TY - JOUR
T1 - Hydrodynamic cavitation and photocatalysis for effluent treatment
T2 - Key operating parameters and synergistic effects
AU - De-Nasri, Sebastien J.
AU - Sarvothaman, Varaha P.
AU - Kelly, Caroline
AU - Nagarajan, Sanjay
AU - Manesiotis, Panagiotis
AU - Robertson, Peter K.J.
AU - Ranade, Vivek V.
N1 - Publisher Copyright:
© 2023 The Author(s)
PY - 2023/10/1
Y1 - 2023/10/1
N2 - A combination of hydrodynamic cavitation and photocatalysis (HC-PC) is a promising water treatment technology for the removal of recalcitrant pollutants. In this work, we investigated influence of key parameters of this hybrid technology such as initial concentration, catalyst loading, pH, re-circulating flow rate and cavitation device/scale on degradation of three model pollutants (coumarin, paracetamol and dichloroaniline). Unlike previous HC-PC studies, the individual and combined systems were investigated for each parameter to determine their effect on system performance and overall synergy. We report a dependence of logKow for both systems, with highest removal (100% in 20 min with AC-PC, 37% in 120 min, or 350 passes, with HC-PC) and synergy (Synergistic index of 2.8 and 1.2 for AC-PC and HC-PC, respectively) associated with the more hydrophobic compound, dichloroaniline. HC-PC performance increased and synergy decreased with increasing catalyst loading, and the inverse effect was found with initial concentration (C0: 17.5 to 70 ppm). Similarly, pH decreased performance but increased synergy and low re-circulating flow rate increased performance but decreased synergy. Detailed analysis of these results indicated the utilisation of in-situ generated H2O2 from recombined OH radicals is the main contributor of the observed synergy, and not physical interactions between cavities and photocatalyst particles. Following this, for the first time, influence of cavitation device type (based on linear flows and swirling flows) and device scale on overall performance of HC-PC system was quantified. Vortex based cavitation device was found to provide a 20% and 25% higher performance and synergy compared to a linear flow based cavitation device like orifice. The results presented here provide valuable insights into the synergy of HC and photocatalytic systems.
AB - A combination of hydrodynamic cavitation and photocatalysis (HC-PC) is a promising water treatment technology for the removal of recalcitrant pollutants. In this work, we investigated influence of key parameters of this hybrid technology such as initial concentration, catalyst loading, pH, re-circulating flow rate and cavitation device/scale on degradation of three model pollutants (coumarin, paracetamol and dichloroaniline). Unlike previous HC-PC studies, the individual and combined systems were investigated for each parameter to determine their effect on system performance and overall synergy. We report a dependence of logKow for both systems, with highest removal (100% in 20 min with AC-PC, 37% in 120 min, or 350 passes, with HC-PC) and synergy (Synergistic index of 2.8 and 1.2 for AC-PC and HC-PC, respectively) associated with the more hydrophobic compound, dichloroaniline. HC-PC performance increased and synergy decreased with increasing catalyst loading, and the inverse effect was found with initial concentration (C0: 17.5 to 70 ppm). Similarly, pH decreased performance but increased synergy and low re-circulating flow rate increased performance but decreased synergy. Detailed analysis of these results indicated the utilisation of in-situ generated H2O2 from recombined OH radicals is the main contributor of the observed synergy, and not physical interactions between cavities and photocatalyst particles. Following this, for the first time, influence of cavitation device type (based on linear flows and swirling flows) and device scale on overall performance of HC-PC system was quantified. Vortex based cavitation device was found to provide a 20% and 25% higher performance and synergy compared to a linear flow based cavitation device like orifice. The results presented here provide valuable insights into the synergy of HC and photocatalytic systems.
KW - Advanced oxidation process
KW - Hybrid techniques
KW - Hydrodynamic cavitation
KW - Photocatalysis
UR - http://www.scopus.com/inward/record.url?scp=85167424127&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2023.145241
DO - 10.1016/j.cej.2023.145241
M3 - Article
AN - SCOPUS:85167424127
SN - 1385-8947
VL - 473
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 145241
ER -