Ultrasound-Assisted Advanced Oxidation Process Using Perovskite-Type LaMnO3 Nanospheres

Among the perovskite oxide community, La-based perovskites have garnered considerable interest due to their remarkable properties including catalytic, electrocatalytic, photocatalytic, sensing, electrical, magnetic, and optical characteristics. Herein, rhodamine-B (RB) dye has been reported to be sono-catalytically decomposed by an ultrasound-assisted advanced oxidation process (AOP) using perovskite-type LaMnO3 (LMO) nanospheres synthesized via ultrasonic approach. Several physiochemical characterizations such as XRD, FT-IR, XPS, SEM, TEM, and SEM-EDS investigations were used to investigate the LMO perovskite nanospheres. Then, LMO potential for adsorption and the sonocatalytic decolorization of RB dye in an aqueous solution are examined. With LMO perovskites, the adsorption and removal kinetics of RB correspond to the pseudo-first-order model. Furthermore, by utilizing the pseudo-first-order, the RB dye process is removed with improved efficacy in the following sequence: Agitation alone: 3.76×10-4 min-1 Collapse

Key Words

• Adsorption
• Degradation
• Pseudo-first-order kinetics
• Rhodamine-B dye
• Scavenger
• Ultrasonication

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MESH Headings Collapse

Grants

• SPARC/2018-2019/P236/SL SPARC

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Affiliation(s)

Madappa C Maridevaru Nanomaterials & Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Tiruchirappalli, 620015, India Department of Chemistry, College of Science, Sultan Qaboos University, P.O. Box- 36, P.C. 9 123, Al-Khoudh, Muscat, Oman
Reshma Kaimal Nanomaterials & Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Tiruchirappalli, 620015, India
Rengaraj Selvaraj Department of Chemistry, College of Science, Sultan Qaboos University, P.O. Box- 36, P.C. 9 123, Al-Khoudh, Muscat, Oman
Abdullah Al Souwaileh Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
Ming Xuan Sun School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China
Sambandam Anandan Nanomaterials & Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Tiruchirappalli, 620015, India
Muthupandian Ashokkumar School of Chemistry, University of Melbourne, Melbourne, Vic, 3010, Australia

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Reactive Capture and Conversion of CO2 into Hydrogen over Bifunctional Structured Ce1-xCoxNiO3/Ca Perovskite-Type Oxide Monoliths

Carbon capture, utilization, and storage (CCUS) technologies are pivotal for transitioning to a net-zero economy by 2050. In particular, conversion of captured CO2 to marketable chemicals and fuels appears to be a sustainable approach to not only curb greenhouse emissions but also transform wastes like CO2 into useful products through storage of renewable energy in chemical bonds. Bifunctional materials (BFMs) composed of adsorbents and catalysts have shown promise in reactive capture and conversion of CO2 at high temperatures. In this study, we extend the application of 3D printing technology to formulate a novel set of BFMs composed of CaO and Ce1-xCoxNiO3 perovskite-type oxide catalysts for the dual-purpose use of capturing CO2 and reforming CH4 for H2 production. Three honeycomb monoliths composed of equal amounts of adsorbent and catalyst constituents with varied Ce1-xCox ratios were 3D printed to assess the role of cobalt on catalytic properties and overall performance. The samples were vigorously characterized using X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), N2 physisorption, X-ray photoelectron spectroscopy (XPS), H2-TPR, in situ CO2 adsorption/desorption XRD, and NH3-TPD. Results showed that the Ce1-xCox ratios-x = 0.25, 0.50, and 0.75-did not affect crystallinity, texture, or metal dispersion. However, a higher cobalt content reduced reducibility, CO2 adsorption/desorption reversibility, and oxygen species availability. Assessing the structured BFM monoliths via combined CO2 capture and CH4 reforming in the temperature range 500-700 °C revealed that such differences in physiochemical properties lowered H2 and CO yields at higher cobalt loading, leading to best catalytic performance in Ce0.75Co0.25NiO3/Ca sample that achieved 77% CO2 conversion, 94% CH4 conversion, 61% H2 yield, and 2.30 H2/CO ratio at 700 °C. The stability of this BFM was assessed across five adsorption/reaction cycles, showing only marginal losses in the H2/CO yield. Thus, these findings successfully expand the use of 3D printing to unexplored perovskite-based BFMs and demonstrate an important proof-of-concept for their use in combined CO2 capture and utilization in H2 production processes.

Synthesis of Ce0.1La0.9MnO3 Perovskite for Degradation of Endocrine-Disrupting Chemicals under Visible Photons

The UN Environmental Protection Agency has recognized 4-n-Nonylphenol (NP) and bisphenol A (BPA) as among the most hazardous chemicals, and it is essential to minimize their concentrations in the wastewater stream. These industrial chemicals have been witnessed to cause endocrine disruption. This report describes the straightforward hydrothermal approach adopted to produce Ce0.1La0.9MnO3 (CLMO) perovskite’s structure. Several physiochemical characterization approaches were performed to understand the Ce0.1La0.9MnO3 (CLMO) perovskite crystalline phase, element composition, optical properties, microscopic topography, and molecular oxidation state. Here, applying visible photon irradiation, the photocatalytic capability of these CLMO nanostructures was evaluated for the elimination of NP and BPA contaminants. To optimize the reaction kinetics, the photodegradation of NP and BPA pollutants on CLMO, perovskite was studied as a specification of pH, catalyst dosage, and initial pollutant concentration. Correspondingly, 92% and 94% of NP and BPA pollutants are degraded over CLMO surfaces within 120 and 240 min, respectively. Since NP and BPA pollutants have apparent rate constants of 0.0226 min−1 and 0.0278 min−1, respectively, they can be satisfactorily fitted by pseudo-first-order kinetics. The decomposition of NP and BPA contaminants is further evidenced by performing FT-IR analysis. Owing to its outstanding photocatalytic execution and simplistic separation, these outcomes suggest that CLMO is an intriguing catalyst for the efficacious removal of NP and BPA toxicants from the aqueous phase. This is pertinent for the treatment of endocrine-disrupting substances in bioremediation.

Aqueous Acetamiprid Degradation Using Combined Ultrasonication and Photocatalysis Under Visible Light

Acetamiprid (ACE), a neonicotinoid pesticide widely used in pest control, was found in high concentrations in soils, rivers, and lakes. In the present study, ACE degradation was investigated using visible light driven photocatalysis over nitrogen-graphene oxide (N-GO) and palladium-graphene oxide (Pd-GO)-doped ZnO photocatalysts combined with ultrasonication implemented either as a pretreatment (sonolysis) or operated simultaneously with photocatalysis (sonophocatalysis). The effectiveness of the two ACE degradation processes was determined separately. The sonolysis pretreatment allowed reaching almost 40% acetamiprid conversion within 30 min of reaction. Pursuing with the photodegradation reaction in the presence of N-GO-ZnO and Pd-GO-ZnO resulted in a maximum conversion of 98% of ACE within 5 h. As for the sonophotocatalysis process, the reaction time was shortened from 5 to 2 h with 100% acetamiprid conversion. In addition, the photocatalysts were shown to keep their activity even after 5 sonophotocatalytic cycles, thus proving their reusability.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11270-022-05867-4.