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Facile green synthesis of organosilica nanoparticles by a generic “salt route”
摘要： Colloidal silica has wide applications and the global demand of specialty silica is continually increasing. Therefore, it is significant to develop a synthetic method that is simple, versatile, energy-saving, ecologically benign, and easily scalable. Biomimetic synthesis of colloidal silica represents a promising strategy; however, it often requires the synthesis or extraction of specialized macromolecules. In this paper, we present a novel aqueous, one-pot, and green route for synthesis of organosilica nanoparticles. The reaction systems contain only water, an organosilane precursor, a salt, and a commonly used surfactant or amphiphilic polymer. The reaction was performed at ambient conditions without adding any additional solvent, energy, and harsh chemicals. The key findings include the novel identification of 5 salts (i.e. nitrite, fluoride, dibasic phosphate, acetate, and sulfite) that can catalyze organosilica condensation and the resulting formation of nano-colloids. Moreover, the presence of amphiphilic molecules is essential for salt catalysis at low salt concentrations and at nearly neutral pH. Solid-state NMR and in-situ ATR-FTIR studies confirmed that organosilica condensation is highly efficient under the mild reaction condition. In conclusion, the present study demonstrates that "soft" interaction between salts and surfactants (or polymers) can be utilized to construct an effective platform for synthesis of "hard" organosilica particles. The proposed method is generic and applicable to a wide range of commonly used surfactants (viz. non-ionic, anionic, cationic) and amphiphilic polymers, as well as to organosilanes with various hydrophobic functional groups (e.g. mercaptopropyl, vinyl, and methyl).
关键词： Salts,Microreactors,Surfactants,Organosilica nanoparticles,Biomimetic synthesis,Colloids
更新于2025-09-23 15:22:29
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Photo-microfluidic chip reactors for propene complete oxidation with TiO2 photocalyst using UV-LED light
摘要： In this study, we present a photo-microreactor illuminated with a low power LED light as a highly efficient system to achieve the total oxidation of propene using a TiO2 photocatalyst. This abatement system (photo-microreactor) consists in an immobilized benchmark photocatalyst (TiO2, P25) inside a commercial glass microchannel chip (UV transparent microfluidic chips, internal volume of 9.5 μl) using a packed-bed configuration without any previous treatment. The P25 inside the microreactor shows a nearly homogenous filling of the particles resulting in a low pressure drop throughout the system. In terms of propene abatement (Catalytic activity), the P25 inside the commercial microreactor reaches total propene conversion (100%) under flow conditions at low concentrations (100 ppmv) due to shorter diffusion distances, large surface-to-volume ratios, efficient heat transfer, and the improved light penetration inside the microchannel. Moreover, the prepared microreactor uses a low consumption power (LED), low residence time and presents a relatively low pressure drop making this device (P25 inside a commercial microreactor) very interesting for the abatement of volatile organic compounds at low concentration for example at indoor ambient due to its small size (45 × 15 mm).
关键词： Microreactors,LEDs,VOCs,Photocatalysis,TiO2
更新于2025-09-16 10:30:52
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An Optical Microreactor Enabling In Situ Spectroscopy Combined with Fast Gas-Liquid Mass Transfer
摘要： A liquid core waveguide membrane microreactor combining intense light matter interaction for in situ sensing and/or photo activation and excellent gas-liquid mass transfer is presented. Basis is a liquid-filled Teflon AF tube, which provides light transmission within the liquid core and gas permeation through the wall. The study shows that a wide spectral range (UV-vis) with relatively low optical losses is accessible. A working regime preventing gas bubble formation was deduced for semi-batch and in flow operation for gas pressures up to 8 bar. Residence time distribution experiments revealed Bodenstein numbers from 21 to 60 in the studied flow range. As example, the methylene blue catalyzed oxidation of D-glucose by O2 was studied at different pressures, while methylene blue was monitored in situ.
关键词： Teflon amorphous fluoropolymers,Optical microreactors,In situ spectroscopy,Gas-liquid reactions,Tube-in-tube contactor
更新于2025-09-10 09:29:36