Nano CaO Research Articles

Evaluation of Okra (Abelmoschus esculentus) Powder and Nano CaO as Alternative Clarifiers for Lime in the Processing of Sugarcane Juice

Evaluation of Okra (Abelmoschus esculentus) Powder and Nano CaO as Alternative Clarifiers for Lime in the Processing of Sugarcane Juice

Optimization of Biodiesel Production from Waste Cooking Oil Using Nano Calcium Oxide Catalyst

AbstractThe use of nano calcium oxide as a catalyst in biodiesel production has gained attention due to its high catalytic activity, low cost, and environmental friendliness. It efficiently converts triglycerides to fatty acids and methyl esters. In the present study, nano CaO was prepared by precipitation and characterized by various techniques. The results showed that the nano CaO has high purity, nanoscale crystal size, good thermal stability, and high specific surface area. Biodiesel was produced by transesterification from waste cooking oil, methanol, and the nano catalyst. Response surface methodology was applied to predict the optimum parameters for the production of the biodiesel based on its yield. The produced biodiesel was characterized by FTIR spectroscopy and GC‐MS and evaluated according to ASTM D6571.

MOF-derived nano CaO for highly efficient CO2 fast adsorption

Calcium looping is considered to be one of the best approaches for industrial CO2 high-temperature capture, whereas current CaO-based sorbent suffers poor cyclic performance, especially the relations between precursor structure and CO2 fast adsorption capacity still need to be further revealed. In this work, three calcium-based metal frameworks (Ca-MOFs) with specific structures were employed as precursors to obtain nano CaO through a two-step thermal transition process. It was found that LAC MOF-derived CaO achieved a fast adsorption capacity of 11.8 mmol g−1 (78 % of total adsorption) after 4 cycles. This was because the fiber bundle-like original LAC MOF structure changed gradually to nanosheets after 600 °C pyrolysis and finally formed regular CaO spheres with an average size of 100 nm after an 800 °C -calcination, thereby preventing further aggregation of CaO particles during the thermal transition process. In addition, the adsorption performance did not rely on pore structure, and thus pore-blocking showed little influence on the performance of CO2 capture. Hence, high stability can be achieved simply by avoiding particle sintering. The systematic study marks the significance of precise tailoring of nano-CaO for achieving the desired performance of CO2 fast adsorption.

Evaluation of Antimicrobial Activity of Newly Prepared Calcium Oxide Based Nanosealer Using Agar Diffusion Test


 Aim of the study: The antimicrobial activity of a root canal sealer can increase the success rate of endodontic treatments. The key of antimicrobial properties of calcium based sealers laid in their composition and alkalinity. The invention and applications of newer materials are quintessential in every field especially in endodontics. This reality has led to growing interest in the use of biomaterials products that comprised of both mineral and organic components as those in the teeth. This study was performed to assess the antibacterial activity of newly prepared calcium oxide based nanosealer and compare the result with BioRoot sealer
 Materials and methods: The CaO nanopowder was firstly prepared from calcinated cowrie seashell using ball milling and ultrasonic irradiation methods, and then the CaO nanopowder was used as the main component in the preparation of an experimental nanosealer powder part. After several pilot studies, the final formula for the prepared sealer that gave the best clinical sealer consistency and properties within the limits of ANSI/ADA Specification No.57/2012 was as the following. The powder part consists mainly of nano CaO (44%) in addition to glutamic amino acid, zirconium oxide (20nm), and silica oxide (15-20) nm, while the liquid part consists mainly from distilled water in addition to propylene glycol. The Antimicrobial activity of the prepared sealer was evaluated by agar diffusion test against E.faecalis and E.faecium, after 1, 2, 3, and 7 days of incubation at 37˚C. Zone of bacterial inhibition was measured and analyzed statistically using Independent sample t – test at (p=0.05) levels.

