Photocatalytic Degradation of 4-Nitrophenol by C, N-TiO2: Degradation Efficiency vs. Embryonic Toxicity of the Resulting Compounds

Abstract

The photocatalytic activity of TiO2 based photocatalysts can be improved by structural modification and elemental doping. In this study, through rational design, one type of carbon and nitrogen co-doped TiO2 (C, N-TiO2) photocatalyst with mesoporous structure was synthesized with improved photocatalytic activity in degrading 4-nitrophenol under simulated sunlight irradiation. The photocatalytic degradation efficiency of the C, N-TiO2 was much higher than the anatase TiO2 (A-TiO2) based on absorbance and HPLC analyses. Moreover, using zebrafish embryos, we showed that the intermediate degradation compounds generated by photocatalytic degradation of 4-nitrophenol had higher toxicity than the parent compound. A repeated degradation process was necessary to render complete degradation and non-toxicity to the zebrafish embryos. Our results demonstrated the importance of evaluating the photocatalytic degradation efficiency in conjunction with the toxicity assessment of the degradation compounds.

Electrochemical Detection of 4-Nitrophenol by Using Graphene Based Nanocomposite Modified Glassy Carbon Electrodes: A Mini Review

“…4-NPh which is present in industrial wastewater, home wastewater and agricultural wastewater can cause infections in humans and other living organisms as shown in Figure 1. Numerous techniques have been explored for the complete oxidation of 4-NPh such as biodegradation [23], microbial catabolism [24], Fenton reagents [25], photocatalytic degradation [26] and electrochemical techniques [27]. However, these methods can make different aromatic compounds like p-benzoquinone, 4-nitrocathechol, hydroquinone and phenol and they have shown higher toxicity than 4-NPh [28][29].…”

Simple Environmentally-Friendly Reduction of 4-Nitrophenol

“…Several methods have been proposed for the partial or total oxidation of 4-NP, including microbial catabolism [9,10], photocatalytic degradation [10][11][12][13], biodegradation [14][15][16], Fenton [17,18] and electrochemical methods [19][20][21]. Alternatively, chemical or electrochemical reduction of 4-NP to 4-aminophenol (4-AP in Scheme 1) is also suggested.…”

“…Electrosynthesis of 4-aminophenol (4-AP) through the reduction of 4-nitrophenol (4-NP) to 4-hydroxyaminophenol (4-HAP). Deprotonation of 4-NP to 4-nitrophenoxide (4-NPO) after the addition of base.Several methods have been proposed for the partial or total oxidation of 4-NP, including microbial catabolism [9,10], photocatalytic degradation [10][11][12][13], biodegradation [14-16], Fenton [17,18] and electrochemical methods [19][20][21]. Alternatively, chemical or electrochemical reduction of 4-NP to 4-aminophenol (4-AP in Scheme 1) is also suggested.…”

Ruthenium Supported on Ionically Cross-linked Chitosan-Carrageenan Hybrid MnFe2O4 Catalysts for 4-Nitrophenol Reduction

“…Due to the environmental concerns related to water disposal, water scarcity and water pollution, there is a growing interest in the transformation of these harmful organic pollutants into non/less toxic composite in aqueous solutions under mild conditions [2]. Several techniques have been employed for nitrophenol degradation in polluted water, including membrane filtration, photodegradation, adsorption and chemical reduction [3][4][5][6][7]. Among these techniques, chemical reduction of nitrophenol is one of the 2 of 12 most popular techniques to address this issue due to its high efficiency [8].…”