Preparation Of Water-Resistant Adsorbent Polypyrrole And Its Adsorption Properties For CO₂/H₂O

The increasing GHGs emission has led to a growing greenhouse effect and caused many problems such as melting glaciers and ecological imbalances.In order to effectively alleviate greenhouse effect,measures must be taken to strictly control CO2 emissions.The flue gas emitted by the thermal power plant contains a large amount of CO2,so the CO2 in the flue gas must be adsorbed and discharged.Conventional CO2 adsorbents have a higher adsorption capacity for CO2,but if water vapor is present in the flue gas,the adsorbent will fail.Therefore,it is necessary to study an adsorbent which maintains good adsorption performance in a wet environment.In this paper,the pyrrole monomer was used as the raw material,and ferricchloride was used as the oxidant.The adsorption polypyrrole material was prepared by chemical oxidation in an acid solution with a certain pH value.The synthesized materials were polypyrrole powder by X-ray diffraction analysis,Fourier infrared spectroscopy and scanning electron microscopy.The thermal stability analysis showed that the polypyrrole material had good stability in the range of 250℃.In this paper,the effects of pH value of inorganic acid solution,type of inorganic acid and oxidant,amount of oxidant,reaction temperature and reaction time on the adsorption performance of polypyrrole CO2 were investigated.The results show that the adsorption performance of the material deteriorates with the increase of pH value.The adsorption properties of the materials prepared at pH 0.4 and 0.8 are about the same.When HNO3,HCl and H2SO4 are used as inorganic acids,the adsorption properties of different materials are the same.When oxidants are selected from CuCl2,FeCl3,(NH4)2S2O8 and H2O2,The adsorption properties of the materials prepared with CuCl2 and FeCl3 are significantly better than other materials.When FeCl3 is used as the oxidant,the saturation dosage is 7.9g FeCl3/mL Py,the optimum synthesis temperature is 50℃.And the optimal synthesis time is 2.5h when FeCl3 is used as the oxidant,the sample quality has reached 90%of the final mass at this time.When CuCl2 is used as the oxidant,the saturation amount is 12.5 g CuCl2/mL Py,and the optimum synthesis temperature is 30℃.The adsorption thermodynamic analysis and CO2/N2 adsorption selectivity analysis were carried out for each sample prepared by optimal conditions.The results show that the adsorption selectivity of Qst and CO2 decreases with the increase of CO2 adsorption.The penetrating experimental device is self-assembled in the laboratory and is used to test the two-component CO2/H2O adsorption performance of different materials at a certain temperature and relative humidity.The results showed that when the pH of the nitric acid solution was 0.8,the oxidant was FeCl3,and the reaction temperature was 30℃,the adsorption performance of the CO2/H2O two-component penetration experiment of the material was the best.The CO2 adsorption amount was 0.8 mmol/g at a temperature of 33℃ and a relative humidity of 53%.As the adsorption temperature is at 33 ℃,42 ℃,55℃,the CO2 adsorption amount of the sample gradually decreased with the temperature rises.as the relative humidity is at 15%,33%,52%,the amount of CO2 adsorbed by the sample gradually increased with the relative humidity rises.The results showed that the presence of water vapor facilitates the adsorption of CO2 by the material.The results show that the polypyrrole can maintain good CO2 adsorption performance in the presence of a certain amount of water.Therefore,the polypyrrole can be applied to CO2 capture in wet industrial flue gas.This study is of great significance.