2023

Jump to: 2022, 2021

12 pages, 1614 KiB

Open AccessArticle

Impact of Dragon Fruit Waste in Microbial Fuel Cells to Generate Friendly Electric Energy

by Rojas-Flores Segundo, Santiago M. Benites, Magaly De La Cruz-Noriega, Juan Vives-Garnique, Nélida Milly Otiniano, Walter Rojas-Villacorta, Moisés Gallozzo-Cardenas, Daniel Delfín-Narciso and Félix Díaz

Sustainability 2023, 15(9), 7316; https://doi.org/10.3390/su15097316 - 27 Apr 2023

Cited by 3 | Viewed by 2616

Abstract

Pollution generated by the misuse of large amounts of fruit and vegetable waste has become a major environmental and social problem for developing countries due to the absence of specialized collection centers for this type of waste. This research aims to generate electricity [...] Read more.

Pollution generated by the misuse of large amounts of fruit and vegetable waste has become a major environmental and social problem for developing countries due to the absence of specialized collection centers for this type of waste. This research aims to generate electricity in an eco-friendly way using red dragon fruit (pitahaya) waste as the fuel in single-chamber microbial fuel cells on a laboratory scale using zinc and copper electrodes. It was possible to generate voltage and current peaks of 0.46 ± 0.03 V and 2.86 ± 0.07 mA, respectively, with an optimum operating pH of 4.22 ± 0.09 and an electrical conductivity of 175.86 ± 4.72 mS/cm at 8 °Brix until the tenth day of monitoring. An internal resistance of 75.58 ± 5.89 Ω was also calculated with a maximum power density of 304.33 ± 16.51 mW/cm² at a current density of 5.06 A/cm², while the FTIR spectra showed a decrease in the initial compounds and endings, especially at the 3331 cm⁻¹ peaks of the O–H bonds. Finally, the yeast-like fungus Geotrichum candidum was molecularly identified (99.59%). This research will provide great opportunities for the generation of renewable energy using biomass as fuel through electronic devices with great potential to generate electricity. Full article

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2022

Jump to: 2023, 2021

14 pages, 2356 KiB

Open AccessArticle

Improving Barrier Properties of Xylan-Coated Food Packaging Papers with Alkyl Ketene Dimer

by Petronela Nechita, Mirela Roman, Alina Cantaragiu Ceoromila and Andreea Veronica Dediu Botezatu

Sustainability 2022, 14(23), 16255; https://doi.org/10.3390/su142316255 - 06 Dec 2022

Cited by 4 | Viewed by 1450

Abstract

In order to improve the hydrophobicity of xylan hemicellulose, a simple procedure of its chemical modification with alkyl ketene dimer (AKD), a non-toxic, cost-effective, and eco-friendly chemical, was performed. For this purpose, the reaction products of beech wood xylan and different amounts of [...] Read more.

In order to improve the hydrophobicity of xylan hemicellulose, a simple procedure of its chemical modification with alkyl ketene dimer (AKD), a non-toxic, cost-effective, and eco-friendly chemical, was performed. For this purpose, the reaction products of beech wood xylan and different amounts of hydrophobic AKD were used for paper surface treatment. Thus, the coatings of about 4.5 g/m² were applied on both sides of base paper in single and three successive layers. To obtain a complete reaction between AKD and xylan hemicellulose, the coated papers were thermal cured (about 110 °C) and the effects of AKD content on the barrier (water, oil, and water vapours) and mechanical properties were analysed. The structural analyses by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) of coated samples emphasized the presence of β-keto-ester compounds as a result of the reaction between xylan hemicelluloses and AKD. This is confirmed by the improving of barrier properties as the AKD content in coating dispersion is higher. The good barrier performance and improved strength properties were obtained for the coated papers with xylan hemicellulose and 1% AKD applied on paper surface in three successive layers (about 4.5 g/m²). In this case, the water vapours transmission rate (WVTR) was 35% lower than those untreated and the resistance to air passing through coated papers was over 3 times higher compared with base paper. There are no results reported on the chemical reaction of xylan hemicelluloses with AKD as well as its application in coatings for paper packaging. In this context, the obtained results in this study can contribute to expand the applications area of hemicelluloses offering a sustainable strategy for the developing of food packaging papers with appropriate barrier properties using biopolymer coating materials. Full article

