Progress of Bio-Calcium Carbonate Waste Eggshell and Seashell Fillers in Polymer Composites: A Review

Development of Cracked Egg Detection Device Using Electric Discharge Phenomenon

Eggs are a highly nutritious food; however, those are also fragile and susceptible to cracks, which can lead to bacterial contamination and economic losses. Traditional methods for detecting cracks, particularly in processed eggs, often fall short due to changes in the eggs' physical properties during processing. This study was aimed at developing a novel device for detecting egg cracks using electric discharge phenomena. The system was designed to apply a high-voltage electric field to the eggs, where sparks were generated at crack locations due to the differences in electrical conductivity between the insulative eggshell and the more conductive inner membrane exposed by the cracks. The detection apparatus consisted of a custom-built high-voltage power supply, flexible electrode pins, and a rotation mechanism to ensure a complete 360-degree inspection of each egg. Numerical simulations were performed to analyze the distribution of the electric field and charge density, confirming the method's validity. The results demonstrated that this system could efficiently detect cracks in both raw and processed eggs, overcoming the limitations of existing detection technologies. The proposed method offers high precision, reliability, and the potential for broader application in the inspection of various poultry products, representing a significant advancement in food safety and quality control.

A novel approach for the modification of eggshell powder and its application for lead and methylene blue removal

Water pollution is one of the major concerns due to rapid industrialization and urbanization. Wastewater treatment has been an area of great interest for the researchers and among many technologies developed for water treatment, adsorption is the most preferred due to its efficiency and ability of been economical method. In this research, eggshell powder (ESP) is converted into modified eggshell powder (MESP) through chemical and thermal treatment (at 550 °C for 2 h) to use it as an adsorbent to remediate Pb2+ and Methylene blue (MB) from water, then it is transferred into modified eggshell powder magnetic composite (MESPMC) with iron coating to resolve the separation challenges and to boost the MESP's adsorption efficiency. FTIR analysis identified the functional groups of ESP, MESP, and MESPMC. XRD analysis reveals a hexagonal crystal structure of calcite in MESP and a combination of the hexagonal crystal structure of calcite and the cubic crystal structure of iron in MESPMC. The Scherrer equation is used to determine the average crystallite sizes of MESP and MESPMC, which are 22.59 nm and 12.15 nm, respectively. The SEM image shows the irregular shape of the MESP and MESPMC particles, as well as the active coating layer in MESPMC. EDX analysis reveals that Ca (20.92 %), O (56.83 %), and Fe (41.03 %), O (48.83 %) are the most abundant elements in MESP and MESPMC respectively. TGA analysis points out that MESPMC outperforms MESP in terms of thermal stability between 600 and 750 °C. MESP and MESPMC were found to be very efficient adsorbent for lead and methylene blue in aqueous medium. At 40 mg/mL adsorbent dosage, ESP, MESP, and MESPMC had the highest yields of Pb2+ removal, with 46.996 %, 99.27 %, and 99.78 % respectively at 200 rpm for 60 min with 25 °C. Furthermore, at the 0.5 mg/mL adsorbent dosage, ESP, MESP, and MESPMC have the maximum removal efficiency of methylene blue, with 47.19 %, 90.1 %, and 92 %, respectively at 200 rpm for 30 min with 25 °C. In both cases, the removal efficiency of MESPMC is slightly higher than that of MESP and much higher than that of ESP. Additionally, the results confirm that MESP and MESPMC are potential environment-friendly bio sources to remediate heavy metal (Pb2+) and methylene blue dye from water.

Synthesis of hydroxyapatite from eggshells via wet chemical precipitation: a review

In conjunction with the global trend towards sustainable industry, this review provides a summary of the research endeavors and efforts made in the field of exploiting eggshells in the production of hydroxyapatite (HA). HA is one of the most used biomaterials and has attracted considerable attention over the years towards biomedical applications. As the traditional production of HA from calcium and phosphorus chemical precursors synthetically has bottlenecks of being expensive, complex, time consuming, and results in a low biocompatible product, natural resources have become an attractive alternative option to synthesize HA, with trace elements providing a higher performance. Eggshell, with a growing production annually, is potentially a promising natural resource for HA production. Many studies have used different wet chemical precipitation routes to produce HA with properties comparable to synthetic HA. Thus, this review provides an overview of the various routes that can be used to synthesize HA from eggshells. In this review, the synthesis of HA from eggshells via wet chemical precipitation methods is specifically discussed in term of synthesis parameters and properties of the synthesized HA. This review should aid in choosing the most suitable route for HA production with the optimum parameters for obtaining the desired properties to meet the requirements of biomedical applications such as tissue engineering.