Microwave assisted biodiesel production from chicken feather meal oil using Bio-Nano Calcium oxide derived from chicken egg shell

Environmental concerns have initiated the search for greener measures to mitigate pollution issues. Bio Nano CaO was synthesized by reducing CaO extracted from chicken egg shell using tea decoction. The synthesized material was characterized by physico-chemical techniques such as XRD, TGA, BET surface area analyser, TGA and SEM techniques. XRD studied confirmed the crystalline nature of material. The prepared material was found to be stable till 450 οC from TGA study. The SEM pictures displayed uniform and discrete particles which portrays the high probable sites that maximises the catalytic activity. The optimization of microwave assisted Biodiesel synthesis from chicken feather oil through Transesterification process using the bio-synthesized catalytic material was the main aim of the study. A 500 W microwave irradiation of Chicken feather meal oil using 8:1 Methanol:Oil input, 1% Bio Nano CaO concentration, 5 min of reaction time resulted in 95% conversion of chicken feather meal oil into chicken feather meal methyl esters. The Biodiesel was showed low viscosity (4.15 mm2/s), high heating value (50 MJ/kg), high flash point (153οC), reasonable pour point (12 οC) and good cetane number (50 min). The future works will be concentrated on the engine studies related to Torque, fuel consumption, emission data by using the synthesized Biodiesel.

Biodiesel production from Custard apple seeds and Euglena Sanguinea using CaO nano-catalyst

This short communication investigated biodiesel production from Euglena Sanguineamicroalgaeand custard appleusing nano CaO as a heterogeneous catalyst. Different solvents were used to extract the oil at a fixed speed, time, and temperature for the samples to estimate the optimized oil yield%. The catalyst was synthesized by sol gel method in nano-scale. It was further characterized by FTIR spectroscopy, SEM, and XRD. The algal oil was pre-treated and trans-esterified with a catalyst to produce alkyl esters. The optimized process variables were determined using response surface methodology by varying parameters such as methanol to oil ratio and catalyst weight% for algal bio-oil and MeOH to oil ratio, time, and catalyst weight% for seed oil. The GC–MS was done to characterize the presence of biodiesel. Kinetic studies were done for the optimized condition for the algal oil and seed oil and it follows the pseudo-first order reaction.

Facile synthesis of carbon quantum dot ‑carbon nanotube composites on an eggshell-derived catalyst by one-step chemical vapor deposition

Carbon nanotubes (CNTs) based composites such as carbon quantum dot-CNT (CQD-CNT) demonstrate excellent performance in the fields of bioimaging and biomedicine. Nevertheless, CQD-CNT composites were mostly prepared by multiple and cumbersome steps, including the synthesis of CQDs, functionalization of CNTs and subsequent assembly of CQDs on CNTs. Here, a facile one-step synthesis of CQD-CNT was successfully conducted on an active CaO supported FeCo (Fe-Co/CaO) catalyst derived from waste eggshells via chemical vapor deposition, and other CNT-based composites such as carbon fiber-graphene sheet-CNT (CNF-GNS-CNT) and CNF-CNT as well as CNTs were also synthesized by modulating the catalyst support, growth temperature and growth time. The catalysts and produced CNTs and CNT-based composites were analyzed by multiple characterization tools. The results showed that nano CaO supported FeCo catalyst only synthesized MWCNTs, whereas Fe-Co/CaO was favorable for the synthesis of CNT-based composites. Cobalt oxides and iron oxides were well dispersed in the fresh Fe-Co/CaO catalyst, and FeCo alloy particles of different sizes were formed after catalyst reduction and heating to different growth temperatures. At a low growth temperature of 750 °C, CNF-GNS-CNT was synthesized on Fe-Co/CaO, in which CNTs and CNFs were grown on small (~10 nm) and larger (~30 nm) metal particles, respectively, whereas GNSs were mainly produced on CaO. At a high growth temperature of 850 °C, surface area and pore volume of catalysts decreased greatly, and higher solubility of carbon atoms in metal particles resulted in less desorbed CHx, which is not favorable for the growth of GNSs. Instead, CQD-CNT composites were selectively synthesized at 850 °C, which was ascribed to the oxidation corrosion of CNFs by OH radicals, but with the extension of growth time, only CNTs were produced due to the complete oxidation of CQDs. Further, larger metal particles were produced at a higher temperature of 950 °C, which were wrapped by graphite, and the partial deactivation of metal particles led to a few small particles remained active for CNT growth with a low carbon yield.

