A gas-liquid separator has a housing having an inlet for receiving a gas-liquid stream and an outlet for discharging a gas stream. A nozzle structure in the housing has a plurality of nozzles that receive the gas-liquid stream and accelerate the gas-liquid stream therethrough to create a plurality of gas-liquid jets. An inertial collector in the housing causes a sharp directional change of the gas-liquid jets, causing separation of liquid particles from the gas-liquid stream to produce the gas stream. The inertial collector has a porous collection substrate. According to the present disclosure, at least one of the following three conditions is met: (a) the porous collection substrate comprises fibers of small diameter and has low packing density; (b) the porous collection substrate comprises oleophobic fibers; and (c) the nozzle structure and the inertial collector are configured to allow for full expansion of the plurality of gas-liquid jets.