Effects of operating parameters and additives on degradation of phenol in water by the combination of H₂O₂and hydrodynamic cavitation

Abstract

A B S T R A C TThe combination of H 2 O 2 and hydrodynamic cavitation has been used to degrade phenol in water. The effects of parameters including inlet pressure (P1), orifice geometries of hydrodynamic reactor, initial concentration of H 2 O 2 , the presence of dissolved gases and catalysts (CuO, Fe, and TiO 2 ) have been discussed. It revealed that increased P1, more number of holes on plates, optimum initial H 2 O 2 concentration, the higher flow rate of oxygen, and the presence of Fe or CuO are more favorable in phenol degradation. Nitrogen has different effect on cavitation from oxygen. Furthermore, the identification of primary intermediates of the reaction (hydroquinone, catechol, benzoquinone, and resorcin) indicated that hydroxyl radicals are involved in phenol degradation mechanisms.

A review on Fenton-like processes for organic wastewater treatment

“…The microbubbles can grow continuously until they reach a critical size, which can cause a violent implosive collapse. The rapid implosion of cavitation bubbles is followed by a localized extremely high temperature and high pressure of about 5000 °C and 500 atm, respectively [135][136][137]. Under this kind of extreme conditions water can be transformed into different oxidizing species via pyrolysis, such as H•, HO•, HO2 -•, and H2O2 [44,138].…”

“…A typical scheme for acoustic cavitation and an ultrasonic-Fenton/Fenton-like system are shown in Figure 7 and Figure 8, respectively. The hydrodynamic cavitation can be generated by the orifice plate and/or slit venturi at the laboratory scale [133,134,137]. In the liquid-solid system, however, the mechanism of enhancing Fenton-like processes by the cavitation bubbles is different from that in the homogeneous system mentioned above.…”

Quantifying OH radical generation in hydrodynamic cavitation via coumarin dosimetry: Influence of operating parameters and cavitation devices

“…In a study of phenol degradation, Wu et al . [41] varied the gas atmosphere with nitrogen and oxygen, and compared it with their baseline conditions. Of the five datasets presented, the sparging of nitrogen (0.05 L/min N 2 , in 70 L) was the only one which seemed to alter the degradation of phenol, lowering it from 22.5 to 15 % in 90 min.…”

Degradation of magenta dye using cavitation‐based transducers to glass marble: Lab to semi‐pilot scale operations

“…Furthermore, when compared to the cavity bubble-induced oxidation reactor, HC provides slightly higher degradation. Wu et al (2015) reported 27.2% degradation of phenol using a combination of HC (multiple orifice plates) and TiO 2 (anatase to rutile, 3:1). The results of the cavity bubble-induced oxidation reactor are also consistent with Taylor et al (2015).…”