Waste-Derived Green Nanocatalyst for Biodiesel Production: Kinetic-Mechanism Deduction and Optimization Studies

This research focuses on deducing the kinetic mechanism for biodiesel production catalyzed by a CaO nanocatalyst derived from waste cockle shells via thermal hydration–dehydration treatment. In addition, the CaO nanocatalyst preparation method via thermal hydration–dehydration-related parameters (hydration duration, recalcination temperature, and recalcination duration) was studied and optimized. The transesterification reaction catalyzed by the CaO nanocatalyst followed the Langmuir–Hinshelwood kinetic mechanism with surface reaction as the rate-limiting step. The relatively low activation energy (3786.7 J/mol) for a transesterification reaction offered by the CaO nanocatalyst enhanced the reaction rate to 27.3% FAME yield/hr. The optimal conditions for the thermal hydration–dehydration treatment used to develop the nano CaO catalyst were 6 h of hydration duration, 650 °C of recalcination temperature, and 3 h of recalcination duration. Of biodiesel yield, 94.13% was obtained at a moderate temperature of 60 °C and 3 h reaction time during the transesterification of palm oil catalyzed by the nano-CaO. SEM, BET, and TPD results proved that the CaO nanocatalyst had a large surface area (13.9113 m2/g) and high pore volume (0.0318 cm3/g) that were rich in active sites (1046.46 μmol CO2/g), and the pore diameter (33.17 nm) was accessible to reactants and products.

Dual approach transformation of human finger and toe nail pruning into MgO/CaO nanoalloy

Interventions of biological entities mediated nanobiotechnological syntheses, in the strive to adapt inexpensive green approaches for constructing materials in the nanodimension for achieving targeted applications with improved performances, are being increasingly preferred. In context, this research article reports to bring into existence applaud able technique, concerning waste utilization for conversion into value added nanomaterial, to manage environmental issues as well as suffice biomedical demands and meet tough challenges from several domains. Pruning nail plates of the fingers and toes, has been a routine affair for the maintenance of personal care, in human civilization. Here we focus the bioengineering of MgO/CaO nanoalloy, by transforming remnant vestigial human finger and toe nail pruning, through dual approach protocols. Obtained yields through direct heat and following chemical treatment protocols were around 61.9% and 62.0%, respectively. Noticeable, quadrangular nanostructural arrangement in sequential array was observed for the MgO/CaO nanoalloy engineered through sol-gel chemical processing prior to thermal decomposition. Chemical treatment of the precursor enabled, formation of large stretches of uniform nanopattern and homogenous distribution to a great extent, from hydroxides of Mg and Ca instead of their salts. The scalable self-assembly with imparted ordered alignment shall inevitably manifest improved nanoalloy activity rather than the randomly distributed nanostuctures attained from direct thermal decomposition of their salts. The multifunctional green MgO/CaO nanoalloy, having tested thermal stability, consisting substantive Ca and Mg, incorporates the dual advantageous of nano MgO and nano CaO, logistically rendering superior benefits. Required characterizations were performed for the investigation of the significant nanostructures, comprising magnificent quadrangular nanobricks, nanorods and nanospheres, derived from the renewable bioresource.

