scholarly journals Degradation of Aqueous CONFIDOR® Pesticide by Simultaneous TiO2 Photocatalysis and Fe-Zeolite Catalytic Ozonation

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3327
Author(s):  
Muhammad Raashid ◽  
Mohsin Kazmi ◽  
Amir Ikhlaq ◽  
Tanveer Iqbal ◽  
Muhammad Sulaiman ◽  
...  

Due to the importance of water for human survival and scarcity of freshwater resources, wastewater treatment has become very important recently. Some persistent pollutants, such as pesticides, are not removed even after multiple conventional wastewater treatment techniques. Advanced oxidation processes (AOPs) are one of the novel techniques that can be used to treat these persistent compounds. Photocatalytic ozonation is a promising AOP that combines photocatalysis and ozonation for synergistic effects and faster degradation of persistent pollutants. However, usually, only a photocatalyst is used while combining photocatalysis and ozonation. In this work, both a photocatalyst and ozonation catalyst have been simultaneously used for the degradation of commercially available CONFIDOR® pesticide, a Bayer product with Imidacloprid as the active ingredient. TiO2 is employed as a photocatalyst, and Fe-coated Zeolite is employed as an ozonation catalyst. The results show that the reaction rate increases by 1.4 times if both catalysts are used as compared to the use of one photocatalyst only. Almost complete removal (>99%) of pollutant is achieved after 20 min with the simultaneous use of a catalyst when imidacloprid with an initial concentration of 100 mg/L is subjected to 250 W/m2 UV of a wavelength of 253.7 nm and 100 mg/h ozone, where it takes 30 min if only one photocatalyst is used. The paper also explores the effect of initial concentration, UV intensity, catalyst dose and catalyst reuse while also briefly discussing the kinetics and mechanism.

2013 ◽  
Vol 10 (3) ◽  
pp. 376-385 ◽  

Advanced oxidation processes (AOPs) are widely used for the removal of recalcitrant organic constituents from industrial and municipal wastewater. The aim of this study was to review the use of titanium dioxide/UV light process, hydrogen peroxide/UV light process and Fenton’s reactions in wastewater treatment. The main reactions and the operating parameters (initial concentration of the target compounds, amount of oxidation agents and catalysts, nature of the wastewater etc) affecting these processes are reported, while several recent applications to wastewater treatment are presented. The advantages and drawbacks of these methods are highlighted, while some of the future challenges (decrease of operational cost, adoption of strategies for processes integration) are discussed.


Author(s):  
Gamallo Maria ◽  
Moldes-Diz Yolanda ◽  
Taboada-Puig Roberto ◽  
Lema Juan Manuel ◽  
Feijoo Gumersindo ◽  
...  

Environments ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 116
Author(s):  
Yi-Ping Lin ◽  
Ramdhane Dhib ◽  
Mehrab Mehrvar

Polyvinyl alcohol (PVA) is an emerging pollutant commonly found in industrial wastewater, owing to its extensive usage as an additive in the manufacturing industry. PVA’s popularity has made wastewater treatment technologies for PVA degradation a popular research topic in industrial wastewater treatment. Although many PVA degradation technologies are studied in bench-scale processes, recent advancements in process optimization and control of wastewater treatment technologies such as advanced oxidation processes (AOPs) show the feasibility of these processes by monitoring and controlling processes to meet desired regulatory standards. These wastewater treatment technologies exhibit complex reaction mechanisms leading to nonlinear and nonstationary behavior related to variability in operational conditions. Thus, black-box dynamic modeling is a promising tool for designing control schemes since dynamic modeling is more complicated in terms of first principles and reaction mechanisms. This study seeks to provide a survey of process control methods via a comprehensive review focusing on PVA degradation methods, including biological and advanced oxidation processes, along with their reaction mechanisms, control-oriented dynamic modeling (i.e., state-space, transfer function, and artificial neural network modeling), and control strategies (i.e., proportional-integral-derivative control and predictive control) associated with wastewater treatment technologies utilized for PVA degradation.


2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Eid H. Alosaimi ◽  
Nadia Azeem ◽  
Noor Tahir ◽  
Asim Jilani ◽  
Muhammad Zahid ◽  
...  

The rapid population growth and economic development have largely contributed to environmental pollution. Various advanced oxidation processes have been used as the most viable solution for the reduction of recalcitrant pollutants and wastewater treatment. Heterogeneous photocatalysis is one of the broadly used technologies for wastewater treatment among all advanced oxidation processes. Graphitic carbon nitride alone or in combination with various other semiconductor metal oxide materials acts as a competent visible light active photocatalyst for the removal of recalcitrant organic pollutants from wastewater. Rational designing of an environment-friendly photocatalyst through a facile synthetic approach encounters various challenges in photocatalytic technologies dealing with semiconductor metal oxides. Doping in g-C3N4 and subsequent coupling with metal oxides have shown remarkable enhancement in the photodegradation activity of g-C3N4-based nanocomposites owing to the modulation in g-C3N4 bandgap structuring and surface area. In the current study, a novel ternary Fe-doped g-C3N4/Ag2WO4 visible light active photocatalyst was fabricated through an ultrasonic-assisted facile hydrothermal method. Characterization analysis included SEM analysis, FTIR, XRD, XPS, and UV-Visible techniques to elucidate the morphology and chemical structuring of the as-prepared heterostructure. The bandgap energies were assessed using the Tauc plot. The ternary nanocomposite (Fe-CN-AW) showed increased photodegradation efficiency (97%) within 120 minutes, at optimal conditions of pH = 8, catalyst dose = 50 mg/100 ml, an initial RhB concentration of 10 ppm, and oxidant dose 5 mM under sunlight irradiation. The enhanced photodegradation of rhodamine B dye by ternary Fe-CN-AW was credited to multielectron transfer pathways due to insertion of a Fe dopant in graphitic carbon nitride and subsequent coupling with silver tungstate. The data were statistically assessed by the response surface methodology.


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