PMID- 19321374
OWN - NLM
STAT- MEDLINE
DCOM- 20091020
LR  - 20090529
IS  - 1873-2828 (Electronic)
IS  - 1350-4177 (Linking)
VI  - 16
IP  - 6
DP  - 2009 Aug
TI  - Physical insights into the sonochemical degradation of recalcitrant organic 
      pollutants with cavitation bubble dynamics.
PG  - 769-81
LID - 10.1016/j.ultsonch.2009.02.009 [doi]
AB  - This paper tries to discern the mechanistic features of sonochemical degradation 
      of recalcitrant organic pollutants using five model compounds, viz. phenol (Ph), 
      chlorobenzene (CB), nitrobenzene (NB), p-nitrophenol (PNP) and 2,4-dichlorophenol 
      (2,4-DCP). The sonochemical degradation of the pollutant can occur in three 
      distinct pathways: hydroxylation by ()OH radicals produced from cavitation 
      bubbles (either in the bubble-bulk interfacial region or in the bulk liquid 
      medium), thermal decomposition in cavitation bubble and thermal decomposition at 
      the bubble-liquid interfacial region. With the methodology of coupling 
      experiments under different conditions (which alter the nature of the cavitation 
      phenomena in the bulk liquid medium) with the simulations of radial motion of 
      cavitation bubbles, we have tried to discern the relative contribution of each of 
      the above pathway to overall degradation of the pollutant. Moreover, we have also 
      tried to correlate the predominant degradation mechanism to the physico-chemical 
      properties of the pollutant. The contribution of secondary factors such as 
      probability of radical-pollutant interaction and extent of radical scavenging (or 
      conservation) in the medium has also been identified. Simultaneous analysis of 
      the trends in degradation with different experimental techniques and simulation 
      results reveals interesting mechanistic features of sonochemical degradation of 
      the model pollutants. The physical properties that determine the predominant 
      degradation pathway are vapor pressure, solubility and hydrophobicity. 
      Degradation of Ph occurs mainly by hydroxylation in bulk medium; degradation of 
      CB occurs via thermal decomposition inside the bubble, degradation of PNP occurs 
      via pyrolytic decomposition at bubble interface, while hydroxylation at bubble 
      interface contributes to degradation of NB and 2,4-DCP.
FAU - Sivasankar, Thirugnanasambandam
AU  - Sivasankar T
AD  - Department of Chemical Engineering, Indian Institute of Technology Guwahati, 
      Guwahati 781 039, Assam, India.
FAU - Moholkar, Vijayanand S
AU  - Moholkar VS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20090227
PL  - Netherlands
TA  - Ultrason Sonochem
JT  - Ultrasonics sonochemistry
JID - 9433356
RN  - 0 (Free Radicals)
RN  - 0 (Organic Chemicals)
RN  - 0 (Water Pollutants, Chemical)
SB  - IM
MH  - Free Radicals/chemistry
MH  - Organic Chemicals/*chemistry
MH  - *Ultrasonics
MH  - Waste Management/*instrumentation
MH  - Water Pollutants, Chemical/*chemistry
EDAT- 2009/03/27 09:00
MHDA- 2009/10/21 06:00
CRDT- 2009/03/27 09:00
PHST- 2008/12/19 00:00 [received]
PHST- 2009/02/06 00:00 [revised]
PHST- 2009/02/16 00:00 [accepted]
PHST- 2009/03/27 09:00 [entrez]
PHST- 2009/03/27 09:00 [pubmed]
PHST- 2009/10/21 06:00 [medline]
AID - S1350-4177(09)00028-5 [pii]
AID - 10.1016/j.ultsonch.2009.02.009 [doi]
PST - ppublish
SO  - Ultrason Sonochem. 2009 Aug;16(6):769-81. doi: 10.1016/j.ultsonch.2009.02.009. 
      Epub 2009 Feb 27.