Raw Eggshell Research Articles

Synthesis of Sustainable Binary Calcium Monosilicate Ceramics from Bio-waste: Effect of Sintering Temperature on Microstructure and Electrical Properties

This study was conducted to synthesise calcium monosilicate ceramics using rice husks and raw eggshells and investigated the effect of sintering temperature on the physical,microstructure and electrical properties of the final product. The high content of calcium and silicon in eggshells and rice husks, respectively promote the use of waste materials in the production of calcium monosilicates by mixing in a molar ratio 1CaO:1SiO2 and fired at different sintering temperatures for 2 hours with a heating rate of 10°C/min. A good correlation between sintering temperature, structural, microstructure, and electrical properties of calcium silicate was observed. The structural and morphological evolutions were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with electron dispersive X-ray analysis (EDX). XRD analysis showed that the main crystalline phases of synthesised calcium monosilicate are pseudowollastonite (ICSD 98-005-2598) at 1250°C, and the phases of SiO2 also exist in different types of minerals. Besides, a small amount of larnite, Ca2SiO4 was traced at 1100°C and 1200°C. Fourier Transforms Infrared (FTIR) spectra showed the presence of characteristic functional groups in the precursor powder. In Nyquist plots, the summit frequency of the dominant arc decreases with increasing sintering temperatures. It may be attributed to the co-effect of the grain size and pore. A larger value of impedance at a lower frequency suggests an essential role of boundaries in governing the electrical properties of the sintered ceramics. As the sintering temperature increases, the microstructure of the sintered samples becomes denser while conductivity performance decreases. This is due to the reduction of particle interfaces and charge transfer.

Calcium oxide from eggshell wastes for the removal of pharmaceutical emerging contaminant: Synthesis and adsorption studies

The objective of this work is to study the removal efficiency of pharmaceutical emerging contaminant ibuprofen from aqueous environment by using cost-effective material, such as calcium oxide derived from raw eggshell wastes, it is synthesized through calcination process for removal of ibuprofen. The study of the surface morphology and functional groups of the calcium oxide as adsorbent was performed using SEM and FTIR. The study suggests that there are different factors such as contact time, pH, initial concentration and adsorbent dosage influence the adsorptive removal of ibuprofen from aqueous media. The isotherm model such as Langmuir, Freundlich and Temkin were also investigated to study the adsorption equilibrium behaviors of ibuprofen uptake by using calcined eggshell, CaO. Henceforth, the highest removal efficiency of ibuprofen from aqueous solution is 93.72% at contact time of 60 min at pH 10 with initial concentration of 10 mg/L using dosage of 0.04 g. The pH study shows that ibuprofen adsorption increased with increase in pH from 4 to 10, while removal efficiency decreased at pH 14. Simultaneously, the adsorption isotherm of Langmuir model is best fitted for the adsorption process (R2 = 0.958) on monolayer adsorption. In this study, CaO is identified as an economical, high-efficiency and eco-friendly dormant adsorbent for removal of ibuprofen from aqueous environment.

Characterization of Bio-Cement Reinforced with Eggshell Composites

Eggshells are an interesting inorganic compound with a chemical composition and crystallographic structure similar to that of CaCO3. This study aims to acquire a better understanding of the use of eggshells, which are commercially incorporated into cement mixtures, to increase the mechanical strength of cement-eggshell composite. The cement mixture was prepared by incorporating different compositions (5, 10, and 15 wt.%) of eggshell powder. The raw eggshells were cleaned, crushed, dried, sieved into small pieces, and mixed with the cement according to the desired composition. Analysis of the eggshell powder showed similar peaks to CaCO3, indicating that eggshells can be used as a calcium source. The results indicated that the addition of 10 wt.% finely ground eggshell powder improved the compressive and flexural strength of the cement mix. It was also found that eggshell powder can potentially be used as a filler, as it exhibited the highest water absorption at 15 wt.%. The use of eggshells as a reinforcing component in environmentally friendly cement mixes has the potential to improve the environment by reducing waste, the need for conventional cement resources, and the pollution caused by excessive cement mining.

