Eggshell Waste Research Articles

WASTE EGGSHELL AND SAWDUST AS REINFORCEMENTS FOR SUSTAINABLE POLYESTER COMPOSITES: MECHANICAL CHARACTERIZATION AND ENVIRONMENTAL DURABILITY ASSESSMENT

This research endeavor undertakes an experimental investigation into the bending and tensile properties of polyester composites reinforced with waste eggshell powder and sawdust particles at 35 wt.%. Valorizing these waste materials as reinforcements contributes to sustainable practices, waste minimization, and environmental pollution mitigation. Composite samples were fabricated using hand lay-up and compression molding techniques. The effects of environmental exposure to water, acidic, and basic media immersion on the mechanical performance were evaluated to assess durability. Experimental characterization through tensile and three-point bending tests determined mechanical properties, stress-strain behavior, and failure mechanisms. Additionally, finite element analysis (FEA) simulations complemented the experiments by providing insights into stress distributions, deformations, and potential failure initiation sites within the composites under flexural loading. The computational models accurately captured the reinforcing effects of the waste materials and the degradation induced by environmental exposure, validating the experimental trends. Incorporating waste natural fibers significantly enhanced polyester's bending strength by 140% (sawdust) and 75% (eggshell), and tensile strength by 13% (sawdust) and 10% (eggshell). However, environmental exposure degraded properties to varying extents, with water immersion reducing tensile strength by 63% (sawdust) and 3% (eggshell), and flexural strength by 63% (sawdust) and 3% (eggshell). The acidic medium caused 58% (sawdust) and 23% (eggshell) reductions in tensile strength, and similar flexural strength degradations. Strikingly, the basic medium decreased eggshell composite tensile strength by 170% and flexural strength by 6%, while sawdust composite strengths declined by 44%.

Assessment of waste eggshell powder as a limestone alternative in portland cement

The decarbonization of the concrete industry is an ongoing pursuit. One solution towards this goal is the use of limestone powder in portland cement. Waste eggshell has tremendous potential as an alternative calcite filler in cement due to its similarities with limestone. In this research, the feasibility of adding 15% and 35% ground eggshell in portland cement to make cement mortars was investigated. The hydration mechanism of eggshell and limestone blended cements was compared through the heat of hydration, phase assemblage, electrical resistivity, compressive strength, and shrinkage measurements. The experimental results showed that cement mortars with ground eggshell attained similar compressive strength as that with limestone. However, eggshell mixtures demand more mixing water to compensate the hydrophobicity of the eggshell membrane. The high calcite content in both eggshell and limestone accelerates the hydration of cement at 15% replacement, but ground eggshell retards cement hydration at 35% replacement due to the dominant influence of the membrane. Overall, eggshell waste is a feasible sustainable alternative to limestone powder at up to 15% portland cement replacement levels. Lifecycle assessment and cost analysis showed that adding 15% ground eggshell in cement concrete further reduces its embodied carbon and energy and cost compared to cement concrete containing limestone powder.

Improved visualisation of ACP-engineered osteoblastic spheroids: a comparative study of contrast-enhanced micro-CT and traditional imaging techniques

This study investigates osteoblastic cell spheroid cultivation methods, exploring flat-bottom, U-bottom, and rotary flask techniques with and without amorphous calcium phosphate (ACP) supplementation to replicate the 3D bone tissue microenvironment. ACP particles derived from eggshell waste exhibit enhanced osteogenic activity in 3D models. However, representative imaging of intricate 3D tissue-engineered constructs poses challenges in conventional imaging techniques due to notable scattering and absorption effects in light microscopy, and hence limited penetration depth. We investigated contrast-enhanced micro-CT as a methodological approach for comprehensive morphological 3D-analysis of thein-vitromodel and compared the technique with confocal laser scanning microscopy, scanning electron microscopy and classical histology. Phosphotungstic acid and iodine-based contrast agents were employed for micro-CT imaging in laboratory and synchrotron micro-CT imaging. Results revealed spheroid shape variations and structural integrity influenced by cultivation methods and ACP particles. The study underscores the advantage of 3D spheroid models over traditional 2D cultures in mimicking bone tissue architecture and cellular interactions, emphasising the growing demand for novel imaging techniques to visualise 3D tissue-engineered models. Contrast-enhanced micro-CT emerges as a promising non-invasive imaging method for tissue-engineered constructs containing ACP particles, offering insights into sample morphology, enabling virtual histology before further analysis.

