Microwave-assisted synthesis of photoluminescent carbon dots from palm fronds biomass wastes

Abstract Oil palm fronds (OPF) is one of the largest biomass sources in Malaysia that has been underutilized. In this work, OPF has been used as a precursor to synthesize carbon dots (CDs) via microwave irradiation method. The impacts of irradiation power and duration and the reacting solution have been investigated. It was discovered that CDs with the highest photoluminescence intensity was obtained at microwave irradiation power of 385 W for 30 s. Irradiation at lower or higher power resulted in incomplete or over carbonization that reduced the fluorescence property. In addition, CDs synthesized with diethylene glycol (DEG) as reacting solution possessed higher photoluminescence intensity as compared to ultrapure water solution. This could be attributed to more complete CDs formation that happened at higher temperature, which could only be achieved by DEG solution (higher boiling point). The CDs were then tested as a sensor for lead (II) ions. The UV-vis absorbance was found to be reduced with the presence of lead (II) ions. This indicated that the lead (II) ions might interact with CDs and disrupted with the absorbance of UV light. Overall, OPF could be a potential precursor for the synthesis of low-cost and easily available CDs for environmental applications.

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Microwave-Assisted Synthesis of Amikacin Modified N,S co-Doped Carbon Dots for Escherichia coli Detection

Chemosensors ◽

10.3390/chemosensors7040061 ◽

2019 ◽

Vol 7 (4) ◽

pp. 61

Author(s):

Fajar Amelia Rachmawati Putri ◽

Mudasir Mudasir ◽

Kinichi Morita ◽

Suherman Suherman

Keyword(s):

Escherichia Coli ◽

Carbon Dots ◽

Limit Of Detection ◽

Low Cost ◽

Microwave Assisted Synthesis ◽

E Coli ◽

Microwave Assisted ◽

Average Size ◽

Doped Carbon Dots ◽

Co Doped

Fluorescent amikacin modified nitrogen, sulfur co-doped carbon dots (amikacin modified N,S-CDs) were synthesized by a facile and low-cost one-step microwave-assisted specifically for selective detection of Gram-negative bacteria Escherichia coli (E. coli). Amikacin is a semi-synthetic amino glycoside antibiotic and it was employed in this study to increase the fluorescence response of N,S-CDs by providing binding ligand towards E. coli. The effect of thiourea content as the source of nitrogen and sulfur dopants was investigated prior to the preparation of amikacin modified N,S-CDs. The formation of amikacin modified N,S-CDs were characterized by using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Transmission electron microscope (TEM), UV-Vis spectrophotometer, and spectrofluorometer. Amikacin modified N,S-CDs was identified to be successfully synthesized from the wavenumber shift of the C=O stretching mode. Amikacin modified N,S-CDs were amorphous with an average size of 7 nm. Fluorescence spectra showed that the highest intensity was obtained at thiourea content of 50% and amikacin mass of 25 mg. By comparing fluorescence responses of all the investigated amikacin modified N,S-CDs, the limit of detection (LOD) was attained by 25 mg amikacin modified N,S-CDs at 1.526 cfu mL−1.

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MICROWAVE–ASSISTED SYNTHESIS OF MOLYBDENUM DISULFIDE (MoS2)

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/55/1b/12091 ◽

2018 ◽

Vol 55 (1B) ◽

pp. 57

Author(s):

Nguyen Thi Minh Nguyet

Keyword(s):

Electron Microscopy ◽

Microwave Irradiation ◽

Molybdenum Disulfide ◽

Low Cost ◽

Lithium Ion ◽

Microwave Assisted Synthesis ◽

X Ray Diffraction ◽

Heating Rates ◽

Transmission Electron ◽

Synthesis Procedure

Molybdenum disulfide (MoS2) nanostructured has been synthesized by a facile and rapid microwave, in which ethylene glycol can act as an excellent susceptor of microwave irradiation. The structure and morphology of MoS2 were characterized by X–ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that nanometer scaled (< 100 nm) molybdenum disulfide with different morphologies can be successfully fabricated by microwave liquid–state method. Microwave irradiation can make localized heating that allows higher heating rates and shorter processing time. The low–cost synthesis procedure paves the way for the exploitation of the present product as electrode material in lithium ion batteries (LIBs).

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Biochar Nanoparticles over TiO2 Nanotube Arrays: A Green Co-Catalyst to Boost the Photocatalytic Degradation of Organic Pollutants

Catalysts ◽

10.3390/catal11091048 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1048

Author(s):

Marco Pinna ◽

Gilberto Binda ◽

Marco Altomare ◽

Marcello Marelli ◽

Carlo Dossi ◽

...