Response surface methodology for optimizing adsorption process parameters for tadalafil removal by raw eggshell

AbstractExcessive discharge of pharmaceutical wastes into the surface water causes harmful effect on environment, so its removal has aroused much attention in recent years. This study investigated the potential of raw eggshell as a low cost adsorbent on the removal of tadalafil by adsorption experiments. Characterization of adsorbent was investigated using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and X-ray diffraction (XRD). To comprehensively evaluate the independent and interacting effects of several process factors, such as pH, temperature, and amount of adsorbent, Box-Behnken design was used. According to results of variance analysis (ANOVA) it was concluded that the second-order model had strong statistical relevance and was characterized by a high coefficient of determination (R2) value. It was clear from the experimental results that as the pH level and adsorbent amount were raised, so was the removal efficiency. At pH 5, 25 °C, and 7.5 g/100 mL of adsorbent, the greatest removal efficiency of 72.9% was attained. Furthermore, the analysis of equilibrium data showed that, in comparison to the Langmuir isotherm model, the Freundlich isotherm model offered a better fit for dye removal. Furthermore, the adsorption kinetic was also evaluated and it was obtained the adsorption followed by pseudo second order model for the tadalafil removal onto eggshell.

Valorization of waste eggshell for CO2 sorbents production by sol-gel citric acid treatment in a fixed-bed reactor

This study assesses the potential of the eggshells as a promising and alternative CO2 adsorbent. With the aim of enhancing the CO2 capture performance of raw eggshell, it was modified by sol-gel citric acid treatment. Both adsorbents were characterized by N2 adsorption-desorption, XRF, XRD and SEM techniques. Preliminary adsorption tests in TGA revealed that the acid-modified eggshell achieved significantly higher carbonation conversion than the raw eggshell adsorbent in the 650–750 ºC adsorption temperature range, reaching a carbonation conversion of 69% at 700 ºC. The cyclic performance of the modified eggshell, tested in TGA at 700 ºC under 15 vol% CO2, confirmed that sol-gel acid treatment led to a very stable adsorbent, with a slight improvement in CO2 adsorption capacity during the first four cycles (from 0.54 to 0.58 gCO2 gads−1), followed by stable performance due to self-reactivation phenomena. Moreover, additional experiments were carried out in a fixed bed reactor under more realistic conditions to study the influence of temperature (600–750 ºC) and CO2 flow rate (50–125 mL min−1) using the modified eggshell. An increase in temperature under 15 vol% CO2 stream led to a decrease in the carbonation conversion of the adsorbent, with the maximum CO2 uptake at 600 ºC (0.64 gCO2 gads−1). Regarding the role of the CO2 flow rate at 700 ºC, increasing from 75 to 125 mL min−1 CO2 had minimal effect, maintaining a capture amount of approximately 0.49 gCO2 gads−1. These results confirmed the potential of the acid-modified eggshell as a low-cost and environmental friendly adsorbent for CO2 capture, which indeed may significantly improve the economic feasibility of the CCUS processes.

Metal- based eggshell particles prepared via successive incipient wetness impregnation method as a promoted sorbent for CO2 capturing in the calcium looping process

Cyclic adsorption by using of bio-waste eggshell particles as a cheap, accessible and environmentally friendly CaCO3 source has been considered as one of the important methods to decrease or remove CO2 from the flue gas. However, deactivation of eggshell particles and CO2 capture capacity decaying with increasing the cycle’s number remained as an important challenge. Using metal nitrates as one of the modification methods has been proposed by the researchers to overcome this problem. Current study investigates the influence of three metal nitrates of Al, La and Mg added to the eggshell particles via successive incipient wetness impregnation (SIWI) method to improve their adsorption performance. The TGA results at the end of the 20th carbonation/calcination cycle revealed a meaningful relationship between CaO molar conversion of eggshell modified with metal nitrates and their crystallite size as well as the surface area of the sorbents, so that the smaller the crystal size and the larger the surface area, the higher the molar conversion of CaO could be achieved. Due to the highest conversion obtained for Mg-containing sample, the effect of different weight percentages of this additive was also investigated. Results showed that 5 wt% MgO contained eggshell particles could be reported as the most outstanding sample for its improved molar conversion, capture capacity at the end of 20th carbonation/calcination cycle and BET surface area, which were 30.18%, 0.23 gr CO2/gr adsorbent and 3.5 m2/g while the corresponding amounts for raw eggshell were 17.26%, 0.11 gr CO2/gr adsorbent and 1.63 m2/g, respectively.

