Study On The Adsorption And Separation Performance Of Biobutanol By Modified Lignin

In the process of producing butanol by ABE fermentation,the toxicity inhibition of the butanol on the fermentation strain leads to low fermentation yield,low product concentration and large energy consumption in subsequent separation.The timely removal of butanol by adsorption separation can reduce the product inhibition and the product performance is stable.At the same time,the process energy consumption is low.Lignin is the second richest biomass resource on earth.The adsorption materials with excellent properties were prepared from lignin for the separation of butanol,which could not only improve the quality of lignin utilization,but also increase the fermentation yield of butanol.In this paper,the adsorption properties of lignin on butanol,acetone and ethanol in simulated fermentation broth(ABE fermentation broth)were investigated,and the adsorption mechanism was discussed.The results show that the maximum adsorption capacity of lignin is greater than other common adsorbents,and it is easy to desorb.The adsorption performance of lignin has no significant change during the recycling process.The adsorption process satisfied the pseudo-first-order kinetics model,and the equilibrium data was more consistent with the Langmuir-Freundlich isotherm model.Thermodynamic studies show that the adsorption process of butanol on lignin in the range of 293 to 313 K was a spontaneous endothermic process,while a spontaneous exothermic process from 313 to 323 K.The mechanism of lignin adsorbing butanol,acetone and ethanol is the combination of hydrogen bond and ?-?.AIMIAL was prepared by dissolution classification and the adsorption performance of AIMIAL on butanol/acetone/ethanol was studied.Compared with unclassificated lignin,the maximum adsorption capacity of AIMIAL for butanol,acetone and ethanol increased by 75.34 %,95.73 % and 76.27 %,respectively,and the adsorption rate is accelerated.The ABE concentration in the condensate increased by 35.76 %.There was no significant change in the adsorption property of AIMIAL during the recycling process.In the simulated fermentation broth,AIMIAL showed high selectivity to butanol.Strong hydrogen bonding and ?-? between AIMIAL and butanol,acetone and ethanol formed in the adsorption process.Lignin-based hydrogels(LGD)adsorbent with temperature sensitivity were prepared by radical polymerization.The swelling and de-swelling behavior of LGD series hydrogels were investigated and determined the LGD3 with a better adsorption performance.Compared with the untreated lignin,the adsorption capacity of LGD3 on butanol,acetone and ethanol were increased by 220.67 %?344.14 % and 312.70 %,respectively,and the adsorption rate is accelerated.The adsorption rate was accelerated,and the ABE concentration in the desorption solution was increased by 62.88 %.