Abstract Phenol removal and recovery from wastewaters are highly demanded in industries due to its high toxicity and industrial importance. It can transport through the silicon-based rubber polydimethylsiloxane (PDMS) via the solution-diffusion mechanism. To improve the phenol removal efficiency in extractive processes, dense PDMS membranes with different macromolecular structures have been developed and evaluated in this work. The condensation-cured PDMS membranes (PA) with network architecture exhibited higher phenol partition coefficients (K) than the hydrosilylation-cured PDMS membranes with linear and branch architectures. This was attributed to the four-armed quaternary-siloxy linkages formed in the three-dimensional network structure, increasing the free volume for phenol passage and hydrogen bonding between phenol and PDMS matrix. The K of PA was further enhanced by optimizing the PDMS precursor chain length and cross-linker amount, and the corresponding membrane mechanical properties and phenol overall mass transfer coefficients (k0) were examined. The optimal PA formulation was utilized to fabricate a highly effective nanofibrous composite membrane via spray coating. The resultant composite membrane exhibited a k0 of 18.3 ± 1.3 × 10−7 m/s in an aqueous-aqueous extractive process, significantly outperforming the commercial counterpart with 45% increment. This is the first demonstration of the importance of PDMS macromolecular structures on phenol extraction. The newly-developed condensation-cured PDMS could contribute to the fabrication of highly effective composite membranes for various extractive processes.

中文翻译：

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通过优化苯酚传输的聚二甲基硅氧烷结构开发高性能纳米纤维复合膜

摘要 废水中苯酚的去除和回收因其高毒性和工业重要性而受到工业界的广泛关注。它可以通过溶液扩散机制穿过硅基橡胶聚二甲基硅氧烷 (PDMS)。为了提高提取过程中的苯酚去除效率，本工作开发并评估了具有不同大分子结构的致密 PDMS 膜。具有网络结构的缩合固化 PDMS 膜 (PA) 比具有线性和分支结构的氢化硅烷化固化 PDMS 膜表现出更高的苯酚分配系数 (K)。这归因于在三维网络结构中形成的四臂季-甲硅烷氧基键，增加了苯酚通过的自由体积以及苯酚和 PDMS 基质之间的氢键。通过优化 PDMS 前体链长和交联剂的量，PA 的 K 进一步提高，并检查了相应的膜机械性能和苯酚整体传质系数 (k0)。利用最佳的 PA 配方通过喷涂制备高效的纳米纤维复合膜。所得复合膜在水-水萃取过程中的 k0 为 18.3 ± 1.3 × 10−7 m/s，显着优于商业膜，增加了 45%。这是首次证明 PDMS 大分子结构对苯酚提取的重要性。新开发的缩合固化 PDMS 有助于制造用于各种提取过程的高效复合膜。