Stearate-Coated Biogenic Calcium Carbonate from Waste Seashells: A Sustainable Plastic Filler

Waste seashells from aquaculture are a massive source of biogenic calcium carbonate (bCC) that can be a potential substitute for ground calcium carbonate and precipitated calcium carbonate. These last materials find several applications in industry after a surface coating with hydrophobic molecules, with stearate as the most used. Here, we investigate for the first time the capability of aqueous stearate dispersions to coat bCC powders from seashells of market-relevant mollusc aquaculture species, namely the oyster Crassostrea gigas, the scallop Pecten jacobaeus, and the clam Chamelea gallina. The chemical-physical features of bCC were extensively characterized by different analytical techniques. The results of stearate adsorption experiments showed that the oyster shell powder, which is the bCC with a higher content of the organic matrix, showed the highest adsorption capability (about 23 wt % compared to 10 wt % of geogenic calcite). These results agree with the mechanism proposed in the literature in which stearate adsorption mainly involves the formation of calcium stearate micelles in the dispersion before the physical adsorption. The coated bCC from oyster shells was also tested as fillers in an ethylene vinyl acetate compound used for the preparation of shoe soles. The obtained compound showed better mechanical performance than the one prepared using ground calcium. In conclusion, we can state that bCC can replace ground and precipitated calcium carbonate and has a higher stearate adsorbing capability. Moreover, they represent an environmentally friendly and sustainable source of calcium carbonate that organisms produce by high biological control over composition, polymorphism, and crystal texture. These features can be exploited for applications in fields where calcium carbonate with selected features is required.

Apatite/Chitosan Composites Formed by Cold Sintering for Drug Delivery and Bone Tissue Engineering Applications

In the biomedical field, nanocrystalline hydroxyapatite is still one of the most attractive candidates as a bone substitute material due to its analogies with native bone mineral features regarding chemical composition, bioactivity and osteoconductivity. Ion substitution and low crystallinity are also fundamental characteristics of bone apatite, making it metastable, bioresorbable and reactive. In the present work, biomimetic apatite and apatite/chitosan composites were produced by dissolution-precipitation synthesis, using mussel shells as a calcium biogenic source. With an eye on possible bone reconstruction and drug delivery applications, apatite/chitosan composites were loaded with strontium ranelate, an antiosteoporotic drug. Due to the metastability and temperature sensitivity of the produced composites, sintering could be carried out by conventional methods, and therefore, cold sintering was selected for the densification of the materials. The composites were consolidated up to ~90% relative density by applying a uniaxial pressure up to 1.5 GPa at room temperature for 10 min. Both the synthesised powders and cold-sintered samples were characterised from a physical and chemical point of view to demonstrate the effective production of biomimetic apatite/chitosan composites from mussel shells and exclude possible structural changes after sintering. Preliminary in vitro tests were also performed, which revealed a sustained release of strontium ranelate for about 19 days and no cytotoxicity towards human osteoblastic-like cells (MG63) exposed up to 72 h to the drug-containing composite extract.

Biomimetic Use of Food-Waste Sources of Calcium Carbonate and Phosphate for Sustainable Materials-A Review

Natural and renewable sources of calcium carbonate (CaCO3), also referred to as "biogenic" sources, are being increasingly investigated, as they are generated from a number of waste sources, in particular those from the food industry. The first and obvious application of biogenic calcium carbonate is in the production of cement, where CaCO3 represents the raw material for clinker. Overtime, other more added-value applications have been developed in the filling and modification of the properties of polymer composites, or in the development of biomaterials, where it is possible to transform calcium carbonate into calcium phosphate for the substitution of natural hydroxyapatite. In the majority of cases, the biological structure that is used for obtaining calcium carbonate is reduced to a powder, in which instance the granulometry distribution and the shape of the fragments represent a factor capable of influencing the effect of addition. As a result of this consideration, a number of studies also reflect on the specific characteristics of the different sources of the calcium carbonate obtained, while also referring to the species-dependent biological self-assembly process, which can be defined as a more "biomimetic" approach. In particular, a number of case studies are investigated in more depth, more specifically those involving snail shells, clam shells, mussel shells, oyster shells, eggshells, and cuttlefish bones.

Characterization of Hydrothermally Decomposed and Synthesized CaCO3 Reinforcement from Dead Snail Shells

The development of new materials from marine resources presents a significant challenge due to the complexity of the associated materials and biology technologies. During this work, the snail shell, which naturally increases in thickness over time to protect the snail, has been identified as one of them. In this study, we investigated the use of powdered snail shells as a potential alternative to ceramics in the creation of customized composites. Our main objective is to explore the hydrothermal decomposition of the snail shell powder to remove undesirable components. To achieve this, we crushed and ground-washed dead snail shells and subjected them to hydrothermal decomposition using an autoclave and furnace at a temperature of 200, 220, 250, or 300 °C. We then analyzed the resulting samples using scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) techniques to determine changes in their composition and structure. Our findings demonstrate that all samples contained the elements Ca, C, and O, as confirmed by SEM/EDS results. XRD results show that hydrothermal decomposition at 250 °C led to good crystallization with maximum peak intensities observed at various diffraction angles. This indicates that the resulting material may have promising properties for use in composite materials. Overall, our study provides valuable insights into the use of snail shell powder as a potential material source for customized composites. Future studies could explore the optimization of the hydrothermal decomposition process and investigate the mechanical properties of the resulting materials to further develop this promising avenue of research.

