When sonochemistry meets heterogeneous photocatalysis: designing a sonophotoreactor towards sustainable selective oxidation

Giannakoudakis, Dimitrios A.; Łomot, Dariusz; Colmenares, Juan Carlos

doi:10.1039/d0gc00329h

Cited by 42 publications

(28 citation statements)

References 67 publications

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“…[ 56,57 ] Details regarding the optimization of the photocatalysis tests are in the Supporting Information and elsewhere. [ 20,28 ] The results presented in Figure showed an almost 100% conversion of BnOH on P25, and 61% on USprec. Interestingly, the selectivity of benzyl alcohol (PhCHO) on USprec was >99% and on P25, only 41%.…”

Section: Resultsmentioning

confidence: 97%

“…The material was tested either in a gaseous phase against toxic vapors of a chemical warfare agent (a mustard gas surrogate), or in a liquid phase, for selective oxidation of benzyl alcohol, a model lignin‐biomass derived compound. [ 28 ] For the synthesis, a strongly basic aqueous solution (NaOH 10 m ) was placed inside a cup horn sonicator/reactor. Under ultrasonication (500 kHz) and stable temperate (60 °C), titanium isopropoxide in an isopropanol solution (1:3 volumetric ratio) was added with a controllable rate (0.5 mL min −1 ), followed by 10 min aging prior to the filtration, washing, and drying (80 °C, 16 h).…”

Section: Introductionmentioning

confidence: 99%

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Boosting the Photoactivity of Grafted Titania: Ultrasound‐Driven Synthesis of a Multi‐Phase Heterogeneous Nano‐Architected Photocatalyst

Giannakoudakis

Qayyum

Łomot

et al. 2020

Adv Funct Materials

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The herein presented low‐power high‐frequency (500 kHz) ultrasound‐assisted precipitation synthesis (LPHF‐US) leads to a unique multiphase nano‐structured titanium dioxide, grafted with oxygen‐containing organic functionalities. The material exhibits a high porosity (surface area 326 m2 g−1 and total pores volume 0.484 cm3 g−1) and heterogeneous surface chemistry. In the used LPHF‐US synthetic protocol, the energy‐demanding calcination step leading to crystallization is eliminated and an organic residue is simultaneously grafted to the surface. That organic residue affects the anatase nanocrystals, size (4–7 nm), which are embedded in an amorphous titanium hydroxide network. This nanomaterial shows superior performance as a heterogenous photocatalyst either in a gaseous phase by decomposing toxic vapors of chemical warfare agents (a mustard‐gas surrogate), or in a liquid phase by selectively oxidizing benzyl alcohol, a model lignin‐biomass‐derived compound. The grafted organic phase enhances the catalyst's photoreactivity under visible light, by acting as a photosensitizer (antenna effect) and/or as a source of chromophores.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Boosting the Photoactivity of Grafted Titania: Ultrasound‐Driven Synthesis of a Multi‐Phase Heterogeneous Nano‐Architected Photocatalyst

Giannakoudakis

Qayyum

Łomot

et al. 2020

Adv Funct Materials

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“…For example, ultrasound can assist water coagulation regeneration, and its operation is simple, it takes a short time, and offers environmental protection [35]. Ultrasound can assist in the synthesis of new chitin derivatives, and the combination with light radiation in heterogeneous selective catalysis is a very innovative method [36,37]. In terms of extraction and separation, ultrasonic treatment can extract plant proteins from different sources [38].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Extraction of Bioactive Compounds from Baphicacanthus cusia Leaves by Hydrophobic Deep Eutectic Solvents

