Study On The Synthesis And Adsorption Performance Of A Metal Organic Framework/Polymer Nanohybrid Composite

Volatile organic compounds(VOCs)are the crucial precursors that form the fine particulate matter(PM2.5),secondary organic aerosol(SOA)and ozone(O3)in the atmosphere.VOCs control has become an important task that resolves the reginal and complex air pollution.Adsorption technology is one of the most widely used treatment technology of VOCs waste gases at home and abroad recently.Adsorption technology has some advantages including resource recycling,simply technological process and low one-time investment cost,etc.The mainstream adsorbent used in industry is activated carbon,but it has poor hydrophobicity,when dealing with waste gas containing moisture will greatly reduce its adsorption performance as well as its pores are easily blocked.After the adsorption saturation of activated carbon,it is difficult to regenerate activated carbon.Waste activated carbon is also likely to produce secondary pollution.Aimed at the shortcoming of activated carbon,we developed a metal-organic frameworks ZIF-8/polydivinylbenzene nanohybrid composite in this work.The nanohybrid composite was characterized by XRD,FTIR,SEM and BET.Toluene and ethyl acetate are used as model VOC pollutants,the adsorption capacity of ZIF-8/PDVB were investigated.Different means of regenerative performance of ZIF-8/PDVB were studied as well.In this work,the nanocomposite named ZIF-8/PDVB was synthesized by combining polydivinylbenzene with metal-organic framework ZIF-8.The nanohybrid composite was characterized by XRD,FTIR,SEM BET and TGA.Results indicate that ZIF-8/PDVB composite was successfully synthesized via formation of coordination bond among Zn2+,carboxyl group and 2-methyl imidazole.ZIF-8/PDVB has abundant pore structures containing mesoporous and microporous.Abundant pore structures mean a large potential adsorption capacity.At the same time as the monomer is organic matter,organophilic of ZIF-8/PDVB appear.VOCs adsorption performance of ZIF-8/PDVB was studied through static adsorption and dynamic adsorption method,respectively.The results show that ZIF-8/PDVB's static saturated adsorption amount of toluene,ethyl acetate and phenol were 1.6093 g/g?0.7245 g/g and 0.6836 g/g,respectively,which are greater than the contradistinctive adsorbents during the experiment.ZIF-8/PDVB's dynamic saturated adsorption amount of toluene and ethyl acetate were 550.21 mg/g and 147.01 mg/g,respectively,which are greater than the ZIF-8 and PDVB as well.Also,we explore ZIF-8/PDVB's dynamic adsorption of toluene in different humidity conditions.ZIF-8/PDVB's adsorption performance of toluene is not affected by water vapor under RH=50 % and 80 %.By reason of hydrophobic,ZIF-8/PDVB's saturated adsorption amount of toluene is close to RH=0 %.Excellent adsorbent,however,embodies in not only adsorption performance but also regeneration performance.In this work,the regenation performance of ZIF-8/PDVB was investigated through different regeneration method(thermal desorption and vacuum desorption),regeneration parameters(temperature and time)and adsorption-desorption cycling experiment.The results show that desorption efficiency will be higher when the temperature is higher whether thermal desorption or vacuum desorption.Desorption efficiency will be higher when desorption time is longer at the same temperature.The vacuum desorption efficiency is higher at the same conditions.100 % desorption efficiency can be reached at 80 ? and 20 min in vacuum desorption,however,80 % desorption efficiency can be reached at 100 ? and 2 h in thermal desorption.The adsorption efficiency and desorption efficiency of ZIF-8/PDVB are larger than 90 % and almost 100 % after 10 times adsorption-desorption cycling,respectively.