Calcium Oxide

Price fluctuation of petroleum-based diesel, climate change, emerging mandate obligations, availability of new feedstock and the upgrading of conversion technologies are expected to drive biodiesel market to grow robustly in the next coming 10 years. However, the current bottleneck in biodiesel production is the lack of economical sustainable conversion technologies. Generally, industrial production of biodiesel is greatly relied on alkaline homogeneous transesterification reaction. Limitation of the technology, such as multistep process which incur extra pre-step for high acid oil treatment and post-step for biodiesel purification and alkali washing as diminished the economic feasibility and low environmental impact of the entire biodiesel process. Heterogeneous catalysis offers immense potential to develop simple transesterification process, including one step reaction, easy separation, reusability of catalyst, and green reaction. Thus, the aim of this paper is to review the biodiesel production technologies such as blending, micro-emulsion, pyrolysis, and transesterification. Furthermore, recent studies on heterogeneous catalyzed transesterification were presented by discussing the issues such as catalytic performance on different types of biodiesel feedstock, transesterification reaction conditions, limitations encountered by heterogeneous catalysts, and reusability of solid catalysts. The heterogeneous catalysts presented in this review is mainly focused on solid base catalysts, which include single metal oxides, supported metal oxide, binary metal oxide, hydrotalcite, and natural waste shell-based catalyst. Furthermore, current perspectives on application of heterogeneous catalyzed technology in biodiesel industry were discussed herein. (C) 2015 AIP Publishing LLC.

Link to Full-Text Articles :
http://scitation.aip.org/content/aip/journal/jrse/7/3/10.1063/1.4919082

Choline chloride (ChCl)-based deep eutectic solvents (DESs) with different amides or polyols as hydrogen bond donors were tested as cosolvents in the ethanolysis of expired sunflower oil catalyzed by either calcined or non-calcined CaO. These cosolvents promoted the ethanolysis by a successful activation of non-calcined CaO, which was ascribed to the CaCO 3 and Ca(OH) 2 dissolution from the surface of the solid catalyst particles. With both cal-cined and non-calcined CaO, the polyol-based solvents gave higher fatty acid ethyl esters (FAEE) content than the amide-based solvents. Among the amide-based DESs, choline chloride:urea (ChCl:U) was the most efficient acti-vator of non-calcined CaO. Choline chloride:ethylene glycol (ChCl:EG) and choline chloride:propylene glycol (ChCl:PG) were more efficient than choline chloride:glycerol (ChCl:G) even with non-calcined CaO. However, ChCl:G might be more suitable than the others since the use of glycerol, a by-product of the ethanolysis, could reduce the overall biodiesel production costs. FTIR and XRD analyses of the used and separated CaO were performed in order to get more insight into the catalytically active phase(s). Also, the mechanisms of the CaO activation in the presence of the DESs were considered. The phase separation of the reaction mixture was faster in the presence of the DESs. Since ChCl:U and ChCl:G DESs are nontoxic, biodegradable, biorenewable and " green " solvents and provide the elimination of the calcination step of CaO, thus reducing the overall process costs, the non-calcined CaO catalytic systems with these DESs are recommended for further optimization.

This study aims to observe the changes in the structural characterization and physical properties of calcium-praseodymium-cobalt oxide thermoelectric materials with graphene doping. Structural characterizations were examined via X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and Fourier Transformed Infrared Spectroscopy (FTIR) measurements. Temperature-dependent thermal conductivity and Seebeck coefficient were measured by Physical Properties Measurement System (PPMS). In the SEM images, the samples were observed to be crystalline and showed enhanced fusion with graphene doping. There were no impurities in the samples according to the EDX results and all sample components were observed in these results. The properties and structures of the bonds in the XRD results were also visible in the FTIR results. According to the PPMS results, it was determined by measurements and graphs that graphene doping provided a significant and changeable effect to the thermoelectric materials. Published by the AVS.