Keyword(s):

Photocatalytic Activity ◽

Photocatalytic Degradation ◽

Uv Light ◽

Water Solution ◽

Low Cost ◽

Organic Pollutant ◽

Tio2 Nanotube ◽

Raw Material ◽

Co Catalysts ◽

Low Temperature Pyrolysis

Biochar nanoparticles (BC NPs), produced by low temperature pyrolysis (350 °C) of microalgae (Nannochloropsis sp.) and nutshells, are proposed as low-cost and sustainable co-catalysts to promote the photocatalytic activity of TiO2 nanotube (NT) arrays towards the degradation of methylene blue (MB) used as an organic pollutant model molecule. BC NPs (size < 25 nm) were obtained by treating bulk BC (i.e., biomass after pyrolysis) by sonication–centrifugation cycles in a water solution. The filtered BC NPs dispersion was deposited by simple drop-casting on the TiO2 NT support. The BC loading was varied by performing multiple depositions. Photocatalytic experiments under UV light (365 nm) revealed that the decoration with BC NPs significantly improves the TiO2 photoactivity. Such enhancement is mainly influenced by the amount of BC deposited; upon optimizing the BC deposition conditions, the rate of photocatalytic degradation of MB increases approximately three times with respect to bare TiO2, almost irrespective of the nature of the raw material. The greater photocatalytic activity of BC-TiO2 can be attributed to the synergistic combination of reactant/product adsorption and catalytic degradation of the adsorbed organic pollutant, as well as an improved charge carrier separation and electron transfer.

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Microwave-assisted synthesis of cyclen functional carbon dots to construct a ratiometric fluorescent probe for tetracycline detection

Journal of Materials Chemistry C ◽

10.1039/c8tc02982b ◽

2018 ◽

Vol 6 (36) ◽

pp. 9636-9641 ◽

Cited By ~ 29

Author(s):

Zhi Shen ◽

Cheng Zhang ◽

Xinling Yu ◽

Jian Li ◽

Zhenyang Wang ◽

...

Keyword(s):

Citric Acid ◽

Microwave Irradiation ◽

Fluorescent Probe ◽

Carbon Dots ◽

Microwave Assisted Synthesis ◽

Microwave Assisted ◽

Ratiometric Probe ◽

Fluorescent Carbon Dots ◽

Tetracycline Detection ◽

Ratiometric Fluorescent Probe

Fluorescent carbon dots were synthesized by microwave irradiation of cyclen and citric acid to construct a ratiometric probe for tetracycline detection.

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Microwave Assisted Synthesis of Dibenzo-[b,f][1,5]diazocine Derivatives for Photocatalytic Water Splitting Applications

Asian Journal of Chemistry ◽

10.14233/ajchem.2021.23056 ◽

2021 ◽

Vol 33 (3) ◽

pp. 627-631

Author(s):

S.K. Cho ◽

J.H. Jung ◽

Y. Sissembayeva ◽

J.H. Song ◽

D.I. Jung ◽

...

Keyword(s):

Microwave Irradiation ◽

Water Splitting ◽

Noble Metals ◽

Low Cost ◽

Precious Metals ◽

Microwave Assisted Synthesis ◽

Reaction Conditions ◽

Photocatalytic Water Splitting ◽

Microwave Assisted ◽

Hydrogen Molecules

Photocatalytic water splitting converts solar energy to storable hydrogen molecules which has the highest energy per mass. Most catalysts for photocatalytic water splitting utilize noble metals or precious metals. Organic photocatalysts are attracting more attention owing to several advantages like light weight, low cost, defined structure and tunability. In this study, the synthesis of several dibenzo[b,f][1,5]- diazocines via microwave irradiation for water splitting application is reported. Microwave irradiation facilitates fast, safe and simple synthesis in green reaction conditions. Mini library of dibenzo[b,f][1,5]diazocines were created in order to understand substituents effect on the photocatalytic activity.

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Microwave-assisted conversion of palm kernel shell biomass waste to photoluminescent carbon dots

Scientific Reports ◽

10.1038/s41598-020-78322-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Wei Lun Ang ◽

Cheldclos A. L. Boon Mee ◽

Nonni Soraya Sambudi ◽

Abdul Wahab Mohammad ◽

Choe Peng Leo ◽

...

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Carbon Dots ◽

Heavy Metal Ions ◽

Low Cost ◽

Palm Kernel ◽

Photoluminescence Intensity ◽

Biomass Waste ◽

Palm Kernel Shell ◽

Irradiation Period

AbstractIn the present work, palm kernel shell (PKS) biomass waste has been used as a low-cost and easily available precursor to prepare carbon dots (CDs) via microwave irradiation method. The impacts of the reacting medium: water and diethylene glycol (DEG), and irradiation period, as well as the presence of chitosan on the CDs properties, have been investigated. The synthesized CDs were characterized by several physical and optical analyses. The performance of the CDs in terms of bacteria cell imaging and copper (II) ions sensing and removal were also explored. All the CDs possessed a size of 6–7 nm in diameter and the presence of hydroxyl and alkene functional groups indicated the successful transformation of PKS into CDs with carbon core consisting of C = C elementary unit. The highest quantum yield (44.0%) obtained was from the CDs synthesised with DEG as the reacting medium at irradiation period of 1 min. It was postulated that the high boiling point of DEG resulted in a complete carbonisation of PKS into CDs. Subsequently, the absorbance intensity and photoluminescence intensity were also much higher compared to other precursor formulation. All the CDs fluoresced in the bacteria culture, and fluorescence quenching occurred in the presence of heavy metal ions. These showed the potential of CDs synthesised from PKS could be used for cellular imaging and detection as well as removal of heavy metal ions.

