Study On Adsorption Of MAF-6 For 1-butanol And PDMS Matrix Membranen Pervaporation Performance

Biobutanol,one of the most promising biofuels,can be produced by the fermentation process of biomass.However,the serious end-product inhibition results in a low 1-butanol concentration in the fermentation broth,leading to high energy consumption in the downstream separation process via distillation.In comparison,adsorption and pervaporation are regarded as the most significant separation technologies for 1-butanol enrichment and recovery from aqueous solutions due to the advantages such as low energy consumption,low economic cost,simple operation and high separation efficiency.Therefore,MAF-6 and MAF-6/PDMS mixed matrix membranes were prepared,and the potential of MAF-6 in adsorption and pervaporation separation of 1-butanol were investigated.Firstly,the hydrophobic MAF-6 particles were prepared to examine their adsorption and desorption performance for 1-butanol.The results show that the adsorption process reaches equilibrium in less than 40 min and the maximum adsorption capacity of butanol reaches 242 mg/g at 25℃.According to the thermodynamic study,the adsorption process is a spontaneous and exothermic physical adsorption process.In addition,MAF-6 has excellent desorption and regeneration performance.The adsorbate can be completely desorbed from the MAF-6 at 80℃ for 120 min.The energy consumption of this desorption process is only 21.36%of that of traditional distillation.Next,based on the excellent butanol adsorption and desorption performance of MAF-6,the hydrophobic porous MAF-6 particles were doped into PDMS to fabricate MAF-6/PDMS mixed matrix membranes.Results demonstrate that the hydrophobicity of PDMS membrane is improved with the water contact angle being increased from 112.70 to 118.1° after being doped with MAF-6.The swelling degree experiment shows that MAF-6 greatly improves the adsorption ability of PDMS membrane towards butanol.More importantly,when MAF-6 doped into PDMS polymer matrix,a simultaneous enhancement was observed in flux and separation factor,namely breaking the trade-off.Compared with the PDMS membrane,the total flux and separation factor of MAF-6/PDMS mixed matrix membrane are increased by 41.93%and 23.30%,respectively,for separating 1.5 wt%1-butanol/water aqueous solution at 55℃.In addition,the heat energy consumption of pervaporation process is decreased from 4.27 kJ/g to 3.71 kJ/g via the doping of MAF-6,which is only 13.80%of that of the traditional distillation method,and it is also superior to the adsorption method,showing the great advantages of energy saving.Finally,the pervaporation separation performances of several common industrial wastewater were explored.The pervaporation performances of PDMS membrane for methyl ethyl ketoxime aqueous solution,2-butoxy ethanol aqueous solution and methyl acetate aqueous solution at different feed concentrations were investigated and great separation effect was obtained.