A pressure-swing adsorption process for producing a purified nitrogen trifluoride (NF3) product gas from a feed gas contaminated with carbon tetrafluoride (CF4) using a column packed with an adsorbent that exhibits selectivity for NF3 over CF4. The process separates the feed gas into a first product gas having a greater concentration of CF4 than the feed gas and a second product gas having a lesser concentration of CF4 without the use of an inert carrier gas while recovering essentially all of the NF3. The process includes filling the column with the feed gas until the column reaches a first pressure, removing the first product gas, and then removing the second product gas, where after the second product gas is removed the column is at a second pressure. A rinse gas of NF3 and CF4 may be used to remove the first product gas or the second product gas.