Spherical CaCO3: Synthesis, Characterization, Surface Modification and Efficacy as a Reinforcing Filler in Natural Rubber Composites

Natural rubber (NR), an important natural polymer derived from the Hevea brasiliensis tree, has been widely used in the rubber industry owing to its excellent elastic properties. However, it requires reinforcing fillers to improve its mechanical properties for the manufacturing of rubber products. Generally, calcium carbonate (CaCO3) is employed as a non-reinforcing filler. This work aimed to synthesize spherical-shaped CaCO3 at a submicrometric scale without and with surface treatment and explore its utilization as a reinforcing filler in NR composites. The morphological shape and polymorphic phase of CaCO3 were investigated using SEM, TEM, XRD, ATR-FTIR and Raman techniques. The mechanical properties of various amounts (0 to 60 phr) of CaCO3-filled NR composites were explored. As a result, the NR/treated CaCO3 composites provided higher tensile strength than the NR/untreated CaCO3 composites and pure NR at all filler loadings. This may have been due to the improved interfacial interaction between NR and CaCO3 with the improved hydrophobicity of CaCO3 after treatment with olive soap. The optimal filler loading was 20 phr for the highest tensile strength of the rubber composites. In addition, the elongation at break of the NR/treated CaCO3 was slightly decreased. Evidence from SEM and FTIR revealed the vaterite polymorph and shape stability of CaCO3 particles in the NR matrix. The results demonstrate that the particle size and surface treatment of the filler have essential effects on the mechanical property enhancement of the rubber composites. Synthesized spherical CaCO3 could be a potential reinforcing filler with broader application in polymer composites.

Biowelding 3D-Printed Biodigital Brick of Seashell-Based Biocomposite by Pleurotus ostreatus Mycelium

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.

Biometric and gonadosomatic indices and chemical constituents of edible tissues and exoskeletons of Callinectes amnicola and their potential for reuse in the circular economy paradigm

The study investigates some biological indices and chemical compositions of Callinectes amnicola and their potential for reuse in the context of the circular economy paradigm. The total of 322 mixed-sex C. amnicola collected over a period of six months was examined. The morphometric and meristic characteristics were estimated for biometric assessment. The gonads were obtained from the female crabs for gonadosomatic indices. The shell was obtained using the hand removal technique by detaching it from the crab body. The edible and shell portions were processed separately and subjected to chemical analysis. Our findings showed that females had the highest sex ratio across the six months. The slope values (b) for both sexes exhibited negative allometric growth across all months since the slope values obtained were less than 3 (b < 3). The values obtained for Fulton's condition factor (K) of crabs in all examined months were greater than 1. The edible portion had the highest moisture level at 62.57 ± 2.16% and varied significantly (P < 0.05). The high amount of total ash obtained in the shell sample showed that ash is the main mineral present in crab shells and showed a significant difference (P < 0.05). The shell sample had the highest concentrations of Na and CaCO₃. Based on the findings of this study, it was observed that the shell waste contains some essential and transitional minerals (Ca, CaCO₃, Na, and Mg) and can be utilized as catalysts in several local and industrial applications, such as pigments, adsorbents, therapeutics, livestock feeds, biomedical industries, liming, fertilization, and so on. Proper valorization of this shell waste should be encouraged rather than discarding it.

Studying the Fabrication and Characterization of Polymer Composites Reinforced with Waste Eggshell Powder

Polymeric and plastic materials currently have numerous positive impacts due to their unique properties that make them important for various engineering applications. However, sustainability is a vital factor that should be considered, because of environmental issues. Eggshells (ES) are an important way to reduce the impact of nondegradable materials when applied to reinforce different types of polymer matrices, whether natural or synthetic polymers. Therefore, this study is an attempt to explore the potential application of waste eggshell fillers for the first time as a natural reinforcement in polyamide 12 (PA) composites. PA was loaded with three different ratios (3, 5, and 10 wt. %) of eggshell powder. Morphological studies of the PA powder, ES powder, and their composites were carried out by scanning electron microscopy (SEM). Furthermore, differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were performed to study the thermal and chemical properties of the raw materials and the produced composites. The results indicate ES fillers’ potential usage as a reinforcement material to develop the thermal and chemical properties of the PA polymer matrix composites, thereby reducing costs and minimizing the environmental pollution caused by waste eggshells and petroleum-based polymers.