Selective Leaching of Lithium and Beyond: Sustainable Eggshell-Mediated Recovery from Spent Li-Ion Batteries

This study introduces an innovative strategy for the selective leaching of lithium from spent Li-ion batteries. Based on thermodynamic assessments and exploiting waste eggshells as a source of calcium carbonate, an impressive 38% of lithium was dissolved selectively through mechanical milling and water leaching, outperforming conventional thermochemical methods. Afterwards, a hydrogen peroxide-assisted sulfuric acid leaching was also implemented to solubilize targeted elements (Mn, Co, Ni, and Li), with an exceptional 99% efficiency in Mn removal from the leachate using potassium permanganate and a pH range of 1.5 to 3.5. Selective separations of Co and Ni were then facilitated utilizing CYANEX 272 and n-heptane. This comprehensive study presents a promising and sustainable avenue for the effective recovery of Li and associated co-elements from spent lithium batteries.

High Sensitive and Discriminating Colorimetric Assay for S2- Overload in Adaptogenic Herbs Utilizing ZnS Nanoparticle-Enhanced S, N-Doped Eggshell Membrane-Derived Biochar

BackgroundWith the rapid development of industrialization, the excessive emission of S2− have become increasingly serious, leading to a surge in the content of S2− in nature. Rapid and accurate detection of S2- contamination in natural adaptogens is crucial for food safety. Annually, discarded eggshell waste, rich in organic and inorganic materials, poses environmental risks if landfilled. Utilizing waste eggshell membrane biomass for S2- detection is cost-effective, yet designing biochar materials for sensors requires balancing catalytic enhancement and anti-interference capabilities. Improving the catalytic performance of biochar for colorimetric S2- detection without metal ion interference presents a challenging issue. ResultsWe first modified biochar (EBc) derived from waste eggshell membranes using a combination of thiourea and ZnS nanoparticles, fabricating ZnS-decorated, S-N co-doped biochar (ZnS-SN-EBc) nanozymes, which were applied for the colorimetric assay detection of S2- contamination. The addition of thiourea significantly increases the proportion of pyridinic-N in biochar, enhancing the peroxidase-like activity of the nanozyme. The growth of ZnS nanoparticles on the biochar not only enhances the catalytic performance by increasing the S content but also reduces the content of oxidized S, thereby improving resistance to interference. The detection range for S2- was expanded from 0.1 to 45 μM for EBc to 0.05 to 225 μM for ZnS-SN-EBc, and the limit of detection improved to 0.0397 μM. Additionally, ZnS-SN-EBc significantly enhanced metal ion interference resistance. S2- detection in five types of adaptogenic herbs verified the accuracy and practicality of the colorimetric assay, with recovery rates comparable to national standards. SignificanceWe innovatively repurposed waste eggshell membranes to develop a selective and catalytic peroxidase-like nanozyme, ZnS-decorated S-N co-doped biochar (ZnS-SN-EBc). The developed colorimetric assay utilizing ZnS-SN-EBc demonstrates significant potential for the detection of sulfur ions in adaptogenic herbs, thus contributing to both waste resource utilization and the advancement of food safety detection technologies.

