Subjects -> ENVIRONMENTAL STUDIES (Total: 913 journals)
    - ENVIRONMENTAL STUDIES (810 journals)
    - POLLUTION (31 journals)
    - TOXICOLOGY AND ENVIRONMENTAL SAFETY (54 journals)
    - WASTE MANAGEMENT (18 journals)

POLLUTION (31 journals)

Showing 1 - 27 of 27 Journals sorted alphabetically
Aerosol Science and Engineering     Hybrid Journal  
Aerosol Science and Technology     Hybrid Journal   (Followers: 13)
Archives of Environmental Protection     Open Access   (Followers: 3)
Atmospheric Pollution Research     Hybrid Journal   (Followers: 2)
Ciencias Marinas     Open Access   (Followers: 3)
Current Pollution Reports     Hybrid Journal  
Emerging Contaminants     Open Access   (Followers: 1)
Energy and Emission Control Technologies     Open Access   (Followers: 3)
Environmental Chemistry and Ecotoxicology     Open Access  
Environmental Pollutants and Bioavailability     Open Access  
Exposure and Health     Hybrid Journal  
Greenhouse Gases : Science and Technology     Hybrid Journal   (Followers: 4)
Hidrobiológica     Open Access  
Journal of Air Pollution and Health (رتبه علمی- پژوهشی)     Open Access  
Journal of Energy, Environment & Carbon Credits     Full-text available via subscription   (Followers: 4)
Journal of Hazardous, Toxic, and Radioactive Waste     Full-text available via subscription   (Followers: 6)
Journal of Limnology     Open Access   (Followers: 6)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Journal of the Air & Waste Management Association     Hybrid Journal   (Followers: 4)
Jurnal Pengendalian Pencemaran Lingkungan     Open Access  
Latin American Journal of Aquatic Research     Open Access  
Microplastics and Nanoplastics     Open Access   (Followers: 1)
Open Journal of Air Pollution     Open Access   (Followers: 4)
Pollution     Open Access  
Revista Internacional de Contaminación Ambiental     Open Access  
Water, Air, & Soil Pollution : Focus     Hybrid Journal   (Followers: 7)
Water, Air, & Soil Pollution     Open Access   (Followers: 21)
Similar Journals
Journal Cover
Journal of Polymers and the Environment
Journal Prestige (SJR): 0.562
Citation Impact (citeScore): 2
Number of Followers: 1  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1566-2543 - ISSN (Online) 1572-8919
Published by Springer-Verlag Homepage  [2469 journals]
  • Structural Elucidation and Immunostimulatory Activities of Quinoa
           Non-starch Polysaccharide Before and After Deproteinization

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      Abstract: Non-starch polysaccharides derived from natural resources play a significant role in the field of food science and human health due to their extensive distribution in nature and less toxicity. In this order, the immunostimulatory activity of a non-starch polysaccharide (CQNP) from Chenopodium quinoa was examined before and after deproteination in murine macrophage RAW 264.7 cells. The chemical composition of CQNP and deproteinated-CQNP (D-CQNP) were spectrometrically analysed that revealed the presence of carbohydrate (22.7 ± 0.8% and 39.5 ± 0.8%), protein (41.4 ± 0.5% and 20.8 ± 0.5%) and uronic acid (8.7 ± 0.3% and 6.7 ± 0.2%). The monosaccharide composition results exposed that CQNP possesses a high amount of arabinose (34.5 ± 0.3) followed by galactose (26.5 ± 0.2), glucose (21.9 ± 0.3), rhamnose (7.0 ± 0.1), mannose (6.0 ± 0.1) and xylose (4.2 ± 0.2). However, after deproteination, a difference was found in the order of the monosaccharide components, with galactose (41.1 ± 0.5) as a major unit followed by arabinose (34.7 ± 0.5), rhamnose (10.9 ± 0.2), glucose (6.6 ± 0.2), mannose (3.4 ± 0.2) and xylose (3.2 ± 0.2). Further, D-CQNP potentially stimulate the RAW 264.7 cells through the production of nitric oxide (NO), upregulating inducible nitric oxide synthase (iNOS) and various pro-inflammatory cytokines including interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α). Moreover, stimulation of RAW 264.7 cells by D-CQNP takes place along the NF-κB and the MAPKs signaling pathways through the expression of cluster of differentiation 40 (CD40). This results demonstrate that RAW 264.7 cells are effectively stimulated after removal of the protein content in C. quinoa non-starch polysaccharides, which could be useful for develop a new immunostimulant agent. Graphical
      PubDate: 2022-06-01
       