Raw Eggshell as an Adsorbent for Copper Ions Biosorption—Equilibrium, Kinetic, Thermodynamic and Process Optimization Studies

The study on the biosorption of copper ions using raw eggshells as an adsorbent is presented in this paper. The influence of different process parameters, such as: initial pH value of the solution, initial Cu2+ ions concentration, initial mass of the adsorbent, and stirring rate, on the biosorption capacity was evaluated. The SEM-EDS analysis was performed before and after the biosorption process. SEM micrographs indicate a change in the morphology of the sample after the biosorption process. The obtained EDS spectra indicated that K, Ca, and Mg were possibly exchanged with Cu2+ ions during the biosorption process. The equilibrium analysis showed that the Langmuir isotherm model best describes the experimental data. Four kinetic models were used to analyze the experimental data, and the results revealed that the pseudo-first order kinetic model is the best fit for the analyzed data. Calculated thermodynamic data indicated that the biosorption process is spontaneous, and that copper ions are possibly bound to the surface of the eggshells by chemisorption. The biosorption process was optimized using Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD), with the selected factors: adsorbent mass, initial metal ion concentration, and contact time.

Crystallographic characterization of bio-waste material originated CaCO3, green-synthesized CaO and Ca(OH)2

Municipal inorganic waste material (eggshell), which was chosen as the source of calcium carbonate, was utilized to synthesize two industrially valuable inorganic compounds, calcium oxide and calcium hydroxide following a sustainable synthesis method. The crystallographic parameters such as lattice parameter, unit cell volume, crystallite size, microstrain, dislocation density, relative intensity, crystal growth preference, and crystallinity index of raw eggshell, calcium oxide, and calcium hydroxide were explored based on the X-ray diffraction. The polymorphic mole fraction of calcite, vaterite, and aragonite in natural eggshells was also estimated. Crystallite size was calculated with the assistance of the Scherrer equation along with Williamson–Hall Method, Monshi-Scherrer Method, and Liner straight-line method of Scherrer’s equation. A relationship among the crystal growth preference, dislocation density, and microstrain was established for the considering compounds. The raw eggshells and synthesized products were also characterized with the aid of Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR), and Scanning Electron Microscopy (SEM).

Sintering resistant CO2 sorbents prepared by eggshell derived xerogels

• Sustainable and stable CO 2 sorbents were prepared from eggshells. • Lime sorbents were prepared by combustion of carboxylic acid derived xerogels. • Release of gas & heat during xerogel combustion modifies sorbents’ morphology. • Sorbents’ unimodal granulometric distribution minimizes particles coalescence. • Eco-friendly lactic acid sorbent showed the slowest carrying capacity decay. A sol–gel like method was used to prepare CaO sorbents from eggshells, and carboxylic acids, with improved sintering resistance. Sorbent materials obtained by calcination (900 °C) of the calcium xerogels presented different morphologies depending on the acid used as the complexing agent (citric, lactic, oxalic, maleic, acetic, and propionic). Sorbents were tested for cyclic carbonation (700 °C, 15% CO 2 in N 2 )/decarbonation (800 °C, in N 2 ) in a thermobalance. Sorbents had distinct specific areas and porosities resulting from the release of gaseous molecules, and heat, from the thermal decomposition of xerogels. The particle size distribution of sorbents was also a function of the acid. The acid carbon chain and the combustion enthalpy have opposite effects on the morphology of sorbents. The lactic acid-derived sorbent was the most performant showing the lowest carrying capacity decay. After 50 cycles the loss of CO 2 capture capacity was 45% for the lactic acid-modified sorbent, while the unmodified sorbent showed a sorption capacity decay of 74%. Scanning electron microscopy showed, after cyclic carbonation/decarbonation, a sintered morphology for the sorbent derived from raw eggshells. This sorbent presented non-porous large aggregates, while the lactic acid-derived sorbent showed a clear network of voids within the crystals agglomerates and a coral-like morphology that is known to confer sorbent stability. This sorbent was the only sorbent with a particle size distribution closer to the unimodal, while the other samples were bimodal. The absence of smaller particles reduces the contact between sorbent grain boundaries at high temperatures, which minimizes the sintering process.

