Biobased Carbon Dots: From Fish Scales to Photocatalysis

Abstract

The synthesis, characterization and photoreduction ability of a new class of carbon dots made from fish scales is here described. Fish scales are a waste material that contains mainly chitin, one of the most abundant natural biopolymers, and collagen. These components make the scales rich, not only in carbon, hydrogen and oxygen, but also in nitrogen. These self-nitrogen-doped carbonaceous nanostructured photocatalyst were synthesized from fish scales by a hydrothermal method in the absence of any other reagents. The morphology, structure and optical properties of these materials were investigated. Their photocatalytic activity was compared with the one of conventional nitrogen-doped carbon dots made from citric acid and diethylenetriamine in the photoreduction reaction of methyl viologen.

N-Doped Carbon Dot Hydrogels from Brewing Waste for Photocatalytic Wastewater Treatment

“…A set of different CDs were prepared by HTC for 24 h at 200 °C (see the Experimental Section for more details) following the same reaction protocol, while varying the organic precursors . The treatment of BSG in MilliQ water produced grain IPA crude CDs (GI c , 20% wt yield) and grain Stout crude CDs (GS c , 14% wt yield).…”

“…A set of different CDs were prepared by HTC for 24 h at 200 °C (see the Experimental Section for more details) following the same reaction protocol, while varying the organic precursors. 35 The treatment of BSG in MilliQ water produced grain IPA crude CDs (GI c , 20% wt yield) and grain Stout crude CDs (GS c , 14% wt yield). On the other hand, BSY were carbonized using the corresponding residual beer as a solvent, giving yeast IPA crude CDs (YI c , 36% wt yield) and yeast Stout crude CDs (YS c , 37% wt yield).…”

“…An alternative way can be represented by the transformation into nanomaterials. In particular, in the last decade carbon dots (CDs) emerged as innovative materials. − CDs are classified as pseudospherical particles of diameter lower than 10 nm, usually showing a graphitic structure, complete solubility in water, and prominent photoluminescence (PL) properties. − In addition to these peculiar characteristics, the possibility to derive CDs from biomass employing easy and economic protocols makes them very appealing from a sustainability point of view. − Several studies have been recently carried out to understand their structure and PL behavior, highlighting a strict correlation with the adopted synthetic strategy. − In particular, hydrothermal treatments generally produce a mixture of organic fluorophores and CDs, both contributing to the final PL. , By isolating the two components, it has been shown that while CDs exhibit an excitation-dependent PL, the PL of the organic fluorophores is independent of the excitation wavelength. − …”

Synthesis, optical properties and applications of red/near-infrared carbon dots

“…[2][3][4][5][6] Due to their excellent optoelectrical properties, they have been widely used in various applications, including solar cells, light emitting diodes (LED), luminescent solar concentrators (LSCs), in the field of biosensors and bio-imaging, and, finally, as photocatalysts. [2][3][4][5][6][7][8][9] During the last two decades, many types of QDs have been successfully designed and produced using different approaches, including physical and chemical methods. [2][3][4][5][6] Typically, inorganic QDs are composed of metal elements, such as Pb, Cd, In, Ag, which are either toxic or containing non-earth-abundant rare metals.…”

Fish-Waste-Derived Gelatin and Carbon Dots for Biobased UV-Blocking Films

“…These carbon nanomaterials were exploited for the preparation of UV-blocking films using them as additives in poly­(vinyl alcohol) ,,, nanocellulose , starch, or carboxymethylcellulose . In one of our previous papers, we demonstrated the possibility to obtain luminescent CDs from bass scales with high in photoelectron transfer properties . This new class of CDs has been fully characterized from the morphological and optical point of view, highlighting a natural nitrogen doping without the need of external doping agents.…”