Preparation And Adsorption Properties Of Mesoporous Nitrogen-doped Carbon Materials

The adsorption technology has the characteristics of simple operation,high efficiency,wide adaptability and without secondary pollution,which is an effective method to solve the problem of separation and purification.The key to achieve high-efficient adsorption is to develop adsorbents with high adsorption performance and regeneration ability.The mesoporous nitrogen-doped carbon(MNCs)material has large specific surface area,mesoporous structure and rich surface active functional groups,which has been considered as an ideal adsorbent.However,the complicated preparation process,which usually requires the use of templating agents,etc.,has limited the applications of MNCs.The purpose of this project is to prepare MNCs by one-step cross-linking of small molecular organic materials.Applications of the as prepared MNCs in dye adsorption and hydrogen peroxide purification have been investigated.Firstly,MNCs were synthesized by using pyromellitic dianhydride and melamine as carbon and nitrogen source.By changing the proportion of transition metals and calcination temperatures,a series of MNCs with different mesoporous structures were prepared.The addition of iron has a positive effect on the formation of mesoporous structures of carbon materials,which can effectively increase the specific surface area and pore volume of the materials.At the same time,the increase in the calcination temperature is beneficial to the above metal-assisted carbonization process.Organic dye adsorption experiments show that the dye adsorption process of the as-prepared MNCs conforms to the pseudo-second-order kinetic equation.The mesoporous carbon(MNC-10)prepared at 800 ℃ and 10% iron addition has the best adsorption activity,and the adsorption capacity of Congo red and Acid fuchsin is 1550 and 1456 mg/g,respectively,significantly higher than commercially available activated carbon materials.The exhausted adsorbent can be separated from aqueous solution by magnetic separation,and which can still maintain a high adsorption activity after 5adsorption-cycle experiments.Subsequently,the adsorption and purification performance of MNC-10 for impurities in hydrogen peroxide was explored.By adjusting the amount of MNC-10 can effectively coordinate the relationship between the hydrogen peroxide purification effect and the amount of hydrogen peroxide decomposition.Among them,when the dosage of MNC-10 is 0.2 g/L,the TOC adsorption equilibrium concentration in hydrogen peroxide is 10.53 mg/L,the adsorption capacity is 2128.5 mg/g,the decomposition amount of hydrogen peroxide is 4.92%,and the adsorption and purification performance is excellent.In addition,MNC-10 also has a good adsorption and purification effect on some specific metal ions and other anions in the hydrogen peroxide solution.