Starch consolidation of calcium carbonate as a tool to develop lightweight fillers for LDPE-based plastics

Calcium carbonate (CaCO3) is used as a filler to improve the stiffness and processability of plastics at low cost. However, its high density limits the quantity to be used. In this work, the feasibility of using starch consolidation of eggshells-derived CaCO3 (ES) to develop lightweight fillers for low density polyethylene (LDPE)-based materials was studied. Starch, recovered from potato by-products, was combined with ES, gelatinized, dried, and milled as a fine powder. The obtained ES/starch-based particles were then compounded with LDPE and their influence on chromatic, mechanical, morphological, and density properties of mold injected LDPE-based materials was studied. Commercially available CaCO3 (COM) was used as control. ES/starch particles were 18 times less dense than the commercially available CaCO3 (2.62 g cm-3). When incorporated into LDPE-based formulations, ES/starch originated brownish materials with lower density (1.18 g cm-3) and higher stiffness (542 MPa of Young's modulus) than those produced with the COM sample (1.33 g cm-3 of density; 221 MPa of Young's modulus). Therefore, starch consolidation of ES revealed to be a promising approach to develop lightweight fillers able to provide stiffness and color to LDPE-based plastics, while valorizing biomolecules-rich by-products.

Recycled polyester filled with eggshells waste-based nano CaCO3: thermo-mechanical and flame-retardant features

Improved environmental-friendly fire-retardant nanocomposite.

Mechanical Behaviour and Impact of Various Fibres Embedded with Eggshell Powder Epoxy Resin Biocomposite

Natural fiber composites are becoming an alternate material to synthetic fiber composites, and the use of eggshell bio-filler has been explored in polymer composites as environmental protection. Jute, coir, and sisal fibers were utilized in this research to make composites out of natural fibers. Polymer composites were made using epoxy resin with different amounts of eggshell powder (ESP) as fillers (2%, 4%, 6%, 8%, and 10% of weight). The mechanical and biodegradability properties of the synthesized composites were investigated. The testing results showed that composites with an optimum percentage of 6% ESP as filler improved mechanical characteristics significantly in all three fiber composites. Among the three fibers, coir fiber with 6% ESP added showed a substantial increase in tensile, flexural, impact, and hardness strength properties by 34.64%, 48.50%, 33.33%, and 35.03%, respectively. In addition, the percentage weight loss of coir fiber composites at 9 weeks is noteworthy in terms of biodegradability testing. As a result, epoxy composites containing eggshell fillers could be employed in applications requiring better tensile, flexural, impact, and hardness strength.

Versatile Polypropylene Composite Containing Post-Printing Waste

The paper presents the results of the research on the possibility of using waste after the printing process as a filler for polymeric materials. Remains of the label backing were used, consisting mainly of cellulose with glue and polymer label residue. The properly prepared filler (washed, dried, pressed and cut) was added to the polypropylene in a volume ratio of 2:1; 1:1; 1:2; and 1:3 which corresponded to approximately 10, 5, 2.5 and 2 wt % filler. The selected processing properties (mass flow rate), mechanical properties (tensile strength, impact strength, dynamic mechanical analysis) and thermal properties (thermogravimetric analysis, differential scanning calorimetry) were determined. The use of even the largest amount of filler did not cause disqualifying changes in the determined properties. The characteristics of the obtained materials allow them to be used in various applications while reducing costs due to the high content of cheap filler.

Calcium hydroxide recycled from waste eggshell resources for the effective recovery of fluoride from wastewater

In the hunt of waste recovery pathways, eggshells emerged as a potential adsorbent for fluoride because they contain plenty of calcium. However, as the main component, calcite has weak interaction with fluoride. In this study, calcium hydroxide was derived from waste eggshells successfully by an aging treatment with moisture for fluoride recovery from water. The X-ray diffraction (XRD) and infrared spectroscopy (FT-IR) analyses indicate that CaO in calcined egg shells (AEG900) is completely converted to calcium hydroxide. The adsorption experiments showed that the adsorption capacity of AEG900 for fluoride was improved by nearly 29.21% compared with the calcined eggshells without the aging treatment. In the batch experiment, the temperature effect is the most significant for the adsorption process, and nearly a half increment of removal rate is achieved by increasing the temperature by 30 °C. Further research revealed that the adsorption process fitted well with the pseudo-second order model and the Langmuir–Freundlich isotherm model, with a maximum adsorption capacity of 370.15 mg g⁻¹. Moreover, precipitation was regarded as the main step for fluoride removal mechanism based on the calculated results of the surface complexation model. X-ray photoelectron spectroscopy (XPS) results showed that the stable fluorite formed in situ of AEG900 avoids calcium loss in water. Finally, AEG900 was applied in fluoride removal with real-life groundwater and industrial wastewater, and the results showed that the final fluoride concentration could meet the WHO requirement and industrial wastewater discharge standard.