Application of waste eggshells elevates phytoremediation efficiency of Pb-Zn mine-contaminated farmland and mitigates soil greenhouse gas emissions: A field study

Remediating heavy metal (HM)-contaminated farmlands and sequestering soil carbon for emission reduction have been prominent topics in environmental research in recent years. However, few studies have looked into the soil greenhouse gas (GHG) impacts of growing hyperaccumulators in composite HM-contaminated farmland, as well as agronomic measures to remediate soil HMs while mitigating GHG emissions. To investigate fertilization measures to improve phytoremediation efficiency and mitigate GHG emissions, S. photeinocarpum was planted with three different fertilization measures on farmland contaminated by lead-zinc (Pb-Zn) mines (1200 kg ha−1 eggshell, 125 kg ha−1 28-homobrassinolide, and 16.7 kg ha−1 mineral potassium fulvic acid) during its growth period. The findings are as follows: Eggshell application significantly enhanced the translocation factor (TF) of Pb, Zn, and cadmium (Cd) from the roots to the shoots of Solanum photeinocarpum. Moreover, eggshells notably increased the bioaccumulation factor (BCF) of Cd and Pb in plant shoots by 120.75% and 159.09%, respectively. Regarding GHG emissions, the combined application of eggshells and 28-homobrassinolide substantially lowered the global warming potential (GWP) of the soil. Correlation analyses revealed that eggshell application increased the relative abundance of the Gemmatimonadota bacterial phylum in the soil, facilitating Pb and Cd migration from the roots to shoot tissues in S. photeinocarpum. Eggshell use inhibited nitrate nitrogen (NO3−-N) transformation into nitrous oxide (N2O) by the Myxococcota bacterial phylum and reduced N2O release from the soil. The application of low-cost eggshells can achieve a win-win situation of soil HM remediation and GHG emission reduction, as well as provide simple and scalable management measures for HM-contaminated farmland.

A mini-review on egg waste valorization.

Each year, approximately million tons of waste is generated from eggshells disposed of in landfills. This waste is challenging to manage because of the odor and microbiological development. However, eggshells have potential applications as a solid byproduct. They can be modified and used in various industries such as metal, polymer and ceramic composites, in the production of biodiesel, heavy metal absorption from wastewater, and even as a biomaterial to substitute bone tissues. Furthermore, eggshells can be used as a cheap adsorbent for the treatment of contaminated waterways. They are also a great source of calcium and fertilizer for plants, animals and humans. Chicken eggshells can even be used as a catalyst for converting waste frying oil into biofuel. This review highlights the challenges and opportunities of eggshell waste valorization in the food industry. © 2024 Society of Chemical Industry.

Analisa Perbandingan Biaya dan Mutu Beton Menggunakan Serbuk Cangkang Telur untuk Mereduksi Pemakaian Semen

Concrete is a very important construction material in construction so that the use of concrete is widely used. In the use of conventional concrete, there are many problems that arise, such as the use of so much cement that can affect the environment. In this study, the use of eggshell powder will be used to reduce the amount of cement in the proportion of the concrete constituent mixture as well as in the use of powder and can reduce the cost of using cement which is relatively expensive. In addition, chicken egg shell waste contains calcium carbonate where it is known that one of the constituent ingredients of Portland Cement (SP) is calcium carbonate. This study uses SNI 03-2834-2000, to calculate the proportion of the concrete mixture. Testing the compressive strength of this concrete using cylindrical specimens with a diameter of 150 mm (0.15 m) and a height of 300 mm (0.30 m) as many as 15 samples with the amount of chicken egg shell powder used at 0%, 1%, 2%, 3% and 4%. From the results of testing the average compressive strength at the age of 7 days and then converted to the age of 28 days, the average compressive strength at 0% eggshell percentage is 25.76 MPa, 1% is 22.80 MPa, 2% is 20.43 MPA, 3% is 20.13 MPa, 4% is 19.98 MPa. The greater the percentage of chicken egg shell powder, the compressive strength of the concrete decreases. For the cost of 0% concrete mix is Rp. 11,414.5, 1% is Rp. 11,342.5, 2% is Rp. 11,270.5 3% is, Rp. 11,198.5, 4% is Rp. 11,150.5 the cost of concrete using egg shell powder relatively cheaper.