Kinetics of Transesterification of Croton megalocarpus Oil Using Alkaline Earth Catalysts with Conventional and Microwave Heating

Transesterification kinetics of Croton megalocarpus oil to produce fatty acid methyl esters (FAME) was studied using homogeneous NaOH and heterogeneous alkaline earth Nano MgO, MgO, Nano CaO, CaO, Reoxidized CaO, SrO, and BaO catalysts. Characteristic surface, bulk, and chemical properties of the heterogeneous catalysts were obtained which included surface area, pore properties, scanning electron micrography, X-ray diffraction, basic strength, and basicity. The catalyst porosity varied as Nano MgO > Nano CaO > MgO > CaO > CaO-RO > SrO > BaO and basicity as BaO > SrO > Nano CaO > CaO RO > CaO > Nano MgO > MgO. Catalysts NaOH, BaO, SrO, and Nano CaO gave a good FAME yield (>50%), and reaction order and rate constant have been reported for these catalysts, for both conventional heating and microwave irradiation. The overall reaction for NaOH was of 1st order for microwave irradiation with respect to triglyceride and of 2nd order with respect to triglyceride under conventional heating. For the heterogeneous catalysts, the overall reaction was of 3rd order, 2nd order with respect to triglyceride and 1st order with respect to methanol for both heating methods. Reaction rate constants for microwave irradiation were higher than those for conventional heating due to faster reaction rates under such heating. BaO was the most active heterogeneous catalyst, followed by SrO and Nano CaO, which was in accordance with their basicity.

Phase composition, sinterability and bioactivity of amorphous nano-CaO-SiO2-CuO powder synthesized by sol-gel technique

Nowadays, the advancement of sciences urged the scientists to synthesize nano materials having a good bioactivity. Amorphous nano CaO–SiO2–CuO materials were prepared by sol-gel method and investigated for their phase composition, sinterability and bioactivity. To detect the crystallization temperature, calcination was conducted at different temperatures. Phase composition was examined by XRD and confirmed by FTIR. Bioactivity of prepared powder was assessed through soaking in simulated body fluid (SBF) then examined by FTIR. Also, concentrations of Ca, P, Si and Cu in (SBF) solution were recorded by inductive coupled plasma (ICP). Furthermore, the antibacterial properties were evaluated against S. aureus and S. epidermidis bacteria. The prepared powders were sintered up to 1300 °C and their physico-mechanical properties were studied. The results revealed that the materials calcined at 600 and 800 °C exhibited amorphous character while that calcined at 1000 °C was crystalline in nature. Sintering up to 1300 °C led to production of dense bodies having appropriate physico-mechanical properties. The mechanical properties increased with increasing sintering temperature and decreasing CuO content except fracture toughness which increased with increasing CuO content. Also, the results pointed out that the lower the CuO content in the samples; the higher are their bioactivity and antibacterial behavior. Furthermore, the amorphous ones exhibited better bioactivity than the crystalline ones.

Greener nanoscience: Piper betel leaf extract mediated synthesis of CaO nanoparticles and evaluation of its antibacterial and anticancer activity

Abstract The present study reports the antimicrobial and anticancer activities of green synthesized calcium oxide nanoparticles. The antimicrobial activity was assessed by agar well diffusion method. Maximum activity was observed for E. coli and minimum for S. mutans. The anticancer activity was determined by MTT assay against the cell line A549. The IC50 value of nano CaO was found to be 92.08 µg/mL. The experimental results suggest the applicability of synthesized CaO NPs as potential antibacterial and anticancer agents.