Journal of Vacuum Science & Technology A 37, 061201 (2019); https://avs.scitation.org/doi/pdf/10.1116/1.5121253?class=pdf

This study consists of the optimization of the methyl ester yields produced via transesterification of palm oil using CaO/Al2O3 solid base catalyst. Response Surface Methodology (RSM) in combination with Central Composite Design (CCD) was used to optimize the operating parameters. Alcohol/oil molar ratio, catalyst content in the reaction medium and reaction temperature were chosen as the variables and the response selected was the amount of methyl ester yields. All the reactions were performed in a batch laboratory scale reactor for 5 h; the optimum reaction conditions obtained were approximately alcohol/oil molar ratio of 12:1, catalyst content of 6 wt.% and reaction temperature of 65 °C. The results from ICP-MS exhibited insignificant leaching of the CaO active species into the reaction medium and the reusability of the catalyst was successfully tested in two subsequent cycles. Under certain reaction conditions the glycerol obtained was almost colorless. © 2009 Elsevier B.V. All rights reserved.

http://ac.els-cdn.com/S0378382009003051/1-s2.0-S0378382009003051-main.pdf?_tid=a1db0a48-2363-11e4-b3fd-00000aab0f02&acdnat=1407987335_53f85d1174b65a2ec5a5c02ab128f15a 
http://www.sciencedirect.com/science/article/pii/S0378382009003051

The melting behaviour of calcium monoxide has been revisited by quasi-containerless laser heating under controlled atmosphere. The current results suggest that the large discrepancy in the literature data for the melting temperature of CaO is probably linked to the influence of the environmental oxidising/reducing conditions. The CaO solidification point measured in this work is (3222 ± 25) K in an oxidising environment, in agreement with previous research performed under similar conditions. In a reducing atmosphere, the liquid/solid transition occurs at a slightly, but systematically lower, less accurately reproducible temperature, (3192 ± 40) K. These phase transition temperatures are not depending on the external pressure, up to 0.3 MPa. In the latter case, radiance and optical spectroscopy measurements revealed a more abundant formation of colour centres, i.e. a higher concentration of oxygen defects in the material, which can affect the thermodynamic stability of the solid at very high temperatures. A similar behaviour may be expected to occur in multi-component material systems including CaO.

The duck and chicken eggshell wastes were applied as raw materials for the preparation of heterogeneous catalyst in biodiesel production. Prior to use, the calcium carbonate (CaCO3) content in the waste shell was converted to calcium oxide (CaO) by calcining at 600-900C for 4h. The physicochemical properties of the solid oxide catalyst were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method. The catalytic activity of the catalyst in transesterification of palm oil with methanol was evaluated, and the fuel properties of obtained biodiesel were measured. The effect of reaction time, reaction temperature, methanol/oil molar ratio, catalyst loading, and reusability of catalyst was also investigated. Eggshell waste is a bioresource for the production of heterogeneous base catalyst that can be successfully utilized for the synthesis of biodiesel with high purity.

Durante la ejecución de obras de ingeniería es común que el suelo que
se desea utilizar no cumpla con los criterios de calidad que la normativa
correspondiente exige para garantizar la estabilidad estructural de la obra. Para aquellos casos en los que el valor del índice de plasticidad del suelo excede el máximo permitido, la estabilización química ha demostrado los mejores resultados. En esta investigación se realizó un análisis comparativo del rendimiento del óxido de calcio (CaO) o cal viva, y el cloruro de sodio (NaCl) o sal de mesa, como agentes estabilizadores. Se agregaron estos agentes químicos en distintas proporciones al suelo en estudio y se monitorizaron las variaciones del límite líquido, límite plástico y el índice de plasticidad. Los resultados demostraron, contrario a lo que tradicionalmente se espera, que para el caso del suelo en estudio el mejor agente estabilizador es el cloruro de sodio o sal de mesa, debido a que no solo es más efectivo en disminuir el índice de plasticidad, sino que además es más barato que la cal.