Synthesis and characterization of metal oxide based ion exchanger from chicken egg shell biomass for the removal of arsenic from water

A new metal oxided-based high capacity biosorbent for As(III) was designed and synthesized from egg shell biomass and characterized using FTIR, FE-SEM, EDX, XRD, chemical analysis. For this, raw egg shell (RES) powder was first dissolved with HCl and mixed with ZrOCl2∗8H2O solution then precipitated to obtain hydrated double oxide precipitate (HDOP), which was employed for As(III) removal. As(III) biosorption onto HDOP is fast, depends on pH and As(III) concentration. Pseudo second order kinetics and Langmuir isotherm models successfully described the As(III) biosorption mechanism. HDOP provided exchangeable hydroxide/or chloride ligands for improved biosorption of As(III). Maximum biosorption capacity of HDOP for As(III) from Langmuir isotherm modelling was found to be 40 mg g−1 at optimum pH 10. Chloride and nitrate cause negligible interference whereas sulphate and phosphate significantly reduced As(III) biosorption capacity of HDOP. HDOP completely removed arsenic from contaminated ground water and the remaining concentration was reached below the safe drinking water standard (10 μg L−1) set by WHO. Moreover, HDOP exhibited effective regeneration and high stability with As(III) removal up to 8 cycles. Thus, HDOP synthesized from egg shell biomass can be used as a low cost, environmentally benign and high capacity biosorbent for the treatment of arsenic polluted water.

Adsorption of deoxynivalenol by APTS-TEOS modified eggshell powder

Deoxynivalenol (DON) is widely contaminated in foods and feeds, which greatly threatens human and animal health. Due to its stable physicochemical properties, DON can be hardly eliminated by heating or ultraviolet radiation. In the present study, the biowaste eggshells were firstly modified into effective DON adsorbents, which are ATPS (triethoxysilane) + TEOS (aminopropyl triethoxysilane) modified 500 °C/700 °C-calcined eggshell powders under acetic/propionic acid-catalyzation (500-CSAE, 500-CSPE, 700-CSAE, 700-CSPE). The adsorption rates of DON on the raw eggshell powder, 500-CSAE, 500-CSPE, 700-CSAE, and 700-CSPE in acidity-adjusted buffer solution were 14.6%, 53.0%, 47.8%, 29.9%, and 31.2%, respectively. Characteristic analysis implied that the mesopore structures and enriched Si-OH groups in the modified eggshell powders are involved in DON adsorption. Besides, 500-CSAE, 500-CSPE, and 700-CSPE were verified to numerically alleviate the viability loss of IPEC-J2 cells caused by DON. In conclusion, the novel modified eggshell powders exhibit great application prospects for DON control in foods and feeds.

Catalytic efficiency of raw and hydrolyzed eggshell in the oxidation of crystal violet and dye bathing wastewater by thermally activated peroxide oxidation method

In this study, hydrochar-based-eggshell was prepared via the subcritical water medium (SCWM) and used as a catalyst in the thermally activated peroxide oxidation (TAPO) approach for crystal violet and dye bathing wastewater degradation. The catalytic activities for the raw eggshell (RES) and hydrochar-based-eggshell (HES) were compared. RES and HES were characterized using a scanning electron microscope (SEM),energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transforms infrared spectroscopy (FT-IR). The affecting parameters on the degradation process were optimized using response surface methodology (RSM). The effects of temperature (293–333 K), amount of catalyst (5–25 mg/50 mL), the concentration of H2O2 (0–8 mM), and treatment time (10–70 min) on the TAPO method were investigated using central composite design (CCD). For the crystal violet removal, two models were developed. Both models were significant and can be used to describe the design space. Also, the dye bathing wastewater degradation was described by another developed model, which had a high correlation coefficient (R2 = 0.97). In general, catalytic activity for HES was higher than RES. The degradation of crystal violet reached 98.10% when a 20 mg HES catalyst and 6 mM H2O2 at 323 K for 55 min were used. While 97% of the color of dye bathing wastewater was removed in 55 min at 323 K using 25 mg of HES and 4 mM H2O2. This study showed that the hydrolyzed eggshells could be used in the oxidation of crystal violet and dye bathing wastewater by the thermally activated peroxide oxidation method.

