UV-Based Advanced Oxidation Processes of Remazol Brilliant Blue R Dye Catalyzed by Carbon Dots

Abstract

UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82-) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 °C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82-, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min−1 and UV/1.02 mM S2O82-/TIP-CD-0.0345 min−1.

Nanomaterial-Based Advanced Oxidation/Reduction Processes for the Degradation of PFAS

“…The molecular degradation processes in AOP are designed for the production of the hydroxyl radical ( * OH), or other reactive oxygen species (ROS) that can be transformed into the hydroxyl radical, like the superoxide (O2 *-) and peroxyl (HO2 * ) radicals. * OH radicals are extremely reactive oxidizers (oxidation potential of the OH radical is ap-proximately 2.8 V) and non-selective towards organic pollutants in water [41][42][43]. Other specific strong oxidant radical species can be produced when other chemical precursors are coupled with basic AOP, like for example persulfate anion that generates the sulfate radical (SO4 *-) [43].…”

“…* OH radicals are extremely reactive oxidizers (oxidation potential of the OH radical is ap-proximately 2.8 V) and non-selective towards organic pollutants in water [41][42][43]. Other specific strong oxidant radical species can be produced when other chemical precursors are coupled with basic AOP, like for example persulfate anion that generates the sulfate radical (SO4 *-) [43].…”

Combined Experimental and Theoretical Investigation into the Photophysical Properties of Halogenated Coelenteramide Analogs

“…The fluorescence spectra were analyzed via fluorescence spectroscopy, using a standard 10 mm quartz cuvette, with a Horiba Yvon Fluoromax-4 fluorimeter [58]. The emission…”

“…The fluorescence spectra were analyzed via fluorescence spectroscopy, using a standard 10 mm quartz cuvette, with a Horiba Yvon Fluoromax-4 fluorimeter [58]. The emission and excitation spectra were obtained with a 1 nm capture interval and 2 nm slit width.…”

Continuous Flow Photooxidative Degradation of Azo Dyes with Biomass‐Derived Carbon Dots

“…For this application, in fact, CDs are used mainly as synthetic hybrid composites with other wide bandgap semiconductors. [44], [45], [46], [47] In one of our previous work we demonstrated the possibility to hydrothermally synthesize CDs with high ability in photoelectron transfer starting from fishery waste. [48] These carbon nanomaterials are fully biobased and biodegradable and, in the present work, the idea to exploit their photocatalytic behaviour in order to degrade azo dyes was developed.…”