In this work the response surface methodology (RSM) in conjunction with the central composite design (CCD) were used to optimize the activity of CaO/Al2O3 solid catalysts for the production of biodiesel. In order to measure the catalyst activity, we used palm oil as a representative raw material for the conversion to biodiesel. The biodiesel production was carried out in a batch laboratory scale reactor. The results showed that both the calcination temperature and the amount of calcium oxide loaded on the support had significant positive effects on the biodiesel yield. The maximum basicity and biodiesel yield obtained were about 194 μmol/g and 94%, respectively. Overall, the catalyst showed high performance at moderate operating conditions and its activity was maintained after two cycles. © 2009 Elsevier B.V. All rights reserved.

http://ac.els-cdn.com/S0926860X09004840/1-s2.0-S0926860X09004840-main.pdf?_tid=37188ce8-2364-11e4-a4f0-00000aacb35d&acdnat=1407987585_84b5785349eaf3dd76ae1aa6727333bb 
http://www.sciencedirect.com/science/article/pii/S0926860X09004840

Biomass has demonstrated to be an appropriate substitute for petroleum-based fuel since this energy can solve petroleum-based fuel-related problems. This research was carried out to investigate the suitability of palm oil refinery pilot plant waste to be considered as raw material for producing biodiesel catalytically using 15 wt% Ni/CaO (ES; eggshell). The catalyst was characterized using Thermal Gravimetric Analysis (TGA) and it was found that nitrate precursor and other impurities were fully decomposed at 800 C. Besides that, this research focused on the Fatty Acid Methyl Ester (FAME) characterizations using Gas Chromatography (GC), Fourier-Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) as well as physical properties (density, flash point, volatility and kinematic viscosity) of FAMEs were measured according to ASTM D6751. It was revealed that higher catalyst loading of 8:1000 (ratio of catalyst, g to palm oil refinery pilot plant waste, ml) contributes to higher esters content which are 90.31%. Carbonyl and methoxy group presence in the FAMEs from IR spectra result (1741.10 cm À1 and 1170.33 cm À1) proved that the FAMEs were produced. Additionally, results obtained from physical properties ratify that the FAMEs produced have aligned with the ASTM standard. The density , flash point, kinematic viscosity and volatility were found to be 0.877 g/cm 3 at 15°C, 130°C, 2.51 mm 2 /s at 40°C and 1.02 kPa respectively. From this work, the pilot plant dry fractionation waste consists of mainly olein and stearin has been successfully converted into biodiesel using waste eggshells based catalyst.

Calcium oxide (CaO) sorbents have been recently used for removal of CO2 gases in fossil fuel-fired power plant. However, there are some limitations of CaO in CO2 capturing such as rapid loss of activity during the capture cycles, which is a result of sintering, attrition, and consequent elutriation. Therefore, this paper has demonstrated a novel synthesis method to produce CaO at room temperature to avoid abovementioned drawbacks. In addition, introduction of ionic surfactant of sodium dodecyl sulfate to the CaO formation solution has shown a positive result of formation of homogeneous spherical particle with a mean Z-average diameter of 345.2 nm and polydispersion index (PDI) of 0.335 by dynamical light scattering measurement. Subjected to a high calcination temperature of 1200 o C, developed CaO is able to maintain a CO2 uptake capacity of 0.1025 gCO2/gsorbent under 30 minutes of carbonation time. Despite its lower CO2 uptake capacity compared to maximum theoretical limit of 0.78 gCO2/gsorbent, CaO particles is able to withstand a high calcination temperature of 1200 o C and reported a particle size distribution ranged from 0.4-1.2 m after calcination which is just slightly larger than fresh developed CaO. Given that such small narrow distributed size of CaO, developed CaO at room temperature is good for packed-bed reactor in calcium looping processes and more studies are required to find a suitable support for fluidized bed reactor type. This successful synthesis story of CaO particle at room temperature has unraveled the possibility to develop nanosized CaO at room temperature in order to achieve high CO2 uptake capacity while enjoying its superior thermal stability over multiple carbonation/calcination cycles.

