Monitoring the Ozonation of Phenol Solutions at Constant pH by Different Methods

Contreras, Edgardo Martín; Bértola, Nora Cristina; Zaritzky, Noemí Elisabet

doi:10.1021/ie200999h

Cited by 8 publications

(4 citation statements)

References 29 publications

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“…In the ozonation process, it is frequently observed that the ozone consumption rate will remarkably decrease with a rapid increase of the ORP and the reduction of pollutant removal efficiency, while the pollutant concentration goes below a certain value [48,49]. So, the ORP is a useful indicator in the control of O 3 addition, to minimize the process cost [48,50,51]. For the mineral flotation, the ORP is found to determine the oxidation of collectors and speciation of metal ions [41,44].…”

Section: Evolution Of Solution Ph Orp and Conductivitymentioning

confidence: 99%

Degradation of Thiol Collectors Using Ozone at a Low Dosage: Kinetics, Mineralization, Ozone Utilization, and Changes of Biodegradability and Water Quality Parameters

Lin

et al. 2018

Minerals

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Ozonation at a high O3 dosage can achieve high efficiencies in removing flotation reagents but it has a low ozone-utilization rate. The ozonation of potentially toxic thiol collectors (potassium ethyl xanthate (EX), sodium diethyl dithiocarbamate (SN-9), O-isopropyl-N-ethyl thionocarbamate (Z-200) and dianilino dithiophoshoric acid (DDA)) was investigated in an ozone-bubbled reactor at a low O3 dosage of 1.125 mg/(min·L). The degradation kinetics, mineralization, ozone utilization, changes of biodegradability, and water quality parameters were studied, and the degradation behaviors of four collectors were compared. Thiol collectors could be effectively degraded with a removal ratio of >90% and a mineralization ratio of 10‒27%, at a low O3 dosage. The ozonation of thiol collectors followed the pseudo first-order kinetics, and rate constants had the order of kSN-9 > kEX > kZ-200 > kDDA. The Z-200 and DDA were the refractory flotation reagents treated in the ozonation process. After ozonation, the biodegradability of EX, SN-9, and DDA solutions was remarkably raised, but the biodegradability of Z-200 only increased from 0.088 to 0.15, indicating that the Z-200 and its intermediates were biologically persistent organics. After ozonation, the solution pH decreased from 10.0 to 8.0‒9.0, and both the conductivity and oxidation-reduction potential increased. The ozone utilization ratio in decomposing thiol collectors was above 98.41%, revealing almost complete usage of input O3. The results revealed that thiol collectors could be effectively degraded by O3, even at a low dosage, but their degradation behaviors were quite different, due to intrinsic molecular properties.

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Section: Evolution Of Solution Ph Orp and Conductivitymentioning

confidence: 99%

Degradation of Thiol Collectors Using Ozone at a Low Dosage: Kinetics, Mineralization, Ozone Utilization, and Changes of Biodegradability and Water Quality Parameters

Lin

et al. 2018

Minerals

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“…Several authors propose the use of oxidation–reduction potential (ORP) measurements to monitor the oxidation of several xenobiotics using advanced oxidation processes. − Although ORP measurements were recently used to monitor several biological wastewater treatment processes, − to our knowledge, the use of ORP to monitor an enzymatic system to remove xenobiotics has not been proposed in the literature. For this reason, in this contribution a method to of the HRP mediated oxidation of three model pollutants (orange II, phenol, and bisphenol A) with fed-batch addition of hydrogen peroxide based on ORP measurements was developed.…”

Section: Introductionmentioning

confidence: 99%

Monitoring the Enzymatic Oxidation of Xenobiotics by Hydrogen Peroxide through Oxidation–Reduction Potential Measurements

Urrea

Haure

Contreras

2018

Ind. Eng. Chem. Res.

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In this work, three xenobiotics (orange II, phenol, and bisphenol A) were oxidized by hydrogen peroxide in the presence of a horseradish peroxidase (HRP) using a fed-batch system. During the experiments, the oxidation− reduction potential (ORP) of the reaction mixture was measured continuously. Results demonstrate that ORP values only increased when both substrates of the enzyme (hydrogen peroxide and the target compound) were present in the reaction mixture. For all of the tested pollutants, the continuous addition of hydrogen peroxide caused an increase in ORP values. When the reducing substrate was depleted, the addition of an excess of hydrogen peroxide caused a decrease of ORP values. The time at which ORP reached a maximum represented the end of the oxidation process. This maximum could be easily detected by means of the derivative of ORP as a function of time. To extend the application of the developed technique, the enzymatic oxidation of a binary mixture of BPA and OII was also followed using ORP measurements. Results were similar to those observed with only one reducing substrate. This work demonstrates that ORP measurements can be useful to maximize hydrogen peroxide efficiency through the controlled addition of the oxidant during the oxidation of OII, phenol, and BPA catalyzed by HRP. This approach allows a minimization of time and process costs since the reaction end-point can be easily detected on a real-time basis.

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“…The experiments were carried out at various ozone doses, and ozone consumption, mass transfer and pseudo-first order decolouration rate constants were explored. Ozone removal of five fragrance compounds in tap water and secondary effluent was and the proton production (Hp) was proposed as indicators to monitor the ozonation of phenol solution at constant pH (Contreras et al, 2011). The results indicated that ORP was effective for all testing pHs (5-11), while Hp was only useful for pH higher than 9.…”

Section: Nanotechnology Applications and Hybridmentioning

confidence: 99%

Physico‐Chemical Processes

Chelme-Ayala¹,

Afzal²,

Ding³

et al. 2012

Water Environment Research

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Monitoring the Ozonation of Phenol Solutions at Constant pH by Different Methods

Cited by 8 publications

References 29 publications

Degradation of Thiol Collectors Using Ozone at a Low Dosage: Kinetics, Mineralization, Ozone Utilization, and Changes of Biodegradability and Water Quality Parameters

Degradation of Thiol Collectors Using Ozone at a Low Dosage: Kinetics, Mineralization, Ozone Utilization, and Changes of Biodegradability and Water Quality Parameters

Monitoring the Enzymatic Oxidation of Xenobiotics by Hydrogen Peroxide through Oxidation–Reduction Potential Measurements

Physico‐Chemical Processes

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