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2021

Jump to: 2023, 2022

13 pages, 1558 KiB

Open AccessArticle

Influence of Printing Technique and Printing Conditions on Prints Recycling Efficiency and Effluents Quality

by Marina Vukoje, Ivana Bolanča Mirković and Zdenka Bolanča

Sustainability 2022, 14(1), 335; https://doi.org/10.3390/su14010335 - 29 Dec 2021

Cited by 4 | Viewed by 2490

Abstract

The aim of this work was to determine the influence of the conventional offset printing technique and digital electrophotography printing with liquid toner (LEP) on some optical properties of recycled fibres. A series of LEP prints was made with the variation of the [...] Read more.

The aim of this work was to determine the influence of the conventional offset printing technique and digital electrophotography printing with liquid toner (LEP) on some optical properties of recycled fibres. A series of LEP prints was made with the variation of the negative voltage of the developing drum (−200 V, −280 V, −350 V, and −430 V) after calibration of the machine and achieving standard densitometry values. Besides deinkability aspects, the quality of wastewater effluents after process of prints recycling was observed in order to make a conclusion regarding how different printing techniques, conditions in printing process, and different types of inks can affect the wastewater effluents. Results of image analysis showed that by increasing the negative voltage of developing drum in LEP printing technique, the formation of large ink particles on handsheet from recycled pulp increases. Depending on the size of the negative voltage of the developing drum, under the same experimental conditions, handsheets made from LEP recycled fibres have lower whiteness gain, brightness gain, and ΔERIC of handsheets compared to those made from the offset prints. In addition, a certain correlation was found between IE_ERIC (ink elimination), chemical oxygen demand (COD), and total organic carbon (TOC) of wastewater effluents after recycling of LEP prints and offset prints as well. Organic water pollution parameters (COD and TOC) showed higher values in wastewater after recycling of offset prints compared to recycling of LEP prints. Full article

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17 pages, 4344 KiB

Open AccessArticle

The Acoustic Performance of Expanded Perlite Composites Reinforced with Rapeseed Waste and Natural Polymers

by Silviu Nastac, Petronela Nechita, Carmen Debeleac, Cristian Simionescu and Mihai Seciureanu

Sustainability 2022, 14(1), 103; https://doi.org/10.3390/su14010103 - 23 Dec 2021

Cited by 9 | Viewed by 2963

Abstract

Lignocelluloses residues from the post-harvest crop are receiving great scientific attention nowadays. Generally, the composite materials based on lignocelluloses waste present low density and weight, and better insulation properties compared with those petroleum-based. This study presents the results of experimental investigations regarding soundproofing [...] Read more.

Lignocelluloses residues from the post-harvest crop are receiving great scientific attention nowadays. Generally, the composite materials based on lignocelluloses waste present low density and weight, and better insulation properties compared with those petroleum-based. This study presents the results of experimental investigations regarding soundproofing capabilities for a composite material based on expanded perlite (EP) and natural polymers matrix (starch) reinforced with rapeseed stalks waste. The preparation of light-weight samples of composites was performed at room temperature through a mechanical mixing process of EP with starch polymers and rapeseed residues until optimum moisture content composition was obtained. Rapeseed stalks long fibers were avoided through the preliminary dry grinding procedure, and the composite was air-dried at room temperature for 48 h. Four samples of composites with different ratio of EP and rapeseed waste were considered. The evaluation of sample sound insulation characteristics was performed using the transfer-matrix method based on a four-microphone acoustic impedance tube. The paper concludes that the proposed composite provides comparative sound insulation capabilities to actual materials, with few particular aspects presented within the paper. Thus, these new materials are promising as a viable alternative to the actual large-scale utilization solutions in soundproofing applications. Full article

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23 pages, 5822 KiB

Open AccessArticle

Numerical Study of Cylindrical Tropical Woods Pyrolysis Using Python Tool

by Nidhoim Assoumani, Merlin Simo-Tagne, Fatima Kifani-Sahban, Ablain Tagne Tagne, Maryam El Marouani, Marcel Brice Obounou Akong, Yann Rogaume, Pierre Girods and André Zoulalian

Sustainability 2021, 13(24), 13892; https://doi.org/10.3390/su132413892 - 15 Dec 2021

Cited by 4 | Viewed by 1920

Abstract

In this paper, the thermal behavior of large pieces of wood pyrolysis has been modeled. Two mathematical models coupling heat transfer equations to chemical kinetics were used to predict the pyrolytic degradation of a 25 mm radius wood sample, assumed to be dry [...] Read more.