Synthesis of eco-friendly CaCO3@Zn-Al MMO core-shell nanoflowers photocatalyst using bio–eggshell waste for improved photocatalytic degradation of RhB under visible light irradiation

In this study, a type-I heterojunction was synthesized based on eggshell waste doped mixed metal oxide (ES@ZnAl MMO) for the degradation of RhB dye under visible light irradiation. The ES@ZnAl MMO core-shell was synthesized using waste eggshell and layered double hydroxide (LDH) as primary precursors. After their mechanochemical assembly and thermal treatment, CaCO3 was formed in both calcite and vaterite forms, alongside mixed metal oxides derived from the LDH (ZnO and Al2O3). The formation of a heterojunction between the semiconductors results in an improved activation of sites, a decrease in bandgap energy from 5.72 to 3.44 eV, and an increase in degradation capacity. The elemental composition, morphology, structural, and optical properties of the ES@ZnAl MMO nanocomposite were analyzed using various techniques. The optimal ES@ZnAl MMO photocatalyst demonstrated superior performance, reaching over 98% of RhB dye degradation under optimal conditions, outperforming pure ZnAl LDH, ZnAl MMO, and ES. After five run cycles, the ES@ZnAl MMO heterojunction still maintained a high photocatalytic performance for RhB dye (99%). Furthermore, it displayed high performance in degrading various other pollutants, including OG, IC, MB, and 2.4-DP, with degradation efficiencies of 97%, 99%, 99%, and 87%, respectively. This economically advantageous heterojunction showed its importance in environmental remediation, presenting a promising solution for addressing diverse pollution challenges.

Eco-Friendly Facile Conversion of Waste Eggshells into CaO Nanoparticles for Environmental Applications.

Amongst the many types of food waste, eggshells contain various minerals and bioactive materials, and they can become hazardous if not properly disposed of. However, they can be made useful for the environment and people by being converted to environmentally friendly catalytic materials or environmental purification agents. Simple calcination can enhance their properties and thereby render them suitable for catalytic and environmental applications. This work aimed to prepare CaO from waste eggshells and examine its effectiveness in photocatalytic pollution remediation, electrocatalytic activity, optical sensing, and antibacterial activities. As opposed to other techniques, this calcination process does not require any chemical reagents due to the high purity of CaCO3 in eggshells. Calcium oxide nanoparticles were prepared by subjecting waste eggshells (ES) to high-temperature calcination, and the synthesized CaO nanoparticles were characterized for their structural, morphological, chemical, optical, and other properties. Furthermore, their photocatalytic degradation of methylene blue dye and antibacterial efficiency against Escherichia coli and Staphylococcus aureus were investigated. It was found that the green-converted CaO can be efficiently used in environmental applications, showing good catalytic properties.

Valorization of Eggshell as Renewable Materials for Sustainable Biocomposite Adsorbents—An Overview

The production and buildup of eggshell waste represents a challenge and an opportunity. The challenge is that uncontrolled disposal of generated eggshell waste relates to a sustainability concern for the environment. The opportunity relates to utilization of this biomass resource via recycling for waste valorization, cleaner production, and development of a circular economy. This review explores the development of eggshell powder (ESP) from eggshell waste and a coverage of various ESP composite sorbents with an emphasis on their potential utility as adsorbent materials for model pollutants in solid–liquid systems. An overview of literature since 2014 outlines the development of eggshell powder (ESP) and ESP composite adsorbents for solid–liquid adsorption processes. The isolation and treatment of ESP in its pristine or modified forms by various thermal or chemical treatments, along with the preparation of ESP biocomposites is described. An overview of the physico-chemical characterization of ESP and its biocomposites include an assessment of the adsorption properties with various model pollutants (cations, anions, and organic dyes). A coverage of equilibrium and kinetic adsorption isotherm models is provided, along with relevant thermodynamic parameters that govern the adsorption process for ESP-based adsorbents. This review reveals that ESP biocomposite adsorbents represent an emerging class of sustainable materials with tailored properties via modular synthetic strategies. This review will serve to encourage the recycling and utilization of eggshell biomass waste and its valorization as potential adsorbent systems. The impact of such ESP biosorbents cover a diverse range of adsorption-based applications from environmental remediation to slow-release fertilizer carrier systems in agricultural production.