  • Ionically Crosslinked Chitosan/Tragacanth Gum Based Polyelectrolyte
           Complexes for Antimicrobial Biopackaging Applications

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      Abstract: The novel polyelectrolyte complexes (PEC) were prepared by mixing different Wt% of Tragacanth gum (TG) to Chitosan (CS) and systematic evaluation of multifunctional properties of colloidal solution and films was carried out. The formation of PEC was dependant on the order of mixing of solutions. Particle size analysis, Zeta potential and FTIR confirmed the formation of PEC. SEM studies revealed the homogeneous distribution of colloidal particles on the surface. Contact angle analysis, water solubility, and moisture adsorption studies revealed the hydrophobicity of films. Further, the water vapor transmission rate and oxygen permeability of the control film was improved significantly and found to be in the range of polyethylene terephthalate by ionic crosslinking of TG and CS. Ionic crosslinking significantly enhanced antibacterial, antioxidant activity and rate of degradation in soil. Obtained biofilms exhibited far better preservation ability than commercial polyethylene films. Hence, biofilms could be used in antimicrobial packaging applications. Graphical
      PubDate: 2022-06-01
       
  • Physical Properties of Cured Self-green Epoxidized Natural Rubber with
           Amino Acid

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      Abstract: Abstract The environmental-friendly and sustainable development is a top concern of rubber industry. Here we reported a green method to fabricate a class of epoxidized natural rubber (ENR) by employing many amino acids as a self-crosslinker. Moreover, the covalent crosslinks result in strong interfacial interaction between plant amino acid (PAA) and ENR, enabling exceptional reinforcement of the rubber matrix. Moreover, the cured ENR/PAA blend exhibits good oil or methanol resistance. The chemical structure of the cured ENR/PAA blend was also confirmed by FTIR. The moisture content and moisture absorption of this sample enhanced after the addition of the PAA in the ENR. The elongation at break of this specimen was improved after the addition of the PAA. After use, this sample easily decomposed in natural soil. Consequently, amino acid self-crosslinked ENR manifests excellent toluene resistance. The cured ENR/PAA blend gel offers cost-effective, good performance for oil uptakes with great reusability, which is up to reach 20 times. With no carcinogenic and environmentally toxic additives included, this work provided a new strategy to prepare high-performance green rubber composites without pollution.
      PubDate: 2022-06-01
       
  • Reinforcing Paper Strength with High Viscosity Aminated Cellulose
           Nanocrystal by Forming Nanocrystal Networks

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      Abstract: Abstract Higher tensile and bursting strength are paramount concerns in paper-based packaging materials. Herein, the aminated cellulose nanocrystal (A-CNC) was synthesized by the amination reactions firstly, and the base paper was reinforced via coating hydroxypropyl methylcellulose (HPMC) and A-CNC. The surface morphology and tensile strength of the coated composite paper were characterized and the rheological performance of A-CNC was also investigated. The results clearly demonstrated that coating of HPMC/A-CNC significantly increased the dry tensile strength of composite paper by 1.035 times (32.88 MPa) as compared with base paper (16.16 MPa). In addition, the paper strength as coated with A-CNC was also higher than that of unmodified CNC, which was attributed to the improvement of viscosity of A-CNC. The composite papers coated HPMC/A-CNC showed a great potential in packaging applications with higher mechanical strength.
      PubDate: 2022-06-01
       
