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1.
Saudi Dent J ; 36(5): 712-717, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38766293

RESUMEN

Objective: To determine the "biocompatibility" of a soft denture liner impregnated with apigenin and seashell nanoparticles via histopathological assessment in rabbit models. Materials and Methods: Twenty-six albino rabbits aged 5-7 months and weighing, 1.25-1.5 kg were randomly divided into apigenin and seashell-modified groups, n = 13 each). A total of 104 disc-shaped specimens (3 mm thick and 5 mm in diameter) of a heat-cured soft liner, (GC, USA) were prepared. In the apigenin group, each rabbit was subcutaneously implanted with 4 specimens: (positive control, unmodified-liner, and 0.25 %, 0.5 %, and 1 % of apigenin-modified liner). In the seashell group, rabbits were implanted with positive control and 1.25 %, 2.5 % and 5 % seashell-modified liner. A non-implanted incision was performed for all the groups as a negative control. Histopathological observations were evaluated according to inflammatory and angiogenesis scores 14 days after implantation. Results: A significant decrease in inflammatory responses and an increase in angiogenesis were observed for both apigenin and seashell-modified soft liner groups. Higher compatibility effectiveness was positively related to and recorded in the increased ratios of nanoparticles within the soft liner material. Conclusion: Apigenin and seashell-modified soft liners at higher ratios 1% and 5% respectively were more compatible with the rabbit mucosa.

2.
Materials (Basel) ; 17(5)2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38473694

RESUMEN

Nowadays, the sustainable development of the construction industry has become a focus of attention. Crushing and grinding waste seashells originating from the fishery industry, such as oyster shells, cockle shells, mussel shells, and scallop shells, into different particle sizes for usage as aggregate and cement in concrete or mortar provides an effective and sustainable solution to environmental problems by reducing natural resource dependence. Numerous studies have attempted to analyze the suitability of waste seashell as a possible alternative to natural aggregates and cement in concrete or mortar. This paper presents an up-to-date review of the characteristics of different types of waste seashell, as well as the physical, mechanical, durability, and other notable functional properties of seashell concrete or mortar. From the outcome of the research, waste seashell could be an inert material, and it is important to conduct a series of proper treatment for a better-quality material. It is also seen from the results that although the mechanical properties of seashell concrete have been reduced, they all meet the required criteria set by various international standards and codes. Therefore, it is recommended that the replacement of seashells as aggregate and cement should not exceed 20% and 5%, respectively. Seashell concrete or mortar would then have sufficient workability and strength for non-structural purposes. However, there is still a lack of investigation concerning the different properties of reinforced concrete members using seashells as the replacement of aggregate or cement. Further innovative research can solidify its utilization towards sustainable development.

3.
Materials (Basel) ; 16(24)2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38138807

RESUMEN

In this study, the influence of acid solutions on the production of precipitated calcium carbonate (PCC) using seashells was investigated. In terms of the Ca dissolution efficiency and atmosphere for dissolving CO32-, the results indicate that HCl, HNO3, CH3COOH, and HCOOH at 1.0 M were the most ideal among the acid solutions. The use of weak acids resulted in the low degree of dissolution of Al and Fe. These impurities could be mostly removed through the pH adjustment process, leading to PCC with a purity of 99% or more. Further, CH3COOH and HCOOH exhibited low CaCO3 carbonation efficiency owing to the hydrogen bonding of the carboxyl group and its hindering effect on the growth of CaCO3 particles. In addition, in the presence of the carboxyl group, the morphology tended to be oval, and the particle size was small. Particularly, when CH3COOH was used, the combined effect of the low initial Ca ion concentration and slow CO2 dissolution rate resulted in minimal changes during the carbonation time and the smallest particle size. However, variations in the degree of Ca concentration with a change in the acid solution concentration influenced the dominance of nucleation and particle growth, leading to variations in the particle size. The results of this study revealed that when manufacturing PCC using seashells, the appropriate acid solution must be selected to obtain the required PCC properties.

