Multipollutant Abatement through Visible Photocatalytic System

Abstract

Water pollution damages the aquatic environment due to the presence of organic contaminants, which in turn is distressing to the ecosystem. Photocatalytic activity is a greener and promising method to degrade these organic contaminants. In this research, we present the degradation of diverse water pollutants through zinc/iron oxide nanoparticles serving as photocatalysts. The photocatalyst was studied for its efficiency to photodegrade congo red, brilliant green and para nitro phenol. Moreover, it also presented an antibacterial activity against the bacterium E. coli. Photocatalyst was characterized via X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, and fourier-transform infrared spectroscopy. Tauc plot was used to measure the optical band gap (1.84 eV). The effect of various parameters such as catalyst dose, contact time, dye dose/concentration and pH were also investigated to determine the optimum point of maximum degradation through response surface methodology. A face-centered composite design was used, and a quadratic model was followed by congo red, brilliant green dyes and para nitrophenol. The maximum photodegradation efficiencies were 99%, 94.3%, and 78.5% for congo red, brilliant green and phenol, respectively. Quantum yield for congo red, brilliant green and para-nitrophenol were 9.62 × 10−8, 1.17 × 10−7 and 4.11 × 10−7 molecules/photons, while the reaction rates were 27.1 µmolg−1h−1, 29.61 µmolg−1h−1 and 231 µmolg−1h−1, respectively.

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“…92,93 This process triggers a series of redox reactions that efficiently convert pesticide molecules into nontoxic substances. The use of photocatalytic degradation in addressing pesticide contamination is a novel and versatile approach 94 which illustrates a typical schematic diagram of photocatalytic degradation of pesticides 95 (Fig. 10).…”

Visible Light Photodegradation of Glyphosate and Methylene Blue using Defect-Modified Graphitic Carbon Nitride Decorated with Ag/TiO2

“…The average particle size of prepared materials was calculated using the Debye-Scherrer formula. D = kλ/β Cosθ ( 16) "D" indicates particle size, "K" is Scherrer constant, λ is the wavelength of the X-ray, and β shows the full width at half maximum of the diffraction peak in Equation (16).…”