Calcium hydroxide derived from eggshells can remove F⁻ efficiently in water with the adsorption capacity of 370.15 mg g⁻¹, and the final concentration can meet the guidelines of the WHO, which is below 1.5 mg L⁻¹.

Turning Seashell Waste into Electrically Conductive Particles

Biomaterials such as seashells are intriguing due to their remarkable properties, including their hierarchical structure from the nanometer to the micro- or even macroscopic scale. Transferring this nanostructure to generate nanostructured polymers can improve their electrical conductivity. Here, we present the synthesis of polypyrrole using waste seashell powder as a template to prepare a polypyrrole/CaCO3 composite material. Various synthesis parameters were optimized to produce a composite material with an electrical conductivity of 2.1 × 10−4 ± 3.2 × 10−5 S/cm. This work presents the transformation of waste seashells into sustainable, electronically conductive materials and their application as an antistatic agent in polymers. The requirements of an antistatic material were met for a safety shoe sole.

Enhancement of the mechanical and acoustical properties of flexible polyurethane foam/waste seashell composites for industrial applications

The importance of this work is the use of waste seashells WSS (5, 10, 15, 20, 25, and 30 wt.%) as a bio-filler to enhance the mechanical and acoustical characteristics of flexible polyurethane foam (FPU). Petroleum-based polyol was partially replaced by 25% castor oil resulting in high renewable content. The WSS was characterized by X-ray photoelectron spectroscopy (XPS). The chemical structure and morphological features for castor oil-based flexible polyurethane waste seashells (CO-FPU-WSS) composites were detected using Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM) techniques, respectively. Besides, the mechanical, non-acoustical and acoustical properties were investigated. The results indicated that bio-based FPU composites possessed better compressive strength than neat FPU foam. In addition, FPU composites enhance the sound absorption below 500 Hz. A 6 cm air gap behind the sample shifted the absorption toward 400 Hz (0.85) for CO-FPU-WSS 25% composite with a broader band. Thus, the FPU foam composite is considered a promising candidate for sound absorption applications such as for the automotive and building industries.

Tuning polymorphs of precipitated calcium carbonate from discarded eggshells: effects of polyelectrolyte and salt concentration

Biowaste eggshells are a valuable source of calcium carbonate suitable for various applications. In this study, spherical vaterite and calcite calcium carbonate polymorphs have been synthesised from discarded eggshells by the precipitation technique at ambient temperature. The influence of initial salt concentration with different polyelectrolytes such as ethylene glycol (EG), polyethylene glycol (PEG, 600 and 6000), and poly(sodium 4-styrenesulfonate) (PSS) at various w/v% concentrations on the polymorph crystal formation of precipitated calcium carbonate (PCC) particles was studied. The results indicated that PCC crystals with spherical, star-shaped and yarn shaped morphologies can be obtained based on the concentration of calcium ions and the presence of different polyelectrolyte solution. At low salt molar concentration, PEG-6000 and PSS polyelectrolytes were found to promote the formation of spherical vaterite calcium carbonate particles with particle mean diameters of 5.05 μm and 2.17 μm, respectively. Furthermore, silver nanoparticles were also loaded into the PCC particles in situ, and the surface area significantly increased from 2.2813 m2 g-1 in untreated ground eggshells to 30.4632 m2 g-1 in PCC particles in the presence of PSS and silver colloid solution. The EDS mapping revealed the average wt% of silver atoms loaded in PCC particles in the presence of PSS polyelectrolyte was lower (1.44 wt%) than in the presence of PEG-6000 (4.27 wt%) due to the silver encapsulation possibility during the core-shell formation, as confirmed by SEM images. The silver nanoparticle-loaded PCC particles in this study can be incorporated into the polymer matrix and employed for antimicrobial food packaging or wound dressing application.

Manufacturing nano novel composites using sugarcane and eggshell as an alternative for producing nano green mortar

The purpose of this study is to demonstrate the impact of incorporating two different types of green nanomaterials (sugarcane and eggshell) on destructive and non-destructive properties of mortar. Nano sugarcane (NSC) was manufactured by calcining sugarcane at temperatures of 600 °C for 3 h. On the other hand, nano eggshell (NES) was manufactured by calcining eggshell at temperatures of 600 °C for 6 h. The sugarcane ash and eggshell ash were then milled to nano size. The final nano-sized product replaced Portland cement with different dosages of 2, 4 and 6%. Sixteen mortar mixtures were designed and prepared using only NSC or only NES or a combined hybrid of NSC and NES. Consistency, compressive strength, flexural strength and microstructure analysis (scanning electron microscopy and energy-dispersive X-ray) tests were conducted to investigate the influence of replacement materials on the performance and properties of mortars. The results showed that the use of nano sugarcane and nano eggshell enhanced the compressive strength and reduced permeability of green mortar due to the micropore structure. At the ages of 7 and 28 days, mortars containing a replacement ratio of 2% (0.5% NSC + 1.5% NES) had remarkably improved mechanical properties, and the improvement in compressive strength reached 21.3% and flexural strength to 10.08% when compared to the control sample. The efficiency of NSC and NES in increasing mortar strength was also confirmed by microstructure analysis.

