Degradation of pentachlorophenol aqueous solutions using a continuous flow ultrasonic reactor: experimental performance and modelling

Abstract

The degradation of aqueous solutions of pentachlorophenol (PCP) in a three-stage sonochemical reactor operating in the continuous flow mode has been investigated. The experimental reactor may be considered as a series of three high-frequency ultrasonic units. The influence of several parameters such as ultrasonic power, reactor volume and volumetric feed flow rate on the reactor performance is reported. Application of classical basic chemical engineering principles leads to a model that enables us to predict the PCP concentration within the reactor. In steady state, experimental conversion rates are shown to be in good agreement with model predictions.

Sonochemical Treatment of Water Polluted by Chlorinated Organocompounds. A Review

“…For example, Zhang and Hua [54] also reported that the rate of degradation of PCBs at 20 kHz was accelerated at higher sound intensities. Gondrexon et al [59] reported, for a continuous flow ultrasonic reactor, an increase of the rate conversion of pentachlorophenol with increasing power input, reaching values of rate conversion close to 80%.…”

“…In addition, specific studies, such as the evolution of the pH [39] to acidic values, or the correlation of the molecule properties (vapor pressure) with the kinetics of the process and degradation mechanism [13,40,41,42,43] have been reported. Not only aliphatic compounds but also chlorinated aromatic compounds such as chlorotoluenes [ 44 ], chlorobenzenes [ 45 , 46 , 47 , 48 , 49 ] mixtures of chlorobenzene with trichloroethylene [ 50 , 51 , 52 ], p-chlorobenzoic acid [ 53 ], PCBs [ 54 ], chlorophenols [3,35,48,55,56,57,58,59,60,61] and chlorinated pesticides [58,62,63] have also been the subjects of study, providing a wide range of examples from volatile, nonvolatile, hydrophobic and hydrophilic compounds and their respective behaviors. In the following, the general trends of the operational variables reported in literature and those specifically observed for chlorinated compounds are presented.…”

“…Despite the fact that these conclusions are relevant enough to consider a further and careful development of sonochemical technology, it is also true that all these studies have been carried out at laboratory scale, where in-depth analysis of the experiment was not always considered. In addition, some difficulties have been reported in the scale-up of the process in the past [59] but, nowadays, the technology has improved enough to provide competitive equipment [135 and references therein].…”

Efficient H2O2/CH3COOH oxidative desulfurization/denitrification of liquid fuels in sonochemical flow-reactors

“…Typical flow systems have been applied in sonocrystallization [3], water treatment processes [4] and in the production of biodiesel [5]. An increase in reactor volume leads to a simultaneous increase in the ultrasonic power needed to maintain the same power density and owing to the power limitation of each single transducer, a large-scale reactor requires several ultrasonic transducers [6].…”

Ultrasound enhancement of microfiltration performance for natural organic matter removal

“…The degradation of microcystins by ultrasound of frequency 150 kHz at a 40 W output has recently been reported (Zhang et al, 2005). Pentachlorophenol degradation has similarly been carried out at 500 kHz and 80 W (Gondrexon et al, 1999).…”