Calcined Eggshell Research Articles

Optimization of calcined eggshell as an effective coagulant for treating colloidal particles in complex effluents in the CPCP industry: mechanistic insights, scale-up design, and comparative analysis with alum

Highly turbid industrial effluent poses significant challenges to environmental sustainability. In this study, we investigated the optimal aggregation kinetics for the removal of colloidal and turbid particles in Cosmetics and Personal Care Products (CPCP) industrial effluent using calcined eggshell (CES) and industrial-grade aluminum sulfate as flocculants. The effluent characteristics were determined following ASTM specifications, and process optimization was carried out using a response surface design approach. The optimal operating conditions at a settling time of 3 min were found to be pH 8, 0.2 g/L dosage of CES, pH 10, and 0.3 g/L of alum dosage. The flocculation efficiencies of CES and alum were found to be 80% and 78%, respectively, demonstrating the effectiveness of both flocculants in removing colloidal particles and reducing turbidity in CPCP effluent. Mechanistic studies revealed that CES achieved particle removal through enmeshment and inter-particle bridging with a significant aggregation rate (1.3 × 10−7) and a lower floc breakup tendency (2.8 × 10−14) compared to alum-sweep flocculation. The hydrodynamics at a velocity gradient of 269s−1 ≤ G ≤ 29s−1 indicated spontaneous agglomeration within a flocculation period of ≤10 min, indicating rapid and efficient particle removal. The findings of this study justify the use of CES as a sustainable and effective option for the removal of colloid/turbid particles from CPCP effluent. The optimized operating conditions and mechanistic insights into the flocculation process contribute to establishing an optimized sedimentation geometry, with specified aspect ratio, detention time, hypothetical settling, and sludge depth for CES, ensuring the favorable stability of the finished CPCP effluent before discharge.

Evaluation of the potential of activated sludge biomass from Nigeria as a feedstock for biodiesel production

AbstractDepleting fossil fuel reserves and the effects of greenhouse gases on climate change have led to the investigation of alternative energy sources such as biofuel, including biodiesel and renewable diesel. Unfortunately, the cost of the feedstock exceeds 70% of the total production cost. The current work investigates the potential of utilizing a waste product (activated sludge biomass) from wastewater treatment, as an alternative feedstock for biodiesel production. The activated sludge biomass was pretreated with subcritical water to enhance the lipid yield before extracting the lipid using solvent extraction. The result showed that lipid yield from the activated sludge was 4.73–8.58%. After subcritical water pretreatment with varying residence time, temperature, and biomass loading, the lipid yield increased by 158.04–400%. Gas chromatography–mass spectrometry (GC–MS) analysis of the fatty acid methyl esters (FAME) from the transesterification of the lipid extract using calcined egg shell as a catalyst identified the following lipids: triglyceride, fatty acids, sphingolipid, phospholipid, glycerolipid, glycerophospholipid, steroid, and cholesterol. The predominant lipid was triglyceride, and the high percentage of unsaturated fatty acids, including arachidonic acid (23.54%), eicosadienoic acid (8.37%), and oleic acid (6.23%) suggest that the lipid extract is a potential feedstock for biodiesel production.

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.

Exploring the influence of calcinated eggshell powder on lightweight foamed concrete: A comprehensive study on freshness, mechanical strength, thermal characteristics and transport properties

This research aimed to explore the feasibility of using calcined eggshell powder (CESP) as a substitute for cement in the production of lightweight foamed concrete (LWFC), considering its high calcium content. Ten LWFC mixtures consisting of two densities of 600 kg/m3 and 1200 kg/m3 were produced and tested. Each density comprised mixtures with varying proportions of CESP, ranging from 0% to 20% in increments of 5%. The ES was calcined at 900 °C to convert the CaCO3 into CaO. The fresh, transport, mechanical, microstructural, and thermal properties were investigated. The findings revealed that the slump flow and setting times progressively decreased as the CESP proportion increased. The water absorption, sorptivity and intrinsic air permeability improved steadily as the CESP proportions were increased from 5% to 20%. Additionally, the compressive strength, flexural strength, splitting tensile strength, modulus of elasticity, and drying shrinkage went through an initial increase and then a decrease, and the optimal CESP replacement rate was found to be 15%. The 28-days compressive, flexural and splitting tensile strengths enhancements with 15% CESP replacement were 44.3%, 41.2% and 41.7% and 39.7%, 56.5% and 57.6% for 600 kg/m3 and 1200 kg/m3 densities respectively compared to control mix. Besides, a marginal rise in thermal conductivity and diffusivity was observed as the proportion of CESP increased. Based on the SEM and pore dispersion results, the incorporation of up to 15% CESP into both LWFC densities resulted in an improved microstructure and enhanced pore dispersion, leading to the formation of a greater amount of C–S–H compounds. The findings were substantiated by enhanced mechanical properties, transport characteristics and SEM results.

