Experimental Study On Adsorption Performance Of Sulfur Dioxide In Flue Gas By Polyamine-based Composite Absorbent

The desulfurization technology of organic amineis is a New type of regenerative desulfurization technology,and it is the focus of academic research.Polyaniline?PANI?as adsorbent can effectively adsorb SO₂ in flue gas,low raw material cost,simple preparation process,stable operation environment,recyclable absorbent,and by-product fertilizer.Unlike the organic amine adsorbents currently studied,it has high thermal stability.It is not necessary to cool the flue gas directly to adsorb and not evaporate.Because of polyaniline's the aggregate structure,the particles can mutually fuse in the process of desulfurization,resulting in the decrease of the adsorption efficiency.This study uses polyamine-based composite absorbents that are respectively made of the attapulgite,diatomite,vermicuklite and aniline to absorb SO₂ in flue gas.The polyaniline was used as matrix,attapulgite,diatomite and vermiculite as skeleton.Because of attapulgite,diatomite and vermiculite also have a high thermal stability,and have a large surface.They can provide better attachment condition to the polyaniline produced by in situ polymerization of aniline.The polyaniline is dispersedly attached to their surfaces,which can effectively reduce the polyaniline particles contact with each other,and avoid the fusion of particles in the process of desulfurization.The main conclusions are as follows:?1?The principle of adsorption of SO₂ by polyaniline is mainly chemical adsorption.When SO₂ is adsorbed by polyaniline,the doping of SO₂ occurs on nitrogen atoms with N=Q=N.The polyamine-based composite absorbents can absorb SO₂ because of polyaniline in composite absorbent.The composites doped with attapulgite,vermiculite and diatomite had better excellent adsorption effect for SO₂ than that of PANI modified with nothing under experimental conditions.?2?Polyaniline appears purple,and it is non-conductive insulator.The conductivity of doped-polyaniline has been greatly improved,becomes dark green,with conductivity.The doped polyaniline can be de-doped into purple polyaniline of insulation by reaction with ammonia.Doping and de-doping can be carried out in a variety of media,and this process is reversible.?3?Under the same conditions,adsorption efficiency of SO₂ by PANI/ATP composite absorbent were:10:1>2:1>5:1>1:1>2:1,adsorption efficiency of SO₂ by PANI/ diatomite were:5:1>1:2>1:1>2:1>10:1,and adsorption efficiency of SO₂ by PANI/vermiculite were:1:2>5:1>10:1>1:1>2:1.The higher the amount of polyaniline in the composite absorbent,the better the adsorption efficiency of the adsorbent.Instead related to the specific surface area and pore size of the adsorbent,and the effect of pore size on its adsorption efficiency is dominant.?4?Polyaniline-based composite adsorbents can be desorbed by the addition of ammonia,with a certain degree of recyclability,and after repeated cycles still have excellent adsorption capacity.?5?Adsorption efficiency of sulfur dioxide by polyamine based composite first increased and then reduced with the increase of temperature between 25? and200?,and the adsorption effect is better in the temperature range of 100¹80?.