scholarly journals A Review on Advanced Oxidation Processes (AOPs) for Wastewater Remediation

2020 ◽  
Vol 32 (11) ◽  
pp. 2677-2684
Author(s):  
V.S. Solanki ◽  
B. Pare ◽  
P. Gupta ◽  
S.B. Jonnalagadda ◽  
R. Shrivastava

In 21st century, organic and domestic wastes and discharges from varied chemical and manufacturing industries to water bodies become a critical issue and challenge for the researchers, engineers and policy makers. Advanced oxidation processes (AOPs) are efficient, sustainable, economically viable and green techniques to elimination on-degradable organic pollutants by biological and traditional processes. A number of research articles have been published from the past two decades on the wastewater treatment using various advanced oxidation processes. The main objective of this review paper is to provide the quick view for researchers, academicians and scientists in the area of wastewater treatment using various types of AOPs, which incorporate green principles involves in the processes for removal of different pollutants and contaminants including dyes, phenols, pesticides, herbicides etc. from wastewaters, with emphasis on the degradation efficiency of various photocatalysts. The formation reactions of •OH radical and the mechanisms of degradation of various organic pollutants in the wastewater is also discussed. This review covers various types of advanced oxidation processes, viz., ozone-based processes, photocatalysis and Fenton-based reactions.

Industrialization and modernization in recent times have led to a water crisis across the world. Conventional methods of water treatment like physical, chemical and biological methods which comprise of many commonly used techniques like membrane separation, adsorption, chemical treatment etc. have been in use for many decades. However, problems like sludge disposal, high operating costs etc. have led to increased focus on Advanced Oxidation Processes (AOPs) as alternative treatment methods. AOPs basically involve reactions relying on the high oxidation potential of the hydroxyl (OH•) free radical. They have the potential to efficiently treat various toxic, organic pollutants and complete degradation of contaminants (mineralization) of emerging concern. Many different types of homogenous as well as heterogenous AOPs have been studied viz: UV/H2O2, Fenton, Photo-Fenton, Sonolysis, Photocatalysis etc. for treatment of a wide variety of organic pollutants. Different AOPs are suitable for different types of wastewater and hence proper selection of the right technique for a particular type of pollutant is required. The inherent advantages offered by AOPs like elimination of sludge disposal problems, operability under mild conditions, ability to harness sunlight, non selective nature (ability to degrade all organic and microbial contamination) etc. have made it one of the most actively researched areas in recent times for wastewater treatment. Despite the benefits and intense research, commercial applicability of AOPs as a practical technique for treating wastewater on a large scale is still far from satisfactory. Nevertheless, positive results in lab scale and pilot plant studies make them a promising water treatment technique for the future. In the present chapter, an attempt has been made to discuss all aspects of AOPs beginning with the fundamental concepts, classification, underlying mechanism, comparison, commercialization to the latest developments in AOPs.


Industrialization and modernization in recent times have led to a water crisis across the world. Conventional methods of water treatment like physical, chemical and biological methods which comprise of many commonly used techniques like membrane separation, adsorption, chemical treatment etc. have been in use for many decades. However, problems like sludge disposal, high operating costs etc. have led to increased focus on Advanced Oxidation Processes (AOPs) as alternative treatment methods. AOPs basically involve reactions relying on the high oxidation potential of the hydroxyl (OH•) free radical. They have the potential to efficiently treat various toxic, organic pollutants and complete degradation of contaminants (mineralization) of emerging concern. Many different types of homogenous as well as heterogenous AOPs have been studied viz: UV/H2O2, Fenton, Photo-Fenton, Sonolysis, Photocatalysis etc. for treatment of a wide variety of organic pollutants. Different AOPs are suitable for different types of wastewater and hence proper selection of the right technique for a particular type of pollutant is required. The inherent advantages offered by AOPs like elimination of sludge disposal problems, operability under mild conditions, ability to harness sunlight, non selective nature (ability to degrade all organic and microbial contamination) etc. have made it one of the most actively researched areas in recent times for wastewater treatment. Despite the benefits and intense research, commercial applicability of AOPs as a practical technique for treating wastewater on a large scale is still far from satisfactory. Nevertheless, positive results in lab scale and pilot plant studies make them a promising water treatment technique for the future. In the present chapter, an attempt has been made to discuss all aspects of AOPs beginning with the fundamental concepts, classification, underlying mechanism, comparison, commercialization to the latest developments in AOPs.


