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Modification of Electro-Fenton Process with Granular Activated Carbon for Phenol Degradation – Optimization by Response Surface Methodology

Thwaini Hind H., Salman Rasha H.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 9

92--104

EN

As a result of rapid industrialization and population development, toxic chemicals have been introduced into water systems in recent decades. Because of its excellent efficiency and simple design, the three-dimensional (3D) electro-Fenton method has been used for the treatment of wastewater. The goal of the current study is to explore the efficiency of phenol removal by the 3D electro-Fenton process, which is one of the advanced oxidation processes (AOPs). In the present work, the effect of the addition of granular activated carbon (GAC) particles to the electro-Fenton system as the third electrode would be investigated in the presence of graphite as the anode and nickel foam as the cathode, which is the source of electro-generated hydrogen peroxide (H2O2). The influence of operation parameters (current density, electrolysis time, and GAC) on catalytic performance will be studied, which will be adjusted by the response surface methodology (RSM). The pH was adjusted to 3, and the airflow was set to 10 L/h. According to the results the nickel foam was an excellent cathode material choice. The best conditions for phenol elimination were at current density of 3.56 mA/cm2, FeSO4.7H2O dosage of 0.1 mM, GAC of 30 g, and a time of 3 h to attain the removal rates of phenol and chemical oxygen demand (COD) of 98.79% and 93.01%, respectively. The results showed that time had a higher effect on the phenol and COD removal efficiency, while the impact of current density was lower. The model equation’s high R2 value (97.90%) demonstrates its suitability.

2

The role of TiO2 NPs catalyst and packing material in removal of phenol from wastewater using an ozonized bubble column reactor

Alattar Saja A., Sukkar Khalid A., Alsaffar May A.

Acta Innovations

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2023

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no. 46

93--105

EN

Phenol is present as a highly toxic pollutant in wastewater, and it has a dangerous impact on the environment. In the present research, the phenol removal from wastewater has been achieved using four treatment methods in a bubble column reactor (treatment by ozone only, using packed bubble column reactor with ozone, utilizing ozone with TiO2 NPs catalyst in the reactor without packing, and employing ozone with TiO2 NPs in the presence of packing). The effects of phenol concentration, ozone dosage, TiO2 NPs additions, and contact time on the phenol removal efficiency were determined. It was found that at a contact time of 30 min, the phenol removal was 60.4, 74.9, 86.0, and 100% for the first, second, third, and fourth methods, respectively. The results indicated that the phenol degradation method using catalytic ozonation in a packed bubble column with TiO2 NPs is the best treatment method. This study demonstrated the advantages of using packing materials in a bubble column reactor to enhance the mass transfer process in an ozonation reaction and then increase the phenol removal efficiency. Also, the presence of TiO2 NPs as a catalyst improves the ozonation process via the production of hydroxyl routs. Additionally, the reaction kinetics of ozonation reaction manifested that the first order model is more applicable for the reaction. Eventually, the packed bubble column reactor in the presence of TiO2 NPs catalyst provided a highperformance removal of phenol with a high economic feasibility.

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Phenol Oxidation in the Photo-Fenton Process Catalyzed by Clinoptylolite Modified with Co

Świderska-Dąbrowska R.

Rocznik Ochrona Środowiska

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2015

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Tom 17, cz. 1

113--124

PL

W pracy przedstawiono wyniki badań utleniania fenolu w procesie foto-Fentona z zastosowaniem heterogenicznego katalizatora Co-Clin (naturalny klinoptylolit, modyfikowany jonami Co(II)). Analiza widm EDS mikroskopem skaningowym wykazała, że modyfikacja ma charakter powierzchniowy i wewnątrzkanałowy, a krystality Co3O4 są nierównomiernie rozproszone na powierzchni zeolitu – więcej jest ich wzdłuż struktury krystalicznej i charakteryzują się większą zawartością Co (ok. 1,4% wag.). Przy wyższej z badanych, dawce zeolitu 5 g/l (zawierającej ok. 43 mg Co) po 4 godzinach procesu utleniania, usunięto zaledwie 20% TOC. Jednocześnie badania wykazały, że w wyniku rozkładu zmniejsza się stężenie fenolu, a powstaje jako produkt pośredni głównie hydrochinon i w śladowej ilości rezorcyna. W badanym zakresie czasu trwania reakcji utleniania nie powstawały kolejne jej produkty. Podczas reakcji utleniania, wraz z obniżaniem się pH roztworu, z powierzchni zeolitu wymywane są jony Co(II), które nie wpływają jednak znacząco na efektywność procesu foto-Fentona. Przy udziale homogenicznego katalizatora uzyskano zaledwie 4% usunięcie TOC, które było porównywalne z efektem uzyskanym w układzie bez katalizatora: H2O2+UV. Świadczy to, że utlenianie fenolu zachodzi przede wszystkim w heterogenicznym procesie foto-Fentona, aczkolwiek jego niewielka efektywność wyklucza zastosowanie katalizatora Co-Clin w skali technicznej do utleniania zanieczyszczeń przemysłowych.