Recuperation and characterization of calcium carbonate from residual oyster and clamshells and their incorporation into a residential finish

The final disposal of waste generated by human activities has been turned into a great challenge; until now, little attention has been paid to organic waste, particularly from the restaurant sector. This work describes the process of obtaining calcium carbonate contained in oyster and clam shells re-collected in seafood restaurants. The IR absorption spectra of all the samples revealed the presence of characteristic bands of the carbonate group located at 872, 712 and 1414 cm^-1; the peak at 1081 cm^-1 of the clamshells confirms the presence of the aragonite phase. The SEM images allow observing a granular morphology whose agglomerates having a size within the range of 0.5-15 μm in brown shells, and a lower dispersion prevails in the grey species and oyster shells that go from 0.3 to 5.9 μm. All of the shells were found to be composed of carbon (C), oxygen (O₂) and calcium (Ca) in different concentrations. The calcium carbonate obtained from clamshells has an orthorhombic crystalline structure, while the oyster carbonate has a rhombohedral structure as the calcium carbonate used in the construction industry; the morphology particles also coincide with each other. The material obtained combined with a mixture composed of resin, cellulose, and granules were used to prepare a paste, which was used as a residential finish.

Process Technology for Development and Performance Improvement of Medical Radiation Shield Made of Eco-Friendly Oyster Shell Powder

As radiation-based techniques become increasingly important tools for medical diagnostics, medical professionals face increasing risk from the long-term effects of scattered radiation exposure. Although existing radiation-shielding products used in medicine are traditionally lead-based, recently, the development of more eco-friendly materials such as tungsten, bismuth, and barium sulfate has drawn attention. However, lead continues to be superior to the proposed alternative materials in terms of shielding efficiency and cost effectiveness. This study explores the feasibility of radiation shielding materials based on the shells of bivalve mollusks such as oysters that are discarded from aquaculture, thereby preventing them from going into landfills. In addition, a firing process for enhancing the shielding efficiency of the original material is proposed. Experiments show that shielding sheets comprising 0.3 mm thick layers of oyster shell achieve a shielding efficiency of 37.32% for the low-energy X-rays typically encountered in medical institutions. In addition, the shielding efficiency was improved by increasing the density of the powdered oyster shell via plastic working at 1200 °C. This raises the possibility of developing multi-material radiation shields and highlights a new potential avenue for recycling aquaculture waste.

Characterization of CaCO3 Filled Poly(lactic) Acid and Bio Polyethylene Materials for Building Applications

Noise pollution has been identified as a cause of a broad spectrum of diseases, motivating researchers to identify building materials capable of attenuating this pollution. The most common solution is the use of gypsum boards, which show a good response for low frequencies but have a poorer response for high frequencies. In addition, due to environmental concerns associated with buildings, the use of materials that minimize environmental impacts must be favored. In this research, two biopolymers, a poly(lactic) acid and a bio-polyethylene, were filled with two typologies of calcium carbonate, and their soundproofing properties were tested using impedance tubes. In addition, the morphology of the fillers was characterized, and here we discuss its impact on the mechanical properties of the composites. The results showed that the incorporation of calcium carbonate into bio-based thermoplastic materials can represent a strong alternative to gypsum, because their mechanical properties and sound barrier performance are superior. In addition, the inclusion of mineral fillers in thermoplastic materials has a positive impact on production costs, in addition to preserving the advantages of thermoplastics in terms of processing and recycling. Although the use of carbonate calcium decreases the mechanical properties of the materials, it enables the production of materials with insulation that is four-fold higher than that of gypsum. This demonstrates the potential of these materials as building lightweight solutions.

