Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky pr. 29, Moscow 119991, Russia.
Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Sciences, Profsoyuznaya ul. 70, Moscow 117393, Russia.
Adv Colloid Interface Sci. 2015 Aug;222:716-27. doi: 10.1016/j.cis.2014.11.005. Epub 2014 Nov 23.
For the first time, the effect of asymmetry of the membrane transport was studied for organic solvents and solutes upon their nanofiltration through the plasma-modified membranes based on poly(1-trimethylsilyl-1-propyne) (PTMSP). Plasma treatment is shown to provide a marked hydrophilization of the hydrophobic PTMSP surface (the contact angle of water decreases from 88 down to 20°) and leads to the development of a negative charge of -5.2 nC/cm(2). The XPS measurements prove the formation of the oxygen-containing groups (Si-O and C-O) due to the surface modification. The AFM images show that the small-scale surface roughness of the plasma-treated PTMSP sample is reduced but the large-scale surface heterogeneities become more pronounced. The modified membranes retain their hydrophilic surface properties even after the nanofiltration tests and 30-day storage under ambient conditions. The results of the filtration tests show that when the membrane is oriented so that its modified layer contacts the feed solution, the membrane permeability for linear alcohols (methanol-propanol) and acetone decreases nearly two times. When the modified membrane surface faces the permeate, the membrane is seen to regain its transport characteristics: the flux becomes equal to that of the unmodified PTMSP. The well-pronounced effect of the transport asymmetry is observed for the solution of the neutral dye Solvent Blue 35 in methanol, ethanol, and acetone. For example, the initial membrane shows the negative retention for the Solvent Blue 35 dye (-16%) upon its filtration from the ethanol solution whereas, for the modified PTMSP membrane, the retention increases up to 17%. Various effects contributing to the asymmetry of the membrane transport characteristics are discussed.
首次研究了有机溶剂和溶质通过基于聚(1-三甲基硅基-1-丙炔)(PTMSP)的等离子体改性膜进行纳滤时，膜传递的不对称性的影响。结果表明，等离子体处理显著提高了疏水 PTMSP 表面的亲水性（水的接触角从 88 度降低到 20 度），并导致负电荷为-5.2 nC/cm(2)。XPS 测量证明了由于表面改性形成了含氧基团（Si-O 和 C-O）。AFM 图像显示，等离子体处理的 PTMSP 样品的小尺度表面粗糙度降低，但大尺度表面不均匀性变得更加明显。即使在纳滤测试和环境条件下储存 30 天后，改性膜仍保留其亲水表面性质。过滤测试的结果表明，当膜定向使得其改性层与进料溶液接触时，线性醇（甲醇-丙醇）和丙酮的膜透过率降低近两倍。当改性膜表面朝向渗透物时，膜恢复其传输特性：通量等于未改性的 PTMSP。在甲醇、乙醇和丙酮中的中性染料溶剂蓝 35 的溶液中观察到明显的传输不对称效应。例如，初始膜在从乙醇溶液过滤溶剂蓝 35 染料时表现出负保留（-16%），而对于改性的 PTMSP 膜，保留增加到 17%。讨论了导致膜传递特性不对称的各种影响。