Effect of Process Parameters on the Tensile Strength of the Developed Composite of Al 6065 in Stir Casting Process

There are numerous techniques of producing metal matrix composites (MMC) like infiltration, stir casting process, sinter-forging, diffusion bonding etc. Stir casting process is amongst the most known technique to synthesize MMC. In current study an agro-based MMC is prepared by stir casting process using waste eggshell and rice husk as primary and secondary reinforcements and Al 6065 as base material. Process parameters (PP) have a major impact on tensile strength of finally prepared composite. The major factors also called as process parameters in stir casting process that is having a determining impact in tensile strength of hybrid MMC are temperature as well as speed of stirring, duration of stirring and temperature at which the reinforcement is allowed to be poured. The primary aim behind the current work is to evaluate the optimal values of process parameters in friction stir casting process. 9 separate samples have been prepared at different PP for analyzing tensile strength of composite and these samples were machined as per the ASTM standards for performing the test of tensile strength. It was concluded that maximum tensile strength value was found at a stirring speed of 320 rpm, optimal stirring temperature was 630°C and the time of stirring was 25 minutes. At these values of PP, the tensile strength of prepared composite was improved by 35% in contrast to that of the base material.

Synthesis of nanoporous carbon from Ulva lactuca activated by eggshell for CO2 capture: a novel approach to waste valorization.

Facing the daunting challenge of climate change, driven by escalating greenhouse gas concentrations, our research introduces an innovative solution for CO2 capture. We explore a novel nanoporous carbon derived from Ulva lactuca, activated with eggshell waste, spotlighting waste valorization in mitigating atmospheric CO2. Through a systematic methodology encompassing variable carbonization temperatures (700-900°C) and nitrogen flow rates (2-4ml/min), complemented by a suite of characterization techniques, we unveil the synthesis of this pioneering adsorbent. Our study not only presents a novel, sustainable pathway for CO2 capture but also demonstrates superior performance, particularly with the NC800-4 sample, achieving a CO2 capture capacity of 1.40mmol/g at 30°C, alongside demonstrating consistent adsorption efficiency over four successive adsorption/desorption cycles. This breakthrough underscores the potential of leveraging waste for environmental remediation, offering a dual solution to waste management and carbon capture, utilization, and storage (CCUS) applications.

Radiation shielding and spectroscopic features of replacement materials: Reusing of agricultural and industrial wastes

Environmental pollution increases due to the large amounts of waste production and raw material consumption depending on the increasing population. Agricultural and industrial wastes which are some of the sources of the pollution need to be reuse to reduce the negative impact on the environment and also contribute positive effect to the economy. In this context, industrial wastes such as clay types (red and green) and agricultural wastes such as egg shell, walnut shell and banana shell were used to prepare materials which can be used as replacement materials for construction industry. Radiation attenuation parameters (mass attenuation coefficients, effective atomic number, linear attenuation coefficients, mean free path, half-value layer, exposure and energy absorption build up factors, fast neutron removal cross-section) were acquired by Phy-X/PSD code. Spectroscopic techniques (XRD, EPR, SEM-EDS) were performed for the structural analysis. The existence of calcite main phase peaks (≈29.7) as well as SiO2 (≈20° and 26°) and cellulose phases (≈16° and 34.7°) were observed by XRD. Mn+2 sextet lines with five weak doublets attributed to the forbidden transition lines of Mn+2 and a singlet with a g value of ≈2.00 and linewidth of ≈10 G were recorded by EPR. Among the samples, it was found that K1 (Red clay (20%)-eggshell waste (60%)-Bayburt stone waste (20%)), K3 (Red clay (60%)-eggshell waste (20%)-Bayburt stone waste (20%)), C3 (Red clay (60%)-eggshell waste (20%)-walnut shell waste (20%)) and Z3 (Green clay (60%)-egg shell waste (20%)-Bayburt stone waste (20%)) have the highest shielding potentials. All samples examined with good protection performances can be used as substitute materials instead of cement or aggregate for the aim of reusing the wastes and supporting the environmental and economic benefits.