4.
Biomimetics (Basel) ; 8(6)2023 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-37887635

RESUMEN

Mycelium biocomposites are eco-friendly, cheap, easy to produce, and have competitive mechanical properties. However, their integration in the built environment as durable and long-lasting materials is not solved yet. Similarly, biocomposites from recycled food waste such as seashells have been gaining increasing interest recently, thanks to their sustainable impact and richness in calcium carbonate and chitin. The current study tests the mycelium binding effect to bioweld a seashell biocomposite 3D-printed brick. The novelty of this study is the combination of mycelium and a non-agro-based substrate, which is seashells. As well as testing the binding capacity of mycelium in welding the lattice curvilinear form of the V3 linear Brick model (V3-LBM). Thus, the V3-LBM is 3D printed in three separate profiles, each composed of five layers of 1 mm/layer thickness, using seashell biocomposite by paste extrusion and testing it for biowelding with Pleurotus ostreatus mycelium to offer a sustainable, ecofriendly, biomineralized brick. The biowelding process investigated the penetration and binding capacity of the mycelium between every two 3D-printed profiles. A cellulose-based culture medium was used to catalyse the mycelium growth. The mycelium biowelding capacity was investigated by SEM microscopy and EDX chemical analysis of three samples from the side corner (S), middle (M), and lateral (L) zones of the biowelded brick. The results revealed that the best biowelding effect was recorded at the corner and lateral zones of the brick. The SEM images exhibited the penetration and the bridging effect achieved by the dense mycelium. The EDX revealed the high concentrations of carbon, oxygen, and calcium at all the analyzed points on the SEM images from all three samples. An inverted relationship between carbon and oxygen as well as sodium and potassium concentrations were also detected, implying the active metabolic interaction between the fungal hyphae and the seashell-based biocomposite. Finally, the results of the SEM-EDX analysis were applied to design favorable tessellation and staking methods for the V3-LBM from the seashell-mycelium composite to deliver enhanced biowelding effect along the Z axis and the XY axis with <1 mm tessellation and staking tolerance.

5.
Data Brief ; 50: 109570, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37767122

RESUMEN

The dataset currently available comprises data on the removal rates of heavy metals (Ba, Se, Cr, Fe, Cd, As, and Co) through the incorporation of seashells and palm oil kernel shells into pervious concrete for stormwater treatment. Stormwater runoff was collected from commercial areas in Taman University, Skudai, Johor, Malaysia. The stormwater samples underwent filtration and were preserved in high-density polyethylene (HDPE) bottles at a temperature of 4 °C for use as incoming water. The outgoing water, referred to as effluent, was obtained from tests performed on pervious concrete samples after a curing period of 28 days. The pervious concrete mixes were created with a water-to-binder ratio (w/b ratio) of 32% and a sand ratio of 10%. Three different levels of palm oil kernel shell and seashell content were used as coarse aggregate replacements: 0%, 25%, and 50%. Two single-size group were considered for both palm oil kernel shell and seashell: (6.3-9.5 mm) and (4.75-6.3 mm). Heavy metal analyses were conducted on the influent and effluent using a PerkinElmer ELAN 6100 Series Inductively Coupled Plasma- Mass Spectrometer (ICP-MS). The available datasets consist of both raw and analyzed data.

6.
Heliyon ; 9(6): e17036, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37484264

RESUMEN

The seashell-shaped wind turbine (spiral wind turbine SWT), a brand-new form of the horizontal axis wind turbine, is intended for metropolitan use. SWTs have the additional advantage of being installed anywhere without considering their surroundings, as they do not need to be located facing the wind direction. The present work introduces various designs of the rotor of the seashell wind turbine to achieve the greatest performance. Two types of turbine spiral profiles (logarithmic and Archimedean) are investigated with changing the turbine opening angle (θ). Utilizing the turbulence model SST k-ω, the equations of Reynolds-averaged Navier-Stokes (RANS) are solved and hence the power coefficient (CP) is calculated. A comprehensive comparison of the findings for both configurations indicates that the turbine of the Archimedean spiral profile with θ of 60° generates the best performance. The seashell wind turbine with the Archimedean profile at a θ of 60° has a maximum CP = 0.266825 at λ = 2.5. The seashell wind turbine with the Archimedean profile has the best performance than traditional Archimedes wind turbines which were studied previously by other researchers. The maximum percentage increase in the CP of the seashell turbine with the Archimedean profile compared to the conventional Archimedes turbine equals 14.52%.