Biodiesel Synthesis from Waste Vegetable Oil Utilizing Eggshell Ash as an Innovative Heterogenous Catalyst

The objective of this research is to explore the production of biodiesel using Waste Vegetable Oil (WVO) as the primary feedstock and calcined eggshell ash as an environmentally sustainable catalyst. The WVO, characterized by a Free Fatty Acid (FFA) content of 2.86%, serves as the primary feedstock for biodiesel production through transesterification. The eggshell ash undergoes a rigorous process, including washing with distilled water to remove impurities, drying at 100ºC for 24 hours, crushing into fine particles, and final calcination in a muffle furnace at 900ºC. Process optimization is achieved by varying key reaction parameters, including temperature, catalyst loading, and the methanol-oil molar ratio. The optimal conditions are identified at 65°C, utilizing a methanol-oil molar ratio of 6:1 and a 5wt% catalyst loading. Under these optimized reaction conditions, a substantial biodiesel yield of 91.3% is obtained. The produced biodiesel meets the stringent quality requirements specified by the American Standard (ASTM D 6751) and European Standard (EN 14214) for biodiesel fuel, ensuring its suitability for various applications. This study demonstrates the potential of utilizing calcined eggshell ash as an eco-friendly catalyst for sustainable biodiesel production from WVO.

Can waste eggshell replace commercial zeolites as catalyst for bio-oil production?

The utilisation of calcium oxide (CaO) from waste chicken eggshells, fishbone, and dolomite as a catalyst in the co-pyrolysis of empty fruit bunch (EFB) and high-density polyethene plastic (HDPE) was investigated and compared with existing commercial zeolite catalysts (HZSM-5, NaY, and FCC). In-situ catalytic co-pyrolysis of EFB-HDPE was performed for each CaO and zeolite-based catalyst. Gas Chromatography-Mass Spectrometry (GC-MS) was used to analyse the hydrocarbon content of the bio-oil produced by pyrolysis. The highest hydrocarbon content (61.62%) was obtained from the calcined eggshell (CES) catalyst and was comparable to that of the commercial zeolite catalyst, HZSM-5, with a hydrocarbon content of 53.53%. Brunauer–Emmett–Teller (BET) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX) analysis, and Particle Size Analysis (PSA) have proven the viability of CaO-based catalysts in the co-pyrolysis process for bio-oil production via fast pyrolysis. The CES achieved the desired pore diameter (175.15 nm) which was exhibited in the morphology analysis (SEM) and exhibited a uniform arrangement of calcium oxide particles and a porous structure. This finding provides fundamental insight into CaO from organic waste as a suitable alternative to zeolite catalysts in the co-pyrolysis of organic and inorganic feedstocks.

Catalytic Pyrolysis of Hydrochar by Calcined Eggshells for Bioenergy Production: Improved Thermo-Kinetic Studies and Reduced Pollutant Emissions

Bioenergy production from hydrochar via catalytic thermal conversion is of increasing importance to easing the energy shortage. The catalytic pyrolysis characteristics of hydrochar derived from sawdust (HSD) with calcined eggshell (CES) were investigated by the thermogravimetric–Fourier transform infrared spectroscopy–mass spectrometry (TG-FTIR-MS) method. Kinetic and thermodynamic parameters were determined by two iso-conversional model-free methods, namely, Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO). The results demonstrated that HSD exhibited a high fuel quality, with elevated carbon content (54.03%) and an increased high calorific value (21.65 MJ Kg−1). CES significantly enhanced the pyrolysis behavior of HSD by promoting the secondary cracking of organic vapors under the synergistic effect of CaO and mineral elements. Compared to non-catalytic pyrolysis, the residual mass and average activation energy of HSD-CES decreased by 29.61% and 14.10%, respectively, and the gaseous products of H2 and CO from HSD-CES increased by 26.14% and 22.94%, respectively. Furthermore, the participation of CES effectively suppressed the emission of pollutants in the HSD pyrolysis process, with a 27.13% reduction in CH4, a 22.76% reduction in HCN, and a 20.28% reduction in NH3. This study provides valuable guidance on the potential use of hydrochar for renewable energy production.