Biotechnological Applications of Eggshell: Recent Advances

The eggshell (ES) provides protection against pathogenic and physical insults while supplying essential metabolic and nutritional needs for the growing avian embryo. It is constituted mainly of calcium carbonate arranged as calcite crystals. The global chicken egg production in 2018 was over 76.7 million metric tons. In industrialized countries, about 30% of eggs are processed at breaker plants that produce liquid egg products and large quantities of solid ES waste. ES waste is utilized for a variety of low-value applications, or alternatively is disposed in landfill with associated economic and environmental burdens. The number of patents pertaining to ES applications has increased dramatically in recent years; of 673 patents granted in the last century, 536 (80%) were published in the last two decades. This review provides a snapshot of the most recent patents published between 2015 and 2020, with emphasis on different biotechnological applications of ES waste, and summarizes applications for biomedical, chemical, engineering, and environmental technologies. Biomedical technologies include the production of calcium lactate, calcium phosphate, and health-promoting products, while chemical technologies include plant growth promoters, food processing and production, and biodiesel oil catalysis along with active calcium, carbon, soluble proteins, organic calcium, and ultrafine calcium carbonate sources. Engineering technologies address material engineering and nanoparticle production, while environmental technologies pertain to production of biomass, solubilization of sludge as well as production of magnetic ES adsorbents and adsorption of heavy metals, organics, total nitrogen and fluoride, soil pollutants, and radioactive compounds. Although the number of ES-based patents has exponentially increased in the last decade, exploration of innovative top-down approaches and ES development as a physical platform are new endeavors that are expected to further increase the upscaling of ES waste exploitation.

Physicochemical Characteristics of Chicken Eggshell Flour Produced by Hydrochloric Acid and Acetic Acid Extraction

Backgrdound: Several previous researchers have prepared chicken eggshell flour using hydrochloric acid (HCl) and acetic acid (CH3COOH) solvents. However, the results of the physicochemical characteristics still very diverse. This study aims to produce chicken eggshell flour using two different types of solvents (4% HCl and CH3COOH 2N) and determine the proper solvent to obtain better physicochemical characteristics. Method: This type of research was descriptive quantitative. The research stages initiated by preparing chicken eggshell samples by maceration using 4% HCl and CH3COOH 2N. Afterward, chemical characteristics (moisture content, ash, calcium carbonate, calcium, and phosphorus) and physical characteristics (yield) of eggshell flour were determined. Processing and data conducted by using the IBM SPSS statistic program Result: The higher levels of calcium, calcium carbonate, phosphorus, ash, yield, and lower water content of the eggshell powder were generated by extraction using 4% HCl than 2N acetic acid (CH3COOH). Conclusion: The physicochemical characteristics of the eggshell powder extracted from the 4% HCl were better than the 2N acetic acid (CH3COOH)

Transfer of enrofloxacin, ciprofloxacin, and lincomycin into eggshells and residue depletion in egg components after multiple oral administration to laying hens

Regardless of whether antimicrobial drugs are administered to laying hens legally or illegally, residues of these drugs may be present in the eggs. Even if the eggs are not intended for human consumption, byproducts/biowaste, such as eggshells, may contain residues of the drugs used, which may pose a risk to human health and the environment. In the presented research, 2 different groups of laying hens received enrofloxacin (10 mg/kg body weight) and lincomycin (20 mg/kg body weight) once daily for 5 d. Eggs were collected daily and the concentration of enrofloxacin, its metabolite ciprofloxacin, and lincomycin residue in the eggshells, whole eggs, egg yolks, and egg whites were determined by ultra-high-performance liquid chromatography-tandem mass spectrometry. This study demonstrates the transfer of enrofloxacin, ciprofloxacin, and lincomycin into the eggshells and provides evidence for the distribution into the eggshells after administration of these drugs to laying hens. The enrofloxacin residues were detected in the eggshell for 10 d after cessation of treatment, ciprofloxacin and lincomycin were rapidly eliminated and 2 d after finish drugs administration they were no longer detected in the eggshell.

Thermally Induced Aragonite-Calcite Transformation in Freshwater Pearl: A Mutual Relation with the Thermal Dehydration of Included Water

This study focuses on the relationship between the aragonite-calcite (A-C) transformation and the thermal dehydration of included water in the biomineralized aragonite construction using freshwater pearl. These thermally induced processes occur in the same temperature region. The thermal dehydration of included water was characterized through thermoanalytical investigations as an overlapping of three dehydration steps. Each dehydration step was separated through kinetic deconvolution analysis, and the kinetic parameters were determined. A single-step behavior of the A-C transformation was evidenced using high-temperature X-ray diffractometry and Fourier transform infrared spectrometry for the heat-treated samples. The kinetics of the A-C transformation was analyzed using the conversion curves under isothermal and linear nonisothermal conditions. The A-C transformation occurred in the corresponding temperature region of the thermal dehydration, ranging from the second half of the second dehydration step to the first half of the third dehydration step. Because the thermal dehydration process is constrained by the contracting geometry kinetics, the movement of the thermal dehydration reaction interface can be a trigger for the A-C transformation. In this scheme, the overall kinetics of the A-C transformation in the biomineralized aragonite construction is regulated by a contracting geometry.