  • Characterization of Lipopeptides Biosurfactants Produced by a Newly
           Isolated Strain Bacillus subtilis ZNI5: Potential Environmental
           Application

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      Abstract: Abstract Aiming the production of lipopeptides biosurfactants (BioS), we isolated a new strain identified as Bacillus subtilis ZNI5 from a hydrocarbon contaminated soil. Lipopeptides purification by anionic exchange chromatography and identification by Reverse Phase High Performance Liquid Chromatography–Mass Spectrometry (RP-HPLC–MS) permitted the selection of different homologues divided into four families. The first family corresponds to Surfactin isoforms with molecular weights of 1007, 1021 and 1035 Da; the second family correspond to Iturin isoforms with molecular weights of 1028, 1042 and 1056 Da; the third family correspond to a single isoform called Licheniformin with molecular weight of 1410 and the fourth family correspond to newly identified isoforms named Inesfactin with molecular weights of 973 and 987 Da. Regarding the functional properties of the ZNI5 BioS, it was characterized as a powerful surface-active agent that decreases the Surface Tension of water from 72 mN/m to about 32 mN/m with a CMC value of 350 mg/L more efficient than chemical surfactants (Triton X100; CTAB and SDS). Moreover, it has the capacity to disperse oil to about 80 mm at a concentration of 800 mg/L showing close efficiencies to the listed chemical surfactants. In addition, the physic–chemical characterization of the surface activities of ZNI5 BioS showed great thermal, pH and salts activity and stability enabling its use in the bioremediation fields and for diverse industrial applications.
      PubDate: 2022-06-01
       
  • Electrospun Composite Nanofibers Based on Poly (ε-Caprolactone) and
           Styrax Liquidus (Liquidambar orientalis Miller) as a Wound Dressing:
           Preparation, Characterization, Biological and Cytocompatibility Results

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      Abstract: Abstract In this study, styrax liquidus (sweet gum balsam) extracted from Liquidambar orientalis Mill. incorporated PCL fibrous scaffolds were prepared using the electrospinning method. The effects of the styrax liquidus content on the prepared scaffolds were investigated using different physico-chemical and morphological analyses. Then, the styrax-loaded nanofibers were examined for their antioxidant activity, anti-biofilm, metal chelating, antimicrobial and DNA cleavage properties. The results obtained from these studies showed that the nanofibers exhibited effective biological activity depending on the weight ratio of the styrax liquidus. In light of the data obtained from the characterization and biological studies, a sample with high ratio of balsam was built for determining the cytocompatibility analysis in vitro. The cytotoxicity studies of the selected membrane were conducted using mouse embryonic fibroblast cells. The fibrous scaffolds lead to increase the cell number as a result of high viability. According to the results, we propose a novel biocompatible electrospun hybrid scaffold with antioxidant and antimicrobial properties that can be used as wound healing material for potential tissue engineering applications.
      PubDate: 2022-06-01
       
  • Improving the Antibacterial Activity of Curcumin Loaded Nanoparticles in
           Wastewater Treatment by Enhancing Permeability and Sustained Release