Mechanical properties of eggshells powder reinforced recycled high-density polyethylene

This study investigated the effect of thermal treated eggshells powder on the mechanical properties of recycled high-density polyethylene (r-HDPE) composite. Thermal treated eggshellspowder, which was labelled as carbonised eggshells powder (CESP), was prepared at a low pyrolysis temperature of 400°C for one hour. The mechanical performance of the polymer composite reinforced with CESP was compared with the untreated dried raw eggshells powder (ESP) reinforced polymer composite. Each composite sample was prepared with a weight ratio of r-HDPE/filler varied at 90/10, 80/20, and 70/30. The polymer composite was prepared through a melt blending method in an internal mixture at 175° at 32 RPM mixing rate. The composite samples were tested flexural analysis, while structure and morphology were characterised using Fourier Infrared Transformer (FTIR) and Scanning Electron Microscope (SEM). Based on the finding, the interfacial adhesion of the composite between filler and matrix has improved with ESP and CESP, respectively. The composite with CESP filler at 70/30 shows the optimum flexural strength and modulus of 32.21 MPa and 2.06 GPa, respectively. Overall, the introduction of CESP offers a better performance in improving the mechanical properties of the composite as compared to ESP.

Effect of using calcined eggshells as a cementitious material on early performance

This study focuses on the viability of using calcined eggshells (CES) as a partial replacement of cement by analysing early age performance. Eggshells found on the landfill sites are contaminated with smelly organic components. One of the recommended ways for extracting pure stable calcite from waste eggshells is to remove the volatile component and organic components by calcining them. To get the calcined eggshells, raw eggshells were calcined at 400°C, 600°C, and 800°C. Each temperature was held constant for the duration of one hour, two hours, and three hours, respectively. These calcined eggshells were replaced with cement at the rate of 5%, 10%, and 15% in addition to the mixes containing eggshells and limestone with the same replacement level. For early age performance, setting times were estimated using the Vicat method, the heat evolution was monitored using isothermal calorimetry during the first 24 h and the compressive strength after 24 h were measured. Due to the disturbance of sulphate (SO3) balance, a certain reduction was observed in the setting time. The calcined eggshell proved to be a better accelerator as compared to both eggshells and limestone. In the heat evolution curve, the secondary shoulder peak appears in mixes containing high-temperature calcined eggshells which indicates the formation of the AFm phase. The cumulative heat release associated with calcined eggshells is higher as compared with eggshells and raw eggshells when replaced with cement. Moreover, the compressive strength was found higher in the calcined eggshells with undecomposed calcite as compared to the calcined eggshells with decomposed calcite. Also, the reverse trend was observed in heat of hydration versus strength correlation in decomposed and undecomposed calcite condition.

Determination of Fuel Properties of Biodiesel from Sand Apple Seed Oil with Automotive Gas Oil Blend

The objective of this study was to determine the fuel properties of Sand Apple Ethyl Ester (SAEE) and its blends with Automotive Gas Oil (AGO).using eggshell as catalyst. Sand apple seed oil (SASO) obtained was characterized based on America Society for Testing and Material (ASTM D6751) to determine acid value, saponification, iodine content, density, kinematic viscosity, flash point, cloud point and pour point. Sand Apple fruits were processed and oil extracted using solvent extraction method. Raw eggshells were calcined at 800oC for 120 min in the muffle furnace. SAEE was blended with AGO at 5 – 25 % mix. Data obtained was analyzed using ANOVA at P < 0.05 significant level. Cloud and pour points obtained for SASO are 4.68 and 3.09℃ . Flash point was 103℃ which fell within ASTM D93 range indicating that SASO is safe for handling and storage. Heating value was 42.61 MJ/kg, slightly lower than that of diesel oil of 44.8 MJ/kg shows that AGO has ability to produce heat of combustion than SASO. Iodine value was 80.71 g I/100g while acid value was determined to be 2.62 mgKOH/g, which was higher than that of ASTM D6751 of 0.5 mgKOH/g. Sulphur contents for AGO and SASO–AGO blends were 0.006, 0.009, 0.014, 0.016 and 0.004%, respectively. Low sulphur values indicates that hazardous sulphur dioxide emission of SAEE has reduced. This study established that all the properties obtained, except acid value, fell within the ASTM specification and could suitably be compared with those of fossil diesel.