In this paper, the thermal behavior of large pieces of wood pyrolysis has been modeled. Two mathematical models coupling heat transfer equations to chemical kinetics were used to predict the pyrolytic degradation of a 25 mm radius wood sample, assumed to be dry in the first model and wet in the second, when heated to 973.15 K. The reactions involved in the pyrolysis process are assumed to be endothermic. The diffusion of bounded water during the process is taken into account in the second model, where the heat transfer equation has been coupled to that of the diffusion of moisture. This model, although simple, provides more information on the drying and pyrolysis processes during the heating of wood, which is its originality. It can therefore be advantageously used to calculate the temperature distribution in a pyrolysis bed. The equations of the two models, discretized by an explicit finite difference method, were solved numerically by a program written in Python. The validation of both models against experimental work in the literature is satisfactory. The two models allow examination of the temperature profile in the radial direction of wood samples and highlighting of the effect of temperature on some thermal, physical and physicochemical characteristics. Full article

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16 pages, 3833 KiB

Open AccessArticle

Xylan Hemicellulose: A Renewable Material with Potential Properties for Food Packaging Applications

by Petronela Nechita, Roman Mirela and Florin Ciolacu

Sustainability 2021, 13(24), 13504; https://doi.org/10.3390/su132413504 - 07 Dec 2021

Cited by 16 | Viewed by 4300

Abstract

Xylan hemicelluloses are considered the second most abundant class of polysaccharides after cellulose which has good natural barrier properties necessary for foods packaging papers and films. Xylan exists today as a natural polymer, but its utilisation in packaging applications is limited and not [...] Read more.

Xylan hemicelluloses are considered the second most abundant class of polysaccharides after cellulose which has good natural barrier properties necessary for foods packaging papers and films. Xylan exists today as a natural polymer, but its utilisation in packaging applications is limited and not sufficiently analysed. In this study, the performances of hardwood xylan hemicellulose in forming uniform films and as biopolymer for paper coatings were analysed. The xylan-coated paper and film samples were tested regarding their water, air, and water vapour permeability, water solubility, mechanical strength, and antimicrobial activity against pathogenic bacteria. Structural analyses of xylan hemicelluloses emphasised a high number of hydroxyl groups with high water affinity. This affects the functional properties of xylan-coated papers but can facilitate the chemical modification of xylan in order to improve their hydrophobic properties and extend their areas of application. The obtained results unveil a promising starting point for using this material in food packaging applications as a competitive and sustainable alternative to petroleum-based polymers. Full article

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23 pages, 18736 KiB

Open AccessArticle

The Valorization of Biolignin from Esparto Grass (Stipa tenacissima L.) Produced by Green Process CIMV (Compagnie Industrielle de la Matière Végétale) for Fertilization of Algerian Degraded Soil: Impact on the Physicochemical and Biological Properties

by Amal Bendouma, Zohra Houyou, Abdelaziz Gherib and Hicham Gouzi

Sustainability 2021, 13(23), 13462; https://doi.org/10.3390/su132313462 - 06 Dec 2021

Viewed by 1754

Abstract

This study proposes a new use for a paper industry waste material, lignin, in agriculture and agronomy as a fertilizer for arid soils, while following a strategy aiming to both increase the amount of organic matter in these soils and decrease the impact [...] Read more.

