Ammonia removal from air stream and biogas by a H2SO4 impregnated adsorbent originating from waste wood-shavings and biosolids

A new and cost-effective adsorbent N-TRAP, made from waste wood-shavings and anaerobically digestion biosolids and impregnated with H2SO4, was applied for the ammonia removal from air stream and biogas with high efficiency and effectiveness. Bearing a 75-80 and 65 wt.% sulfuric acid, the N-TRAPs mediated with wood shavings and biosolids showed the maximum ammonia adsorption capacity of 260-280 and 230 mg g−1, respectively. Gas temperatures (20 and 60 °C) and moisture content (100% relative humidity) had no significantly negative effect on ammonia capture performance when temperature in the fixed-bed column was kept equalled to or slightly above the feed gas temperature. The pressure drop increased significantly when NH3 began to break through the N-TRAP stripper due to the formation of ammonium sulfate blocking the vacuum space of packed adsorbent. At last, an alternative N-TRAP filter bed design was proposed to resolve the problem of pressure drop evolution.