSTRACT

In the present investigation, novel photoluminescent and transparent biocomposite films based on chitosan reinforced with styrylbenzothiazolium-g-cellulose nanocrystal for anti-counterfeiting applications were successfully prepared by casting solvent. Three novel styrylbenzothiazolium derivatives were synthesized by Knoevenagel condensation and characterized by FTIR, 1H, 13C NMR and photoluminescence analysis. These photochromic compounds have been used to functionalize cellulose nanocrystal and the resulting fluorescent photonic materials were characterized by FTIR, 13C-CP/MAS NMR as well as photoluminescent analysis to confirm the successful grafting. It can be concluded that the addition of 5 wt% of fluorescent modified CNC to chitosan matrix increase the photoluminescent properties as well as improved the mechanical properties of the Cs/CNC-dye biocomposite films. These photoluminescent biocomposite film hold promising applicative value in anti-counterfeiting material in large-scale.


Subject(s)
Cellulose/chemistry , Chitosan/chemistry , Styrenes/chemistry , Carbon-13 Magnetic Resonance Spectroscopy , Nanocomposites , Nanoparticles , Proton Magnetic Resonance Spectroscopy , Spectroscopy, Fourier Transform Infrared
16.
Environ Sci Pollut Res Int ; 28(11): 14018-14027, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33201510

ABSTRACT

To overcome the titanium oxide limitations, Fe2O3- and Fe3O4-modified TiO2 (3:1) nanoparticles were synthesized by a humid and solid path, respectively. These nanoparticles were embedded in sodium alginate biopolymer to prepare beads with efficient adsorption and photocatalytic behaviors in cationic dye degradation under both UV and visible irradiations. Operating conditions were investigated such as initial methylene blue (MB) concentration and contact time to evaluate their impact on the process. The bead recycling was also scrutinized. We have come to the conclusion that Fe2O3-modified TiO2-Alg displayed superiorities, including expanded responsive wavelength range in the visible region (up to 700 nm), narrower band gap (1.79 eV), and better efficiency for MB removal in terms of adsorption capacities and photocatalytic effectiveness under both UV and visible irradiations. Furthermore, these beads can be effortlessly recovered from the reaction medium after the photocatalytic process and reused up to 5 cycles without any noteworthy decline in their initial properties.


Subject(s)
Iron , Titanium , Adsorption , Catalysis
17.
Curr Microbiol ; 78(1): 86-94, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33104853

ABSTRACT

This study aims to develop new formulations for microbial fertilizers Pseudomonas fluorescens Ms-01 (Pf) and Azosprillum brasilense DSM1690 (Ab) using two kinds of clay minerals. The studied formulations were prepared as hybrid materials based on halloysite and alginate [Ha-Ag] or montmorillonite and alginate polymers [Mt-Ag] and were applied to the bacterial strains to develop low cost, efficient, and slow-release capsules. Their efficiency was evaluated in comparison with alginate [Ag] as the control. The produced capsules were spherical in shape and were chemically and physically characterized and further analyzed for their swelling ratios, soil biodegradability, release kinetics of microbial cells, and their survival stability over 3 months of storage under different conditions (room temperature vs 4 °C). The effect of the capsules on the growth of wheat plants was also investigated. Results showed that both formulations were able to preserve bacterial survival which reached 14.8 log CFU g-1 after 3 months storage in the halloysite formulation. The swelling ratios were ranged between 61.5 ± 1.35% and 36.5 ± 5% for the montmorillonite and the halloysite formulations, respectively. The release kinetics revealed the slow-release capacity of the capsules mainly with the halloysite formulation which significantly released bacterial cells after 15 days of incubation in saline water (15.24 log CFU mL-1). The application of the capsules to wheat plants significantly increased root and shoot biomasses and nitrogen content in the roots. In conclusion, halloysite minerals seem to be more adapted as additive to alginate in microbial encapsulation.


Subject(s)
Alginates , Fertilizers , Bentonite , Capsules , Clay
18.
Carbohydr Polym ; 245: 116506, 2020 Oct 01.
Article in English | MEDLINE | ID: mdl-32718617

ABSTRACT

Fiber-reinforced polymers have emerged as one of the most popular methods to improve the polymers' characteristics owing to their prominent properties. This study aimed to investigate the properties of cellulose microfibers (CMF), cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF) extracted from hemp stalks, then their effect as reinforcement for the PVA-polymer. CMF have been extracted from hemp stalks with a diameter and yield of 16.96 µm and 63 %, respectively. Needle-shaped CNC were obtained from CMF using sulfuric acid hydrolysis at two hydrolysis times, while CNF exhibited a web-like structure obtained using TEMPO-oxidation followed by mechanical treatment. Cellulose derivatives were utilized to develop cellulose-based PVA composites; their transparency, chemical structure, thermal stability and mechanical properties were investigated. The incorporation of nanocellulose demonstrated a significant increase in mechanical properties compared to the neat PVA. The extracted nanocellulose could be used as nanofillers for the preparation of transparent and mechanically strong PVA-based nanocomposites.