Crude biodiesel was proven as a cosolvent in the methanolysis of sunflower oil catalyzed by calcined CaO. This reaction was modeled and optimized statistically in terms of reaction temperature (33.2–66.8 °C), methanol-to-oil molar ratio (3.5:1–8.5:1) and catalyst concentration (0.219–1.065 mol/L). The cosolvent loading was 10 wt% (based on oil weight). The optimum reaction conditions were found to be: the methanol-to-oil molar ratio of 7.1:1, the catalyst concentration of 0.74 mol/L and the reaction temperature 52 °C, ensuring the best esters content of 99.8%, for the reaction time of 1.5 h, which is close to the reported experimental value of 98.9%. Also, the used catalyst was recycled with no additional treatment in the further four consecutive cycles under the following reaction conditions: methanol-to-oil molar ratio 6:1, the concentration of catalyst 0.642 mol/L (only in the first run), the reaction temperature 50 °C, cosolvent-crude biodiesel loading 10 wt% to oil weight. The second recycling reaction provided the highest FAME content of 97.7% after 5 h.

Heterogeneous catalysts are promising for the transesterification reaction of vegetable oils to produce biodiesel. Unlike homogeneous, heterogeneous catalysts are environmentally benign and could be operated in continuous processes. Moreover they can be reused and ...

Heterogeneous catalysts are promising for the transesterification reaction of vegetable oils to produce biodiesel. Unlike homogeneous, heterogeneous catalysts are environmentally benign and could be operated in continuous processes. Moreover they can be reused and regenerated. However a high molar ratio of alcohol to oil, large amount of catalyst and high temperature and pressure are required when utilizing heterogeneous catalyst to produce biodiesel. In this paper, the catalytic activity of several solid base and acid catalysts, particularly metal oxides and supported metal oxides, was reviewed. Solid acid catalysts were able to do transesterification and esterification reactions simultaneously and convert oils with high amount of FFA (Free Fatty Acids). However, the reaction rate in the presence of solid base catalysts was faster. The catalyst efficiency depended on several factors such as specific surface area, pore size, pore volume and active site concentration. © 2009 Elsevier B.V. All rights reserved.

http://ac.els-cdn.com/S0378382009000629/1-s2.0-S0378382009000629-main.pdf?_tid=944422d4-2363-11e4-be00-00000aacb362&acdnat=1407987312_4885f84527f97d6f59c2ddefc0defb50 
http://www.sciencedirect.com/science/article/pii/S0378382009000629

Hydroxyapatite (HA) which compose around 70 % of our bone is an example of bioactive ceramics most commonly used in bone implantation. Because of their excellent bioactivities, hydroxyapatites are regarded as attractive biomedical materials. In this work we have succeeded in producing hydroxyapatite powder by using eggshell waste as the raw material. Eggshell waste is available in huge quantity from food processing, egg breaking and hatching industries. The process involved drying and thermal decomposition of eggshell into calcium oxide followed by hydrothermal reaction at low temperature with diammonium hydrogen phosphate and water. The produced hydroxyapatite powder is extraordinarily fine with nanosize primary particles. Its high purity proved that the product fulfills medical requirement. The present invention provides an environmentally beneficial and cost effective method of producing medical grade hydroxyapatite materials utilizing eggshell waste.

http://link.springer.com/chapter/10.1007/978-3-540-69139-6_85

Transesterification of soybean oil and ethanol catalyzed by calcium oxides prepared from the calcinations of CaO, Ca(OH) 2 , limestone, and Ca(OH) 2 /CaO as solid base catalysts was investigated. It was found that the catalytic activities significantly depended upon their base site strengths and their structures. Increases in catalytic performance of CaO could be achieved by loading Ca(OH) 2 on CaO and calcinations at a high temperature. The catalytic reaction using a 9:1 molar ratio of ethanol to oil at 70 °C, using CaO loaded with 3.7 wt% Ca(OH) 2 exhibited the optimal results, where the conversion of soybean oil reached 96.3% after 10 hrs of the reaction.

