Mechanistic approach to intensification of sonochemical degradation of phenol

Sivasankar, Thirugnanasambandam; Moholkar, Vijayanand S.

doi:10.1016/j.cej.2008.10.004

Cited by 77 publications

(46 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We attribute this result to the presence of oxygen in air bubble that conserves the radicals formed out of dissociation of water vapor. 27,28 3. With rise in static pressure to 200 kPa (or 2 bar), both chemical and physical effects of cavitation bubbles get eliminated.…”

Section: Simulations Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Physical mechanism of sono‐Fenton process

2013

Self Cite

View full text Add to dashboard Cite

Hybrid advanced oxidation processes (AOPs), where two or more AOPs are applied simultaneously, are known to give effective degradation of recalcitrant organic pollutants. This article attempts to discern the physical mechanism of the hybrid sono-Fenton process with identification of links between individual mechanism of the sonolysis and Fenton process. An approach of coupling experimental results with simulations of cavitation bubble dynamics has been adopted for two textile dyes as model pollutants. Fenton process is revealed to have greater contribution than sonolysis in the overall decolorization of both dyes. H 2 O 2 added to the liquid medium as a Fenton reagent scavenges• OH radicals produced by cavitation bubbles. Addition of only H 2 O 2 to the medium during sonolysis does not yield marked difference in decolorization. Elimination of transient cavitation with application of elevated static pressure to the medium does not alter the extent of decolorization. The synergy between sonolysis and Fenton process is, thus, revealed to be negative. The dissolved oxygen in the medium is found to play an important role in decolorization through conservation of oxidizing radicals.

show abstract

Section: Simulations Resultsmentioning

confidence: 99%

“…27,28 The dissolved oxygen can help conservation of the • OH radicals generated through Fenton reactions as well as cavitation bubbles through following reaction…”

Section: Contemplations and Conjecturesmentioning

confidence: 99%

Physical mechanism of sono‐Fenton process

2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Unlike conventional chemical reactions, the sonochemical reactions are dependent upon the rate of scavenging [91] of the radicals. The scavenging means the reactions of different types of radicals to produce other oxidative species.…”

Section: Sonochemical Methodsmentioning

confidence: 99%

“…So if the concentration of phenol near the cavitation bubble is lower, they recombine and discourage the phenol degradation. Sivasankar et al [91] The reaction of OH l with O 2 Unlike the oxygen, Fe 2þ scavenging process is due to ionic nature which is limited to bulk medium only. Fe 2þ reacts mainly with H 2 O 2 , produced by recombination of OH l radicals and liberated in the bulk system with transient collapse of the bubble.…”

Section: Sonochemical Methodsmentioning

confidence: 99%

Sonochemical Degradation of Phenol in the Presence of Inorganic Catalytic Materials

Pankaj

Verma²

2010

Theoretical and Experimental Sonochemistry Involving Inorganic Systems

View full text Add to dashboard Cite

Degradation of phenol in its aqueous solutions, using various techniques, including ultrasound, have been examined and discussed to better understand the mechanisms involved therein and the advantages as well as the disadvantages associated with the use of inorganic catalytic materials. IntroductionSonochemical degradation of organic molecules [1], employing cavitational effect is not new. Many simple [2] and complex molecules [3] from modest to very high toxicity levels, polluting the aquatic life and the environment have been successfully reduced to relatively non-toxic or lesser harmful species, if not degraded completely by the ultrasound. Although the degree of degradation and the duration of sonication varied considerably, depending upon the nature of moieties, but the sonochemical degradation undergoes either without the addition of extra chemicals or involves the minimum amounts of non-toxic chemicals such as photocatalyst TiO 2 , Fenton's reagent etc., hence can be termed as a green technology. The purpose of this article is to review the sonochemical degradation of phenol, under different experimental conditions and in the presence of several other active chemicals to understand better the mechanisms involved in all such processes.Phenol is an important chemical, from the point of its industrial and commercial applications, but is of great environmental apprehension due to its toxicity. Its chemical name is hydroxybenzene which is more acidic compared to aliphatic alcohols hence is also known as carbolic acid [4]. At ambient temperature and pressure it is a hygroscopic crystalline solid, which is colourless when pure [5] but

show abstract

“…The bubble collapse occurs within as small time as 50 ns, and it is almost adiabatic. During the collapse of the bubble, many species are formed such as H 2 • OH radical is the most predominant radical species [21,22] having an oxidizing potential of 2.33 V [9,23]. For greater details in cavitation concepts, we would like to refer the readers to see the state of art reviews by Xu et al [4], Apfel [24], Gong and Hart [25], Suslick et al [26], and Gogate and Pandit [27].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation and Investigation of System Parameters of Sonochemical Process

Chakma

Moholkar

2013

Chinese Journal of Engineering

Self Cite

View full text Add to dashboard Cite

This paper presents the effects of various parameters that significantly affect the cavitation. In this study, three types of liquid mediums with different physicochemical properties were considered as the cavitation medium. The effects of various operating parameters such as temperature, pressure, initial bubble radius, dissolved gas content and so forth, were investigated in detail. The simulation results of cavitation bubble dynamics model showed a very interesting link among these parameters for production of oxidizing species. The formation of• OH radical and H 2 O 2 is considered as the results of main effects of sonochemical process. Simulation results of radial motion of cavitation bubble dynamics revealed that bubble with small initial radius gives higher sonochemical effects. This is due to the bubble with small radius can undergo many acoustic cycles before reaching its critical radius when it collapses and produces higher temperature and pressure inside the bubble. On the other hand, due to the low surface tension and high vapor pressure, organic solvents are not suitable for sonochemical reactions.

show abstract

Mechanistic approach to intensification of sonochemical degradation of phenol

Cited by 77 publications

References 52 publications

Physical mechanism of sono‐Fenton process

Physical mechanism of sono‐Fenton process

Sonochemical Degradation of Phenol in the Presence of Inorganic Catalytic Materials

Numerical Simulation and Investigation of System Parameters of Sonochemical Process

Contact Info

Product

Resources

About