Kinetic and mechanism investigation on the photochemical degradation of atrazine with activated H2O2, S2O82− and HSO5−

Activation of peroxymonosulfate by magnetic catalysts derived from drinking water treatment residuals for the degradation of atrazine.

Iron can be found in all mammalian cells and is of critical significance to diverse cellular activities within human bodies. Widespread applications and the underlying chemical and biological funda...

Performances and mechanisms of efficient degradation of atrazine using peroxymonosulfate and ferrate as oxidants

Peroxymonosulfate (PMS) heterogeneous activation by Co3 O4 -modified catalyst has shown significant implications to generate free radicals for organic pollutants degradation in water. In this study, PMS heterogeneous activation was applied to degrade atrazine (ATZ) using Co3 O4 -mediated titanium dioxide nanoparticles (Co3 O4 /TiO2 NPs), which were synthesized by sol-gel method. Firstly, characteristics of the fresh and used Co3 O4 /TiO2 NPs were analyzed via SEM, TEM, XRD, EDS, and XPS techniques. Then, the influences of several key parameters (i.e., Co3 O4 /TiO2 NPs dose (0.02-0.3g/L), PMS dose (0-0.6mM), initial pH (3.0-11.0), and co-existing anions) on the ATZ degradation were investigated systematically. Besides, control systems were set up to verify the high efficiency of Co3 O4 /TiO2 NPs. In addition, the radical scavenging experiments revealed that sulfate and hydroxyl radicals were generated in the Co3 O4 /TiO2 -PMS system, while sulfate radicals were the dominant reactive species responsible for ATZ degradation. Furthermore, the stability and reusability of the Co3 O4 /TiO2 NPs were investigated after four consecutive experiments. Based on the identified products, possible degradation pathways of ATZ in the Co3 O4 /TiO2 -PMS system were proposed. Finally, the possible reaction mechanism of Co3 O4 /TiO2 -PMS system was proposed according to the comprehensive analysis. Findings of this study provided useful information for the application of Co3 O4 /TiO2 NPs in recalcitrant organic contaminants degradation. PRACTITIONER POINTS: Co3 O4 /TiO2 NPs were synthesized via the simple sol-gel method. Co3 O4 /TiO2 NPs possessed excellent catalytic performance for PMS to eliminate ATZ. Sulfate radicals play a dominant role in the degradation of ATZ. ATZ degradation pathways and reaction mechanism in the system were proposed.

Degradation of atrazine by persulfate activation with copper sulfide (CuS): Kinetics study, degradation pathways and mechanism

Efficient degradation of atrazine by magnetic porous copper ferrite catalyzed peroxymonosulfate oxidation via the formation of hydroxyl and sulfate radicals

Recently, notable attempts have been devoted to removing emerging pollutants from water resources. Benzotriazole (BTA) as an emerging pollutant has widely been detected in the aquatic environment and water resources. In the current work, peroxymonosulfate (PMS) and persulfate (PS) were added to a TiO2/UV system for BTA degradation, as electron acceptors to overcome recombination of hole and electron. Additions of PMS and PS to the photocatalysis process considerably increased removal efficiency. The rate constants of UV/TiO2/PMS, UV/TiO2/PS and UV/TiO2 were 0.0217 min(-1), 0.0152 min(-1) and 0.0052 min(-1) respectively. The results showed that pH significantly affected the UV/TiO2/PMS system while it marginally affected UV/TiO2/PS. Scavenging experiments using alcohols indicated that in acidic pH, the dominant oxidant was sulfate radical in both systems. The contribution of hydroxyl radical in BTA degradation was boosted at alkaline and neutral conditions especially in the UV/TiO2/PMS system. Moreover, other scavenging experiments implied that reaction of radicals occurred at both the catalyst surface and in solution. The mineralization results showed that PMS and PS significantly increased chemical oxygen demand and total organic carbon removal efficiencies. In general, presence of PMS in the photocatalysis process had a better performance compared to PS in terms of BTA removal and mineralization.

Peroxymonosulfate activation by hydroxylamine-drinking water treatment residuals for the degradation of atrazine

Effect of inorganic, synthetic and naturally occurring chelating agents on Fe(II) mediated advanced oxidation of chlorophenols

Enhanced degradation of atrazine by nanoscale LaFe1-xCuxO3-δ perovskite activated peroxymonosulfate: Performance and mechanism

Improving the degradation of atrazine in the three-dimensional (3D) electrochemical process using CuFe2O4 as both particle electrode and catalyst for persulfate activation

Persulfates work effectively in a wide pH range and present great potential for wastewater purification. However, the development of efficient, cost-effective, and environmentally friendly heterogeneous catalysts is still challenging. In this study, an innovative catalyst for peroxymonosulfate (PMS) activation to degrade target contaminant atrazine is proposed. The catalyst is based on a combination of Cu-Fe spinel (CuFe2O4) and aluminium oxide (γ-Al2O3). The samples synthesised were fully characterised by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results show that all composite catalysts (CCs) had greater catalytic reactivity than spinel; the degradation of atrazine increased from 49%-94% when Cu-Fe spinel was replaced by a composite catalyst (CuFe2O4: γ-Al2O3 = 1:1; CC1). When the loading of Cu-Fe metals was equivalent, the pseudo-first-order rate constant with CC1 (0.37 min–1) was around 37 times that with Cu-Fe spinel (0.01 min–1). Both sulfate radicals and hydroxyl radicals were found to be the active species generated during the activation of PMS by CCs, and sulfate radicals were primarily responsible for the degradation of atrazine. The findings from this study will contribute to the advancement of wastewater treatment technology in Hong Kong and the rest of the world.

Efficient degradation of atrazine with porous sulfurized Fe2O3 as catalyst for peroxymonosulfate activation

Highly efficient activation of peroxymonosulfate by natural negatively-charged kaolinite with abundant hydroxyl groups for the degradation of atrazine

Degradation of atrazine by Bi2MoO6 activated peroxymonosulfate under visible light irradiation