This study proposes a new use for a paper industry waste material, lignin, in agriculture and agronomy as a fertilizer for arid soils, while following a strategy aiming to both increase the amount of organic matter in these soils and decrease the impact of pollution caused by industrial discharges that contain organic and/or inorganic pollutants generated by the paper industry. In fact, this method works to improve soil quality through a new carbon-rich bioorganic fertilizer (biolignin) that results from a green method called CIMV, a targeted depollution objective of the paper industry. Over the course of 180 days, we monitored the physicochemical and biological characteristics of degraded soils treated with three different biolignin treatments of 0 (D0), 2 (D1), and 4 (D2) g/kg. The humification was then evaluated by the equation E4/E6. A remarkable variation of the physicochemical and biological parameters was observed in D1 and D2: temperature 12–38 °C, humidity 9–29%, and pH 7.06–8.73. The C/N ratio decreased from 266 to 49. After 180 days, the improvement in soil carbon content for the three treatments D0, D1, and D2 was 14%, 19%, and 24%, respectively. A maximum bacterial biomass of 152 (CFU/g soil) was observed on the 30th day for D1. Maximum laccase activity for D2 was observed on the 120th day. D1 and D2 recorded a significant degree of humification compared to D0. The best indicator of humification E4/E6 was observed in D1, where the value reached 2.66 at the end of the treatment period. The D2 treatment showed a remarkable effect improving the fertility of the degraded soil, which confirms that biolignin is a good fertilizer. Full article

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20 pages, 1470 KiB

Open AccessArticle

Growth of Black Soldier Fly Larvae Reared on Organic Side-Streams

by Laurens Broeckx, Lotte Frooninckx, Laurien Slegers, Siebe Berrens, Isabelle Noyens, Sarah Goossens, Geert Verheyen, Ann Wuyts and Sabine Van Miert

Sustainability 2021, 13(23), 12953; https://doi.org/10.3390/su132312953 - 23 Nov 2021

Cited by 40 | Viewed by 5633

Abstract

Black soldier fly (BSF) larvae may play a role in a circular economy by upcycling low-value organic streams into high value biomass. In this paper, the capacity of BSF larvae to process 12 organic side-streams (mono-streams) and two standard substrates (chicken start mash [...] Read more.

Black soldier fly (BSF) larvae may play a role in a circular economy by upcycling low-value organic streams into high value biomass. In this paper, the capacity of BSF larvae to process 12 organic side-streams (mono-streams) and two standard substrates (chicken start mash and Gainesville diet) was investigated. Survival, larval mass, feed conversion ratio, and waste reduction were evaluated in relation to the proximate composition of the side-streams used. Survival rates larger than 80% were observed for 10 of the organic mono-streams and the two standard substrates. Maximum mean larval weight ranged from 38.3 mg up to 176.4 mg regardless of high survival and was highly correlated with substrate crude protein content. Feed conversion ratio (range 1.58–8.90) and waste reduction (range 17.0–58.9%) were similar to values reported in other studies in the literature. On low protein substrates (e.g., apple pulp), survival rates remained high, however, possibly due to protein deficiency, limited larval growth was observed. It is concluded that several low value organic side-streams can successfully be processed by BSF larvae, thereby opening the possibility of lowering the costs of BSF farming. Potentially mixing nutritionally distinct mono-streams into a mixed substrate might improve BSF performance. However, more research is needed for optimizing diets to guarantee production of BSF larvae of constant yield and quality. Full article

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15 pages, 5230 KiB

Open AccessArticle

Fabrication of Mg-Doped Sargassum Biochar for Phosphate and Ammonium Recovery

by Ye-Eun Lee, Yoonah Jeong, Dong-Chul Shin, Kwang-Ho Ahn, Jin-Hong Jung and I-Tae Kim

Sustainability 2021, 13(22), 12752; https://doi.org/10.3390/su132212752 - 18 Nov 2021

Cited by 5 | Viewed by 1833

Abstract

Biochars prepared from macro-algae have a lower C/N ratio compared to lignocellulosic biochar, which is advantageous for direct nutrition. In particular, Sargassum, a marine macro-algae, has a high Mg content; hence, it can be expected to adsorb P and N simultaneously. In [...] Read more.

