Lead adsorption in a serpentine millichannel‐based packed‐bed device: Effect of hydrodynamics and mixing characteristics

Abstract

The present study depicts the hydrodynamics and the mixing characteristics in a millichannel‐based serpentine fixed‐bed device to attain the particular demands of the miniature adsorption devices' fabrication. Residence time distribution analyses were accomplished to analyze the velocity distribution inside the packed bed geometry. The effects of operating variables on the system hydrodynamics and mixing and their impact on the lead adsorption characteristics were enunciated. New correlations were proposed for the frictional resistance and axial dispersion of the fluid. The parametric effects on the lead ions [Pb(II)] adsorption were studied in the same millichannel geometry packed with the graphene oxide coated glass beads. The kinetics of the adsorptive removal process is assessed by the Thomas model and the Yoon–Nelson model. The regeneration study of the said millichannel‐based fixed‐bed device was also executed.

Mixing characteristics for the single and air‐water two‐phase flows in miniaturized parallel multichannel‐based devices

“…The RTD curves become sharper at the greater flow rate, which represents the lower mean residence time ( t m ) for the single‐phase flow (Figure 2A). The RTD curves become broader when the channel dispersion number, which is the Peclet number's reversal, increases, as shown in Figure 2A 44–46 . In the case of the two‐phase flow, when the flow rate of one phase increases, leaving the other unaltered, the residence time decreased, and the RTD curves become sharper due to the increment of the velocity of the phases (Figure 2B,C).…”

“…The RTD curves become broader when the channel dispersion number, which is the Peclet number's reversal, increases, as shown in Figure 2A. [44][45][46] In the case of the twophase flow, when the flow rate of one phase increases, leaving the other unaltered, the residence time decreased, and the RTD curves become sharper due to the increment of the velocity of the phases (Figure 2B,C). When the height of the packed channels (uniform packing materials and the bed porosity) decrease, for a particular flow rate of the fluids, the velocities and the mixing properties of the phases increased, lowing the residence time, and making the RTD sharper (Figure 2B,C).…”

CFD Modeling and Simulation of the Axial Dispersion Characteristics of a Fixed-Bed Reactor

“…Mondal et al reported that the tracer residence time increased at a lower flow rate, which also broadened the residence time distribution curve. 35 This was due to the fact that the diffusive process dominated at a lower flow rate. Furthermore, the residence time distribution density function curve did not exhibit a trailing tail, which implied that there was almost no dead zone in the packed region.…”

“…The correlation was determined via least-squares fitting as follows There was an almost inverse proportional relationship between the mean residence time and inlet velocity. Similarly, Mondal et al 35 investigated the mean residence time in the millichannel-based fixed-bed device for different flow rates. Based on their experimental data, the relationship between mean residence time and flow rate was …”

“…Mondal et al investigated the mixing characteristics of a serpentine millichannel-based packed-bed device. 35 They examined the effect of the flow rate on the residence time distribution and proposed new correlations for the frictional resistance and axial dispersion. More recently, Petrazzuoli et al predicted axial Péclet numbers using direct numerical simulations under single-phase laminar flow conditions.…”