Characterization of Eggshell: A Heterogeneous Catalyst in Transesterification of Sand Apple (Parinari polyandra) Seed Oil


 
 
 The objective of this study was to characterize a low cost heterogeneous catalyst from the transesterification of sand apple (Parinari polyandra B.) biodiesel. Sand apple fruits were processed and oil was extracted using solvent extraction method. Raw eggshells were calcined at 800°C for 120 min in the muffle furnace. Surface properties of the raw and calcined eggshell were characterized using Fourier Transformed Infrared Radiation (FTIR) and X-Ray Fluorescence (XRF). Transesterification of the Sand Apple Oil (SASO) with ethanol in the presence of the calcined catalyst to produce ethyl ester and glycerol were optimized using Central Composite Design at different temperatures and time. Reactants for the transesterification process were the raw SASO and anhydrous ethanol. The study shows that raw eggshell was more stable with hydrogen bond form at 2,724 cm-1an while oil yield of 53.13 % was obtained from sand apple kernels. Ethyl ester yield of 90% was obtained from SASO. The results of transesterification shows the maximum biodiesel yield of 90% was obtained at reaction temperature of 65°C and time of 120 min, while the minimum yield of 70% was obtained at temperature of 55°C and time of 60 min; indicating that biodiesel increase with increase in time. Similarly, yield of ethyl ester of SASO also increased when the reaction temperature increased. The percentages of biodiesel yield obtained from SASO transesterification in this study showed that sand apple is promising oil for biodiesel production as compared with other vegetable oil crop obtained in previous studies
 
 

Glycine tailored effective CaO-based heat carriers for thermochemical energy storage in concentrated solar power plants

Calcium looping process (CaLP) is one of the most perspective thermochemical energy storage (TCES) strategies to meet the demands of developing the 3rd generation concentrated solar power plants (CSP) in the CO2 Brayton cycle. However, the CaO-based heat carriers inevitably experienced severe sintering over the cycles, and their energy storage capacities deteriorated drastically. Research on the energy storage capacity of the CaO-based heat carriers in a closed-loop calcium looping process for thermochemical energy storage (CaLP-TCES; i.e., calcining the CaO-based materials under CO2-rich stream, which is much practical in the industry) is rare. Hence, this work employed a novel recipe to synthesize a variety of organic acid–modified CaO-based heat carriers to explore their thermochemical energy storage performance in a new closed-loop CaLP-TCES system. The energy storage capacity of the materials was evaluated by a simultaneous thermal analyzer (TGA/DSC), and the mechanism behind their promising energy storage performance was explored by X-ray diffraction, field emission scanning electron microscopy, N2 physisorption, reaction kinetics method and so on. Results showed that glycine modified eggshell (“Glycine eggshell”) was an effective heat carrier for the CaLP-TCES system. After 60 repeated cycles at “650 °C – 900 °C,” “Glycine eggshell” accumulated an energy storage capacity of 110.124 kJ/g, which was approximately six times higher than that of “Raw eggshell”. Comprehensively considered the effect of carbonation temperature and calcination temperature on the energy storage/releasing performance of the “Glycine eggshell” materials, “750 °C – 900 °C” was the best option for the closed-loop CaLP-TCES system for the concentrated solar power plants. After glycine modification, the rich mesoporous and macroporous structure in the CaO-based material was generated, thereby improved cyclic thermochemical energy storage performance.

Impact of decalcification on antibacterial properties of eggshell against selected poultry pathogens

Background: Eggshell which is primarily composed of more than 98% calcium carbonate crystal, serves as the physical protective and active barrier structure of egg content. Recently, antimicrobial properties of eggshell are fast becoming center of interest among stakeholders of poultry industry. However, few studies have focused on the rigidity factor of calcium components of eggshell as antimicrobial agent. Thus, this study was designed to determine the effect of decalcification on the ability of eggshell to inhibit common poultry and egg bacterial pathogens.Methods: Raw eggshell denoted as calcified eggshell (CES) and decalcified eggshell (DES) were extracted and made into fine powder. Standard protocol was used for preparations of CES and DES at concentrations of 10, 5, 2.5 and 1.25 mg/ml, and their antibacterial assays on selected bacterial pathogens (Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Salmonella Typhi) were performed by agar diffusion method. Gentamicin 80mg solution (CC1) and distilled water (CC2) served as controls. Data were analysed with SPSS version 20.0 and presented as mean±SD for descriptive statistics. Friedman's two-way test ANOVA was used to compare the differences in mean values between CES, DES, CC1 and CC2 at significance level of p<0.05.Results: The mean zone diameter of inhibition produced by DES (range 13–28mm) for the isolates was significantly higher (p<0.05) than that produced by CES (range 10-21mm). However, the mean zone diameter of inhibition produced by CC1 (gentamicin) (range 16-40mm) was higher than that produced by DES or CES (p<0.05). The concentrations of DES and CES have no significant antibacterial effect on B. subtilis and K. pneumoniae (p>0.05), but had inverse effect on P. aeruginosa. Overall, DES had a better inhibitory effect than CES against B. subtilis, K. pneumoniae and P. aeruginosa, but notably, neither DES nor CES had inhibitory effect on E. coli and S. Typhi.Conclusion: Poor antibacterial effect of CES may be attributed to the calcium-protein interactions within bacterial cell membrane, which hinders absorption or mobility mechanism of the antibacterial factor of the eggshell, but decalcification had significant impact on the antibacterial profile of the eggshell for some bacterial isolates. However, S. Typhi and E. coli were totally resistant to both DES and CES. Breed of eggs with minimal calcified eggshell to withstand transportation fragility, may enhance antibacterial index and shelf-life of table eggs.
 Keywords: Decalcification; Antibacterial; Eggshell; Poultry; Pathogens