Optimisation of transesterification of Croton megalocarpus oil over alkaline earth catalysts using conventional and microwave irradiation by response surface methodology

ABSTRACT Croton megalocarpus oil is a non-edible oil with potential to produce biodiesel in East Africa. Transesterification of the oil and methanol to produce fatty acid methyl ester (FAME) was studied using heterogeneous alkaline earth BaO, SrO, CaO, Nano CaO, Reoxidised CaO (CaO RO), MgO, Nano MgO, BeO catalysts; by conventional heating and by microwave irradiation. Catalysts were characterised by surface area, porosity, basic strength and basicity. FAME yield was obtained through Gas chromatography. Central Composite Design (CCD) was used to optimise process variables (reaction temp. /time, methanol-to-oil ratio, catalyst conc.) for the highest FAME yield through Response Surface Methodology (RSM) plots. Conventional heating gave a higher maximum yield, in the order: BaO(83%) > SrO(77%) > Nano CaO(74%) > CaO RO(42%) > CaO(32%) > Nano MgO(25%) > MgO(20%) > BeO(–). Yields were in order of the observed catalyst basicity, and independent of surface area. New catalyst CaO RO obtained from CaO showed higher activity. BeO showed no activity (<5%). Microwave irradiation gave slightly reduced maximum yields for BaO(78%), SrO(72%) and Nano CaO(62%). However, no such maxima were observed for other catalysts for the chosen reaction time. Microwave was found to be a superior heating mode due to highly reduced reaction times.

Removal of fluoride ion from drinking water by a new Fe(OH)3/ nano CaO impregnated chitosan composite adsorbent

ABSTRACTA novel adsorbent made of freshly obtained calcium oxide nanoparticles and ferric hydroxide dispersed in chitosan matrix (CHI-FCA) was prepared. Batch adsorption study was performed to analyze the effect of initial concentration, contact time, pH, and adsorbent dose on fluoride sorption on CHI-FCA. It was observed that maximum fluoride adsorption was achieved at pH 7.10 at an optimum equilibrium contact time of 180 min with an adsorbent dose of 8 g/L. Moreover, a synergistic effect was observed for fluoride remediation from aqueous medium. FTIR, XRD, DLS, TGA, DTA, and ESEM with EDX analysis were performed for the investigation reported here.

Microwave assisted synthesis of highly crystalline nano CaO from waste egg shells-A low temperature record activity in glycerol carbonate

Microwave assisted synthesis of highly crystalline nano CaO from waste egg shells-A low temperature record activity in glycerol carbonate

Stability of complex catalyst with NiO@TiO2 core-shell structure for hydrogen production

Core-shell NiO@TiO2 and CaO complex catalyst was prepared to improve stability used in the reactive sorption-enhanced reforming (ReSER) process for hydrogen production. NiO@TiO2 as catalyst component was prepared by synthesizing Ni(OH)2 as core via urea hydrolysis, by coating TiO2 shell via adsorption phase reaction technique, and was mixed with nano CaO as CO2 adsorbent to form a complex catalyst. The morphology of NiO@TiO2 and the complex catalyst were characterized by means of TEM, EDS, XRD and N2 physisorption measurements. Hydrogen production performance was investigated in a fixed-bed stainless steel reactor. Results showed that the complex catalyst with core-shell NiO@TiO2 structure has 36 cyclic runs of the ReSER process for hydrogen production, while only nine cycle runs obtained without TiO2 coated as shell. It was revealed that core-shell NiO@TiO2 structure could increase the surface area of complex catalyst and promote the separation of NiO core particles. It was also found that the optimum TiO2 coating time could obtain relative smaller NiO grain. And smaller initial NiO grain in core-shell structure would improve the stability of the complex catalyst.

Impact of nano calcium hydroxide and calcium oxide on some metabolic activities and phenolic compounds of Lupinus termis seedlings

