A set of adsorbents, built from SBA-15 and a sulfonic acid task-specific ionic liquid (IL), have been synthesized and investigated as a novel means of capturing ammonia from air. The adsorbents contain between 3 and 46 wt % IL, and the composite that contains the least amount of IL adsorbs more ammonia than the parent SBA-15. Below 2.0 kPa, all of the composites adsorb more ammonia than the parent SBA-15. Breakthrough experiments were conducted, and the composite materials adsorb more ammonia than activated carbon in both dry and humid conditions. However, the adsorption data are complex and likely reflect adsorption on the silica surface, solubility of the ammonia in the IL, and adsorption resulting from the interaction of ammonia with a sulfonic acid functional group and the interaction of ammonia with water contained in the IL. The ammonia adsorption capacities of the composites are compared with those of numerous other materials including metal organic frameworks, activated carbon, zeolites, MCM-41, zirconium hydroxide, and aerogels. The data show that IL composites adsorb more ammonia at low pressure than many known materials. More broadly, the results illustrate that it is possible to functionalize the pores of an adsorbent with an IL to capture a specific gas in a fixed bed.