A method of removing water from a mixture of hydrogen iodide (HI) and water includes providing a mixture comprising hydrogen iodide and water and contacting the mixture with an adsorbent to selectively adsorb water from the mixture, contacting the mixture with a weak acid to absorb water from the mixture and/or separating the water from hydrogen iodide (HI) by azeotropic distillation to produce anhydrous hydrogen iodide (HI).