Degradation of Phthalic Acids and Benzoic Acid from Terephthalic Acid Wastewater by Advanced Oxidation Processes

Thiruvenkatachari, Ramesh; Kwon, Tae Ouk; Moon, Ilkyeong

doi:10.1080/10934520600754136

Cited by 28 publications

(6 citation statements)

References 36 publications

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“…Hence, in experiments with those probes only the hydroxylated products are typically measured, while the substrate - often added in excess - is routinely not analyzed for. When detection of these substrates is required, it is usually conducted with far less sensitive UV-based methods [ 34 ].…”

Section: Discussionmentioning

confidence: 99%

Phenylalanine as a hydroxyl radical-specific probe in pyrite slurries

2012

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The abundant iron sulfide mineral pyrite has been shown to catalytically produce hydrogen peroxide (H2O2) and hydroxyl radical (.OH) in slurries of oxygenated water. Understanding the formation and fate of these reactive oxygen species is important to biological and ecological systems as exposure can lead to deleterious health effects, but also environmental engineering during the optimization of remediation approaches for possible treatment of contaminated waste streams. This study presents the use of the amino acid phenylalanine (Phe) to monitor the kinetics of pyrite-induced .OH formation through rates of hydroxylation forming three isomers of tyrosine (Tyr) - ortho-, meta-, and para-Tyr. Results indicate that about 50% of the Phe loss results in Tyr formation, and that these products further react with .OH at rates comparable to Phe. The overall loss of Phe appeared to be pseudo first-order in [Phe] as a function of time, but for the first time it is shown that initial rates were much less than first-order as a function of initial substrate concentration, [Phe]o. These results can be rationalized by considering that the effective concentration of .OH in solution is lower at a higher level of reactant and that an increasing fraction of .OH is consumed by Phe-degradation products as a function of time. A simplified first-order model was created to describe Phe loss in pyrite slurries which incorporates the [Phe]o, a first-order dependence on pyrite surface area, the assumption that all Phe degradation products compete equally for the limited supply of highly reactive .OH, and a flux that is related to the release of H2O2 from the pyrite surface (a result of the incomplete reduction of oxygen at the pyrite surface). An empirically derived rate constant, Kpyr, was introduced to describe a variable .OH-reactivity for different batches of pyrite. Both the simplified first-order kinetic model, and a more detailed numerical simulation, yielded results that compare well to the observed kinetic data describing the effects of variations in concentrations of both initial Phe and pyrite. This work supports the use of Phe as a useful probe to assess the formation of .OH in the presence of pyrite, and its possible utility for similar applications with other minerals.

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Section: Discussionmentioning

confidence: 99%

Phenylalanine as a hydroxyl radical-specific probe in pyrite slurries

2012

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“…Radical formation from H 2 O 2 is enhanced in the presence of oxidization agents such as ozone or UV light at 254 nm. The combination of UV light and H 2 O 2 has been applied for several decades for carton decontamination in aseptic packaging (Warriner et al 2000) and also for wastewater treatment (Thiruvenkatachari et al 2006). UV light in combination with H 2 O 2 has been also applied for fresh produce decontamination (Xie et al 2008).…”

Section: Effect Of Physico-chemical Parameters Of Liquid Foodsmentioning

confidence: 99%

Advances in Ultraviolet Light Technology for Non-thermal Processing of Liquid Foods

Koutchma

2009

Food Bioprocess Technol

415

249

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A negative, public reaction is growing over the addition of chemical preservatives to liquid foods and beverages to extend their shelf life and to protect against foodborne pathogens. As a physical method, ultraviolet light (UV) irradiation has a positive consumer image and is of interest to the food industry as a low cost non-thermal method of preservation. Recent advances in the science and engineering of UV light irradiation have demonstrated that this technology holds considerable promise as an alternative to traditional thermal pasteurization for liquid foods and ingredients, fresh juices, soft drinks, and beverages. However, its use for treating foods is still limited due to low UV transmittance of liquid foods. The goal of this review is to provide a summary of the basic principles of UV light generation and propagation with emphasis on its applications for liquid food processing. The review includes information on critical product and process factors that affect UV light inactivation and consequently the delivery of a required scheduled process in liquids foods; measuring and modeling of UV inactivation, and the important effects of UV light on overall quality and nutritional value of liquid foods. The commercially available UV light sources and UV reactor designs that were used for liquid foods treatment are reviewed. The research priorities and challenges that need to be addressed for the successful development of UV technology for liquid foods treatment are discussed.

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“…Thiruvenkatachari et al [10] demonstrated an efficient 80% benzoic acid conversion within 30 min of reaction by homogeneous photo-Fenton systems; additionally, coupling of photo-Fenton oxidation with ozonation led to its complete degradation within 10 min. Andreozzi and Marotta [11] also investigated the activity of Fe 3+ /air/UV (i.e.…”

Section: Introductionmentioning

confidence: 99%