Eggshell waste extract as potential natural corrosion inhibitor for AISI 1020 steel in acidic environment

Eggshell waste extract as potential natural corrosion inhibitor for AISI 1020 steel in acidic environment

Use of Various Industrial and Eggshell Wastes for the Sustainable Construction Sector

The alternative composites’ production alleviates the serious problem generated by global warming. Methods to reduce the amount of cement used in concrete production, for example, are being investigated to determine how to reduce carbon dioxide emissions in many applications. Egg shells and various industrial wastes, which are recommended to use in the construction sector at an appropriately high rate, also cause serious environmental damage. Bottom ash (BA) and marble powder (MP) wastes are used today in civil engineering applications. In addition, it is important to increase the use of eggshells due to their rich calcium carbonate content. In this work, BA and MP wastes were blended with eggshells to produce cement paste composites. Two different sets of composites were prepared during this study. The composites were prepared with cement (80%), BA (20%), and MP (20%) wastes by weight with 0.3%, 0.75%, 1.5%, and 2.5% eggshell waste. The fresh (flow table), physical (dry unit mass, apparent specific gravity, and porosity), mechanical (unconfined compressive strength and flexural strength), and durability (water absorption, seawater resistance) tests were conducted. According to the experimental results, the composites can be classified as lightweight construction materials. The test results showed that 0.75% eggshell by weight of cement in bottom ash and marble powder can be used as an optimum value for better performance. The bottom ash mixtures groups are higher water absorption and porosity values when referring to the marble powder mixture groups. The highest compressive strength value was found at 56.03 MPa in the MP mixture group and 52.79 MPa in the BA mixture groups with these optimum eggshell combinations at 56 days. The MP mixture group showed better resistance to seawater when referring to the bottom ash blended mixtures. Laboratory-produced composites are possible candidates for cost-effective and environmentally friendly building materials. The eggshells have a promising alternative binder for concrete in the near future and they are utilized together with industrial wastes such as BA and MP in sustainable concrete construction.

Potentiality of eggshell waste in synthesis of functional metal-organic frameworks for fuel purification

Nitrogen containing compounds in the liquid fuel are well-known to cause serious corrosive action on the engines and plugging of filters with the formation of gummy compounds. Hence, the removal of nitrogenated compounds from the liquid fuel is highly demanded. The current study focused on the efficient removal of indole and quinoline (as nitrogenated compounds) by Ca based metal organic framework. Formerly, Ca based metal organic framework was synthesized using eggshell wastes as source of Ca by Solvothermal [Ca-BTC (s)] and Microwave [Ca-BTC (m)] techniques. Flower and shell plates like crystals were observed under microscope for the synthesized Ca-BTC (s) and Ca-BTC (m), respectively. Purification of liquid fuel from indole and quinoline by the obtained Ca-BTC was systematically investigated. The adsorption of nitrogenated compounds followed the second order reaction and Langmuir isotherm. Microwave technique showed to be more preferable rather than solvothermal technique, for preparation of Ca-BTC with significantly higher adsorption capacity, whereas, and the affinity was higher towards quinoline compared to indole. Meanwhile, for Ca-BTC (m), the estimated maximum adsorption capacity of indole and quinoline was 490.7 mg/g and 583.4 mg/g, respectively. After 4 regeneration cycles, the adsorption capacity Ca-BTC (m) was lowered by 29 % for indole and 24 % for quinoline. The obtained results confirmed the successful using of eggshell wastes in preparation of Ca-BTC with remarkable efficiency in the liquid fuel purification with quite good recyclability.

