NOVELTY - A microporous adsorbent particulate material comprises external surfaces having pores capable of admitting fluids, and having a nanolayer of a polymeric material extending over the external surface around a pore to partially occlude pore openings to a predetermined extent; and internal surfaces free of the polymeric material.    USE - In bulk storage device and separation system for selectively extracting fluids and selectively adsorbing molecule (e.g. selectively recovering hydrogen, carbon monoxide, methane or a volatile hydrocarbon from a hydrocarbon production effluent fluid); used in a medical apparatus for selective removal of a gas or purification of gas supply; in breathing apparatus for selective removal of a gas or purification of breathable gas supply (claimed); also used in hydrogen enrichment, carbon dioxide capture, methane storage, military and civilian respiratory protection, water scrubbing, pharmaceutical and bio separations and cigarette filters.    ADVANTAGE - The nanolayer is applied to external surfaces, and surrounding the lip of the pores to a limited extent, so that the interior surfaces of the microporous material are free of such nanolayer. This has the natural consequence that the capacity of the pores of the modified microporous material is not greatly affected by process, and the capacity of the modified microporous material is at least 90% of the capacity of the unmodified microporous material. The process modifies the diffusion and wetting characteristics of the microporous material in a controllable and predictable manner. The processed material offers selective entry to the pores of the microporous material depending on the kinetic energy and/or the molecular size of the molecules to be adsorbed.    DETAILED DESCRIPTION - A microporous adsorbent particulate material comprises external surfaces having pores capable of admitting fluids, and having a nanolayer of a polymeric material extending over the external surface around a pore to partially occlude pore openings to a predetermined extent; and internal surfaces free of the polymeric material. The particulate material is a carbon-based microporous material, and internal surfaces exhibit properties associated with microporous carbon. The polymeric material is a silicon-based material and the external surfaces exhibit properties associated with silicon. The nanolayer comprises a surface modifying compound to enhance hydrophobic properties of the external surfaces of the material. INDEPENDENT CLAIMS are included for the following:    (1) an element comprising a microporous adsorbent material attached to a support;    (2) a filter device comprising the element;    (3) a bulk storage device for fluids comprising a container filled with microporous adsorbent material;    (4) a separation system for selectively extracting fluids comprising the filter device having an element containing microporous absorbent material, and a bulk storage device operatively connected such that selectively extracted fluid is transferable to bulk storage device;    (5) process for modifying the surface diffusion and wetting characteristics of a microporous material involving converting a composition comprising a monomer to the form of a plasma, initiating polymerization of the composition, and applying a nanolayer of the plasma composition to a surface of the microporous material to form a modified microporous material; and    (6) process for selectively adsorbing a molecule involving using a modified microporous material for contacting a fluid containing molecule.