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      Abstract: In this research, the antibacterial effect of curcumin entrapped in polymeric nanoparticles (mPEG-PCL/curcumin) on resistant bacteria were investigated. Ring-opening polymerization method was used for the synthesis of mPEG-PCL copolymers at 120 °C. mPEG-PCL and Sn (Oct)2 were used as initiator/catalyst respectively. Curcumin loaded polymeric nanoparticles were prepared using the nanoprecipitation method. The particle size and zeta potential of mPEG-PCL/curcumin were found to be 111.16 ± 3.26 nm and − 5.67 ± 5.26 mv, respectively. TEM, AFM, FTIR and DSC were used to determine the structure of polymeric nanoparticles. The impact of mPEG-PCL/curcumin on wild (w) and standard (s) strains in bacterial media was assessed through the procedures of turbidity assay and colony-forming based on units per milliliter (CFU/mL). The impact of mPEG-PCL/curcumin on wild (w) strains in main wastewater was assessed by colony-forming based on units per milliliter (CFU/mL). mPEG-PCL/curcumin at a concentration of 40 µM had a stronger effect on wild strains of bacteria at 37 °C. However, examination of the performance of mPEG-PCL/curcumin in wastewater showed that mPEG-PCL/curcumin can reduce the total microbial total count at a concentration of 0.125 µM and at 25 °C. Graphical
      PubDate: 2022-06-01
       
  • Optimization and Characterization of Bioactive Biocomposite Film Based on
           Orange Peel Incorporated with Gum Arabic Reinforced by Cr2O3 Nanoparticles
           

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      Abstract: Abstract In this paper, the effect of adding gum arabic at levels of 0–5%, and chromium oxide nanoparticles (Cr2O3 NPs) at levels of 0–3%, were optimized on orange peel-based films by response surface methodology. The obtained results reveal a significant increase in water vapor permeability, weight loss, tensile strength, and Young's modulus of film samples by increasing the percentage of both gum and nanoparticles (p < 0.05). Moreover, the addition of gum arabic and Cr2O3 NPs decreases the thickness, water-solubility, L*, a*, b* indexes while increasing the elongation to the breaking point. Furthermore, the moisture content of the film samples was decreased by the addition of nanoparticles, however, the addition of gum arabic increased this parameter. The obtained results from the morphology of the samples indicated an increase in both roughness and cracks by increasing the percentage of nanoparticles as well as creating a smooth surface with the addition of gum arabic. Besides, the results of Fourier-transform infrared spectroscopy revealed no new peak in the prepared samples, as compared to the control sample. The results of X-ray diffraction indicated that the addition of gum arabic and nanoparticles simultaneously caused the formation of new crystals and increasing the crystallinity of the films. Based on Thermogravimetric analysis results, the thermal stability of films containing the nanoparticles increased, as compared to the control sample. In the meantime, the addition of gum and nanoparticles increased the antimicrobial properties of the film samples, as compared to the control. Overall, those films created by the orange peel including gum arabic and Cr2O3 NPs could enhance the mechanical properties and water vapor permeability of the samples.
      PubDate: 2022-06-01
       
  • Design of Polyhydroxyalkanoate (PHA) Microbeads with Tunable Functional
           Properties and High Biodegradability in Seawater

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      Abstract: Abstract Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) were used to prepare microbeads, with diameter ranging from 50 to 100 µm, by an emulsion-evaporation process. The emulsification-evaporation process enables the formation of spherical polyhydroxyalcanoate beads, with crystalline rates similar to the ones of the former polymer and with important surface roughness as compared to amorphous polylactic acid smooth beads. The mechanical properties of the different PHA beads are also found to be intimately linked with their crystalline content, with modulus varying between 1 and 7 GPa. The degradation behavior of these PHA microbeads was tested under marine environment and revealed a rapid degradation, similar to cellulose, and a degradation rate correlated with the crystalline content. These results emphasize the possibility and interest in developing PHA materials with tunable functions and degradation properties.
      PubDate: 2022-06-01
       
  • Starch-Chitosan Hydrogels for the Controlled-Release of Herbicide in
           Agricultural Applications: A Study on the Effect of the Concentration of
           Raw Materials and Crosslinkers