7.
Molecules ; 28(9)2023 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-37175301

RESUMEN

Transition-metal-doped boron nanoclusters exhibit unique structures and bonding in chemistry. Using the experimentally observed seashell-like borospherenes C2 B28-/0 and Cs B29- as ligands and based on extensive first-principles theory calculations, we predict herein a series of novel transition-metal-centered endohedral seashell-like metallo-borospherenes C2 Sc@B28- (1), C2 Ti@B28 (2), C2 V@B28+ (3), and Cs V@B292- (4) which, as the global minima of the complex systems, turn out to be the boron analogues of dibenzenechromium D6h Cr(C6H6)2 with two B12 ligands on the top and bottom interconnected by four or five corner boron atoms on the waist and one transition-metal "pearl" sandwiched at the center in between. Detailed molecular orbital, adaptive natural density partitioning (AdNDP), and iso-chemical shielding surface (ICSS) analyses indicate that, similar to Cr(C6H6)2, these endohedral seashell-like complexes follow the 18-electron rule in bonding patterns (1S21P61D10), rendering spherical aromaticity and extra stability to the systems.

8.
Materials (Basel) ; 16(6)2023 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-36984349

RESUMEN

In order to study the mechanical and microstructural properties of masonry mortar, combined particles of cockle and scallop seashell wastes were incorporated and analysed through destructive and non-destructive tests. River sand was replaced with the combined seashell particles (SPs) at seven mixes, viz., 0, 5, 10, 15, 20, 25, and 30% with a 0.5 constant water-to-cement ratio (W/C). A mortar mix design of M4-type of BS EN 1996-1-1 was adopted with a target compressive strength of 5.17 MPa at 28 days. The physical, chemical and mineralogy properties of the SPs were analysed through BS standard sieving, X-ray fluorescence (XRF), scanning electron microscopy (SEM), and X-ray diffraction (XRD) methods. The hardened SP-based mortars were subjected to direct compressive strength, rebound hammer, ultrasonic pulse velocity tests, and nonevaporable degree of hydration analysis. The XRF, SEM, and XRD analysis results of the SPs showed over 86% calcium oxide content, irregular and needle-like particles, and hydroxyapatite/calcium silicates, respectively. The direct compressive strength and the non-destructive test results revealed that up to 30% sand replacement with SP in masonry mortar, an improvement of 45% compressive strength could be attained over the control sample. The nonevaporable water method of the degree of hydration analysis showed that after 28 days, hydration increased considerably for the SP-blended mortars over the control, especially the SPM-30 with 30% sand replacement. Therefore, the study concludes that the investigated SPs in blended masonry mortar could benefit an eco-friendly environment and conservation of natural resources.

9.
Materials (Basel) ; 16(4)2023 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-36837361

RESUMEN

In this research, the feasibility of using Acanthocardia tuberculata shell waste from the canning industry in the manufacturing of self-compacting mortar (SCM) was tested. The seashells were finely ground to be used as filler instead of the limestone filler normally used in this type of SCM. First, a physicochemical and microstructural characterisation of all raw materials was carried out, including the particle size distribution of both fillers. Subsequently, the self-compactability properties in the fresh state of SCM were evaluated using a total substitution by volume of limestone filler for seashell powder, using different self-compactiblity parameters. The mineralogical phases of all the SCM tested were identified once hardened by means of X-ray diffraction technique, thermogravimetric and differential thermal analysis. In addition, the mechanical properties, water absorption capacity, dry bulk density and accessible porosity of water of hardened mortars at 28 days of curing were analysed. The effect of replacing limestone filler by Acanthocardia tuberculata filler resulted in a decrease in compressive strength of 29.43, 16.84 and 2.29%, respectively. The results indicate that it is possible to completely replace natural limestone filler with Acanthocardia tuberculata shell filler without significantly affecting the mechanical properties of SCM.