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Microwave-assisted Synthesis of Benzoxazoles Derivatives

Current Microwave Chemistry ◽

10.2174/2213335607999200518094114 ◽

2020 ◽

Vol 7 (3) ◽

pp. 183-195

Author(s):

Musa Özil ◽

Emre Menteşe

Keyword(s):

Microwave Irradiation ◽

Reaction Medium ◽

Pharmaceutical Chemistry ◽

Conventional Heating ◽

High Yield ◽

Microwave Assisted Synthesis ◽

Microwave Assisted ◽

Optical Brighteners ◽

Chemistry Research ◽

Extensive Class

Background: Benzoxazole, containing a 1,3-oxazole system fused with a benzene ring, has a profound effect on medicinal chemistry research owing to its important pharmacological activities. On the other hand, the benzoxazole derivative has exhibited important properties in material science. Especially in recent years, microwave-assisted synthesis is a technique that can be used to increase diversity and quick research in modern chemistry. The utilization of microwave irradiation is beneficial for the synthesis of benzoxazole in recent years. In this focused review, we provide a metaanalysis of studies on benzoxazole in different reaction conditions, catalysts, and starting materials by microwave technique so far, which is different from conventional heating. Methods: Synthesis of different kind of benzoxazole derivatives have been carried out by microwave irradiation. The most used method to obtain benzoxazoles is the condensation of 2-aminophenol or its derivatives with aldehydes, carboxylic acids, nitriles, isocyanates, and aliphatic amines. Results: Benzoxazole system and its derivatives have exhibited a broad range of pharmacological properties. Thus, many scientists have remarked on the importance of the synthesis of different benzoxazole derivatives. Conventional heating is a relatively inefficient and slow method to convey energy in orientation to the reaction medium. However, the microwave-assisted heating technique is a more effective interior heating by straight coupling of microwave energy with the molecules. Conclusion: In this review, different studies were presented on the recent details accessible in the microwave- assisted techniques on the synthesis of the benzoxazole ring. It presents all examples of such compounds that have been reported from 1996 to the present. Benzoxazoles showed an extensive class of chemical substances not only in pharmaceutical chemistry but also in dyestuff, polymer industries, agrochemical, and optical brighteners. Thus the development of fast and efficient achievement of benzoxazoles with a diversity of substituents in high yield is getting more noteworthy. As shown in this review, microwave-assisted synthesis of benzoxazoles is a very effective and useful technique.

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Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽

10.3390/ma14071786 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1786

Author(s):

Carla Queirós ◽

Chen Sun ◽

Ana M. G. Silva ◽

Baltazar de Castro ◽

Juan Cabanillas-Gonzalez ◽

...

Keyword(s):

Water Content ◽

Coordination Polymers ◽

Metal Ion ◽

Low Cost ◽

Microwave Assisted Synthesis ◽

X Ray Diffraction ◽

X Ray ◽

Wide Range ◽

Ft Ir ◽

Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

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A Fast Synthesis and Sintering of Mg2Si1−xSnx (0≤x≤1.0) Solid Solutions by Microwave Irradiation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.417 ◽

2011 ◽

Vol 197-198 ◽

pp. 417-420 ◽

Cited By ~ 1

Author(s):

Shu Cai Zhou ◽

Chen Guang Bai ◽

Chun Lin Fu

Keyword(s):

Microwave Irradiation ◽

Solid Solutions ◽

Microwave Assisted Synthesis ◽

Green Density ◽

X Ray Diffraction ◽

Power Setting ◽

Xrd Patterns ◽

Heating Behavior ◽

Fast Synthesis ◽

Lower Heating

In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnxsolid solutions, Mg2Sil-xSnxsolid solutions have been prepared by Microwave-assisted Synthesis techniques. The heating behavior of Mg, Si and Sn fixed powder was investigated under microwave irradiation. X-ray diffraction (XRD) was used to characterize the powders. The results suggest that the temperature-rising rate is also dependent on the initial green density and higher green density provides lower heating rate while power setting are fixed. XRD patterns show that Mg2Sil-xSnxsolid solutions have been well formed under microwave irradiation.

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