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      Abstract: Abstract Present work aims to synthesize the herbicide-loaded bio-based hydrogels and study the release mechanism. The different ratios of starch and chitosan were chosen as the bio-based resources to form the hydrogel matrix with varying concentrations of two crosslinkers. The synthesized hydrogels were characterized using Fourier transform infrared spectroscopy for reaction completion. Thermogravimetric analysis provided information about the obtained hydrogels’ thermal stability, suggesting the tremendous positive impact of chitosan concentration. Differential scanning calorimetry was done to know the initial trapped water release from the hydrogel matrix and relate the structures with the release rate study. Further, scanning electron microscopy revealed the morphology of the obtained hydrogels and could establish the relation with the corresponding hydrogel structures. The equilibrium swelling degree, release dynamics of atrazine, and diffusion mechanism have also been evaluated. The swelling significantly affected the release behavior, and the hydrogels prepared with glyoxal showed the lowest release rate of atrazine, the release vitality reaching 500 h. Until the concentration of starch and chitosan were equal, release followed the Fickian diffusion mechanism, and as soon as the concentration of chitosan increased, non-Fickian diffusion proceeded.
      PubDate: 2022-06-01
       
  • Amylose Modified Starches as Superabsorbent Systems for Release of
           Potassium Fertilizers

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      Abstract: Abstract High-amylose maize starch (AS) was modified by graft copolymerization with sodium acid maleate and disodium maleate, using the KMnO4-NaHSO3 redox system, and covalently crosslinked with N,N'-bismethylene acrylamide in inverse suspension polymerization process. The resulting modified starches were evaluated as absorbent materials for release fertilizers. Firstly, AS was obtained by leaching from native maize starch and posterior precipitation in ethanol. The gelatinized AS, comonomers, redox pair and crosslinker were dissolved in distilled water, which was used as dispersed phase; while paraffin oil was used as the continuous phase and sorbitan esters as stabilizers. In the reacions, parameters such as the AS amount of 10 wt%/v with respect to the dispersed phase; the degree of neutralization of maleic acid of 80%; the ratio [NaHSO3]/[KMnO4] of 2.6; the ratio between crosslinker and comonomers of 8.9 × 10–4; the stirring speed of 250 rpm; the reaction temperature at 60 °C; and a reaction time of 3 h, were kept constant. All the resulting amylose modified starches were characterized by potenciometric titration, X-ray diffraction and scanning electronic microscopy. The absorption capacity of these materials was studied by analyzing their swelling in various media and different pHs. Finally, the amylose modified starches were evaluated as systems for release fertilizers by measuring the loaded and released amount of fertilizer by gravimetry and conductimetry, respectively.
      PubDate: 2022-06-01
       
  • Extraction of Silk Fibroin with Several Sericin Removal Processes and its
           Importance in Tissue Engineering: A Review

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      Abstract: Abstract Sericin is a sticky protein substance, which is generated by the silk-worm for holding the filaments of silk tightly. The main constituent of natural crude silk is made up of sericin and fibroin. Fibroin and sericin play a vital role in increasing the strength, stiffness and on maintaining the constructional integrality of the cocoon. This review reports the role of several types of degumming agents for the removal of sericin from silk surfaces and an overview of silk fibroin approaches in the tissue engineering field. The prime factors responsible for the removal of sericin (degumming) from silk were systematically analyzed and discussed. The key factors affects on modification of the silk surface are includes surfactant, degumming time, temperature, advanced techniques such as ultra-sonication, microwave radiation, infrared radiation, low-temperature oxygen plasma radiation, and PH. These factors influence either individually or cumulatively at the degumming process. Tissue engineering is an emanate and most optimistic approach to restore tissue malfunction by adopting the concept of the technology being practiced using numerous biomaterials, cells, and the nutrient-specific growth factors. Different types of materials include various bio-material and mainly of silk fibroin constituent of it is conceding most optimistic biomaterials in tissue engineering application. Silk fibroin is a naturalistic protein-based polymer with an eminent physiochemical characteristic, are magnificent biocompatibility, amenable biodegradability, proper oxygen, and water-vapor permeability, and least inflammatory reaction. The critical studies accomplishing on the role of Silk fibroin and various approaches adopted in the degumming process is extensively reviewed and reported.
      PubDate: 2022-06-01
       
