Talluri Vssl Prasad, Patakova Petra, Moucha Tomas, Vopicka Ondrej
Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
Chemical Engineering Department, University of Chemistry and Technology, Prague, Technická 5, 166 28 Praha 6, Czech Republic.
Polymers (Basel). 2019 Nov 26;11(12):1943. doi: 10.3390/polym11121943.
The transient and steady pervaporation of 1-butanol-water mixtures through a poly[1-(trimethylsilyl)-1-propyne] (PTMSP) membrane was studied to observe and elucidate the diffusion phenomena in this high-performing organophilic glassy polymer. Pervaporation was studied in a continuous sequence of experiments under conditions appropriate for the separation of bio-butanol from fermentation broths: feed concentrations of 1.5, 3.0 and 4.5 % of 1-butanol in nutrient-containing (yeast extract) water, temperatures of 37, 50 and 63 °C, and a time period of 80 days. In addition, concentration polarization was assessed. As expected, the total flux and individual component permeabilities declined discernibly over the study period, while the separation factor (average β = 82) and selectivity towards 1-butanol (average α = 2.6) remained practically independent of the process conditions tested. Based on measurements of pervaporation transients, for which a new apparatus and model were developed, we found that the diffusivity of 1-butanol in PTMSP decreased over time due to aging and was comparable to that observed using microgravimetry in pure vapor in 1-butanol. Hence, despite the gradual loss of free volume of the aging polymer, the PTMSP membrane showed high and practically independent selectivity towards 1-butanol. Additionally, a new technique for the measurement and evaluation of pervaporation transients using Fourier transform infrared spectroscopy (FTIR) analysis of permeate was proposed and validated.
研究了1-丁醇-水混合物通过聚1-(三甲基甲硅烷基)-1-丙炔膜的瞬态和稳态渗透蒸发过程，以观察和阐明这种高性能亲有机玻璃态聚合物中的扩散现象。在适合从发酵液中分离生物丁醇的条件下，通过连续的实验序列研究了渗透蒸发：含营养物（酵母提取物）的水中1-丁醇的进料浓度为1.5%、3.0%和4.5%，温度为37、50和63℃，时间段为80天。此外，还评估了浓差极化。正如预期的那样，在研究期间总通量和各组分渗透率明显下降，而分离因子（平均β = 82）和对1-丁醇的选择性（平均α = 2.6）实际上与所测试的工艺条件无关。基于渗透蒸发瞬态的测量（为此开发了一种新装置和模型），我们发现1-丁醇在PTMSP中的扩散系数由于老化而随时间降低，并且与在纯1-丁醇蒸汽中使用微重力法观察到的结果相当。因此，尽管老化聚合物的自由体积逐渐减少，但PTMSP膜对1-丁醇仍表现出高且几乎独立的选择性。此外，还提出并验证了一种使用渗透物的傅里叶变换红外光谱(FTIR)分析来测量和评估渗透蒸发瞬态的新技术。