10.
Heliyon ; 9(2): e13188, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36793976

RESUMEN

Globally, an increasing carbon footprint has had a negative effect on the ecosystem and all living things. One of the sources that produces these footprints is the cement manufacturing process. Therefore, it is crucial to produce a cement substitute to reduce these footprints. The production of a geopolymer binder (GPB) is one of these possibilities. In this study, sodium silicate (Na2SiO3) was used as an activator in the production of geopolymer concrete (GPC) together with steel slag and oyster seashell as precursors. The materials of the concrete were prepared, cured, and tested. Workability, mechanical, durability and characterization test were conducted on the GPC. The results showed that adding a seashell increased the slump value. The optimum GPC compressive strength on a 100 × 100 × 100 mm3 cube for 3, 7, 14, 28, and 56 curing days was obtained with 10% seashell, while seashell replacement exceeded 10% declined in strength. Portland cement concrete achieved better mechanical strength when compared to steel slag seashell powder geopolymer concrete. However, steel slag seashell powder-based geopolymer gained better thermal properties than Portland cement concrete at 20% seashell replacement.

11.
J Mech Behav Biomed Mater ; 137: 105550, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36356422

RESUMEN

Various hydroxyapatite (HA) powders synthesized at different temperatures are deposited on titanium alloy by using an atmospheric plasma spray process. These different HA powders were synthesized from Indian clam seashells through the hydrothermal technique at varying temperatures from 700 to 1000 °C for a 2 h time duration in our previous study. The synthesized HA powders are spray-dried to obtain agglomerated powders suitable for spraying during the coating application. Crystallite size, Ca/P ratio, and crystallinity of agglomerated HA powders and their respective coatings are estimated by standard methods. The microstructure and phases of the feedstock and coating materials are investigated by using a field-emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD), respectively. Further, the HA coatings are characterized in terms of surface roughness, microhardness, porosity, adhesion strength, and wear resistance through the stylus profilometer, Vickers micro-hardness tester, image analysis technique, scratch tester, and ball-on-disc tribometer, respectively. The average surface roughness (Ra) and porosity of the coating are decreased with an increase in the synthesis temperature. The minimum Ra and porosity obtained for the 1000 °C coating sample suggest a high degree of melting of such powder particles. However, the highest adhesion strength noticed in the case of the 900 °C coating sample is due to the high compatibility of such coating material with Ti-alloy substrate in terms of thermal properties. The 900 °C coating sample has also shown the highest microhardness and wear-resistance properties due to its maximum crystallinity among all the HA coatings.


Asunto(s)
Aleaciones , Bivalvos , Animales , Aleaciones/química , Durapatita/química , Titanio/química , Polvos , Exoesqueleto , Materiales Biocompatibles Revestidos/química , Ensayo de Materiales , Propiedades de Superficie
12.
Nanomaterials (Basel) ; 12(20)2022 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-36296871

RESUMEN

Microbial cells and self-produced extracellular polymeric substances assembled to form biofilms that are difficult to remove from surfaces, causing problems in various fields. Seashell-derived calcium hydroxide, a sustainable inorganic material, has shown high bactericidal activity even for biofilms due to its alkalinity. However, its biofilm removal efficacy is relatively low. Herein, we report a biofilm degradation strategy that includes two environmentally friendly reagents: seashell-derived calcium hydroxide and hydrogen peroxide. A biofilm model of Escherichia coli was prepared in vitro, treated with calcium hydroxide-hydrogen peroxide solutions, and semi-quantified by the crystal violet stain method. The treatment significantly improved biofilm removal efficacy compared with treatments by calcium hydroxide alone and hydrogen peroxide alone. The mechanism was elucidated from calcium hydroxide-hydrogen peroxide solutions, which suggested that perhydroxyl anion and hydroxyl radical generated from hydrogen peroxide, as well as the alkalinity of calcium hydroxide, enhanced biofilm degradation. This study showed that concurrent use of other reagents, such as hydrogen peroxide, is a promising strategy for improving the biofilm degradation activity of seashell-derived calcium hydroxide and will contribute to developing efficient biofilm removal methods.

