01920nas a2200229 4500008004100000022001400041245008400055210006900139260010600208300001400314490000700328520107600335653001801411653001501429653001901444653001701463653003201480100002101512700002001533700001901553856011801572 2007 eng d a0009-250900aHydrodynamics and liquid phase residence time distribution in mesh microreactor0 aHydrodynamics and liquid phase residence time distribution in me aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcDEC a7484-74930 v623 a

This paper is focused on the experimental analysis of residence time distribution and phase hold-up in a mesh microreactor. A microreactor, where a finely weaved mesh is sandwiched between two flat plates with specific inlets for gas and liquid, is proposed. The microvolumes formed upon sandwiching the mesh are totally connected and thus it yields a view of several interconnected microvolumes. This system is easy to build and does not need precision micromachining. A high-speed photographic analysis yielded the phase distribution for different mesh types over a wide range of operating gas and liquid flow rates. The RTD was studied by measuring the liquid phase conductivity at the outlet of the reactor. Channeling prevailed for mesh with smaller open area. The ADEM was used for fitting the tracer curves with tailing ends. The RTD and the image analysis for all the mesh types showed hysteresis when the gas flow rate was maintained constant and the liquid flow rate was gradually increased and then decreased. (c) 2007 Elsevier Ltd. All rights reserved.

10ahydrodynamics10ahysteresis10aimage analysis10amicroreactor10aresidence time distribution1 aKulkarni, A., A.1 aGorasia, A., K.1 aRanade, V., V. uhttps://library.ncl.res.in/content/hydrodynamics-and-liquid-phase-residence-time-distribution-mesh-microreactor-002950nas a2200145 4500008004100000245010000041210006900141260000800210490000800218520239000226100002202616700002002638700002102658856012502679 2021 eng d00aHeterogeneous nucleation in citrate synthesis of AgNPs: effect of mixing and solvation dynamics0 aHeterogeneous nucleation in citrate synthesis of AgNPs effect of cOCT0 v4213 a

The heterogeneity issues in silver nanoparticle nucleation (Lee-Meisel route) have been investigated. The final polydispersity and sphericity of the nanoparticles in the Lee-Meisel scheme are shown to depend upon the early time dynamics of silver-citrate complexation. The formation of macromolecular intermediary complexes in the early stages of the reaction is visualized based on online DLS data, TEM analysis, and the mass balances of silver and citrate ions. The reversible complexation between citrate ions and silver citrate is shown to be the limiting step that governs the directional growth of the nanoparticles. The dynamics of the complexation of citrate are seen to form a very rapid step and intense mixing was required for the complexation to happen uniformly across the reaction. This specific observation is also confirmed from the MD simulations. Thus, to get particles of high sphericity, irrespective of the reaction concentration, temperature, or reactor geometry, the mixing time should be <4 s and Da ~ 0.1. Optimal mixing conditions for isotropic growth are suggested based on the reaction kinetics and are also demonstrated with experimental evidence.

1 aDeshpande, J., B.1 aChakrabarty, S.1 aKulkarni, A., A. uhttps://library.ncl.res.in/content/heterogeneous-nucleation-citrate-synthesis-agnps-effect-mixing-and-solvation-dynamics