Microwave-Driven Zeolite−Guest Systems Show Athermal Effects from Nonequilibrium Molecular Dynamics

Abstract

Nonequilibrium molecular dynamics simulations show that steady-state systems obtained by microwave heating are qualitatively different from those at thermal equilibrium. This difference arises because energy transfer from hotter to colder species is not efficient enough to equilibrate the distribution of energy. Under nonequilibrium conditions, we found that microwave radiation can selectively heat methanol in a binary mixture of methanol-benzene adsorbed in faujasite zeolite. The difference in steady-state temperatures follows the trend Tmethanol > Tbenzene > Tzeolite, which is qualitatively consistent with recent experimental results.

Adsorbents regeneration under microwave irradiation for dehydration and volatile organic compounds gas treatment

“…A heterogeneous temperature distribution in the solid, even at a molecular scale [25,26] has often been described. Equilibrium molecular dynamics and simulations on non-equilibrium molecular dynamics made on bare zeolites and on loaded zeolites with methanol and/or benzene [27] confirmed that some atoms (like Na in bare zeolites), sorbent framework or adsorbate molecules can be maintained at different steady state temperatures under an electromagnetic field. This athermal effect arises because the energy dissipation into the framework is not effective enough between the host and the guest molecules to completely thermalize the absorbed energy.…”

Simulating the Relaxation Dynamics of Microwave-Driven Zeolites

“…[19][20][21] All zeolite and guest atoms are subjected to random velocity replacement at random times. The Andersen thermostat has been implemented by specifying three parameters: the target temperature, the number of atoms to be replaced at a time, and the average time between replacements.…”

Non-thermal effects of microwave in sodium chloride aqueous solution: Insights from molecular dynamics simulations

“…The molecular dynamics (MD) simulations as a link between microscopic length and time scales and the macroscopic world of the laboratory: it provides a clue as the interactions between molecules, and obtain 'exact' predictions of bulk properties [35]. Specially, MD simulations have evaluated non-thermal effects of microwave fields on water [36][37][38], zeolites [39,40], polystyrene solutions [41], metal oxides [42] and hydrates [43]. And these studies have provided useful insights for understanding the common behavior of microwave non-thermal.…”