Nanoparticles have experienced increasing interest over the past three decades owing to the development of new synthesis methods and the adaptation of analysis tools with spatial resolutions below one micrometer. Among the different types of nanoparticles developed in recent years (metals, metal oxides, silica, polymers, etc.), significant scientific interest has developed around iron oxide nanoparticles. This review will focus on these magnetic iron oxide nanoparticles. We will first discuss the magnetic properties of iron oxide nanoparticles, then the different methods of synthesis and washing. Finally, we will discuss some functionalization strategies of iron oxide nanoparticles which are developed within our research team.
Chitin and its derivative chitosan are among the most used polysaccharides for biomedical and pharmaceutical applications. Most of the commercially available chitin is obtained from seafood wastes. However, the interest in alternative renewable sources of chitin and chitosan, such as insects, is growing. When new sources are identified, their stability over time has to be evaluated to allow for their commercialization. The aim of this study is to compare the physicochemical properties of chitin extracted from Cicada orni sloughs harvested in three different years (2017, 2019 and 2020) in order to assess the stability of the source and the repeatability of the extraction process. Chitin and its derivative chitosan were characterized by simple techniques such as Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Results suggest that the physicochemical properties of the extracted chitin varied from year to year, and that these differences are not due to the extraction process, but rather to intrinsic differences within the source. We showed that these differences could already be detected by analyzing the raw material (i.e., cicada sloughs) using the above-mentioned simple methods. The chitosan obtained from deacetylation of chitin had a low degree of deacetylation (66.2±1.6%). This low degree of deacetylation can be attributed to the deacetylation process, which is probably not appropriate for this source of chitin.
In this study, two copper(II) complexes, [Cu(C6H8N3S2)2]Cl2 (1) and [Cu(C7H10N3S2)2]Cl2·H2O (2), were synthesized from 2-(thiophen-2-ylmethylene)hydrazine-1-carbothioamide (L1H) and 2-(1-(thiophen-2-yl)ethylidene)hydrazine-1-carbothioamide (L2H) respectively and characterized using various spectroscopic techniques and elemental analyses. The as-prepared complexes were used as single-source precursors for the synthesis of oleylamine-capped (OLA@CuxSy), hexadecylamine-capped (HDA@CuxSy), and dodecylamine-capped (DDA@CuxSy) copper sulphide nanoparticles (NPs) via the thermolysis method at 190 °C and 230 °C and then characterized using powder X-ray diffraction (p-XRD), UV-visible spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The p-XRD diffraction patterns confirmed the formation of crystalline rhombohedral digenite Cu9S5 with the space group R-3m. The TEM images showed the formation of nanoparticles of various shapes including hexagonal, rectangular, cubic, truncated-triangular, and irregularly shaped Cu9S5 nanomaterials. The SEM results showed aggregates and clusters as well as the presence of pores on the surfaces of nanoparticles synthesized at 190 °C. The UV-visible spectroscopy revealed a general blue shift observed in the absorption band edge of the copper sulphide NPs, as compared to bulk CuxSy, with energy band gaps ranging from 2.52 to 3.00 eV. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of the Cu9S5 nanoparticles. The nanoparticles obtained at 190 °C and 230 °C were used as catalysts for the photocatalytic degradation of methylene blue (MB) under UV irradiation. Degradation rates varying from 47.1% to 80.0% were obtained after 90 min of exposure time using only 10 mg of the catalyst, indicating that Cu9S5 nanoparticles have potential in the degradation of organic pollutants (dyes).
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