扫气膜蒸馏

Abstract(#br)This work revolves around the use of porous metal hollow fibers in membrane distillation. Various stages are covered, starting from membrane synthesis up to the testing of a pilot scale membrane module. Mechanically stable metal hollow fibers have been synthesized by phase inversion of a stainless steel particle loaded polymer solution, followed by thermal treatment to remove the polymer and sinter the particles together. The pore surface of the metal fibers has been made hydrophobic by functionalization with polydimethylsiloxane or stearic acid.

通过纺丝工艺制备了高度多孔的聚醚酰亚胺( PEI )中空纤维膜。采用聚二甲基硅氧烷( PDMS )浸渍提拉法对膜进行改性，以增加表面疏水性。该膜用于扫气膜蒸馏( SGMD )工艺分离亚甲基蓝( MB )溶液。从FESEM检查，在膜结构中观察到具有大的指状空洞的开放结构。PEI- PDMS膜呈现较高的表面孔隙率，N2渗透率为15300 GPU，平均孔径为72 nm。超薄PDMS涂层的形成使表面疏水性得到改善，水接触角在104 º左右。此外，涂层使临界进水压力从250 kPa提高到400 kPa。当进料温度为60 ° C时，PEI和PEI - PDMS膜的纯水通量分别为26.2和22.5 kg / m2 h。在SGMD过程的5 d内，PEI和PEI - PDMS的渗透通量分别降低了42 %和19 %。PEI- PDMS膜表现出良好的防污性能，通量恢复率约为89.4 %。通过研究溶液中MB浓度随污垢因子的变化，证实了MB在膜外表面的吸附。改进后的PEI- PDMS膜表现出很高的渗透通量和防污性能，是延长膜蒸馏操作的有前途的参数。