Thermo-Mechanical and Morphological Properties of Polymer Composites Reinforced by Natural Fibers Derived from Wet Blue Leather Wastes: A Comparative Study

The present work investigated the possibility to use wet blue (WB) leather wastes as natural reinforcing fibers within different polymer matrices. After their preparation and characterization, WB fibers were melt-mixed at 10 wt.% with poly(lactic acid) (PLA), polyamide 12 (PA12), thermoplastic elastomer (TPE), and thermoplastic polyurethane (TPU), and the obtained samples were subjected to rheological, thermal, thermo-mechanical, and viscoelastic analyses. In parallel, morphological properties such as fiber distribution and dispersion, fiber-matrix adhesion, and fiber exfoliation phenomena were analyzed through a scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) to evaluate the relationship between the compounding process, mechanical responses, and morphological parameters. The PLA-based composite exhibited the best results since the Young modulus (+18%), tensile strength (+1.5%), impact (+10%), and creep (+5%) resistance were simultaneously enhanced by the addition of WB fibers, which were well dispersed and distributed in and significantly branched and interlocked with the polymer matrix. PA12- and TPU-based formulations showed a positive behavior (around +47% of the Young modulus and +40% of creep resistance) even if the not-optimal fiber-matrix adhesion and/or the poor de-fibration of WB slightly lowered the tensile strength and elongation at break. Finally, the TPE-based sample exhibited the worst performance because of the poor affinity between hydrophilic WB fibers and the hydrophobic polymer matrix.

A Survey of Recent Patents in Engineering Technology for the Screening, Separation and Processing of Eggshell

The chicken egg is a well-known complete food of human daily consumption which serves as a cost-effective, high-quality nutrient resource. About 30% of table eggs are directed to breaker plants in developed countries, leading to the generation of substantial eggshell (ES) waste, which is increasingly explored for potential value-added applications. The number of patents describing ES-based applications has increased dramatically in recent years. This review provides insight into the most recent patents published between 2015 and 2020, with focus on different engineering technologies for the screening, separation, and processing of ES. Screening technologies include detection of ES surface spots and glossiness, ES cracks, and mechanical properties, along with identification of chicken breed and enumeration of surface bacterial count. Collection and separation technologies describe separation strategies of ES from egg white (EW), egg yolk (EY), liquid egg, eggshell membrane (ESM), hatchlings, and cooked egg. Separation of ES from liquid eggs utilizes gravity, rotational forces, or air pressure. Processing of ES involves washing and sterilization along with cutting, crushing, and pulverization technologies that enable the collection of ES suitable for value-added applications. In addition, ES carving (mechanical and laser) opens up the realm of artwork and decoration. Furthermore, intact ES can be utilized for food serving. The exponential increase in innovative screening, separation, collection, and processing technologies reflects industrial interest to upscale low-value ES waste material, and is a first crucial step in the emergence of advanced technologies that exploit the biomedical, chemical, engineering, and environmental applications for ES.

Multi-Class Procedure for Analysis of 50 Antibacterial Compounds in Eggshells Using Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

In this work, for the first time, Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry (UHPLC–MS/MS) method was developed for qualitative and quantitative analysis of veterinary antibiotics (cephalosporins, diaminopyrimidines, fluoro(quinolones), lincosamides, macrolides, penicillins, pleuromutilins, sulfonamides, tetracyclines, and sulfones) in hen eggshells. The sample preparation method is based on a liquid–liquid extraction with a mixture of metaphosphoric acid, ascorbic acid, EDTA disodium salt dihydrate, and acetonitrile. The chromatographic separation was performed on Luna^® Omega Polar C18 10 column in gradient elution mode and quantitated in an 8 min run. Validation such as linearity, selectivity, precision, recovery, matrix effect, limit of quantification (LOQ), and limit of detection (LOD) was found to be within the acceptance criteria of the validation guidelines of the Commission Decision 2002/657/EC and EUR 28099 EN. Average recoveries ranged from 81–120%. The calculated LOQ values ranged from 1 to 10 µg/kg, the LOD values ranged from 0.3 to 4.0 µg/kg, depending on analyte. The developed method has been successfully applied to the determination of antibacterial compounds in hen eggshell samples obtained from different sources. The results revealed that enrofloxacin, lincomycin, doxycycline, and oxytetracycline were detected in hen eggshell samples.

Recent Advances in Marine-Based Nutraceuticals and Their Health Benefits

The oceans have been the Earth's most valuable source of food. They have now also become a valuable and versatile source of bioactive compounds. The significance of marine organisms as a natural source of new substances that may contribute to the food sector and the overall health of humans are expanding. This review is an update on the recent studies of functional seafood compounds (chitin and chitosan, pigments from algae, fish lipids and omega-3 fatty acids, essential amino acids and bioactive proteins/peptides, polysaccharides, phenolic compounds, and minerals) focusing on their potential use as nutraceuticals and health benefits.