The effect of 0.5, 1.0 and 2.0 mM nano calcium hydroxide Ca(OH)2 and calcium oxide CaO orbulk calcium carbonate CaCO3 on growth and metabolic changes of Lupines termis seedlings was assessed.Root fresh and dry weights were increased by nano CaO at 0.5 and 1.0 mM compared with the control, whilethey were decreased by increasing nano Ca(OH)2. Shoot fresh and dry weights were increased by increasingthe concentration of nano Ca(OH)2 and CaO reaching their maximum at 0.5 and 2.0 mM, respectively. BulkCaCO3 concentrations increased root and shoot fresh and dry weights at the highest concentration (2mM).The photosynthetic pigments (chl.a, chl.b and carotenoids) were markedly increased with increasing theconcentration of nano Ca (OH)2, nano CaO and bulk CaCO3 with the highest magnitude recorded for nanoCa(OH)2, while the lowest was for CaCO3. The total soluble carbohydrate biosynthesis of both shoot androot was reduced by nano calcium particles, whereas it was enhanced by bulk calcium compared withcontrol. The root soluble protein was decreased by different concentrations of either nano or bulk calcium,while shoot soluble protein was increased by all calcium treatments compared with the control. The nanocalcium especially Ca(OH)2 activated the protein metabolism compared with the bulk. The root and shootphenolic compounds were decreased by different concentrations of either nano or bulk calcium, except of theshoot phenolic compounds at CaCO3. Nano CaO at 0.5 mM increased shoot phenolic compounds by 10%compared with control.

Stability of the Ni–TiO2@nano CaO/Al2O3 complex catalyst used in ReSER process for hydrogen production

This paper describes the preparation and evaluation of a sorption complex catalyst of Ni–TiO2@nano CaO/Al2O3 for hydrogen production by a reactive sorption-enhanced reforming (ReSER) process. TiO2 coating-modified nano CaCO3 as the precursor of nano CaO was prepared by an adsorption phase technique which was able to strictly control the thickness and structure of surface to improve its durability. Ni–TiO2@nano CaO/Al2O3 was prepared by a mixing method which is general mixing that cannot control the content and structure of catalyst. The microstructure was tested by SEM and XRD, and variation in the sorption property of the catalyst was tested by thermogravimetric analysis (TGA). The results showed that TiO2 coating enhanced the stability of the sorption capacity of the catalyst. X-ray diffraction analysis revealed that the TiO2 coating modification inhibited the growth of Ni crystals and prevented CaO and Al2O3 from forming (CaO)12(Al2O3)7 due to the physical isolation by the TiO2 coating of the nano CaCO3. Evaluation of the modified complex catalyst in the ReSER hydrogen production process revealed significant stability for 13 circulations.

Calcination–carbonation durability of nano CaCO3 doped with Li2SO4

Li2SO4 doped nano CaO (Li2SO4@nano CaO) based CO2 adsorbent has been developed to improve calcination–carbonation durability. Li2SO4@nano CaO adsorbent was obtained by calcination of Li2SO4 doped nano CaCO3 that was prepared by a simple wet solution impregnation method. The morphology and microstructural properties of the adsorbent were examined by scanning electron microscopy (SEM) and nitrogen physisorption tests, and its cyclic calcination–carbonation performance was evaluated by thermogravimetric analysis (TGA). The results show that Li2SO4@nano CaO adsorbent maintains a 51.0% CaO conversion after 11 cycles under the calcination temperature of 750°C and carbonation temperature of 600°C with an optimized Li2SO4 content of 3.0–5.0wt.%. Alternatively, pure nano CaO maintains only a 27.3% conversion at the same conditions. A physical property analysis reveals that the superior performance of Li2SO4@nano CaO adsorbent is attributed to the pore diameter enlargement and to the increase of macro-pore proportion due to Li2SO4 incorporation. Moreover, the carbonation and calcination rates of Li2SO4@nano CaO adsorbent are accelerated compared with nano CaO adsorbent, and the complete decomposition temperature is at least 15°C lower. In comparison with the adsorbent doped with other lithium salts (Li2CO3 and LiCl), Li2SO4@nano CaO adsorbent possesses the best durability under equivalent doping conditions. Furthermore, the positive linear correlation between the complete decomposition temperature and CaO conversion has been maintained.

Preparation of MgO-coated nano CaO using adsorption phase reaction technique for CO2sorption

Preparation of MgO-coated nano CaO using adsorption phase reaction technique for CO2sorption.