13.
Materials (Basel) ; 15(19)2022 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-36234145

RESUMEN

An increasing amount of waste seashells in China has caused serious environmental pollution and resource waste. This paper aims to solve these problems by using waste seashells as modified materials to prepare high-performance modified asphalt. In this study, seashell powder (SP) and stratum corneum-exfoliated seashell powder (SCESP) were adopted to prepare 10%, 20% and 30% of seashell powder-modified asphalt (SPMA) and stratum corneum-exfoliated seashell powder-modified asphalt (SCESPMA) by the high-speed shear apparatus, respectively. The appearance and composition of two kinds of SPs were observed and determined by the scanning electron microscope (SEM). The types of functional groups, temperature frequency characteristics, low temperature performance and adhesion of SPMA were tested by the Fourier-transform infrared (FTIR) spectrometer, dynamic shear rheometer (DSR), bending beam rheometer (BBR) and contact angle meter. The results show that the SP and SCESP are rough and porous, and their main component is CaCO3, which is physically miscible to asphalt. When the loading frequency ranges from 0.1 Hz to 10 Hz, the complex shear modulus (G*) and phase angle (δ) of SPMA and SCESPMA increase and decrease, respectively. At the same load frequency, SCESPMA has a larger G* and a smaller δ than SPMA. At the same temperature, SCESPMA has a larger rutting factor (G*/sin δ) and better high-temperature deformation resistance than SPMA. SP and SCESP reduce the low-temperature cracking resistance of asphalt, of which SCESP has a more adverse effect on the low-temperature performance of asphalt than SP. When SP and SCESP are mixed with asphalt, the cohesion work (Waa), adhesion work (Was) and comprehensive evaluation parameters of water stability (ER1, ER2 and ER3) of asphalt are improved. It is shown that both SP and SCESP have good water damage resistance, of which SCESP has better water damage resistance than SP. These research results have important reference value for the application of waste biological materials in asphalt pavement.

14.
Nanomaterials (Basel) ; 12(11)2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35683701

RESUMEN

Heavy metal ions such as Cr(VI) pose great hazards to the environment, which requests materials and methods for decontamination. Nano zero-valent iron (nZVI) has emerged as a promising candidate for Cr(VI) removal. Herein, harnessing the merits of marine biomass, a heterogeneous water treatment system for the decontamination of Cr(VI) is developed based on the in situ immobilization of nZVI on the seashell powder (SP)-derived porous support. A response surface methodology (RSM) study involving three independent factors is designed and conducted to direct material synthesis and reaction design for products with optimal performances. Under optimal synthetic conditions, the nZVI-loaded seashell powder (SP@nZVI), which is characterized in detail by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), results in a 79% increase in the removal efficiency of Cr(VI) compared to free nZVI. Mechanism studies show that the removal of Cr(VI) by SP@nZVI conforms to the Langmuir adsorption model with a quasi-second order kinetic equation, in which redox reactions between nZVI and Cr(VI) occurred at the SP surface. The results of this work are expected to benefit the reuse of bioresource waste in developing environmental remediation materials.

15.
Polymers (Basel) ; 14(5)2022 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-35267694

RESUMEN

This paper presents the formulation, characterization, and in vitro studies of polymer composite material impregnated with naturally derived hydroxyapatite (HA) particulates for biomedical implant applications. Laevistrombus canarium (LC) seashells (SS) were collected, washed and cleaned, sun-dried for 24 h, and ground into powder particulates. The SS particulates of different weight percentages (0, 10, 20, 30, 40, 50 wt%)-loaded high-density polyethylene (HDPE) composites were fabricated by compression molding for comparative in vitro assessment. A temperature-controlled compression molding technique was used with the operating pressure of 2 to 3 bars for particulate retention in the HDPE matrix during molding. The HDPE/LC composite was fabricated and characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), differential scanning calorimetry (DSC), and TGA. Mechanical properties such as tensile, compression, flexural, hardness, and also surface roughness were tested as per ASTM standards. Mass degradation and thermal stability of the HDPE/LC composite were evaluated at different temperatures ranging from 10 to 700 °C using thermogravimetric analysis (TGA). The maximum tensile strength was found to be 27 ± 0.5 MPa for 30 wt% HDPE/LC composite. The thermal energy absorbed during endothermic processes was recorded as 71.24 J/g and the peak melting temperature (Tm) was found to be 128.4 °C for the same 30 wt% of HDPE/LC composite specimen. Excellent cell viability was observed during the in vitro biocompatibility study for EtO-sterilized 30 wt% of HDPE/LC composite specimen, except for a report of mild cytotoxicity in the case of higher concentration (50 µL) of the MG-63 cell line. The results demonstrate the potential of the fabricated composite as a suitable biomaterial for medical implant applications.

