Preparation And Application Of Composite Adsorbent Based On Polypyrrole

Conductive polymer polypyrrole(PPy)has the advantages of low cost,well stability and easy preparation.The doped polypyrrole has a good adsorption efficiency for dyes and has a wide range of applications in the removal of water pollutants.The adsorption properties were further improved by the combination of polypyrrole and nanometer titanium dioxide.However,PPy/TiO2 nanocomposites have some limitations due to their difficulty in recycling and high cost.In this thesis,citric acid chosen as dopant,polypyrrole was compounded with micron-grade titanium dioxide and sodium alginate.Then PPy/TiO2,B-PPy/TiO2 and PPy/SA-TiO2 composites were prepared for the adsorption of methylene blue in aqueous solution,the effects of various factors on the adsorption and desorption properties were investigated systematically,and the adsorption kinetics and mechanism were studied.It mainly includes the following contents:1.PPy/TiO2 composites are synthesized by in situ polymerization.The results show that after 30 min in 150 mg/L methylene blue solution,when pH is 12,the adsorption efficiency reached 97.3%using 0.4 g adsorbent.When the pH is 1 and the desorption time is 20 min,the desorption efficiency reached 76.5%.After being reused for 10 times,the adsorbent still shows excellent adsorption and circulation performance.Compared with the nanoadsorbent,PPy/TiO2 adsorbent has the advantages of simple recovery,better practical application performance and less secondary pollution.2.B-PPy/TiO2 composites were prepared by using boric acid as crosslinking agent The results show that after 30 min in 150 mg/L methylene blue solution,when pH is 12,the adsorption efficiency reached 90%using 0.4 g adsorbent.When the pH is 1 and the desorption time is 20 min,the desorption efficiency reached 77.5%.In practical application,the problem of the titanium dioxide falling off during the adsorption process is solved,and the recycling performance is improved.3.PPy/SA-TiO2 was prepared by using sodium alginate as carrier.After 30 min in 50 mg/L methylene blue solution,the adsorption efficiency reached 87.3%using 0.08 g adsorbent.When the pH is 1 and the desorption time is 15 min,the desorption efficiency reached 97%.After being reused for 10 times,PPy/SA-TiO2 showed stable morphology,well adsorption performance and excellent repeatability.