Photocatalytic degradation of malachite green pollutant using novel dysprosium modified Zn–Mg photocatalysts for wastewater remediation

Binary Co@ZF/S@GCN S-scheme heterojunction enriching spatial charge carrier separation for efficient removal of organic pollutants under sunlight irradiation

Unraveling the hazardous impact of diverse contaminants in the marine environment: Detection and remedial approach through nanomaterials and nano-biosensors.

A step-scheme (S-scheme) photocatalyst made of sulfurized graphitic carbon nitride/cobalt doped zinc ferrite (S-g-C3N4/Co-ZF) was constructed using a hydrothermal process because the building of S-scheme systems might increase the lifespan of highly reactive charge carriers. Utilizing cutting-edge methods, the hybrid photocatalyst was evaluated by employing TEM, XPS, XRD, BET, FTIR, transient photo-response, UV-vis, EIS and ESR signals. In order to create a variety of binary nanocomposites (NCs), nanoparticles (NPs) of 6% cobalt doped zinc ferrite (Co-ZF) were mixed with S-g-C3N4 at various concentrations, ranging from 10 to 80 wt%. For photocatalytic dye removal, a particular binary NC constructed between S-g-C3N4 and Co-ZF produces a huge amount of catalytic active sites. The findings showed that loading of S-g-C3N4 on 6% Co-ZF NPs serves as a good heterointerface for e−/h+ separation and transportation through the S-scheme S-g-C3N4/Co-ZF heterojunction. By boosting the hybrid system's BET surface area for the photocatalytic process, the addition of 6% Co-ZF improves the system's ability to absorb more sunlight and boosts its photocatalytic activity. The highest photo-removal effectiveness (98%), which is around 2.45 times higher than that of its competitors, was achieved by the hybrid photocatalyst system with an ideal loading of 48% Co-ZF. Furthermore, the trapping studies showed that the primary species involved in the MB aqueous photo-degradation were ˙OH− and h+.

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Construction of a binary S-scheme S-g-C3N4/Co-ZF heterojunction with enhanced spatial charge separation for sunlight-driven photocatalytic performance

To enhance its SO 2 tolerance and further improve the Hg 0 removal performance, Dy was applied to modify the Mn-Fe mixed oxide sorbent. Results showed that appropriate Dy addition promoted the Mn 3 O 4 formation, decreased the grain size, enlarged the surface area, increased the chemisorbed oxygen concentration and weak acid sites of sorbent, thus promoting its Hg 0 removal performance. The calcination at excessive high temperature would result in the grain growth and decrease the sorbent activity. MnFeDy 0.4 -400 (with Dy/Fe molar ratio of 0.4 and calcined at 400 °C) exhibited the best Hg 0 removal performance. Around 86% Hg 0 removal could be achieved over MnFeDy 0.4 -400 under 5% O 2 , 300 ppm NO, 1000 ppm SO 2 and 3% H 2 O. O 2 could replenish the active oxygen species and maintain the surface metal ions at high-valent state, which was essential to Hg 0 removal. With presence of NO, abundant active nitrogenous species could form over MnFeDy 0.4 -400 surface, contributing to the Hg 0 removal. Due to strong basicity, Dy species functioned as a SO 2 trap agent to preserve the predominant active species Mn 3 O 4 , thereby improving the capacity of sorbent to resist SO 2 . The formation of active nitrogenous species over MnFeDy 0.4 -400 would not be significantly affected by SO 2 . Moreover, MnFeDy 0.4 -400 had superparamagnetic property. This enabled spent MnFeDy 0.4 -400 to be separated from fly ash by magnetic separation. Regeneration and stability evaluation tests manifested that MnFeDy 0.4 -400 might be a promising material that could be utilized for Hg 0 removal from flue gas. • MnFeDy 0.4 -400 showed good Hg 0 removal performance and tolerance to SO 2 . • Appropriate Dy addition and calcination temperature contributed to nano-Mn 3 O 4 formation. • Dy species functioned as a SO 2 trap agent to preserve the predominant active species Mn 3 O 4 . • The magnetically responsive MnFeDy 0.4 -400 could be separated from fly ash by magnetic separation. 

J.V.Annie Vinsla

Papers

Impact of dysprosium doped (Dy) zinc ferrite (ZnFe2o4) nanocrystals in photo- fenton exclusion of recalcitrant organic pollutant.