19.
Int J Biol Macromol ; 162: 136-149, 2020 Nov 01.
Article in English | MEDLINE | ID: mdl-32561278

ABSTRACT

With the growing environmental concerns and an emergent demand, a growing attention is turned to eco-friendly superabsorbent hydrogels instead of synthetic counterparts. Hydrogels based on cellulose derivatives can absorb and retain a huge amount of water in the interstitial sites of their structures, stimulating their uses in various useful industrial purposes. In this work, cross-linked superabsorbent composite hydrogel films (CHF) were designed, manufactured and characterized, by taking advantage of the combination of carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC) and newly developed regenerated cellulose (RC) spheres. RC with sphere-like shape was successfully prepared using a green method based on cold phosphoric acid-mediated dissolution of microcrystalline cellulose (MCC) followed by regeneration process using water as anti-solvent. Prior to be used, the morphological and structural properties of RC spheres, with an average diameter of 477 ± 270 nm, were examined by SEM, AFM, XRD, FTIR and TGA techniques. CHF crosslinked with citric acid were, in fact, prepared by solvent casting method with different RC weight fractions (i.e. 0, 2.5, 5, 10 and 15 wt%), then the crosslinking reaction was triggered by thermal treatment at 80 °C during 8 h. Prepared CHF were then characterized in terms of their structural, thermal, tensile and transparency properties. Swelling tests were carried at three different aqueous media (i.e. with a pH = 3, 6.4 or 11) to evaluate the water retention capacity of hydrogel films, as well as, the pH effect on their swelling and hydrolytic degradation properties. Collected results reveal that CHF with low RC content (i.e. RC weight fraction of 2.5 or 5 wt%) have the best tensile and swelling properties, with a tensile strength and a swelling capacity (at pH = 6.4) up to 95 MPa and 4000%, respectively.


Subject(s)
Cellulose/chemistry , Hydrogels/chemistry , Phosphoric Acids/chemistry , Carboxymethylcellulose Sodium/chemistry , Cellulose/analogs & derivatives , Cellulose/ultrastructure , Hydrogels/chemical synthesis , Hydrogen-Ion Concentration , Hydrolysis , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Phosphorus/chemistry , Solvents/chemistry , Spectroscopy, Fourier Transform Infrared , Tensile Strength , Water/chemistry , X-Ray Diffraction
20.
Int J Biol Macromol ; 148: 316-323, 2020 Apr 01.
Article in English | MEDLINE | ID: mdl-31931055

ABSTRACT

In this study, the coated date palm fiber (Dpf) trays were developed using new non-toxic, and eco-friendly materials which are date palm fibers coated with a bio-composite of modified clay (Mt-Tbz). The thiabendazolium was intercalated in the interlayer space of montmorillonite and used in order to enhance the biological properties of final materials. This material was prepared as bilayer material, the first layer contains the treated palm fibers and the second one composes of bio-composite films through coating process. The elaborated coated Dpf trays were characterized using several techniques. The morphological characterization of the Dpf trays and coated Dpf trays (Dpf@Cs/Mt-Tbz), show a better dispersion/distribution of chitosan/montmorillonite modified thiabendazolium salt based coating bio-composite on the fibers surface, these results can improve the mechanical properties of the new coated Dpf trays in term of Young's modulus from 330 MPa to 1035 MPa and tensile strength from 0.5 MPa to 4 MPa. In addition, their inhibitory effect against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa has been investigated. Furthermore, the coating layer increase also the surface hydrophobicity compared to uncoated trays. The present study suggests that the elaborated coated Dpf trays can be used as potential bilayer material in the smart packaging industry.


Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Bentonite/chemistry , Chitosan/chemistry , Dietary Fiber/metabolism , Phoeniceae/chemistry , Escherichia coli/drug effects , Food Packaging/methods , Hydrophobic and Hydrophilic Interactions , Nanocomposites/chemistry , Pseudomonas aeruginosa/drug effects , Staphylococcus aureus/drug effects , Tensile Strength
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