Photochemical Kinetic Modeling of Degradation of Aqueous Polyvinyl Alcohol in a UV/H2O2 Photoreactor

Hamad, Dina; Mehrvar, Mehrab; Dhib, Ramdhane

doi:10.1007/s10924-018-1190-y

Cited by 17 publications

(59 citation statements)

References 25 publications

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“…The excess amount of hydrogen peroxide acts as a scavenger of hydroxyl radicals (Reaction (3) in Table 1) thus forming hydroperoxyl radicals. As shown earlier in the photochemical kinetics mechanism, the hydroperoxyl radical reacts with the PVA polymer (Reaction (17) in Table 1) [38]. Therefore, the probability of hydroxyl radicals attacking the polymer can be significantly reduced.…”

Section: Variation Of the Weight Average M W And Number Average M N Mmentioning

confidence: 70%

“…L/mol s [38] (21) The mechanism of degradation polymer solution using UV irradiation using hydrogen peroxide as an oxidant results in the generation of polymeric hydroxyl radicals, which undergo degradation reactions. The live polymer radicals P • r are the precursor of subsequent polymer chain breakage (Reactions (16)- (19)).…”

Section: Photodegradation Kinetic Model Developmentmentioning

confidence: 99%

“…Polymer degradation is described by a discrete approach so that a mass balance provides a difference-differential equations. The net accumulation rate of dead polymer chains of chain length r is given as follows [38]:…”

Section: Photodegradation Kinetic Model Developmentmentioning

confidence: 99%

“…For water-soluble polymers, it is common to use a different approach, based on discrete population balance equations, to model polymer degradation involving Figure 3. [38]). random scission and end-chain scission in order to predict the evolution of a population of molecules undergoing different scission mechanisms.…”

Section: Model Predictions Of the Process Variablesmentioning

confidence: 99%

See 3 more Smart Citations

Kinetic Modeling of Photodegradation of Water-Soluble Polymers in Batch Photochemical Reactor

Hamad¹,

Mehrvar²,

Dhib³

2019

Kinetic Modeling for Environmental Systems

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Synthetic water-soluble polymers, well-known refractory pollutants, are abundant in wastewater effluents since they are extensively used in industry in a wide range of applications. These polymers can be effectively degraded by advanced oxidation processes (AOPs). This entry thoroughly covers the development of the photochemical kinetic model of the polyvinyl alcohol (PVA) degradation in UV/ H 2 O 2 advanced oxidation batch process that describes the disintegration of the polymer chains in which the statistical moment approach is considered. The reaction mechanism used to describe the photo-degradation of polymers comprises photolysis, polymer chain scission, and mineralization reactions. The impact of operating conditions on the process performance is evaluated. Characterization of the polymer average molecular weights, total organic carbon, and hydrogen peroxide concentrations as essential factors in developing a reliable photochemical model of the UV/H 2 O 2 process is discussed. The statistical moment approach is applied to model the molar population balance of live and dead polymer chains taking into account the probabilistic chain scissions of the polymer. The photochemical kinetic model provides a comprehensive understanding of the impact of the design and operational variables.

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Section: Variation Of the Weight Average M W And Number Average M N Mmentioning

confidence: 70%

Section: Photodegradation Kinetic Model Developmentmentioning

confidence: 99%

Section: Photodegradation Kinetic Model Developmentmentioning

confidence: 99%

Section: Model Predictions Of the Process Variablesmentioning

confidence: 99%

See 2 more Smart Citations

Kinetic Modeling of Photodegradation of Water-Soluble Polymers in Batch Photochemical Reactor

Hamad¹,

Mehrvar²,

Dhib³

2019

Kinetic Modeling for Environmental Systems

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“…The introduction of hydrogen peroxide into the UV/H 2 O 2 process is very important since its lower amount leads to lower efficiency while its higher amount causes to reverse the photoreaction due to its scavenging effect on hydroxyl radicals (Mehrvar et al, 2001;Hamad et al, 2014;2015b). In addition, any residual of hydrogen peroxide beyond threshold amount in the effluent is toxic to microorganisms.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of polyvinyl alcohol degradation in UV/H202 photochemical reactors using different hydrogen peroxide feeding strategies

Hamad¹

2021

Preprint

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Synthetic water-soluble polymers are popular in industry and they are produced in large scale owing to their wide spectrum of applications. In particular, the polyvinyl alcohol polymer (PVA), a well-known refractory pollutant, is abundant in wastewater effluents since it is heavily used in industry as paper coating and polarization layer in liquid crystal displays (LCDs). These polymers are non-biodegradable and contaminant to water resources. Alternatively, they can be effectively removed by advanced oxidation processes (AOPs). This study investigates the photo-oxidative degradation of aqueous PVA solution in UV/H2O2 photoreactors and the effect of hydrogen peroxide feeding strategies on the photoreactor performance. The research covers thoroughly the impact of operating conditions on the polymer number average molecular weight (Mn), TOC content, and H2O2 residual under batch, fed-batch and continuous modes of operation. The experimental results show that the performance of the fed-batch photoreactor was higher than the batch system for similar experimental conditions revealing that the way H2O2 is fed into the system has a considerable effect on the PVA degradation. The experimental result of batch system was used as a guide to develop a photochemical kinetic model of the PVA degradation in UV/H2O2 batch process that describes the disintegration of the polymer chains in which the statistical moment approach was considered. The model predictions are in good agreement with data. Realizing the limitations of batch and fed-batch UV/H2O2 processes, an innovative continuous treatment technique was devised to enhance the process performance and to minimize UV dosage. Response surface methodology (RSM), based on Box-Behnken method, was adopted for design set of experiments required to determine the impact of operating variables and their interaction on the process performance. Finally, the results show that Mn was reduced from 130 kg/mol to 24.9, 20.3, and 2.2 kg/mol, corresponding to percent TOC removal of 41.5, 64.2 and 94.4 and H202 residual of 17, 3 and 1% were achieved in batch, fed-batch (120-min), and continuous (30-min) UV/H2O2 photoreactors, respectively. In addition, the overall power consumption of the process was assessed to determine the economic incentive for continuous feeding strategy and ensure the possibility of the process scale-up.

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Identification and Model Predictive Control (MPC) of Aqueous Polyvinyl Alcohol Degradation in UV/H2O2 Photochemical Reactors

2021

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Photochemical Kinetic Modeling of Degradation of Aqueous Polyvinyl Alcohol in a UV/H2O2 Photoreactor

Cited by 17 publications

References 25 publications

Kinetic Modeling of Photodegradation of Water-Soluble Polymers in Batch Photochemical Reactor

Kinetic Modeling of Photodegradation of Water-Soluble Polymers in Batch Photochemical Reactor

Experimental investigation of polyvinyl alcohol degradation in UV/H202 photochemical reactors using different hydrogen peroxide feeding strategies

Identification and Model Predictive Control (MPC) of Aqueous Polyvinyl Alcohol Degradation in UV/H2O2 Photochemical Reactors

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