The invention provides gas purification methods and systems for the recovery and liquefaction of low boiling point organic and inorganic gases, such as methane, propane, CO2, NH3, and chlorofluorocarbons. Many such gases are in the effluent gas of industrial processes and the invention can increase the sustainability and economics of such industrial processes. In a preferred method of the invention, low boiling point gases are adsorbed with a heated activated carbon fiber material maintained at an adsorption temperature during an adsorption cycle. During a low boiling point desorption cycle the activated carbon fiber is heated to a desorption temperature to create a desorption gas stream with concentrated low boiling point gases. The desorption gas stream is actively compressed and/or cooled to condense and liquefy the low boiling point gases, which can then be collected, stored, re-used, sold, etc. Systems of the invention include an active condensation loop that actively cools and/or compresses a desorption gas stream from said vessel to liquefy low boiling point gases.