Biochars prepared from macro-algae have a lower C/N ratio compared to lignocellulosic biochar, which is advantageous for direct nutrition. In particular, Sargassum, a marine macro-algae, has a high Mg content; hence, it can be expected to adsorb P and N simultaneously. In this study, Sargassum horneri biochar (SB), pyrolyzed at 400, 500, and 600 °C, was doped with innate Mg through water leaching, and nutrient recovery from the wastewater-mimicking solution was confirmed. The biochar pyrolyzed at 600 °C showed maximum Mg adsorption during water leaching, and the efficiency of K and Na removal was also high, at 92.7% and 91.9%, respectively. The addition of MgCl₂ during pyrolysis and high ion exchange did not show distinct advantages for surface modification and nutrient adsorption. X-ray photoelectron spectroscopy analysis confirmed the participation of biochar in the surface adsorption of Mg and PO₄ recovery. The PO₄ sorption capacity of biochar reached >120 mg·g⁻¹, while the sorption capacity for NH₄ was low, at 22.8–28.2 mg·g⁻¹, suggesting that Mg-surface-doped SB presented excellent phosphorus recovery. Hence, upgrading an adsorbent as a wastewater-treatment material and soil ameliorant that recovers nutrients using innate Mg from Sargassum is possible through appropriate surface modification. Full article

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19 pages, 2640 KiB

Open AccessArticle

Producing Direct Food Packaging Using Deinked Office Paper Grades—Deinkability and Food Contact Suitability Evaluation

by Sonja Jamnicki Hanzer, Branka Lozo and Lidija Barušić

Sustainability 2021, 13(22), 12550; https://doi.org/10.3390/su132212550 - 13 Nov 2021

Cited by 6 | Viewed by 2192

Abstract

Paper recycling is the most eco-efficient waste management option, since the use of recycled fibers reduces the need for virgin wood fiber and lowers energy consumption, and hence has a positive effect on the environment. The use of recycled paper is by far [...] Read more.

Paper recycling is the most eco-efficient waste management option, since the use of recycled fibers reduces the need for virgin wood fiber and lowers energy consumption, and hence has a positive effect on the environment. The use of recycled paper is by far the highest in the packaging industry. In food packaging production, recycled paper is often favored over paper and board made from virgin fibers. However, due to the possible hazardous chemicals that can be found in recycled paper, there is a dilemma of how to overcome food safety issues while making food packaging more circular. The objective of the study was to determine if deinked office paper grades could be used as an alternative fiber source in the production of food packaging white top linerboards. For that purpose, three different types of digitally printed papers were submitted to a chemical deinking flotation in laboratory conditions, and the handsheets formed after each recycling trial were tested on the suitability for direct food contact. Evaluation of deinkability for each group of recycled prints was performed, as well. Deinkability was evaluated by calculating the flotation yield, pulp’s brightness and whiteness increase, ink elimination factor, determination of residual ink area, as well as ash content elimination. Food safety evaluation was performed by determining the content of heavy metals (Cd, Pb, Hg, and Cr VI), primary aromatic amines, diisopropylnaphthalenes (DIPN), phthalates, and polychlorinated biphenyls (PCB) from aqueous or organic solvent extracts of recycled paper pulp. The fastness of the fluorescent whitening agents was determined, as well. Of all evaluated deinking flotation efficiency parameters, only flotation yield and ash reduction by flotation were positively assessed. High content of residual ink particles detected after the flotation stage indicates that the flotation was not a successful method for the elimination of disintegrated ink particles, which was also confirmed by deficient results of ink elimination measurements and whiteness increase. Flotation proved to be the least efficient in the recycling of inkjet prints, where the lowest ink elimination, whiteness, and brightness values were achieved. As far as food safety assessment of deinked pulp is concerned, all tested deinked handsheets were found suitable to be used in direct contact with foods. Full article

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23 pages, 4916 KiB

Open AccessArticle

Valorification of Ulva rigida Algae in Pulp and Paper Industry for Improved Paper Characteristics and Wastewater Heavy Metal Filtration

by Florina-Cristiana Caprita, Antoaneta Ene and Alina Cantaragiu Ceoromila

Sustainability 2021, 13(19), 10763; https://doi.org/10.3390/su131910763 - 28 Sep 2021

Cited by 1 | Viewed by 2996

Abstract

This paper presents preliminary results on the possibility of incorporating stranded macroalgae into the papermaking process; analyses of the physical-mechanical properties of filter paper, with the addition of stranded macrophytic marine algae from Ulva rigida species obtained previously; results of SEM–EDX analyses of [...] Read more.

