Global NEST Journal

ISSN:

Print ISSN: 1790-7632

Electronic ISSN: 2241-777X

Issue 3

Volume number:

16

Publication year:

2014

Publication month:

September

Editorial:

global nest_editorial.pdf

Special Issue on Advanced Oxidation Processes (AOPs)

Articles

Simultaneous removal of estrogens and pathogens from secondary treated wastewater by solar photocatalytic treatment

Fanourgiakis S. Frontistis Z. Chatzisymeon E. Venieri D. Mantzavinos D. , Pages:543-552

DOI:

https://doi.org/10.30955/gnj.001389

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Abstract

Recently, the fate of emerging compounds in environmentally relevant samples has attracted considerable attention. Solar semiconductor photocatalysis may offer an appealing methodology to treat such contaminants. At the same time the use of solar photocatalysis for water and wastewater disinfection is a topic well-documented in the literature. In this respect, the simultaneous degradation of synthetic estrogen 17α-ethynylestradiol (EE2) and Escherichia coli removal employing simulated solar radiation and TiO₂ as the photocatalyst was investigated. In general, the more complex the water matrix is the slower E. coli removal becomes, while the presence of E. coli in the reaction mixture did not obstruct EE2 removal.

Although EE2 removal occurred relatively fast, overall estrogenic activity was only partially removed. This implies that other species inherently present in the effluent and/or some photocatalytic transformation by-products may be proportionately more estrogenic than EE2. Overall, the use of solar radiation can constitute an advantageous treatment strategy for the simultaneous removal of micro-pollutants and pathogens from secondary treated effluent.

Strategies for hydrogen peroxide dosing based on dissolved oxygen concentration for solar photo-Fenton treatment of complex wastewater

Miralles-Cuevas S. Prieto-Rodríguez L. De Torres-Socías E. Polo-López M.I. Fernández-Ibañez P. Oller I. Malato S. , Pages:553-560

DOI:

https://doi.org/10.30955/gnj.001332

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Abstract

Hydrogen peroxide consumption is known to be one of the key parameters of the photo-Fenton process responsible for its high operating costs. The purpose of this study was to find out whether adding dissolved oxygen to the reaction medium in a continuous stream of pure oxygen or air with different H₂O₂ dosage strategies could improve the Dorfman mechanism, generating secondary oxidation species that could boost mineralization, and consequently, diminish H₂O₂ consumption. Experiments confirmed less efficient COD elimination. Additional DO slightly increased H₂O₂ consumption, as it initiated a series of reactions generating hydroxyl radical scavengers and H₂O₂ self-decomposition slowing down the reaction. At the same time, the study highlighted that automatic H₂O₂ dosing based on DO setpoints would be a highly attractive control option, however, more detailed studies on the initial amount of hydrogen peroxide and dosing rates must be undertaken.

Water and wastewater disinfection by ultrasound irradiation - a critical review

Naddeo V. Cesaro A. Mantzavinos D. Fatta-Kassinos D. and Belgiorno V. , Pages:561-577

DOI:

https://doi.org/10.30955/gnj.001350

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Abstract

It is well known that chlorine and its compounds, traditionally utilized for water and wastewater disinfection, react with some organic matter to form undesirable by-products, hazardous to human health, known as Disinfection By-Products (DBPs). In many countries very stringent limits for chlorination by-products such as trihalomethanes were set for wastewater reuse. Accordingly, the use of different oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Ultrasound (US) was recently found to be effective for this purpose.

Aim of this work is to review main US disinfection studies, pointing out ultrasound mechanisms as well as its effects in terms of different bacteria inactivation (Total coliform, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Saccharomyces cerevisiae, Klebsiella pneumonia) at both laboratory scale and pilot-scale. To this end, several experimental results were discussed and both focal interest points and encountered problems were summarized.

Moreover the intensification of cavitation phenomena by combined oxidation processes was overviewed and main advantages and disadvantages were pointed out, in order to address future research and promote efficient large scale operations.

Solvothermal synthesis of truncated octahedron Cu2O and their catalytic applications on the degradation of methylene blue

Shao M. Tao P. Song C. Wu S. Cheng M. , Pages:578-586

DOI:

https://doi.org/10.30955/gnj.001340

Paper Topic:

Advanced Oxidation Processes

Issue:

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Abstract

Cu₂O photocatalyst is synthesized by solvothermal method. Morphology and structure of Cu₂O photocatalyst are analyzed by SEM, XRD and N₂ sorption technique. The catalytic performances and reaction kinetics of Cu₂O photocatalyst for the degradation of methylene blue (MB) are investigated. The toxicity effect of Cu₂O photocatalyst on yeast Saccharomyces cerevisiae is also studied. The results show pure Cu₂O photocatalyst with truncated octahedron morphology is obtained and demonstrates good potential on degradation of MB. The degree of MB degradation is improved significantly in the presence of H₂O₂, and the optimum H₂O₂concentration is 1.3 wt%. The degradation rate constant decreases as the initial MB concentration increases, and the degradation reaction can be represented by pseudo-first-order kinetics model. Cu₂O photocatalyst shows a good reusability and slight limited growth rate of Saccharomyces cerevisiae, suggesting it can serve as an effective and recyclable photocatalyst.

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Global NEST Journal

Issue 3

Articles

Simultaneous removal of estrogens and pathogens from secondary treated wastewater by solar photocatalytic treatment

Strategies for hydrogen peroxide dosing based on dissolved oxygen concentration for solar photo-Fenton treatment of complex wastewater

Water and wastewater disinfection by ultrasound irradiation - a critical review

Solvothermal synthesis of truncated octahedron Cu2O and their catalytic applications on the degradation of methylene blue

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