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Comparative study of phenol degradation with a wild-type and genetically modified P. vesicularis (pBR322). plasmid stability and fame profiling

Mrozik A., Swędzioł Ż., Miga S.

Environment Protection Engineering

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2015

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Vol. 41, nr 1

137--155

EN

It was evidenced that P. vesicularis is an efficient degrader of phenol but does not have a reporter system for monitoring bacterial survival in the environment. Therefore, P. vesicularis (pBR322) has been constructed. In this study we experimentally confirmed that introduction of plasmid pBR322 into P. vesicularis did not change its ability to degrade phenol in liquid media and after its inoculation into sterile soil. Moreover, it has been shown that plasmid pBR322 was stable in P. vesicularis during all experiments. Additionally, the pattern of fatty acid methyl esters for P. vesicularis (pBR322) looked similar to that of P. vesicularis under phenol exposure. Some fatty acids, especially branched and cyclopropane ones were sensitive markers of phenol utilization. These findings indicate that P. vesicularis (pBR322) due to the presence of plasmid could be used instead of P. vesicularis in bioaugmentation of phenol-contaminated areas.

5

Zastosowanie katalizatora heterogenicznego ZCu w procesie foto-Fentona

Świderska-Dąbrowska R., Schmidt R.

Gaz, Woda i Technika Sanitarna

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2014

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Nr 7

279--283

PL

W artykule przedstawiono wyniki badań utleniania fenolu w roztworze wodnym z zastosowaniem katalizatora heterogenicznego, zeolitu modyfikowanego jonami Cu(II) w układzie ZCu + H2O2 + UV. Badania wykazały, że efektywność utleniania fenolu jest wyższa w układzie heterogenicznym w porównaniu do homogenicznego. Przy zastosowaniu katalizatora heterogenicznego ZCu następuje utlenianie fenolu głównie do pirokatechiny i hydrochinonu, a ich stężenia po 60 minutach reakcji są prawie trzykrotnie większe w porównaniu do katalizy homogenicznej. Analiza uzyskanych wyników wskazuje na inny mechanizm utleniania przy zastosowaniu heterogenicznego katalizatora ZCu. Wyniki analiz chromatograficznych potwierdziły, że fenol utlenia się z całkowitym zniszczeniem struktury pierścieniowej do kwasu mrówkowego, który następnie utleniany jest do CO2 i H20.

EN

The paper presents results of research on phenol oxidation in the aąueous solution with application of heterogeneous catalyst, zeolite modified with Cu(II) ions in the ZCu + H2O2 + UV configuration. Results proved that phenol oxidation efficiency is higher in the heterogeneous configuration compared to homogeneous. During application of ZCu heterogeneous catalyst phenol is oxidized mostly to catechol and hydroquinone, and their concentrations, after 60 minutes of reaction time, are almost three times higher, in comparison with homogeneous catalysis. Analysis of obtained results shows different mechanism of oxidation with heterogeneous ZCu catalyst applied. Results of chromatographic analyses proved that phenol is oxidized with complete destruction of ring structure to formic acid, which is next oxidized to CO2 and H20.

6

Microbial degradation of phenol by activated sludge in a batch reactor

Duan Z.

Environment Protection Engineering

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2011

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Vol. 37, nr 2

53-63

EN

Biodegradation of phenol in a batch reactor was investigated using activated sludge. The sludge was able to degrade phenol of initial concentrations up to 1.500 mg/dm 3. The optimum temperature and pH for the reaction were determined in extensive tests. The optimum pH was around 6, whereas the temperature showed no significant impact on the biodegradation rates over the investigated conditions. This activated sludge degraded phenol at the maximum rate of 0.048 g phenol/(g VSSźh) at pH 6 and 30 °C, whereas inhibitory effects existed at concentrations higher than 100 mg/dm 3. The Haldane kinetic model was used to elucidate the kinetics of phenol degradation in an activated sludge. The kinetic parameters were estimated to be q max = 0.4695 g phenol/(g VSSźh), K 1 = 28.4860 mg/dm 3, and K s = 603.9869 mg/dm 3, with the correlation coefficient (R 2) of 0.9599. The high q max value for phenol biodegradation shows that the activated sludge exhibited high resistance to phenol.

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Visible light-enhanced degradation of phenol in the presence of modified TiO2

Zaleska A., Górska P., Kowalska E., Hupka J.

Polish Journal of Chemical Technology

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2006

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Vol. 8, nr 2

102-105

EN

Titanium dioxide-based photocatalysts, active in the visible light, were synthesized by the sol-gel method using alkoxide titanium precursor. Organic and inorganic compounds were used as dopants for catalysts preparation. The elemental analysis, X-ray diffraction and diffuse reflectance spectroscopy were used to characterize the catalysts. The photocatalytic activity of the synthesized powders was estimated by measuring the decomposition rate of phenol under the visible light (λ>400 nm) in an aqueous solution. The catalysts modified with thioacetamide were found to be the most photoactive.