Calcium peroxide (CaO2) for use in modified Fenton chemistry

Northup, Abraham; Cassidy, Daniel P.

doi:10.1016/j.jhazmat.2007.07.096

Cited by 239 publications

(136 citation statements)

References 28 publications

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“…In the present study, the labile fractions of As decreased significantly with moderate rate of CaO 2 application, which might be contribute to that CaO 2 application increased the Eh of soil to well-oxidized condition and As(III) would be transform to less mobile specie as As(V) under oxidizing condition (Fuessle and Taylor, 2004;Northup and Cassidy, 2008;Dias et al, 2009). H 2 O 2 liberated from CaO 2 application (via reaction (1)) would resolve into H 2 O and O 2 and increase redox potentials with the production of oxygen making arsenite oxidation possible (Fuessle and Taylor, 2004).…”

supporting

confidence: 47%

“…Calcium peroxide (CaO 2 ) is one of the most versatile and safest substances to handle of the family of solid inorganic peroxy compounds which are considered a ''solid form'' of hydrogen peroxide (Tieckelmann and Steele, 1991 (Northup and Cassidy, 2008). The As(III) stabilization process will be improved by CaO 2 application into soil, because of the reaction of As(III) with H 2 O 2 via reaction (2) (Fuessle and Taylor, 2004).…”

mentioning

confidence: 99%

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Effects of calcium peroxide on arsenic uptake by celery (Apium graveolens L.) grown in arsenic contaminated soil

Liu

Luo

et al. 2012

Chemosphere

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supporting

confidence: 47%

mentioning

confidence: 99%

Effects of calcium peroxide on arsenic uptake by celery (Apium graveolens L.) grown in arsenic contaminated soil

Liu

Luo

et al. 2012

Chemosphere

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“…Sahinkaya et al (2015) suggested that the reaction rate of sludge hydrolysis were up to 50.10 and 33.95 mg/(L$min) by using conventional Fenton and Fenton type process respectively. Northup and Cassidy (2008) reported that CaO 2 was able to maintain oxidation reactions over a long period of time since it was dissolved slowly in water. By contrast, the sludge conditioning by CaO 2 oxidation lasted a long time but it was safe due to its lower reaction rate.…”

Section: Kinetics Of Calcium Ionmentioning

confidence: 99%

Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation

et al. 2016

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a b s t r a c tThe effects of combined calcium peroxide (CaO 2 ) oxidation with chemical re-flocculation on dewatering performance and physicochemical properties of waste activated sludge was investigated in this study. The evolutions of extracellular polymeric substances (EPS) distribution, composition and morphological properties were analyzed to unravel the sludge conditioning mechanism. It was found that sludge filtration performance was enhanced by calcium peroxide oxidation with the optimal dosage of 20 mg/ gTSS. However, this enhancement was not observed at lower dosages due to the absence of oxidation and the performance deteriorated at higher dosages because of the release of excess EPS, mainly as proteinlike substances. The variation in soluble EPS (SEPS) component can be fitted well with pseudo-zero-order kinetic model under CaO 2 treatment. At the same time, extractable EPS content (SEPS and loosely bound EPS (LB-EPS)) were dramatically increased, indicating sludge flocs were effectively broken and their structure became looser after CaO 2 addition. The sludge floc structure was reconstructed and sludge dewaterability was significantly enhanced using chemical re-flocculation (polyaluminium chloride (PACl), ferric iron (FeCl 3 ) and polyacrylamide (PAM)). The inorganic coagulants performed better in improving sludge filtration dewatering performance and reducing cake moisture content than organic polymer, since they could act as skeleton builders and decrease the sludge compressibility.

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“…Without encapsulation, peroxide-based compounds quickly release oxygen upon contact with water, resulting in bursts of oxygen that are too severe and transient for use (21). By encapsulating solid peroxide within a highly hydrophobic biomaterial, we have introduced a diffusional barrier that substantially reduces its reactivity, consequently modulating the release of oxygen for more than 40 d. The reactivity of the encapsulated peroxide is heavily dictated by the rate of water diffusion into the PDMS, because water permeability in PDMS is very low, although it is likely increased by the incorporation of solid peroxide particulates (23).…”

Section: Discussionmentioning

confidence: 99%

“…Oxygen generation via hydration of solid peroxide, however, is too rapid, leading to hyperoxide conditions that result in the buildup of the reaction intermediate hydrogen peroxide and increased susceptibility of side reactions such as hydroxyl radical (OH − ) generation (details in SI Text) (21). Encapsulation of solid peroxide within a polymer could serve to temper its hydrolytic reactivity.…”

mentioning

confidence: 99%

Preventing hypoxia-induced cell death in beta cells and islets via hydrolytically activated, oxygen-generating biomaterials

Pedraza

Coronel

Fraker

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

350

358

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A major hindrance in engineering tissues containing highly metabolically active cells is the insufficient oxygenation of these implants, which results in dying or dysfunctional cells in portions of the graft. The development of methods to increase oxygen availability within tissue-engineered implants, particularly during the early engraftment period, would serve to allay hypoxiainduced cell death. Herein, we designed and developed a hydrolytically activated oxygen-generating biomaterial in the form of polydimethylsiloxane (PDMS)-encapsulated solid calcium peroxide, PDMS-CaO 2 . Encapsulation of solid peroxide within hydrophobic PDMS resulted in sustained oxygen generation, whereby a single disk generated oxygen for more than 6 wk at an average rate of 0.026 mM per day. The ability of this oxygen-generating material to support cell survival was evaluated using a β cell line and pancreatic rat islets. The presence of a single PDMS-CaO 2 disk eliminated hypoxia-induced cell dysfunction and death for both cell types, resulting in metabolic function and glucose-dependent insulin secretion comparable to that in normoxic controls. A single PDMS-CaO 2 disk also sustained enhanced β cell proliferation for more than 3 wk under hypoxic culture conditions. Incorporation of these materials within 3D constructs illustrated the benefits of these materials to prevent the development of detrimental oxygen gradients within large implants. Mathematical simulations permitted accurate prediction of oxygen gradients within 3D constructs and highlighted conditions under which supplementation of oxygen tension would serve to benefit cellular viability. Given the generality of this platform, the translation of these materials to other cell-based implants, as well as ischemic tissues in general, is envisioned.tissue engineering | encapsulation | bioartificial pancreas | diabetes

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Calcium peroxide (CaO2) for use in modified Fenton chemistry

Cited by 239 publications

References 28 publications

Effects of calcium peroxide on arsenic uptake by celery (Apium graveolens L.) grown in arsenic contaminated soil

Effects of calcium peroxide on arsenic uptake by celery (Apium graveolens L.) grown in arsenic contaminated soil

Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation

Preventing hypoxia-induced cell death in beta cells and islets via hydrolytically activated, oxygen-generating biomaterials

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