Research On Typical Adsorbents And Modified Activated Carbons For Removal Of High Concentration Hydrogen Sulfide

Odor pollution is a typical environmental pollution and attracts more and more people's attention in recent years.Hydrogen sulfide which is a typical odor dose great harm to people and it is particularly important to choose the appropriate treatment to reduce the hydrogen sulfur pollution.Adsorption method is widely used without the site and the environment limit,which can timely discharge high concentration of hydrogen sulfide.Therefore,the effect of sorbent for the removal of H₂S of high temperature as well as the effect of modified activated carbon was studied in this work.Also,the desorption regeneration performance of exhausted sorbent was studied.In this paper,the effects of 13X,SBA-15 molecular sieve,alumina and activated carbon?AC?for the removal of high concentration hydrogen sulfide at low temperature were compared.The removal performance of 13X zeolite was better than unmodified activated carbon and alumina without oxygen and water at room temperature,and the breakthrough capacity was 41mg/g.At the same time,this study was to investigate the effect of process conditions for H₂S removal.Choosing the appropriate particle size and reducing a gas hourly space velocity?GHSV?can improve the utilization rate of adsorbent,and the adsorption capacity can be improved with some oxygen.For sorption temperature and water effects,molecular sieve and AC show different trends.The higher the temperature was,the smaller breakthrough capacity the molecular sieve had,the opposite of AC;and certain humidity can improve the desulfurization effect of activated carbon,but the water would greatly decrease the breakthrough capacity.Finally,considering adsorption process conditions,adsorption mechanism and cost aspects,activated carbon sieve has a higher practical value than the molecular.In view of the low adsorption capacity of unmodified activated carbon,activated carbon was impregnated with NaOH,Na₂CO₃ and Cu?NO₃?₂ of different loading.It was found that the desulfurization of modified activated carbon was much higher than unmodified activated carbon.The breakthrough capacity of Cu/AC was 35 times higher than unmodified activated carbon,reaching 75.89mg/g.while the breakthrough capacity of loading 3%NaOH and 8%Na₂CO₃ increased by 40 times.At the same time,the modified activated carbon was characterized by various means.The desorption was carried out by TGA analysis and heat treatment.The oxidation temperature of the modified activated carbon was obviously ahead of time,which means that the modifier changed the chemical properties and the stability of the activated carbon.For exhausted AC,a significant weight loss peak was increased at about 270?,indicating that not only can activated carbon adsorb H₂S at room temperature,but H₂S can be oxidized to elemental sulfur.High concentrations of SO₂ and H₂S were detected in the outlet tail gas.By measuring the change of tail gas concentration during the thermal desorption of the activated carbon,it was determined that the elemental sulfur deposited in the pores could be removed by heating at 270?for 20 min in the air atmosphere.