High purity separation of n-pentane from neopentane using a nano-crystal of zeolite Y

Abstract

A method for the separation of a mixture of n-pentane and neopentane using a nano-crystallite of zeolite Y is reported. This method judiciously combines two well-known, counter-intuitive phenomena, the levitation and the blowtorch effects. The result is that the two components are separated by being driven to the opposite ends of the zeolite column. The calculations are based on the non-equilibrium Monte Carlo method with moves from a region at one temperature to a region at another temperature. The necessary acceptance probability for such moves has been derived here on the basis of stationary solution of an inhomogeneous Fokker–Planck equation. Simulations have been carried out with a realistic and experimentally relevant Gaussian hot zone and also a square hot zone, both of which lead to very good separation. Simulations without the hot zones do not show any separation. The results are reported at a loading of 1 molecule per cage. The temperature of the hot zone is just ∼30 K higher than the ambient temperature. The separation factors of the order of 1017 are achieved using single crystals of zeolite, which are less than 1 μm long. The conditions for including the hot zone may be experimentally realizable in the future considering the rapid advances in nanoscale thermometry. The separation process is likely to be energetically more efficient by several orders of magnitude as compared to the existing methods of separation, making the method very green.

Separation of hydrocarbon mixture of neopentane and n‐hexane using NaY zeolite: Large distinct diffusivity

“…Therefore, the location and width of the hot zone would be different for different mixtures of interest. The EPE landscape of the present mixture (see Figure 4B) is quite different from those of the earlier mixtures and therefore the realization of high degree of separation of the mixture being considered here is non‐trivial 30,31 …”

“…This leads to a very high degree of separation of the mixture. 30,31 A schematic Figure 3 is drawn to describe the Levi-Blow technique below.…”

“…The EPE landscape of the present mixture (see Figure 4B) is quite different from those of the earlier mixtures and therefore the realization of high degree of separation of the mixture being considered here is non-trivial. 30,31 The initial configuration for the simulation consisted of uniformly distributed guest molecules along all three directions. In Figure 5 Similarly, but to a slightly lesser extent n-hexane is largely seen towards the right half of the simulation cell.…”

“…In other words, the molecule is driven in the direction of the gradient. This leads to a very high degree of separation of the mixture 30,31 . A schematic Figure 3 is drawn to describe the Levi–Blow technique below.…”

Synthesis, characterizations and kinetics of MOF‐5 as herbicide vehicle and its controlled release in PVA/ST biodegradable composite membranes

“…More recently, MOF‐5 has been widely studied in gas storage and separation, drug delivery vehicle and adsorption materials [14–17,23,24] . The three‐dimensional framework has channels to accommodate guests, a controlled pore structure, an open skeleton structure, a large pore surface area, and a high thermal stability function [25–27] . Gyanendra Kumaret et al.…”