Preparation of multilayer electrospun nanofibrous scaffolds containing soluble eggshell membrane as potential dermal substitute.

Electrospinning of natural and synthetic polymers has shown to be a great candidate for the fabrication of tissue engineering scaffolds due to their similarity to the nanofibrous structure of natural extracellular matrix (ECM). Moreover, the addition of ECM-like proteins could enhance the biocompatibility of these scaffolds. In this study, soluble eggshell protein (SEP) was first extracted and synthesized from the raw eggshell membrane. The characteristics and biocompatibility of the extracted SEP were evaluated using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis and 3-(4,5- dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide) (MTT) assay. For scaffolds fabrication, a three-layer nanofibrous composite structure was produced using the electrospinning technique. The outer layers composed of polyvinyl alcohol, chitosan, and extracted SEP while the middle layer composed of polyethylene oxide, gelatin, and zinc oxide nanoparticles (ZnO-NPs). For each layer, the electrospinning parameters were adjusted to form bead-free fibers. To improve fibers' stability against body fluids, the produced fibers were crosslinked using glutaraldehyde vapor. Several techniques such as scanning electron microscopy (SEM), energy dispersive X-ray, ATR-FTIR, swelling, tensile test, in vitro biodegradation, and MTT assay were implemented to evaluate the physical, chemical, and biological characterization of the fabricated fibers. The results showed that crosslinked fibers have adequate stability in water, suitable mechanical properties, and promising water uptake capacity. The MTT results also revealed that SEP and ZnO-NPs could increase scaffolds biocompatibility. Moreover, SEM photographs of cultured fibroblasts cells on the scaffolds showed that cells were well attached on the scaffolds and preserve their natural spindle shapes. Altogether, our findings demonstrated that the produced three-layer composite scaffolds are potential candidates for skin tissue engineering.

Eggshell membrane and expanded polytetrafluoroethylene piezoelectric‐enhanced triboelectric bio‐nanogenerators for energy harvesting

With the growing demand for wearable electronic devices, triboelectric nanogenerators (TENGs) provide an effective solution by harvesting human body motions and converting them into electricity. Tribomaterial is one key element for the output performance and application of TENGs. In this study, biomaterial eggshell membrane (ESM) was investigated for use as a piezoelectric-enhanced positive tribomaterial. ESM not only exhibits excellent piezoelectricity due to the amount of hydrogen bonds, but it is also biocompatible and pollution free. The piezoelectricities of raw eggshell membrane (RESM), heated eggshell membrane (HESM), and carbonized eggshell membrane (CESM) were analyzed and compared. Porous expanded polytetrafluoroethylene (ePTFE) was fabricated and used as a negative tribomaterial in the TENG due to its strong electron-acquisition ability. Pairing ESM with an ePTFE resulted in a novel piezoelectric-enhanced triboelectric bio-nanogenerator (P-TENG) with an excellent energy harvesting ability, high-efficiency output performance, and sensitive human motion monitoring. By comparing ePTFE paired with RESM, HESM, and CESM, the CESM/ePTFE P-TENG showed the best output performance due to CESM's piezoelectric enhancement. This bio-P-TENG as a wearable electric device has great potential in biomedical applications.