This paper presents preliminary results on the possibility of incorporating stranded macroalgae into the papermaking process; analyses of the physical-mechanical properties of filter paper, with the addition of stranded macrophytic marine algae from Ulva rigida species obtained previously; results of SEM–EDX analyses of filter paper samples; and results obtained from the filtration of a wastewater from the metallurgical industry, using the improved filter paper samples. In the filter paper recipe, stranded macrophytic seaweed of the species Ulva rigida was added at different percentages of 0.5%, 1%, 2%, 4% and 8%, and the addition was calculated in relation to the absolute dry material. The physicomechanical properties analyzed are grammage, thickness, density, moisture, ash content, breaking load, breaking length, tear resistance, bursting resistance, folding endurance, porosity, smoothness, water absorption and Cobb60 index. Additional information related to the homogeneity of the distribution of elements in the paper mass was obtained by scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDX). The addition of macroalgae to the paper mass improved the strength characteristics of the paper, such as breaking load, breaking length, tearing resistance, folding endurance and water absorption. Following industrial wastewater filtration using filter paper with added seaweed, positive results were obtained in terms of reduction of total Cr, Cu, total Fe and Zn concentrations. Full article

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19 pages, 2359 KiB

Open AccessArticle

Ferulated Pectins from Sugar Beet Bioethanol Solids: Extraction, Macromolecular Characteristics, and Enzymatic Gelling Properties

by Federico Ohlmaier-Delgadillo, Elizabeth Carvajal-Millan, Yolanda L. López-Franco, Maria A. Islas-Osuna, Claudia Lara-Espinoza, Jorge A. Marquez-Escalante, Jose Alfonso Sanchez-Villegas and Agustín Rascon-Chu

Sustainability 2021, 13(19), 10723; https://doi.org/10.3390/su131910723 - 27 Sep 2021

Cited by 3 | Viewed by 1932

Abstract

Pectin from sugar beet (Beta vulgaris L.) (SBP) was extracted from a sugar beet waste (SBW) registering a 4.4% (w/w) yield. SBP presented a weight-average molar mass of 459 kDa, galacturonic acid content of 52.2%, and a low esterification degree [...] Read more.

Pectin from sugar beet (Beta vulgaris L.) (SBP) was extracted from a sugar beet waste (SBW) registering a 4.4% (w/w) yield. SBP presented a weight-average molar mass of 459 kDa, galacturonic acid content of 52.2%, and a low esterification degree (30%). The macromolecular characteristics of SBP revealed a flexible and extended coil chain conformation. The main neutral sugars in SBP were galactose (20.7%), mannose (5.0%), and arabinose (3.60%) while ferulic acid (FA) content was 2.1 µg·mg⁻¹ sample. FA remained in the SBP chain mainly in RG I region even after suffering both, industrial processing and harsh weathering conditions. Consequently, SBP formed covalent gels induced by laccase. Covalent cross-linking content (dimers and trimer of FA) was 0.97 mg·g⁻¹ SBP. The 8-5′, 5-5′, and 8-O-4′ dimers of FA isomers proportions were 75, 17, and 8%, respectively. SBP gels at 4% (w/v ) registered storage (G′) and loss (G″) moduli final values of 44 and 0.66 Pa, respectively. SBP gels were soft and adhesive according to texture profile analysis. Scanning electron microscopy analysis of SBP lyophilized gels revealed an imperfect honeycomb-like structure with 4.5 ± 1.4 µm average cavities diameter. Full article

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18 pages, 3423 KiB

Open AccessArticle

Allantoin from Valuable Romanian Animal and Plant Sources with Promising Anti-Inflammatory Activity as a Nutricosmetic Ingredient

by Rodica Mihaela Dinica, Cristina Sandu, Andreea Veronica Dediu Botezatu, Anna Cazanevscaia Busuioc, Fanica Balanescu, Maria Daniela Ionica Mihaila, Caterina Nela Dumitru, Bianca Furdui and Alina Viorica Iancu

Sustainability 2021, 13(18), 10170; https://doi.org/10.3390/su131810170 - 11 Sep 2021

Cited by 16 | Viewed by 4939

Abstract

Helix aspersa (HA), Helix pomatia (HP) and Symphytum officinale are common organisms in Romania’s biosphere, widely known for their allantoin content and their therapeutic properties. Herein, the allantoin was separated and quantified from the aqueous extracts of Romanian comfrey root and the secretions [...] Read more.

