The Study Of Ammonia Adsorbents

Humus soil was selected as the material of ammonia adsorbents and the way to modify the humus soil was researched to improve its adsorption capacity.The paper aims to develop a kind of higher adsorption capacity, economical and environmental ammonia adsorbent.First, the solution of chloride and sodium hydroxide was used as modifiers in the study and learned how did they take part in the improvement of adsorption performance. The results were the addition of chloride and sodium hydroxide had no positive effect on the improvement of adsorption performance.Then the study used different concentrations of nitrate to deal with humus soil in different conditions and studied its adsorption capacity of ammonia. It showed us how this happened via BET, Boehm titration and FTIR. The results were that the humus soil treated by 3N HNO3 for 12 hours had the biggest adsorption ability. The breakthrough capacity was improved from 0.085mg/g to 1.280mg/g, increased as many as 14 times, while the penetration time of ammonia was improved from less than 10 min to 50 min.Different concentrations of sulfuric acid were used to deal with humus soil in different conditions and studied its adsorption capacity of ammonia. We can learn how it happened via BET and SEM. The best condition was the humus soil treated by 17% H2SO4 for 8 hours, the solid-liquid ratio was 1:8, the temperature was 60℃ and made it neutral, the penetration time of ammonia was improved from less than 10 min to 90 min, a growth of at least 8 times, the breakthrough capacity was improved from 0.085mg/g to 2.3mg/g, an increase of as many as 26 times.Above all, the best one was the humus soil which was treated by 17% H2SO4 for 8 hours, the solid-liquid ratio was 1:8, the temperature was 60℃ and washed two times, then added 0.7% methyl cellulose to the modified humus soil,the adsorbent was made when the water powder ratio was 1:4 and dried in 105℃,then calcined in 200℃ for 2 hours.Adsorbent’s saturation curve and penetration curve were tested in a fixed bed. It showed the penetration time of adsorbent was 3 hours and its breakthrough capacity was 5.0mg/g, the saturation time of adsorbent was 8 hours and its saturation capacity was 12.3mg/g.Then the study showed the influence of different reaction conditions on the adsorbent. The higher the inlets concentration, the shorter penetration time was. The penetration time and adsorption capacity were increased with the increasing of the adsorbents filling height. The adsorption performance improved firstly but decreased with the increasing of humidity, and when the humidity was 80% the penetration time was the longest, which was 3 hours.At last, the study discussed the NH3 removal mechanism of the adsorbent. The results showed that when the flow was humid, the NH3 removal mechanism of the adsorbent included external diffusion, internal diffusion, surface diffusion, physical adsorption, chemical adsorption, physical absorption and chemical absorption, which was called sorption process.The NH3 removal process involveed only external diffusion, internal diffusion, surface diffusion, physical adsorption while the feed gas was dry.