Development of Eco-Friendly Mortars Produced with Blast Furnace Slag, Calcined Eggshell and Brick Waste: Mechanical Behavior and Microstructure Assessment

The granulated blast furnace slag exhibits pozzolanic reactivity when combined with appropriate activator and can be used in a wide range as cement replacement. The aim of this study is to investigate the effect on the mechanical and microstructure properties of incorporating admixture composed by granulated blast furnace slag (GBFS), calcined eggshell (CES), and brick waste (BW), as replacement of cement in the formulation of mortar. Ten different mixes of mortar prismatic specimens were tested with different replacement levels of raw materials (50, 75, and 100%). The results show that the increase in the proportion of raw materials decreases significantly drying shrinkage, dry unit weight and strengths of mixtures mortar compared to control mortar at early age. The decrease in strengths is less important in the long term due the development of pozzolanic reaction. Moreover, the water absorption and open porosity were increased for all cases. The microscopic analysis by Scanning Electron Microscopy (SEM) shows that the proportion of 15% of calcined eggshell powder in admixture, provides more Calcium Silicate Hydrate gel (C-S-H) in the internal cementitious matrix of the mortar, which explains the best mechanical strength provided by this mixture.

Removal of phosphates using eggshells and calcined eggshells in high phosphate solutions

This study was conducted to evaluate the phosphate sorption properties of eggshell (ES) and calcined ESs (C-ESs) in a high-concentration phosphate solution. The C-ESs yield decreased rapidly at 900 °C, indicating that the CaCO3 constituting the ES was converted to CaO by the high calcination temperature. The optimum calcination temperature for phosphate removal using C-ES was 900 °C. The actual sorption amount of phosphate by ES and C-ES900 was in agreement with the Langmuir isothermal sorption equation, and the maximum sorption capacities derived from this equation were 178.6 and 270.3 mg/g, respectively. The sorption rate of phosphate by ES and C-ES900 was divided into two stages: an initial fast sorption stage, followed by a slow sorption stage. The sorption of phosphate by ES was dominantly influenced by the initial pH and salt concentration, whereas C-ES900 exhibited a constant sorption capacity regardless of environmental changes. The SEM–EDS and XRD results demonstrated that phosphate was successfully adsorbed on the ES and C-SE900 surfaces. In this study, it was found that the sorption of phosphate by ES occurred via ion exchange and precipitation reactions and that the sorption of phosphate by C-ES900 was dominantly affected by precipitation. Above all, C-ES can be applied as an effective adsorbent for removing high concentrations of phosphate under a wide range of environmental conditions.

SEM and XRD for removal of heavy metals from industrial wastewater and characterization of chicken eggshell.

Heavy metal toxicity due to industrial wastewater has been a threat to the environment for the past many decades, especially in developing countries. Electroplating Industry wastewater containing heavy metals can become a serious environmental pollutant if not treated appropriately. Present study investigated the removal of nickel and chromium ions from electroplating wastewater using calcined hen eggshells because of it high removal capability, little cost and easy approachability. Characterization of the adsorbent such as proximate analysis, surface charge, X-ray diffraction, and surface area was done prior to adsorption process. Batch adsorption experiment was performed to study the effect of different parameters such as adsorbent dose, contact time, temperature, and pH for adsorbent. Removal percentage of both heavy metals was checked by using calcined eggshell as adsorbent. Comparison was made between nickel and chromium to identify the most effective removal efficacy. It was concluded that utilization of natural waste was found suitable, easier, cost operative and environmental approachable for removal of heavy metals from industrial wastewater. RESEARCH HIGHLIGHTS: To use ecofriendly approach for the treatment of industrial wastewater. To used calcined eggshell as adsorbents for removing metal concentration from industrial wastewater. To find the metal removal potential of calcined eggshell under various environmental conditions like dosage, contact time, temperature, and pH. To checking the efficacy of calcined eggshell.

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.

