Effects of experimental variables on conversion of cockle shell to calcium oxide using thermal gravimetric analysis

Mohamed, Mona A.; Rashidi, Nor Adilla; Yusup, Suzana; Teong, Lee Keat; Rashid, Umer; Ali, Razol Mahari Mohd

doi:10.1016/j.jclepro.2012.07.050

Cited by 21 publications

(10 citation statements)

References 8 publications

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“…TGA-MS of the postreacted sample (Figure S12) showed a release of CO 2 starting at 340 °C and then peaking at 446 °C and with less intensity, at 508 °C. The two distinct CO 2 releases, well within published temperature ranges for magnesite decomposition, are attributed to different sized carbonate particles, a characteristic known to have large impacts on carbonate decomposition temperatures . The measured weight loss assigned to carbonate decomposition between 250° and 700 °C was 7.1% and corresponds to 92 μmol/m 2 magnesite and/or adsorbed carbonate.…”

Section: Resultssupporting

confidence: 66%

“…The two distinct CO 2 releases, well within published temperature ranges for magnesite decomposition, 38 are attributed to different sized carbonate particles, a characteristic known to have large impacts on carbonate decomposition temperatures. 39 The measured weight loss assigned to carbonate decomposition between 250°a nd 700°C was 7.1% and corresponds to 92 μmol/m 2 magnesite and/or adsorbed carbonate. NMR data for the postreacted sample are shown in Figure S13b.…”

Section: Resultsmentioning

confidence: 94%

“…These same bands were observed in Exp#2-Exp#5 at similar adsorbed H 2 O concentrations. See text for details. c See references − . d These bands grew as a function of time after the last water addition of the titration (i.e., the 10th addition in Exp#1, corresponding to an adsorbed H 2 O concentration of 103 μmol/m 2 ). …”

Section: Resultsmentioning

confidence: 99%

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Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide

et al. 2015

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Continental flood basalts are attractive formations for geologic sequestration of carbon dioxide because of their reactive divalent-cation containing silicates, such as forsterite (Mg2SiO4), suitable for long-term trapping of CO2 mineralized as metal carbonates. The goal of this study was to investigate at a molecular level the carbonation products formed during the reaction of forsterite with supercritical CO2 (scCO2) as a function of the concentration of H2O adsorbed to the forsterite surface. Experiments were performed at 50 °C and 90 bar using an in situ IR titration capability, and postreaction samples were examined by ex situ techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), focused ion beam transmission electron microscopy (FIB-TEM), thermal gravimetric analysis mass spectrometry (TGA-MS), and magic angle spinning nuclear magnetic resonance (MAS NMR). Carbonation products and reaction extents varied greatly with adsorbed H2O. We show for the first time evidence of Mg-carbonate surface complexation under wet scCO2 conditions. Carbonate is found to be coordinated to Mg at the forsterite surface in a predominately bidentate fashion at adsorbed H2O concentrations below 27 μmol/m(2). Above this concentration and up to 76 μmol/m(2), monodentate coordinated complexes become dominant. Beyond a threshold adsorbed H2O concentration of 76 μmol/m(2), crystalline carbonates continuously precipitate as magnesite, and the particles that form are hundreds of times larger than the estimated thicknesses of the adsorbed water films of about 7 to 15 Å. At an applied level, these results suggest that mineral carbonation in scCO2 dominated fluids near the wellbore and adjacent to caprocks will be insignificant and limited to surface complexation, unless adsorbed H2O concentrations are high enough to promote crystalline carbonate formation. At a fundamental level, the surface complexes and their dependence on adsorbed H2O concentration give insights regarding forsterite dissolution processes and magnesite nucleation and growth.

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Section: Resultssupporting

confidence: 66%

Section: Resultsmentioning

confidence: 94%

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Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide

et al. 2015

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“…7b), in accordance with the theoretical value (44%). The decomposition temperatures of CaCO 3 powders are remarkably lower than that of geological calcite (~850 C) (Singh and Singh, 2007) and cockle shells (750e950 C) (Mohamed et al, 2012a) due to the crystallite refinement of nanosized CaCO 3 powders. The thermal decomposition of CaCO 3 powders started at lower temperatures (560e564 C) than that of shell powder (600 C), resulting from the size reduction of ball milling.…”

Section: Chemical Analysis Of Caco 3 Powdersmentioning

confidence: 96%

Recycling of shell wastes into nanosized calcium carbonate powders with different phase compositions

et al. 2015

Journal of Cleaner Production

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“…Shan et al [16] studied Ca-based heterogeneous catalyst perspectives synthesized using rich waste materials such as bones, mollusk shells, egg shells, and industrial wastes besides catalytic activity and biodiesel applications of calcium catalysts prospects and challenges were discussed. Mohamed et al [17] derived CaO from cockle shell by calcination at 850 ∘ C, while Nurdin [18] derived CaO catalyst from Paphia undulata shell wastes through calcination at 680 ∘ C for transesterification of Jatropha curcas oil (JCO) and Rubber oil to biodiesel. Choudhury et al [11], Teo et al [12], and Taufiq-Yap et al [13] investigated the transesterification of JCO using CaO of BET 7.114 m 2 /g; 9.2 ± 0.80 m 2 /g; and 9.5 m 2 /g and obtained a biodiesel of 89.36%, 90%, and 85%, respectively, while Margaretha et al [19] experimented with Pomacea sp.…”

Section: Introductionmentioning

confidence: 99%

Active Razor Shell CaO Catalyst Synthesis for Jatropha Methyl Ester Production via Optimized Two-Step Transesterification

Reddy

Saleh

Islam

et al. 2017

Journal of Chemistry

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Calcium based catalysts have been studied as promising heterogeneous catalysts for production of methyl esters via transesterification; however a few were explored on catalyst synthesis with high surface area, less particle size, and Ca leaching analysis. In this work, an active Razor shell CaO with crystalline size of 87.2 nm, BET of 92.63 m 2 /g, pore diameters of 37.311 nm, and pore volume of 0.613 cc/g was synthesized by a green technique "calcination-hydro aeration-dehydration." Spectrographic techniques TGA/DTA, FTIR, SEM, XRD, BET&BJH, and PSA were employed for characterization and surface morphology of CaO. Two-step transesterification of Jatropha curcas oil was performed to evaluate CaO catalytic activity. A five-factor-five-level, two-block, half factorial, central composite design based response surface method was employed for experimental analysis and optimization of Jatropha methyl ester (JME) yield. The regression model adequacy ascertained thru coefficient of determination ( 2 : 95.81%). A JME yield of 98.80% was noted at (3.10 wt.%), (54.24 mol./mol.%), (127.87 min), (51.31 ∘ C), and (612 rpm). The amount of Ca leached to JME during 1st and 4th reuse cycles was 1.43 ppm ± 0.11 and 4.25 ppm ± 0.21, respectively. Higher leaching of Ca, 6.67 ppm ± 1.09, was found from the 5th reuse cycle due to higher dispersion of Ca 2+ ; consequently JME yield reduces to 76.40%. The JME fuel properties were studied according to biodiesel standards EN 14214 and comply to use as green biodiesel.

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Effects of experimental variables on conversion of cockle shell to calcium oxide using thermal gravimetric analysis

Cited by 21 publications

References 8 publications

Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide

Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide

Recycling of shell wastes into nanosized calcium carbonate powders with different phase compositions

Active Razor Shell CaO Catalyst Synthesis for Jatropha Methyl Ester Production via Optimized Two-Step Transesterification

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