  • Recyclable Clay-Supported Heteropolyacid Catalysts for Complete Glycolysis
           and Aminolysis of Post-consumer PET Beverage Bottles

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      Abstract: Abstract In this investigation, the use of phosphotungstic acid (PWA) and phosphomolybdic acid (PMA) as well as Zn2+ containing kaolin and bentonite explored for chemical recycling of post-consumer poly(ethyleneterephthalate) (PET) wastes have been explored. The clay supported catalysts containing 5wt% of the metals and heteropolyacids (HPAs) synthesized using wet impregnation method. Nitrogen adsorption and desorption studies, SEM–EDX mapping, powder XRD, FTIR and XPS analysis have evaluated effect of metal ions and HPAs loading on the surface area, pore volume, elemental composition and crystalline nature. Total surface area of BET increased with a loading of 5 wt% of Zn2+, PWA and PMA on kaolin and bentonite, while the pore volume and pore diameter remain unchanged. SEM and EDAX mapping images showed that the heteropolyacids crystals are well dispersed on the surface and occupied interlayer spaces of the clay support. SEM–EDX showed that bentonite showed a better loading of PWA and PMA compared to kaolin. PET waste water bottles collected from the local market used for the chemical recycling process. The aminolysis reaction using Zn2+ and PWA loaded on bentonite showed complete depolymerisation of PET wastes to produce 87–98% of BHETA. The glycolysis reaction using the above catalysts showed complete depolymerisation at 180–210 °C and yielded 78–90% of BHET. When comparing the clay, bentonite performed well in terms of heteropolyacid loading and afforded a higher yield of BHET and BHETA because of higher loading of Zn and HPA, as supported by SEM–EDX and XPS. We also examined reusability of the catalysts for glycolysis.
      PubDate: 2022-06-01
       
  • Development and Characterization of the Reinforced Soy Protein
           Isolate-Based Nanocomposite Film with CuO and TiO2 Nanoparticles

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      Abstract: Abstract The present study aimed to develop and characterize the soy protein isolate (SPI) nanocomposite film incorporated with CuO and TiO2 nanoparticles (NPs) for application as an active packaging system. The morphology study of films showed that the incorporation of NPs caused the formation of a dense and compact structure. The creation of interactions among SPI matrix and NPs was approved via Fourier transforms infrared structural conformations. The mechanical properties of SPI-based film were improved through the incorporation of NPs. The film sample incorporated with CuO and TiO2 NPs at 1% of concentration showed the lowest water vapor permeability, moisture content, and water solubility. Additionally, the incorporation of both NPs provided antioxidant activity in the SPI-based films. The L* color parameter was significantly (p < 0.05) decreased with the incorporation of NPs, but the a* and b* color parameters were increased. Moreover, the incorporation of CuO and TiO2 NPs increased the opacity in the SPI-based films. In conclusion, the incorporation of CuO and TiO2 NPs provided suitable physicochemical properties for SPI-based films and the developed nanocomposite films could be applied as an active packaging system for different foodstuffs.
      PubDate: 2022-06-01
       
  • Hydrophobic and Flame-Retardant Foam Based on Cellulose

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      Abstract: Abstract A study aimed to prepare cellulose-based hydrophobic, lightweight, and flame retardant foam composites. Cellulose was activated by phosphoric acid followed by blending with dolomite clay of different loading ratios. Gelatin/tannin as an adhesive system was used as a binder. A solution of the environmentally friendly silicone rubber (RTV) was applied onto foam samples via spray-coating to improve their water repealing performance, which was explored by investigating both of water contacting angle and wettability time of the coated foam samples. Flammability characteristics, thermal decomposition, surface morphology, and chemical structure of treated and untreated foams were investigated by flammability test, thermogravimetric analysis, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared. The fire retardancy of foam composites was optimized at low and medium loading of dolomite. Also, the addition of RTV improved the hydrophobicity of composites maintained the fire retardancy of composites with medium loading.
      PubDate: 2022-06-01
       
