Synthesis Of New Porous Materials And The Application In Volatile Organic Compounds Adsorption

The emission of volatile organic compounds（VOCs）will not only cause serious environmental pollution but also endanger human health.Therefore,the adsorption and recovery of VOCs has attracted more and more attention.In this paper,porous materials with different structures,compositions and pore sizes were prepared,and the adsorption applications of their VOCs were investigated.Transmission,scanning electron microscopy（TEM,SEM）,N₂absorption-desorption,Fourier transform infrared spectroscopy（FTIR）and other methods were used to characterize the structures and morphologies of the samples.Static adsorption and dynamic adsorption experiments were used to explore and compare the static and dynamic VOCs adsorption performance of different adsorbents.The research content is as follows:1.Under alkaline conditions,with cetyltrimethylammonium bromide（CTAB）as the surfactant,tetraethylorthosilicate（TEOS）and（1,2-bis（triethoxysilyl）Ethane,BTSE）is a co-condensation of silicon source to synthesize mesoporous organic-inorganic composite Si O₂ hollow spheres.The pore structure and size of the sample can be changed by adjusting the molar ratio of TEOS and BTSE.The experimental results show that with the increase of BTSE,the diameter and wall thickness of MOSs samples increase first and then decrease.When the molar ratio is TEOS:BTSE=80:10,the diameter and wall thickness of MOS-10%s are the largest,are 361 nm and 45nm,respectively,and S_BET(696 m² g^-1),V_t(0.887 cm³ g^-1)of MOS-10%s are the largest.The results of static adsorption experiments show that MOS-10%s has the lowest water vapor adsorption capacity(0.630 g g^-1)and the highest n-hexane,toluene and 92#gasoline static adsorption capacity(1.28 g g^-1,1.25 g g^-1and 1.14 g g^-1,respectively)better than those of SG and AC.At the same time,dynamic adsorption experiments were carried out on MOS-10%s,SG and AC.The results show that compared with AC and SG,MOS-10%s has the best dynamic adsorption and desorption performance and broad prospects in the emission control of VOCs.2.The hollow carbon nanospheres（HCNS-0/4）are activated by Na NH₂,and the samples after activation with larger specific surface areas and more micropores.The effect of the amount of the activator and the activation temperature on HCNS-0/4 was studied.When the mass ratio is HCNS-0/4:Na NH₂=1:3 and the activation temperature is 500°C,the S_BET and V_t of the activated sample HCNS-0/4-3-500°C are the largest,1589 m² g^-1and 1.96 cm³ g^-1,respectively,and have the highest static adsorption of VOCs and water vapor capacity and good stability.The water vapor,n-hexane,toluene and 92#gasoline static adsorption capacity of HCNS-0/4-3-500°C are 2.20 g g^-1,2.70 g g^-1,1.93 g g^-1 and 1.36 g g^-1,respectively,which are147%,33.8%,35.5%and 46.9%higher than those of HCNS-0/4 before activation,and are much higher than those of SG and AC.The dynamic adsorption results show that the dynamic adsorption performance of HCNS-0/4-3-500°C is better than those of SG and AC.3.The biochar（cattail as raw material）was chemically activated to synthesize a biochar material with a larger specific surface area and more micropores than the original biochar.At the same time,the influence of different activating reagents and the mass ratio of activating reagents on the activation of biochar was studied.When Na₂CO₃ is used as the activating reagent,and biochar:Na₂CO₃=1:3,the samples（biochar-Na₂CO₃-1:3）activated at 700°C have the largest S_BET(624 m² g^-1)and V_t(0.211 cm³ g^-1),S_m and V_m are also the largest(393 m² g^-1 and 0.165 cm³ g^-1,respectively).Also biochar-Na₂CO₃-1:3 has better VOCs and water vapor adsorption performance,good stability and regeneration performance.The static adsorption capacity of biochar-Na₂CO₃-1:3 water vapor,n-hexane,toluene and 92#gasoline are 2.12 g g^-1,1.03 g g^-1,0.814 g g^-1 and 0.751 g g^-1,respectively.Compared with the unactivated cattails,the static adsorption capacity of biochar-Na₂CO₃-1:3 increased by 245%,416%,128%and 209%,respectively,and are higher than thoese of SG and AC.Dynamic adsorption experiments show that biochar-Na₂CO₃-1:3 has good dynamic adsorption performance compared with SG and AC.This paper compares the adsorption performance of porous materials with commercial SG and AC through static and dynamic adsorption experiments,and studies the influence of pore structure on adsorption materials.It is found that porous materials have excellent adsorption performance and can be used for the adsorption and recovery of VOCs.