Cai

et al. 2021

Molecules

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Deep eutectic solvents (DESs) are considered as efficient and green solvents for the extraction of bioactive compounds from medicinal plants. In this work, a novel method of DES-based ultrasound-assisted extraction of bioactive compounds from Baphicacanthus cusia leaves (BCL) was established. Systematic screening and the morphology of the original and treated BCL were observed with scanning electron microscopy to determine the extraction efficiency of different solvents. The extraction conditions were optimized by Box–Behnken design (BBD) tests and the optimal extraction conditions were as follows: lactic acid/L-menthol ratio of 5: 2 (mol/mol), solid–liquid ratio of 80.0 mL/g and temperature of 60.5 °C. The extraction yields of tryptanthrin, indigo and indirubin reached 0.356, 1.744 and 0.562 mg/g, respectively. The results of a 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging activity test indicated the feasibility of DESs in the extraction of bioactive compounds. This study indicated that L-menthol/lactic acid was a green and efficient solvent for the extraction of bioactive compounds from BCL, and DES-based ultrasound-assisted extraction could be used as an effective application strategy for the extraction of bioactive compounds from medicinal plants.

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“…Ultrasound irradiation as a source of power for catalytic applications, namely sonocatalysis, also gathers research attention as a promising technique/approach due to physical and chemical effects, which are presented as a result of cavitation phenomena upon ultrasonication of an aqueous media [ 60 ]. Cavitation phenomenon is a process of adiabatic generation, growth and collapse of microbubbles leading to the formation of the known “hot spots” with the temperature and pressure reaching up to 5000 K and 500 atm, respectively [ 61 ]. The elevated temperature and pressure in combination with the formation of free radicals (H•, OH•, and O 2 −•) resulted predominately from the homolytic fission of water, establishing the area close to hot spots as “nano-reactors” of high activity [ 62 ].…”

Section: Photo- and Sono-catalytic Selective Oxidation Of Hmf And Dec...mentioning

confidence: 99%

Carbon-Based Nanocatalysts (CnCs) for Biomass Valorization and Hazardous Organics Remediation

et al. 2022

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The continuous increase of the demand in merchandise and fuels augments the need of modern approaches for the mass-production of renewable chemicals derived from abundant feedstocks, like biomass, as well as for the water and soil remediation pollution resulting from the anthropogenic discharge of organic compounds. Towards these directions and within the concept of circular (bio)economy, the development of efficient and sustainable catalytic processes is of paramount importance. Within this context, the design of novel catalysts play a key role, with carbon-based nanocatalysts (CnCs) representing one of the most promising class of materials. In this review, a wide range of CnCs utilized for biomass valorization towards valuable chemicals production, and for environmental remediation applications are summarized and discussed. Emphasis is given in particular on the catalytic production of 5-hydroxymethylfurfural (5-HMF) from cellulose or starch-rich food waste, the hydrogenolysis of lignin towards high bio-oil yields enriched predominately in alkyl and oxygenated phenolic monomers, the photocatalytic, sonocatalytic or sonophotocatalytic selective partial oxidation of 5-HMF to 2,5-diformylfuran (DFF) and the decomposition of organic pollutants in aqueous matrixes. The carbonaceous materials were utilized as stand-alone catalysts or as supports of (nano)metals are various types of activated micro/mesoporous carbons, graphene/graphite and the chemically modified counterparts like graphite oxide and reduced graphite oxide, carbon nanotubes, carbon quantum dots, graphitic carbon nitride, and fullerenes.

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When sonochemistry meets heterogeneous photocatalysis: designing a sonophotoreactor towards sustainable selective oxidation

Abstract: Proof of concept to interpret the effect of ultrasonication when applied to improve the selective oxidation of aromatic alcohols through heterogeneous photocatalysis.

Cited by 42 publications

References 67 publications

Boosting the Photoactivity of Grafted Titania: Ultrasound‐Driven Synthesis of a Multi‐Phase Heterogeneous Nano‐Architected Photocatalyst

Boosting the Photoactivity of Grafted Titania: Ultrasound‐Driven Synthesis of a Multi‐Phase Heterogeneous Nano‐Architected Photocatalyst

Optimization of Extraction of Bioactive Compounds from Baphicacanthus cusia Leaves by Hydrophobic Deep Eutectic Solvents

Carbon-Based Nanocatalysts (CnCs) for Biomass Valorization and Hazardous Organics Remediation

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