6.8 Conclusion
In this chapter, the different sono-hybrid techniques such as sono-photolysis, sonoFenton, sono–photo-Fenton, sono–photo-ferrioxalate, sono-photocatalysis, and
sono-persulfate have been discussed in detail for the treatment of wastewater.
Fenton, Fenton-like, and hydrogen peroxide-based photolysis processes are dependent on the solution pH, while sonolysis, sonocatalysis, photocatalysis, and
persulfate processes are independent of the solution pH. Moreover, the concentration
of hydrogen peroxide, Fe
2+ ions, and pH of the reaction must be optimized to
achieve the maximum mineralization. With the addition of catalyst nanoparticle
during sonolysis process, the degradation efficiency increases which could be
attributed to the more nucleation sites that help in the formation of cavitation bubbles
on the catalyst’s surface. The hybrid advanced oxidation processes are not always
beneficial for the wastewater treatment as they also have a few disadvantages. In the
hybrid processes, if the generation of
• OH radicals is comparatively large or the
oxidant concentration is in excess in the reaction mixture, the mineralization efficiency drastically reduces as the radicals are either recombined or scavenged by the
oxidants. Therefore, the selection of the right combination of advanced oxidation
processes is very important for efficient wastewater treatment.
References
Adewuyi Y (2001) Sonochemistry: environmental science and engineering applications. Ind Eng
Chem Res 40:4681–4715. https://doi.org/10.1021/ie010096l
Adewuyi Y (2005a) Sonochemistry in environmental remediation-1: combinative and hybrid sonophotochemical oxidation processes for the treatment of pollutants in water. Environ Sci Technol
39:3409–3420. https://doi.org/10.1021/es049138y
Adewuyi Y (2005b) Sonochemistry in environmental remediation-2: heterogeneous sonophotocatalytic oxidation processes for the treatment of pollutants in water. Environ Sci Technol
39:8557–8570. https://doi.org/10.1021/es0509127
Andreozzi R, Caprio V, Insola A, Marotta R (1999) Advanced oxidation processes (AOP) for water
purification and recovery. Catal Today 53:51–59. https://doi.org/10.1016/S0920-5861(99)
00102-9
Arslan I, Balcioğlu IA, Bahnemann DW (2000) Advanced chemical oxidation of reactive dyes in
simulated dyehouse effluents by ferrioxalate-Fenton/UV-A and TiO 2 /UV-A processes. Dyes
Pigments 47:207–218. https://doi.org/10.1016/S0143-7208(00)00082-6
Asiri AM, Al-Amoudi MS, Bazaid SA, Adam AA, Alamry KA, Anandan S (2014) Enhanced
visible light photodegradation of water pollutants over N-, S-doped titanium dioxide and
n-titanium dioxide in the presence of inorganic anions. J Saudi Chem Soc 18:155–163.
https://doi.org/10.1016/j.jscs.2011.06.008
Bagal MV, Gogate PR (2014a) Wastewater treatment using hybrid treatment schemes based on
cavitation and Fenton chemistry: a review. Ultrason Sonochem 21:1–14. https://doi.org/10.
1016/j.ultsonch.2013.07.009
Bagal MV, Gogate PR (2014b) Degradation of diclofenac sodium using combined processes based
on hydrodynamic cavitation and heterogeneous photocatalysis. Ultrason Sonochem
21:1035–1043. https://doi.org/10.1016/j.ultsonch.2013.10.020
210
S. Chakma et al.
In this chapter, the different sono-hybrid techniques such as sono-photolysis, sonoFenton, sono–photo-Fenton, sono–photo-ferrioxalate, sono-photocatalysis, and
sono-persulfate have been discussed in detail for the treatment of wastewater.
Fenton, Fenton-like, and hydrogen peroxide-based photolysis processes are dependent on the solution pH, while sonolysis, sonocatalysis, photocatalysis, and
persulfate processes are independent of the solution pH. Moreover, the concentration
of hydrogen peroxide, Fe
2+ ions, and pH of the reaction must be optimized to
achieve the maximum mineralization. With the addition of catalyst nanoparticle
during sonolysis process, the degradation efficiency increases which could be
attributed to the more nucleation sites that help in the formation of cavitation bubbles
on the catalyst’s surface. The hybrid advanced oxidation processes are not always
beneficial for the wastewater treatment as they also have a few disadvantages. In the
hybrid processes, if the generation of
• OH radicals is comparatively large or the
oxidant concentration is in excess in the reaction mixture, the mineralization efficiency drastically reduces as the radicals are either recombined or scavenged by the
oxidants. Therefore, the selection of the right combination of advanced oxidation
processes is very important for efficient wastewater treatment.
References
Adewuyi Y (2001) Sonochemistry: environmental science and engineering applications. Ind Eng
Chem Res 40:4681–4715. https://doi.org/10.1021/ie010096l
Adewuyi Y (2005a) Sonochemistry in environmental remediation-1: combinative and hybrid sonophotochemical oxidation processes for the treatment of pollutants in water. Environ Sci Technol
39:3409–3420. https://doi.org/10.1021/es049138y
Adewuyi Y (2005b) Sonochemistry in environmental remediation-2: heterogeneous sonophotocatalytic oxidation processes for the treatment of pollutants in water. Environ Sci Technol
39:8557–8570. https://doi.org/10.1021/es0509127
Andreozzi R, Caprio V, Insola A, Marotta R (1999) Advanced oxidation processes (AOP) for water
purification and recovery. Catal Today 53:51–59. https://doi.org/10.1016/S0920-5861(99)
00102-9
Arslan I, Balcioğlu IA, Bahnemann DW (2000) Advanced chemical oxidation of reactive dyes in
simulated dyehouse effluents by ferrioxalate-Fenton/UV-A and TiO 2 /UV-A processes. Dyes
Pigments 47:207–218. https://doi.org/10.1016/S0143-7208(00)00082-6
Asiri AM, Al-Amoudi MS, Bazaid SA, Adam AA, Alamry KA, Anandan S (2014) Enhanced
visible light photodegradation of water pollutants over N-, S-doped titanium dioxide and
n-titanium dioxide in the presence of inorganic anions. J Saudi Chem Soc 18:155–163.
https://doi.org/10.1016/j.jscs.2011.06.008
Bagal MV, Gogate PR (2014a) Wastewater treatment using hybrid treatment schemes based on
cavitation and Fenton chemistry: a review. Ultrason Sonochem 21:1–14. https://doi.org/10.
1016/j.ultsonch.2013.07.009
Bagal MV, Gogate PR (2014b) Degradation of diclofenac sodium using combined processes based
on hydrodynamic cavitation and heterogeneous photocatalysis. Ultrason Sonochem
21:1035–1043. https://doi.org/10.1016/j.ultsonch.2013.10.020
210
S. Chakma et al.