  • Curcumin- A Bio-based Precursor for Smart and Active Food Packaging
           Systems: A Review

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      Abstract: The current scenario of global trends impacts the way in which food is consumed and packed, meaning that change is inevitable and just around the horizon in terms of making food packaging eco-friendlier and more sustainable. Scientific advancements over the past decades have led to a wide spectrum of solutions to this problem in terms of smart, active, and antimicrobial packaging systems. The increasing demand for sustainability paves the way as a golden opportunity for these systems as they have the ability to incorporate biobased precursors like curcumin through advancements in the field of the invisible enabler, biochemistry. Investigating the properties of curcumin as a bioagent can change the dynamics of the current food packaging industry, owing to its non-toxic and eco-friendly nature and a plethora of pharmacological properties. Curcumin is the principal curcuminoid of the golden spice turmeric. Being derived from a ferulic acid, it shows excellent antimicrobial properties against bacterial pathogens like Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli, and fungal cultures such as Penicillium spp. and Candida albicans. This makes it a potential agent in the food packaging industry and used as a natural food additive, dietary supplement, and pH indicator. Curcumin encapsulation has been explored with polymer matrices like polyvinyl alcohol [PVOH], low-density polyethylene [LDPE], polyvinyl acetate [PVAC], polylactic acid [PLA], etc. It has also been studied with metals like zinc as a complex which demonstrated an increase in the bioavailability of curcumin. This article aims to further explore the potential applications of curcumin in eco-friendly and antimicrobial packaging systems, and understand its importance as a bioagent. Graphical
      PubDate: 2022-06-01
       
  • Development of Cellulose from Sugarcane Bagasse and Polyacrylamide-Based
           Hydrogel Composites by Gamma Irradiation Technique: A Study of
           Controlled-Release Behavior of Urea

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      Abstract: Cellulose was successfully purified from sugarcane bagasse by gamma irradiation technique. The crystallinity of cellulose was reduced by gamma irradiation. After that, irradiated cellulose fiber and polyacrylamide hydrogel composite was successfully prepared by means of gamma irradiation technique. The dose of gamma ray was set to be 15, 30, 60 and 90 kGy at room temperature in air. No significant change on structural properties was observed by Fourier transform infrared and X-ray diffraction technique. The existence of porosity was observed by scanning electron microscope. The presence of cellulose was existed in between polyacrylamide network. With the increment on gamma ray dose, pore size and swelling behavior were subsequently decreased. Thermogravimetric analysis reported that hydrogel was thermally stable up to 300 °C. In addition, the release behavior was rapid within 4 h and then it was stable. It was remarkable to note that irradiated cellulose and polyacrylamide hydrogel composite exhibited outstanding properties as a candidate in agricultural farm. Graphical
      PubDate: 2022-06-01
       
  • Enhanced Functional Properties of Biodegradable Polyvinyl
           Alcohol/Carboxymethyl Cellulose (PVA/CMC) Composite Films Reinforced with
           l-alanine Surface Modified CuO Nanorods

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      Abstract: Herein, we described novel biogenic preparation of the CuO nanorods and its surface modification with l-alanine amino acid accelerated by microwave irradiation. The effect of surface functionalized CuO nanorods on the physico-mechanical properties of polyvinyl alcohol/carboxymethyl cellulose films were investigated through various characterization techniques. The tensile strength was improved from 28.58 ± 0.73 to 43.40 ± 0.93 MPa, UV shielding ability and barrier to the water vapors were highly enhanced when PVA/CMC matrices filled with 8 wt% of CuO-l-alanine. In addition, the prepared films exhibited acceptable overall migration limit and readily undergoes soil burial degradation. Nevertheless, CuO-l-alanine incorporated films showed potent antioxidant activity against DPPH radicals and had high antibacterial activity against Staphylococcus aureus and Escherichia coli, and antifungal activity against Candida albicans and Candida tropicalis. Furthermore, the nanocomposite films showed negligible cytotoxic effect on HEK293 and Caco-2 cell lines. In these contexts, the developed nanocomposite films can be implementing as an active food packaging material. Graphical
      PubDate: 2022-06-01
       