Optimization and biosynthesis of calcined chicken eggshell doped titanium dioxide photocatalyst based nanoparticles for wastewater treatment

This study presents, biosynthesis of calcinated eggshell (CES) doped with Titanium dioxide (TiO2,) photocatalyst for photodegradation of methylene blue from synthetic wastewater. The influence of three independent variables for improving photodegradation efficiency was investigated and optimized using response surface methodology of Box–Behnken Design on the removal of methylene blue using the calcined chicken eggshells (CES) doped with titanium dioxide. The experimental result showed that 95.8% degradation efficiency of methylene blue by prepared photocatalyst at a contact time of 180 min, initial concentration of methylene blue of 10 ppm, and calcined eggshells (CES) doped with titanium dioxide dose of 2.5 g/L. The synthesized photocatalyst was characterized by Fourier-transform infrared spectroscopy, UV-spectrometer, and X-ray diffractometer and UV–vis Spectroscopy for determined their functional group, structure, and bandgap energy respectively. Their results depict the calcined eggshell doped with titanium dioxide photocatalyst is a promising option for the degradation of methylene blue from industrial wastewater under the stated condition.HighlightsAnalysis of chicken eggshell wastes are being used as photocatalyst source to calcinated eggshell doped TiO2, i.e., ‘Waste to photocatalyst’ for production of viable sustainable products to bio photocatalyst from wastewater to fulfill the need of an expensive metal-doped catalyst.Photocatalytic degradation of Methylene Blue experiment has been done.The highest degradation efficiency of 95.8% methylene blue was obtained at a contact time of 180 min, 10 ppm of initial concentration of methylene blue, and a dopant dose of 2.5 g/L by using prepared photocatalyst.

Total Phosphorus and Reactive Phosphate Removal from Aquaculture Wastewater using Calcined Eggshell

Phosphorus is the key nutrient in fish feed, and it has been one of the major soluble nutrients found in aquaculture wastewater (AW). This work aims to evaluate the removal of Total Phosphorus (TP) and Reactive Phosphate (PO4 3-) via adsorption in batch studies using thermally calcined eggshell as adsorbent. The effect of calcination temperature (700 – 1000°C), particle size and holding time were investigated. The screening phase showed that calcined eggshell at 800 °C for 30 minutes was the most suitable condition. Characterization of adsorbents revealed that crystalline structure and functional groups were responsible for the TP and PO4 3- removal using calcined eggshell from AW. Adsorption equilibrium was attained after 15 min with the dosage of 0.2 g of the optimized adsorbent, capable of removing more than 97 % of TP and PO4 3- from AW. This finding has proven the ability of calcined eggshell waste as a potential phosphorus adsorbent from liquid effluents.

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
 
 

Effect of Egg Shell Composition on the Flexural and Hardness Properties of Epoxy Resin/ Egg Shell Particles Composite

The effect of calcined egg shell particles on the mechanical properties of epoxy resin had been studied. The egg shell was sun dried for 3 days and calcined at 800oC in an electrically fired furnace model KGVB. The calcined egg shell was ground in a locally fabricated pulverized machine and sieved using Sieve Model 567924/173281Endecotts in accordance with ASTM standard. Microwave digestion system and an inductively coupled plasma mass spectrometer (ICP-MS) were used to determine the chemical composition of the egg shell. The egg shell particles were mixed with epoxy resin to develop a composite casted by open mold casting. The flexural and hardness properties of the developed composite was determined using Universal Testing Machine model TUE-C-100, observing ASTM D790 standard and Rockwell Scale K hardness testing machine according to ASTM D785 respectively. The results showed that the calcined egg shell contained mostly CaO. Maximum flexural strength of 12MPa was observed at 25 wt. % egg shell particles. The highest hardness value of HRN 393 was observed at 20 wt. % egg shell particles. The produced composites may be applied where moderate strength is required.

Phosphorus removal in domestic wastewater treatment plant by calcined eggshell

Abstract Recovery of phosphorus (P) from wastewater is a topic of great interest. Besides being a non-renewable resource, P discharge in receiving waters can trigger algae blooms. The present study aimed to quantify the removal of P from two sites at a wastewater treatment plant using calcined eggshell (CES) as adsorbent. CES was prepared from raw shells calcined at 600 °C (CES600) and 800 °C (CES800). CES at 800 °C proved to be an efficient material for P removal. Efficiencies greater than 70% were achieved using CES800 concentrations of 0.1 g L−1 for synthetic sample, 0.3 g L−1 for preliminary treated wastewater and 20 g L−1 for supernatant from sludge anaerobic digester. The adsorption process was fast, occurring mostly in the first 30 min. Both Langmuir and Freundlich isotherms fitted the experimental data on adsorption. In kinetic experiments, a pseudo-second-order model fitted P adsorption from synthetic, preliminary effluent and digester supernatant. Thermogravimetric analysis showed a 54% eggshell mass loss at 800 °C. Calcination increased calcium and reduced carbon fractions in the eggshells, while increasing the surface area.