16.
J Lasers Med Sci ; 13: e43, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36743145

RESUMEN

Introduction: There is an interest in developing materials with bioactive potential that could block exposed dentinal tubules. This study compared the effects of eggshell and seashell nanoparticles individually or combined with ND:YAG laser on dentinal tubules occlusion and remineralization. Methods: Fifty radicular dentin discs were prepared from freshly extracted human premolars. The smear layer created by cutting was removed using 37% phosphoric acid gel for 15 sec. The discs were divided into five groups according to the applied treatment(A) (n = 10 each): (A1) control, (A2); Nano eggshells, (A3); Nano seashells, (A4); Nano eggshells + Nd: YAG Laser, and (A5); Nano sea shell + Nd: YAG Laser. Each specimen was evaluated for tubular patency and mineral contents before and after each therapy using ESEM-EDXA energy dispersive spectroscopy for the assessment of tubule occlusion and remineralization. Results: ESEM results revealed a statistically significant decrease in the mean percent changes of the dentinal tubules number after the treatment of the experimental groups compared to the control. The greatest percent decrease was recorded in the seashell NPs + Nd: YAG laser, followed by the eggshell NPs + Nd: YAG laser, then Eggshell NPs only and then Seashell NPs only, while the lowest percentage decrease was recorded in the control group. EDXA revealed that the greatest percentage increase in Ca wt% was recorded in the Eggshell + Nd:YAG laser group, followed by Eggshell only, then Seashell only and then Seashell NPs + Nd: YAG laser, while the lowest percent increase was recorded in the control group. The post hoc test revealed no significant difference between the experimental groups. Conclusions: Both eggshell and seashell nanoparticles are effective in the occlusion and remineralization of dentinal tubules. The combined treatments with Nd: YAG laser had no benefits when compared to the effect of treatments alone.

17.
Materials (Basel) ; 14(16)2021 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-34442918

RESUMEN

The search for sustainable resources remains a subject of global interest and the conversion of the abundantly available bivalve shell wastes to advanced materials is an intriguing method. By grinding, calcium carbonate (CaCO3) powder was obtained from each shell of bivalves (cockle, mussel, and oyster) as revealed by FTIR and XRD results. Each individual shell powder was reacted with H3PO4 and H2O to prepare Ca(H2PO4)2·H2O giving an anorthic crystal structure. The calcination of the mixture of each shell powder and its produced Ca(H2PO4)2·H2O, at 900 °C for 3 h, resulted in rhombohedral crystal ß-Ca3(PO4)2 powder. The FTIR and XRD data of the CaCO3, Ca(H2PO4)2·H2O, and Ca3(PO4)2 prepared from each shell powder are quite similar, showing no impurities. The thermal behaviors of CaCO3 and Ca(H2PO4)2·H2O produced from each shell were slightly different. However, particle sizes and morphologies of the same products obtained from different shells were slightly different-but those are significantly different for the kind of the obtained products. Overall, the products (CaCO3, Ca(H2PO4)2·H2O, and Ca3(PO4)2) were obtained from the bivalve shell wastes by a rapidly simple, environmentally benign, and low-cost approach, which shows huge potential in many industries providing both economic and ecological benefits.