  • Polymers, the Light at the End of Dark Fermentation: Production of
           Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by a Photoheterotrophic
           Consortium

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      Abstract: Abstract In this study, the photoheterotrophic consortium C4 was used to produce the copolymer [P(3HB-co-3HV)]. PHA production was enhanced by using response surface methodology (RSM) to determine the effects of different concentrations of acetate and butyrate in mixtures (0.5–3 g L−1), ammonium sulfate and their combinations. This is relevant because PHA accumulation is stimulated by nitrogen limitation. The type and concentration of the substrate determines the monomeric composition and the PHA content (% per cell dry mass (CDM)). The RSM, carbon balance and metabolic behavior analysis results showed that at the lowest ammonium concentration, 0.1 g L−1, and when acetate was in a higher proportion than butyrate, biomass production was favored. In contrast, when the butyrate proportion was high, PHA production increased, reaching a highest production of 58% per CDM. The better conditions were evaluated in a 3-L reactor, and a maximum P(3HB-co-3HV) of 67% was determined. The predominant microbial population consisted of four major species, Macelibacteroides fermentans (37%), Rhodopseudomonas palustris (22%), Acinetobacter sp. (35%), and Clostridium propionicum (2%). Insights into the understanding of copolymer production by photoheterotrophic mixed cultures constitute the basis for developing coupled processes from organic residues. These microorganisms are worth studying since they produce a variety of valuable biotechnological products.
      PubDate: 2022-06-01
       
  • Scalable Manufacturing Green Core–Shell Structure Flame Retardant, with
           Enhanced Mechanical and Flame-Retardant Performances of Polylactic Acid

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      Abstract: As a plastic that can be prepared from biomass resources, polylactic acid (PLA) has the characteristics of being degradable and renewable, and has shown great potential in replacing petroleum-based polymer materials. However, PLA material is flammable, the droplet phenomenon during combustion is still a disadvantage of PLA applications. In this research, a core–shell structure flame retardant was prepared based on polyacrylamide (PAM)/sodium alginate (SA) coated ammonium polyphosphate (APP) via layer-by-layer assembly using water as the assembly medium. The prepared core–shell flame retardant APP@PAM@SA-nDL (where “DL” is the PAM&SA double layer, and “n” represents 1-3DL) was molten compounded with PLA to improve its flame retardancy. APP@PAM@SA-nDL is added to PLA, which not only improves the flame retardancy of PLA composites, but also significantly improves the toughness, and the flame retardancy, flame retardant mechanism, mechanical performance and toughening mechanism of PLA composites were systematically studied. Among the core–shell flame retardants with different layers, the addition of APP@PAM@SA-3DL gives PLA composites excellent flame retardancy and tensile properties. Due to the formation of the cross-linked polymer network structure, 5% APP@PAM@SA-3DL can increase the elongation at break of PLA composites from 19.82 to 294.5%. In addition, 10% of APP@PAM@SA-3DL made the UL-94 of PLA composite materials reach V-0 level and increased the LOI from 19.7% (neat PLA) to 29.2%. The analysis of the carbon layer shows that the excellent flame-retardant performance of PLA composites can be attributed to the formation of a dense carbon layer during condensation and the dilution effect of P-containing free radicals, forming a flame-retardant mechanism with a condensed phase as the main component and a gas phase as a supplement. This high toughness flame-retardant PLA composite material has broad application prospects in the textile field. Graphical
      PubDate: 2022-06-01
       
 
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