To facilitate the production of ethanol from renewable biomass to meet the increasing energy demand with reduced CO2 emissions, molecular simulations are employed to investigate zeolite nanosheets as pervaporation membranes for ethanol extraction with atomic-level understandings. More than 10 zeolite nanosheets with diverse geometric features are systematically studied. All of these studied zeolite nanosheets are computed to offer unprecedentedly large fluxes, with values correlating to the density and size of their permeation channels. Interestingly, our results also show that the separation factor of nanosheets can drastically vary from as promising as 440 to as poor as 6.7. A detailed investigation reveals that the separation factor strongly depends on the product of the adsorption selectivity in bulk zeolites and the ethanol fraction at the channel entrance on the surface. A selection guideline based on the geometric features of zeolites is also proposed; promising nanosheet candidates appear to have the largest cavity diameter of approximately 6 A as well as a small product value between the number of silanols surrounding the channel opening and the largest opening diameter of permeation channels on the surface. The outcomes of this work can help guide the selection of zeolite nanosheets, based on the adsorption properties and/or geometric features, toward the future development of novel membranes for ethanol extraction.