Helix aspersa (HA), Helix pomatia (HP) and Symphytum officinale are common organisms in Romania’s biosphere, widely known for their allantoin content and their therapeutic properties. Herein, the allantoin was separated and quantified from the aqueous extracts of Romanian comfrey root and the secretions of HA and HP snails. This study also focused on determining the antioxidant and anti-inflammatory activities of these Romanian allantoin-rich samples. The plant extracts were obtained through two methods: ultrasonic extraction and enzymatic ultrasonic extraction. A microplate method was used for the quantitative determination of allantoin content. The antioxidant activity was measured by using the DPPH radical scavenging method. The antioxidant capacity of the samples was studied in order to observe the type of interactions generated by the chemical complex present in their composition. High concentrations of allantoin were obtained by enzymatic ultrasonic extraction method (EUE—102 ± 0.74 μg/mL), and also in the water-soluble fraction of the snail secretion (FS1—22.051 μg/mL). The antioxidant screening suggests that Symphytum officinale and snail mucus extracts could be used as promising natural substitutes for synthetic antioxidants in products used for therapeutic purposes. The evaluation of anti-inflammatory activity was also investigated, allantoin-rich samples showing a promising action (FS1—81.87 ± 2.34%). In future, the inclusion of allantoin-rich extracts in various novel pharmaceutical forms for new therapeutic applications could be achieved. The study will continue with the formulation of a nutricosmetic product with snail mucus and Symphytum officinale extract as principal bioactive ingredients. Full article

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16 pages, 6317 KiB

Open AccessArticle

Multi-Scale Minero-Chemical Analysis of Biomass Ashes: A Key to Evaluating Their Dangers vs. Benefits

by Paola Comodi, Azzurra Zucchini, Umberto Susta, Costanza Cambi, Riccardo Vivani, Gianluca Cavalaglio and Franco Cotana

Sustainability 2021, 13(11), 6052; https://doi.org/10.3390/su13116052 - 27 May 2021

Cited by 2 | Viewed by 2088 | Correction

Abstract

A multi-methodic analysis was performed on five samples of fly ashes coming from different biomasses. The aim of the study was to evaluate their possible re-use and their dangerousness to people and the environment. Optical granulometric analyses indicated that the average diameter of [...] Read more.

A multi-methodic analysis was performed on five samples of fly ashes coming from different biomasses. The aim of the study was to evaluate their possible re-use and their dangerousness to people and the environment. Optical granulometric analyses indicated that the average diameter of the studied fly ashes was around 20 µm, whereas only ~1 vol% had diameters lower that 2.5 µm. The chemical composition, investigated with electron probe microanalysis, indicated that all the samples had a composition in which Ca was prevalent, followed by Si and Al. Large contents of K and P were observed in some samples, whereas the amount of potentially toxic elements was always below the Italian law thresholds. Polycyclic aromatic hydrocarbons were completely absent in all the samples coming from combustion plants, whereas they were present in the fly ashes from the gasification center. Quantitative mineralogical content, determined by Rietveld analysis of X-ray powder diffraction data, indicated that all the samples had high amorphous content, likely enriched in Ca, and several K and P minerals, such as sylvite and apatite. The results obtained from the chemo-mineralogical study performed make it possible to point out that biomass fly ashes could be interesting materials (1) for amendments in clayey soils, as a substitution for lime, to stimulate pozzolanic reactions and improve their geotechnical properties, thus, on the one hand, avoiding the need to mine raw materials and, on the other hand, re-cycling waste; and (2) as agricultural fertilizers made by a new and ecological source of K and P. Full article

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