2020 ◽  
Vol 2 (1) ◽  
pp. 4-10
Author(s):  
Lucian Alexandru Constantin ◽  
Mirela Alina Constantin ◽  
Ines Nitoi ◽  
Toma Galaon ◽  
Valeriu Robert Badescu ◽  
...  

Synthetic solutions of flutamide were subject to degradation using three advanced oxidation systems, namely UV/TiO2, UV/H2O2 and UV/H2O2/TiO2. Optimum conditions and degradation kinetics has been established for all three systems. The experimental results showed that all three systems can be successfully used for flutamide degradation with efficiencies higher than 99% and that advanced oxidation processes are showing good potential for degradation of organic pollutants that cannot be suitable removed/degraded using conventional wastewater treatment processes.


2020 ◽  
Vol 8 ◽  
Author(s):  
Xinhui Xia ◽  
Fengyi Zhu ◽  
Jianju Li ◽  
Haizhou Yang ◽  
Liangliang Wei ◽  
...  

High levels of toxic organic pollutants commonly detected during domestic/industrial wastewater treatment have been attracting research attention globally because they seriously threaten human health. Sulfate-radical-based advanced oxidation processes (SR-AOPs) have been successfully used in wastewater treatment, such as that containing antibiotics, pesticides, and persistent organic pollutants, for refractory contaminant degradation. This review summarizes activation methods, including physical, chemical, and other coupling approaches, for efficient generation of sulfate radicals and evaluates their applications and economic feasibility. The degradation behavior as well as the efficiency of the generated sulfate radicals of typical domestic and industrial wastewater treatment is investigated. The categories and characteristics of the intermediates are also evaluated. The role of sulfate radicals, their kinetic characteristics, and possible mechanisms for organic elimination are assessed. In the last section, current difficulties and future perspectives of SR-AOPs for wastewater treatment are summarized.


Author(s):  
Masroor Mohajerani ◽  
Mehrab Mehrvar ◽  
Farhad Ein-Mozaffari

A review of recent advancements in the combination of ultrasonolysis with other advanced oxidation processes is studied. This study is based on the recent achievements and developments in the field of water and wastewater treatment using ultrasonic irradiation by means of acoustic cavitation with other advanced oxidation technologies. The most important parameter in combined methods is the synergetic effect which is a variable relative to the type of contaminant(s) and other physicochemical properties. The synergetic effect has the key role in process intensification so that a higher synergetic effect provides a higher intensified process efficiency. Results showed that sonolysis is a method that can increase the synergetic percentage in lowering fixed and even operating cost of the wastewater remediation. The combination of photolysis, photocatalysis, Fenton, photo-Fenton, and ozonation processes with ultrasonolysis results in hydroxyl radical production and therefore, the degradation of the organic chemicals. The effect of various parameters on the efficiency of combined processes is investigated in the present study. The combined process performance and the synergetic effect depend on the operating conditions and wastewater characteristics. The synergetic effect can enhance the degradation of organic compounds up to 400%. For example, it has been proven that the sonophotocatalytic process shows over 80% improvement with respect to the photocatalysis alone.


2018 ◽  
Vol 17 (11) ◽  
pp. 1573-1598 ◽  
Author(s):  
M. Bartolomeu ◽  
M. G. P. M. S. Neves ◽  
M. A. F. Faustino ◽  
A. Almeida

A review on novel approaches for wastewater remediation based on advanced oxidation processes (AOPs), including the photodynamic approach mediated by tetrapyrrolic derivatives.


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