18.
Sci Total Environ ; 790: 148102, 2021 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-34380237

RESUMEN

The productive sector must incorporate waste into traditional materials in order to grow sustainably. In Galicia (Spain) alone, the canning industry produces over 150,000 metric tons of seashell waste per year. Most of this waste is still disposed of in landfills or open fields due to the lack of a technically feasible, environmentally sustainable, and economically profitable recycling alternative. This paper aims to study the feasibility of a new recycling alternative for seashell waste from industrial canning, based on the production of fireproof material suitable for construction use. The waste was pre-treated in order to remove salts and remaining organic matter and reduce particle size. According to international standards, physical, mechanical, and insulating properties were assessed for four compositions: 0, 40, 60 and 80% of gypsum substituted with pre-treated seashell waste. Results showed that substitution of up 60% gypsum was technically feasible. A Life-Cycle Assessment and a preliminary production cost analysis were performed by analysing a recycling case in Galicia. The case study found that 40-60% gypsum substitution obtained an environmental impact reduction of 0.4%-59% for 13 of the 18 impact categories considered compared with 0% substitution. Increases in the other 5 categories were analysed due to aquatic emissions released in the waste pre-treatment washing process. The locations of the fireproof material production facility and the waste source were a key factor. Production costs could be reduced by 20-31% by using 40-60% gypsum substituted with seashell wastes.


Asunto(s)
Exoesqueleto , Administración de Residuos , Exoesqueleto/química , Animales , Conservación de los Recursos Naturales , Residuos Industriales/análisis , Reciclaje , Instalaciones de Eliminación de Residuos
19.
J Environ Manage ; 280: 111652, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33229112

RESUMEN

Phosphorus (P) concentration beyond threshold limit can trigger eutrophication in stagnant water bodies nevertheless it is an indispensable macronutrient for aquatic life. Even in low P concentration (≤1 mg L-1), P can be detrimental for ecosystem's health, but this aspect has not been thoroughly investigated. The elimination of low P content is rather expensive or complex. Therefore, a unique and sustainable approach has been proposed in which valorized bivalve seashells can be used for the removal of low P content. Initially, acicular shaped aragonite particles (~21 µm) with an aspect ratio of around 21 have been synthesized through the wet carbonation process and used to treat aqueous solutions containing P in low concentration (P ≤ 1 mg L-1). Response surface methodology based Box-Behnken design has been employed for optimization study which revealed that with aragonite dosage (140 mg), equilibrium pH (~10.15), and temperature (45 °C), a phosphorus removal efficiency of ~97% can be obtained in 10 h. The kinetics and isotherm studies have also been carried out (within the range P ≤ 1 mg L-1) to investigate a probable removal mechanism. Also, aragonite demonstrates higher selectivity (>70%) towards phosphate with coexisting anions such as nitrate, chloride, sulfate, and carbonate. Through experimental data, elemental mapping, and molecular dynamic simulation, it has been observed that the removal mechanism involved a combination of electrostatic adsorption of Ca2+ ions on aragonite surface and chemical interaction between the calcium and phosphate ions. The present work demonstrates a sustainable and propitious potential of seashell derived aragonite for the removal of low P content in aqueous solution along with its unconventional mechanistic approach.


Asunto(s)
Carbonato de Calcio , Contaminantes Químicos del Agua , Adsorción , Exoesqueleto , Animales , Ecosistema , Concentración de Iones de Hidrógeno , Cinética , Fosfatos , Fósforo , Agua
20.
Materials (Basel) ; 12(3)2019 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-30691077

RESUMEN

Calcium carbonate from marble and seashells is an eco-friendly, sustainable, and largely available bioresource for producing natural bone-like calcium phosphates (CaPs). Based on three main objectives, this research targeted the: (i) adaptation of an indirect synthesis route by modulating the amount of phosphorus used in the chemical reaction, (ii) comprehensive structural, morphological, and surface characterization, and (iii) biocompatibility assessment of the synthesized powdered samples. The morphological characterization was performed on digitally processed scanning electron microscopy (SEM) images. The complementary 3D image augmentation of SEM results also allowed the quantification of roughness parameters. The results revealed that both morphology and roughness were modulated through the induced variation of the synthesis parameters. Structural investigation of the samples was performed by Fourier transform infrared spectroscopy and X-ray diffraction. Depending on the phosphorus amount from the chemical reaction, the structural studies revealed the formation of biphasic CaPs based on hydroxyapatite/brushite or brushite/monetite. The in vitro assessment of the powdered samples demonstrated their capacity to support MC3T3-E1 pre-osteoblast viability and proliferation at comparable levels to the negative cytotoxicity control and the reference material (commercial hydroxyapatite). Therefore, these samples hold great promise for biomedical applications.

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