Nitrogen and sulfur dual doped porous carbon as metal-free catalyst for oxidative degradation of 4-nitrophenol by persulfate activation

Abstract

The replacement of metals in catalytic processes is highly demanded to improve sustainability and economic growth. Poor stability and metal leaching are the main drawbacks of metal-based catalytic reactions. This work represented the use of nitrogen and sulfur-co-doped mesoporous carbon material ((N, S)-MPC) as a metal-free catalyst for the degradation of 4-nitrophenol (4-NP) as a priority pollutant announced by the Environmental Protection Agency through the persulfate-based advanced oxidation process. A low amount of (N, S)-MPC catalyst (0.3 g/L) exhibited superior performance for the degradation of 4-NP within 3 h at room temperature and unadjusted pH. The COD removal was calculated to be 76% using (N, S)-MPC catalyst. Interestingly, the degradations kinetics of 4-NP followed the zero-order kinetics with the rate constant of 0.505 min−1. The radical quenching experiment was accomplished to investigate the activation pathway of degradation. A real sample from an oil and gas company was treated with the (N, S)-MPC catalyst, which showed excellent total decontamination of 61%. The recyclability and stability of the catalyst have been evaluated for three runs. Owing to the obvious benefits such as high efficiency, metal-free nature, and recyclability, the presented catalyst can improve pollutant removal from aqueous media and practical environmental remediation.

Facet-Dependent Fe2O3/BiVO4(110)/BiVO4(010)/Fe2O3 Dual S-Scheme Photocatalyst as an Efficient Visible-Light-Driven Peroxymonosulfate Activator for Norfloxacin Degradation

“…Compared with the other photocatalytic systems, the catalytic performance of the 20% Fe 2 O 3 /BiVO 4 /PMS/vis system is better than most reported presently (shown in Table S4). ,,,,, Consequently, the system has great potential in removing organic pollutants from wastewater.…”

“…Compared with the other photocatalytic systems, the catalytic performance of the 20% Fe 2 O 3 /BiVO 4 /PMS/vis system is better than most reported presently (shown in Table S4). 14,16,22,34,69,70 •− are approximately 1.5−2.5 × 10 9 and 1.5−7.5 × 10 9 M −1 s −1 , respectively. 16,72 Figure 6a illustrates that the presence of 10 mM TBA and MeOH inhibited the degradation efficiency of NOR by 5 and 19%, respectively.…”

“…To address these issues, researchers have turned to advanced oxidation processes (AOPs). − One promising AOP is the heterogeneous Fenton-like reaction, which involves the activation of persulfates [specifically peroxymonosulfate (PMS) and peroxydisulfate (PDS)]. This reaction has garnered significant attention due to its ability to efficiently mineralize persistent organic pollutants in various water environments, even within a wide pH range. − Compared to the hydroxyl radical (·OH) generated in the conventional Fenton system (Fe 2+ /H 2 O 2 ), the sulfate radical (SO 4 ·– ) produced in the persulfates activation method exhibits several advantages. First, it possesses a higher oxidation potential of 2.5–3.1 V compared to 1.8–2.7 V for ·OH.…”