The CO 2 adsorption time for carbonate species and linear CO 2 formation onto bimetallic CaO/Fe 2 O 3 was investigated. The total basicity for CaO/Fe 2 O 3 was 52.85 cm 3 g-1 which is located at a medium basic site with maximum CO desorption temperature at 454 ℃. The CO 2 adsorption was conducted by using a fluidized bed reactor at 4, 12, 24 and 36 h. The element distribution on the adsorbent showed carbonate formation through an increment of the C element when the CO 2 adsorption time was longer. At 4 h of CO 2 adsorption, the adsorbent is capable of generating bicarbonate, monodentate carbonate and bidentate carbonate species. The vibrational modes of the physisorbed linear CO 2 for CO 2 absorbed product at the absorption region of 2240-2402 cm-1 was identified after 36 h of CO 2 adsorption. The absorption bands were assigned according to the adjacent CO 2 molecule interactions giving formation of the core layer and second layer linear CO 2 on the CaO/Fe 2 O 3 surfaces. The results of the present work show that the addition of CaO on the Fe 2 O 3 surfaces enhanced the basic site of the adsorbent which could generate several carbonate species and CO 2 adsorbed products at ambient condition.

In this work the response surface methodology (RSM) in conjunction with the central composite design (CCD) were used to optimize the activity of CaO/Al 2 O 3 solid catalysts for the production of biodiesel. In order to measure the catalyst activity, we used palm oil as a representative ...

Abstract Er 2 O 3 doped calcia stabilized zirconia based inert matrix fuel containing CeO 2 as a surrogate for PuO 2 was fabricated for a wide range of concentration using the polymer-to-ceramic conversion technique via metal acetate preceramic hybrid polymer solutions. Samples were characterized by XRD, SEM and AFM techniques. Nanocrystallite size variation in the samples was evaluated using peak broadening values by means of the Scherrer formula.

Hydroxyapatite (HA) which compose around 70 % of our bone is an example of bioactive ceramics most commonly used in bone implantation. Because of their excellent bioactivities, hydroxyapatites are regarded as attractive biomedical materials. In this work we have succeeded in producing hydroxyapatite powder by using eggshell waste as the raw material. Eggshell waste is available in huge quantity from food processing, egg breaking and hatching industries. The process involved drying and thermal decomposition of eggshell into calcium oxide followed by hydrothermal reaction at low temperature with diammonium hydrogen phosphate and water. The produced hydroxyapatite powder is extraordinarily fine with nanosize primary particles. Its high purity proved that the product fulfills medical requirement. The present invention provides an environmentally beneficial and cost effective method of producing medical grade hydroxyapatite materials utilizing eggshell waste.

http://link.springer.com/chapter/10.1007/978-3-540-69139-6_85

The duck and chicken eggshell wastes were applied as raw materials for the preparation of heterogeneous catalyst in biodiesel production. Prior to use, the calcium carbonate (CaCO3) content in the waste shell was converted to calcium oxide (CaO) by calcining at 600-900C for 4h. The physicochemical properties of the solid oxide catalyst were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method. The catalytic activity of the catalyst in transesterification of palm oil with methanol was evaluated, and the fuel properties of obtained biodiesel were measured. The effect of reaction time, reaction temperature, methanol/oil molar ratio, catalyst loading, and reusability of catalyst was also investigated. Eggshell waste is a bioresource for the production of heterogeneous base catalyst that can be successfully utilized for the synthesis of biodiesel with high purity.