Treatment of Collapsible Soils with Granulated Blast Furnace Slag and Calcined Eggshell Waste

In order to meet environmental and socio-economic challenges, the recycling of waste to be used in the treatment of geotechnical problems is one of the main ways of preserving the environment with a lower economic value. The objective of this experimental work is to improve the characteristics and to study the mechanical behaviour of collapsible soil treated with a new hydraulic stabilizer composed of Crushed Granulated Blast Furnace Slag (CGBS) active by Eggshell Waste (CES). The specimens were mixed with stabilizer content, varying from 0 to 15% in mass, with an initial water content of 4, 6 and 8% respectively. in mass. Oedometer apparatus was used to study the addition of new hydraulic stabilizer effect on the Collapse Potential. Triaxial tests are also conducted to determine the shear strength parameters (cohesion and internal friction angle) of this treated soil. The results of this research study show that the mechanical properties of the treated collapsible soil were significantly improved. An appreciable reduction in the collapse potential is observed. The addition of 15% of this new stabilizer with initial water content of 4% under a compaction of 60 blows/layer is capable of increasing internal friction angle and cohesion. It can be concluded from this study that the mixture of granulated slag and calcined eggshell can be used as an effective treatment of collapsibility phenomenon at low cost while protecting the environment from industrial waste.

A coagulation-flocculation process combined with continuous adsorption using eggshell waste materials for phenols and PAHs removal from landfill leachate

A sequential treatment consisting of coagulation/flocculation followed by transport column experiment was adopted and used in this work for the treatment of landfill leachate containing phenols and polycyclic aromatic hydrocarbons (PAHs). Coagulation experiment was performed in a standard jar test apparatus using alum as coagulant material. In column experiments, natural eggshell material was used as filter media after calcinations at 750oC either separately or combined with granular activated carbon (GAC). Alum addition at a predetermined optimum dose (3.5 g/L) caused a reduction in total suspended solids (TSS), chemical oxygen demand (COD), total phenols, and total (PAHs) by 82%, 32%, 24%, and 34% respectively. Specific PAHs analysis revealed higher binding affinity of more hydrophobic PAHs toward particles with 50% reduction than those of less hydrophobic PAHs with only 6% reduction. The results obtained from the transport column experiments indicate that calcined eggshell (ESC) particularly when applied as a mixture with GAC can be used as promising adsorbent for both phenols and PAHs. 95% of phenols and PAHs were removed during the first 1,500 pore volumes (PV) of column operation while > 80% were obtained at the end of the experiment (3,500 PV).

Calcined Eggshell for Removal of Victoria Blue R Dye from Wastewater Medium by Adsorption

In this study, the use of calcined eggshell (CE) as an adsorbent in removing Victoria Blue R (VBR) dyestuff from the solution medium was investigated. For this purpose, pH, interaction time, adsorbate concentration, amount of adsorbent, and salt effect parameters were studied to determine the appropriate adsorption conditions. The highest adsorption yield was obtained in pH 2, 2.0 g/L adsorbent and a stirring time of 5 minutes. 97% of the dye was removed under optimum adsorption conditions. The results obtained from the experimental studies showed that the adsorption mechanism is compatible with the pseudo-second-order kinetic model and the Langmuir isotherm model. SEM and IR analyses were performed for the characterization of calcined eggshells (CE).

Optimisation of biodiesel production from dairy effluent scum using calcined egg shell as a transesterification catalyst

The production of biodiesel from dairy effluent scum using calcined egg shell as the transesterification catalyst has been explored. Eggshell powder was calcined at 900 °C for 3 h and used as catalyst. The influence of methanol-oil molar ratio, catalyst concentration and reaction temperature were studied using Response Surface Methodology employing a Central Composite Rotatable Design. An empirical model that relates the yield of biodiesel to the studied factors was obtained. The model has high statistical significance at 95% confidence interval with R2 and adjusted R2 values of 96.31% and 95.75% respectively. Results showed that among the three studied factors, the methanol-oil molar ratio had the greatest contribution to the yield of dairy effluent scum derived biodiesel followed by reaction temperature and finally, the catalyst concentration. Significant interaction effects were also present between methanol-oil ratio and catalyst, catalyst and reaction temperature and methanol-oil ratio and reaction temperature. Accordingly, the optimal variable settings were 14.355:1 methanol-oil molar ratio, 3.09% catalyst loading by weight of pre-treated dairy scum oil and 55.20°C reaction temperature; with a corresponding yield of 92.72%.