Visible-Light Driven Photocatalytic Degradation of 4-Chlorophenol Using Graphitic Carbon Nitride-Based Nanocomposites

Abstract

4-chlorophenol (4-CP), a hydroxylated aromatic compound (HAC), is a recalcitrant and toxic organic pollutant found in industrial wastewater and various environmental media. In this paper, visible-light-activated photocatalysis using graphitic carbon nitride (GCN) was used to treat 4-CP in an aqueous media. Graphitic carbon nitride from different precursors (dicyanamide, urea, and melamine), as well as GCN/silver nanocomposites (AgBr, Ag3PO4, Ag2CrO4, and Ag), were successfully synthesized and characterized by BET, XRD, SEM, EDS, and UV-Vis DRS. The band gaps of the photocatalysts were estimated using the UV-Vis DRS characterization results and Tauc plots. The evaluation of the efficacy of the GCN-based catalysts in degrading 4-CP was conducted with different photoreactors such as a royal blue light-emitting diode (LED), a UV-A LED, LUZCHEM cool white lamps, and a solar simulator. The results showed that GCNs with royal blue LED can effectively degrade 4-CP from aqueous media. Among the different precursors, urea-derived GCN showed the best performance in degrading 4-CP due to its large surface area. GCN/0.3Ag2CrO4 nanocomposite showed a synergistic effect for the enhanced photocatalytic degradation of 4-CP. The degradation of 4-CP with a rate constant of 2.64 × 10−2 min−1 was achieved with a GCN/0.3Ag2CrO4 nanocomposite under royal blue LED irradiation.

Visible Light-Driven Photocatalytic Degradation of Methylene Blue Dye Using a Highly Efficient Mg–Al LDH@g-C3N4@Ag3PO4 Nanocomposite

“…In other words, the arithmetic mean of the initial ionization energy and the atomic electron affinity is defined as X (eq ). E e and E g represent hydrogen-scale free electron energy (∼4.50 eV) and band gap energy, respectively, E normalC normalB = X − E e − 0.5 E g E normalV normalB = E normalC normalB + E g X = 0.5 ( E E A + E i o n ) As a result of irradiation from a visible light source, electrons are excited on g-C 3 N 4 and Ag 3 PO 4 , and electrons move from the VB of these semiconductor materials to the CB (eq ). The CB level of Ag 3 PO 4 is closer to the g-C 3 N 4 VB level; hence the electrons stimulated by the light of Ag 3 PO 4 would recombine with the holes created by the light of g-C 3 N 4 (eq ).…”

“…In other words, the arithmetic mean of the initial ionization energy and the atomic electron affinity is defined as X (eq 4). E e and E g represent hydrogen-scale free electron energy (∼4.50 eV) and band gap energy, respectively, 69 = E X E E 0.5 CB e g…”