Evaluation of the potential use of chicken eggshell waste to manufacture dense/porous bi-layered red floor tiles

Chicken eggshell waste is a significant global source of waste, which calls for sustainable valorization approaches. In light of this, this study introduced a novel approach for the valorization of chicken eggshell waste as a porogenic material to manufacture dense/porous bi-layered red floor tiles. Chicken eggshell waste was used as a substitute for the red floor tile paste by up to 25 wt% in the porous bottom layer. The bi-layered red floor tile specimens were produced by double uniaxial pressing and fired at 1220 ºC. The effect of chicken eggshell waste on the technical properties (linear shrinkage, apparent density, apparent porosity, water absorption, and three-point flexural strength) and fired microstructure of the bi-layered red floor tile specimens was examined. The results indicated that the chicken eggshell waste, mainly composed of CaCO3, influenced the densification behavior and technical properties of the bi-layered ceramic tiles. The findings also suggested that up to 10 wt% of chicken eggshell waste can be used to produce lightweight bi-layered red floor tiles, which can reduce the fired density by up to about 5.4 %, meeting technical requirements comparable to low water absorption floor tiles (BIb group - ISO 13006). These new dense/porous bi-layered red-firing floor tiles are promising for applications in ventilated facades, thus contributing to sustainable development.

Valorization of Fired Clay Bricks Debris (grog) Using Egg Shell and Coconut Shell in the Synthesis of an Ecological Compressed Earth Blocks: Microstructure and Engineering Properties

The aim of this work is to valorize fired clay brick debris (grog, CH) by using egg and coconut shells in the production of eco-friendly compressed earth bricks for sustainable building materials. Samples were cured at ambient temperature (23 ± 3 °C) and obtained by altering different percentages of (CO) and (CN) at 13%, 26% and 40%, respectively; while another mix design of calcined eggshell and coconut shell were incorporated together into the grog powder. Some comprehensive physico-mechanical properties such as water absorption (WA), bulk density (BD), apparent porosity (AP), moisture content (MC), compressive strength (σ) and elastic modulus (EM) were carried out. Chemical composition, X-ray diffraction (XRD) analysis, Fourier Transformed Infra-red (FT-IR), Energy Dispersive X-ray (EDX) analysis and Scanning Electron Microscopy (SEM) were studied. Results show an increase in compressive strength with increasing percentages of calcined eggshell, from 87CH 13CO, 74CH 26CO, 60CH 40CO as 1.38, 2.70, 3.88 MPa, respectively. For 87CH 13CN, 74CH 26CN, 60CH 40CN coconut shell addition show an increase in the percentages of compressive strength. The bulk density decreases with the increase in percentages of calcined eggshell and coconut shell and the percentage of grog decrease. Linear correlation equtions between mechanical properties and mix proportion were determined. SEM micrograph shows a dense microstructure with an agglomeration on the structure. Results obtained indicates an improvement in the engineering properties due to the addition of eggshell waste and these improved properties are suitable to enhance sustainable eco-friendly building materials.

Experimental study on preparation of fly ash-based geopolymer blended with recycled calcium source

A large amount of waste eggshells raises environmental issues. This study uses eggshells as recycled calcium source to synthesize fly ash and eggshell geopolymer (FAEG). The effects of eggshell content, liquid-solid ratio, NaOH/Na2SiO3 ratio, and NaOH solution concentration on the strength of the FAEG were evaluated by unconfined compressive strength (UCS) test. The geopolymerization products and microstructure characteristics of the FAEG were analyzed by XRD, FTIR, TGA, and SEM test. The results show that eggshells acted as recycled calcium sources are capable of significantly enhancing the UCS of the FAEG. The optimal content of eggshells is 15%. The NaOH/Na2SiO3 ratio has a significant effect on the UCS of the FAEG, while the influence of liquid-solid ratio and NaOH concentration is slight. The optimal NaOH/Na2SiO3 ratio is 50:50 and the liquid-solid ratio is recommended to be 0.55. Eggshells take part in the geopolymerization by acting as a precipitating and seeding element in the reaction and favoring the generation of the geopolymeric gels in the FAEG.