| This study's literature has succinctly documented the many advanced oxidative processes(AOPs)and their efficacy in destroying harmful organic pollutants,emphasizing the importance of hydroxyl radicals(·OH).Any hazardous organic contaminants can have their electron(e-)removed by these potent hydroxyl radicals(·OH),resulting in forming a hydroxyl anion and oxidizing or mineralizing these organic hazardous contaminants,converting them to less harmful forms like CO2 and H2O.Traditional Fenton reactions suffer some setbacks due to the requirement of a high iron concentration(50-80 ppm)consumption,restricted pH activity,and sludge disposal problems.The setbacks above have shifted researchers' focus to developing heterogeneous Fentonlike catalysts and photocatalysts with little leaching,excellent catalytic efficiency,and better stability.In the heterogeneous Fenton-like catalysts,the Fe species are immobilized by the solidsupport catalysts to prevent leaching.The catalytic process takes less time than the traditional Fenton process,and semiconductor photocatalysts are inexpensive and pollutant-free.Incorporating Bio-templates improves the composite's performance while also accelerating the breakdown of contaminants.Despite the progress made with the heterogeneous Fenton process,it still suffers some drawbacks,such as a low regeneration rate of Fe2+ from Fe3+,catalyst synthesis necessitates the use of expensive chemicals or time-consuming techniques,and the Fenton-like catalysts is only sensitive to UV light,making it difficult to use natural solar light.Due to these drawbacks,most research has been limited to laboratory-scale studies,whereas industrial-scale applications are constrained due to the aforementioned drawbacks.For practical applications/adoption in treating contaminated water,developing a visible-light-driven,with simple synthesis procedures and a wide pH range effectiveness,reusable,and long-lasting catalyst for the heterogeneous photoFenton process is essential.In this research,visible light-sensitive semiconductors of CuO and WO3 were synthesized using corn stalk as the bio-templates on which Fe3O4 was immobilized..The as-synthesized composite was well characterized by different characterization techniques such as X-ray Diffraction(XRD),Fourier Transform Infrared(FT-IR)spectroscopy,Scanning Electron Microscopy(SEM),Transmission Electron Microscopy(TEM),Higher Resolution TEM(HRTEM),Energy Dispersive X-ray(EDX),UV-Visible spectrophotometer,X-ray Photoelectron Spectroscopy(XPS),Electrochemical Impedance Spectroscopy(EIS),and Thermo Gravimetric Analysis(TGA).The Tetracycline(TC)antibiotic was used as the model pollutant in this study because its presence in the environment has been conspicuous in recent years and has aided in producing and spreading antibiotic-resistant genes and antibiotic-resistant bacteria,both of which pose a severe threat to the environment and human health.The as-synthesized composite catalysts were investigated to degrade TC(50 mg/L)in an aqueous solution using various processes such as adsorption,Fenton,Photocatalysis,hybrid,and Photo-Fenton reaction in the presence of Visiblelight irradiation.1.The first study examines an efficient hybrid degradation procedure for Tetracycline(TC)that coupled Fenton reaction with templated copper oxide(T-CuO)photocatalytic oxidation and then investigated the synergetic degradation impact between Fenton reagent and T-CuO photocatalytic oxidation under the irradiation of visible light.Using cornstalk as a template,biomorphic CuO was effectively fabricated,and the success of this fabrication was confirmed using XRD,XPS,FTIR,and SEM.This research reveals that the synergistic effect of bio-templated copper oxide photocatalysis and the Fenton hybrid process under visible light irradiation was efficient for tetracycline degradation.The most critical influential parameters that could affect the rate of degradation,such as T-CuO doses,Fe2+doses,pH,and the concentration of TC,were studied and optimized.The high degradation efficiency of the hybrid system is attributable to the synergistic effects resulting from the enhanced surface activity of the T-CuO as a photocatalyst and the accelerated Fe3+/Fe2+cycle efficiency of the Fenton reaction process arising from photoinduced electrons from T-CuO.Furthermore,the pseudo-first-order model fitted well into the degradation kinetics,with a kinetic constant of 0.0631 min-1 attained,significantly higher than those of the as-compared processes employed in this research.2.In the second research,a visible-light-driven heterogeneous bio-templated magnetic copper oxide composite(Fe3O4/CuO/C)with a p-n heterostructure is synthesized employing a two-step bio-templating and hydrothermal technique.Field-emission scanning electron microscopy(FE-SEM),Energy dispersive spectroscopy(EDS),Fouriertransform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),X-ray photoelectron spectroscopy(XPS),electrical impedance spectroscopy(EIS),and vibrating sample magnetometer(VSM)were used to analyze the as-synthesized catalyst composite.According to the results,the synthesized composite retains the template's(corn stalk's)original porosity shape,and a significant number of CuO and Fe3O4 particles are loaded onto the template's surface.The Fe3O4/CuO/C composite was used as a catalyst in the heterogeneous photo-Fenton degradation of Tetracycline(TC)when exposed to visible light.The as-synthesized catalyst has high efficiency for TC degradation within 60 minutes when exposed to visible light over a wide pH range,directly linked to its readily available interfacial boundaries,which greatly enhance the migration of photoexcited electrons across a range of different components of the Fe3O4/CuO/C composite.Other variables such as the initial H2O2 concentration,initial TC concentration,and catalyst doses were also investigated.The radical scavenging experiments reveal the identity of ·OH and-·O2 as the prominent radicals responsible for the degradation of TC.The synthesized catalyst's performance was sustained after five cycles,and the use of an external magnetic fieldassisted its recovery.3.The third study describes the photo-Fenton activity of visible-light-driven heterogeneous bio-templated magnetic tungsten oxide composite(Fe3O4/WO3/C)n-n heterostructure catalysts synthesized by bio-templating and hydrothermal procedures for tetracycline degradation when exposed to visible light.The success of the as-prepared catalyst was also confirmed by field emission-scanning electron microscope(FE-SEM),X-ray photoelectron spectroscopy(XPS),High-Resolution Transmission Electron Microscope(HRTEM),and vibrating sample magnetometer(VSM).After 60 mins of visible light irradiation,0.3 g/L of Fe3O4/WO3/C catalysts eliminated 94.6%of the TC(50 mg/L).In this heterogeneous Fenton process,TC was removed via a combination of adsorption and degradation.These findings highlighted the synergistic effects of the catalyst's various components and corroborated the fast redox reaction cycle of Fe3+ to Fe2+.Other parameters like the initial H2O2 concentration,initial concentration of TC,and catalyst dosages were also looked into.This catalytic action was repeated in 5 subsequent trials without a significant loss of efficiency demonstrated by enhanced stability and could be easily removed from the reaction solution for reuse using an external magnet.Finally,the efficiency of the hybrid process,Fe3O4/CuO/C and Fe3O4/WO3/C for TC degradation under visible light irradiation are 95.1,96.1,and 94.1%,respectively.These results show that the visible-light-driven bio-templated magnetic copper oxide(Fe3O4/CuO/C)had a better TC degradation efficiency than others.The synthesis of a heterogeneous catalyst for the removal of refractory organic compounds from wastewater is highlighted in this research study.These advantages suggest that all the as-synthesized composite catalysts could be adopted as the process of choice for eliminating organic molecules in wastewater remediation applications. |
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