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Natural Materials – Composition and Combinations
Published in Graham A. Ormondroyd, Angela F. Morris, Designing with Natural Materials, 2018
In animals, calcium oxalate crystal formation is associated with kidney stones, in which the monohydrate of calcium oxalate is the most common hydrate type. Calcium oxalate adopts a large variety of crystalline forms and hydration types, and studies comparing the effects of concentration, buffering, pH and temperature alter calcium oxalate crystal growth and nucleation (Thongboonkerd et al. 2006).
Decontamination of Heavy-Metal-Laden Sludges and Soils Using a New Lon-Exchange Process
Published in Donald L. Wise, Debra J. Trantolo, Edward J. Cichon, Hilary I. Inyang, Ulrich Stottmeister, Remediation Engineering of Contaminated Soils, 2000
Sukalyan Sengupta, Arup K. SenGupta
the experimental framework for the oxalate system in more detail. In this case, to a 5% (w/v) sludge, fine sand (70%),Na2C2O4(21%), calcite (7.8%), and CuO(0.6%) were mixed. The sludge pH was maintained at 9.0, and CaC2O4 and Cu(OH)2 were the controlling solid phases under these conditions. Thus, the amount of oxalate added was much more than 0.05M. The oxalate added reacted with calcium to form calcium oxalate, a compound with low solubility. Precipitation of calcium oxalate reduced the aqueous-phase oxalate concentration to 0.05M. After the formation of CaC2O4(s), the cyclic process was started.
Monodispersed fine particles of calcium oxalate: morphological dynamics with tuning of the experimental parameters
Published in Journal of Dispersion Science and Technology, 2023
Khalida Akhtar, Shahana Abad, Hina Khalid, Naila Zubair, Syed Sajjad Ali Shah
In particular, calcium oxalate, a calcium salt of oxalate (CaC2O4·xH2O, where x varies from 0 to 3) is the most common biominerals in nature and the most complete group of living materials found in hydrothermal veins. It can crystallize into three forms, that is, monohydrate, dihydrate, and trihydrate, while the monohydrate occurs naturally in the form of minerals in plants forming envelope-shaped crystals and it is thermodynamically stable. Calcium oxalate is one of the major inorganic components of renal stones.[9] Thus, in renal stones, only monohydrate and dihydrate forms were found. These three different forms of calcium oxalate show properties that end up being the focus of various fields of material sciences namely cultural heritage and biomedicine.[10] It is used as a precursor for calcium carbonate and calcium oxide, as it thermally decomposes at different temperatures into these compounds.[11] Furthermore, calcium oxide finds its application in the manufacturing of paper, cement, and high-grade steel and is widely used for medical purposes. While calcium carbonate is used in environmentally friendly items such as drug delivery, microcapsules, and bone-filling materials.[12]
Remediation of oxalate in a homogeneous granulation process in the frame of crystallization
Published in Chemical Engineering Communications, 2022
Roselle Y. Mamuad, Alvin R. Caparanga, Angelo Earvin Sy Choi, Ming-Chun Lu
Calcium oxalate crystals have the forms of monoclinic monohydrate, tetragonal dihydrate and triclinic trihydrate. Nevertheless, the monohydrate structure is the only thermodynamically stable form of calcium oxalate crystals (Grases et al. 1990). The seeded crystallization setup with various fluid dynamic conditions and spontaneous precipitation at highly supersaturated solutions were the only studies in crystallization that concerns the formation of the calcium oxalate monohydrate (Arvaniti et al. 2010; Bouropoulos et al. 1998; Millan et al. 1997). The utilization of calcium oxalate is essential in the manufacturing of organic oxalates and ceramic glazes (Considine and Considine 1995). This can also be used for the determination of rare metals and calcium in the aspect of analytical chemistry (Ryabchikov and Gol’Braikh 2013). Calcium oxalate can also be applied in pyrotechnic formulations to enhance the color of red (Agrawal 2010). Furthermore, calcium oxalate is effective in places suitable for pore sealing rendering to satisfactory water proofing due to its ability to provide a protective patina in a mural facade and marble sculptures (Doherty et al. 2007).
Physicochemical Characterization of Historical Coating Mortars – Case Studies in South Brazil
Published in International Journal of Architectural Heritage, 2022
Fernanda Lamego Guerra, Caroline Giordani, Lucas Volpatto, Jardel Pereira Gonçalves, Mário Mendonça de Oliveira, Angela Borges Masuero, Denise Carpena Coitinho Dal Molin
For sample F1.2 from Frasca House, corresponding to the stucco lustro finish, the XRD (Figure 9b) presents sulfate compounds as gypsum (CaSO4.2H2O) and anhydrite (CaSO4), as expected. The calcite also appears, possibly indicating the use of lime in this plaster. The predominant peak identified in 14.5° 2Ɵ in this sample indicates the presence of hydrated calcium oxalate. As verified in loco, the sample extraction site had a dark-colored biofilm. Although no analysis was performed for biological characterization, the morphological characteristics verified corresponded to the growth of the microorganisms, probably with a fungi predominance. According to Gadd et al. (2014), calcium oxalate is the oxalate most abundantly found in living organisms and in the environment, the main forms are monohydrate (whewellite) and dihydrate (weddellite). Oxalate production is involved in the biodeterioration of rocky and mineral substrates, lignocellulosic materials and alteration and deterioration of cultural heritage (Gadd et al. 2014; Pinzari et al. 2013, 2010). Biosynthesis of oxalic acid and the formation of oxalates, especially those of calcium, is a property found in a wide variety of free-living and symbiotic fungi (Gadd et al. 2014).