CTAB改性膨润土填充PEBAX/PVDF膜渗透汽化降低汽油噻吩含量

Enrichment of thiophene via pervaporation method using CTAB-modified bentonite filled PEBAX /PVDF membrane

用十六烷基三甲基溴化铵(CTAB)对膨润土进行柱撑改性,并对改性前后的膨润土进行吸附实验及红外测定。将改性后膨润土置于填充聚醚共聚乙酰胺(PEBAX)聚合物溶液中,以聚偏氟乙烯(PVDF)超滤膜为支撑膜,制备复合膜,考察复合膜在模拟汽油(噻吩/正庚烷)中的溶胀性能,并进行渗透汽化实验,研究膜的分离性能。利用SEM考察膜的形貌结构。结果发现:30℃下,溶胀度随噻吩质量分数的增加而升高,15 min后达溶胀平衡,并且在填充量为20%时最大。渗透汽化结果表明:在料液温度为30℃,噻吩质量分数为1 100μg/g时,CTAB填充量为20%的PEBAX/PVDF复合膜的渗透通量和硫富集因子分别为2.81 kg/(m2·h)和4.65。

The CTAB-modified bentonite is prepared by using hexadecyl trimethyl ammonium bromide（ CTAB） as modifier. FTIR spectroscopy is used to study the structure of bentonite before and after modification. The CTAB-modified bentonite is then combined with the filled polyether block amide（ PEBAX） solution to fabricate the composited membranes with PVDF ultrafiltration membrane as the support layer. The behaviors of swelling and pervaporation of the membranes in model gasoline consisted of thiophene /n-heptane are studied,respectively. The structure morphology of the membranes is characterized by scanning electron microscope（ SEM）. The swelling degree of the membranes increases with the increase of the thiophene concentration at 30℃. The swelling equilibrium is reached after 15 minutes. When the content of CTAB-modified bentonite is 20 wt%,the swelling of degree reaches maximum. The pervaporation result shows that the total flux and the enrichment factor of thiophene for the composite membrane with 20 wt% of CTAB-modified bentonite are 2. 81 kg·m^- 2·h^- 1and 4. 65,respectively,under the thiophene concentration 1 100 μg /g and at 30℃.