Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

Abstract

Wetting and fouling have significantly affected the application of membrane distillation (MD). In this work, a dip-coating method was used for improving surface hydrophobicity of the polyetherimide (PEI) hollow fiber membrane. An air gap membrane distillation (AGMD) process was applied for treatment of the methylene blue (MB) solution. The porous PEI membrane was fabricated by a dry-wet spinning process and the hydrophobic 2-(Perfluoroalkyl) ethanol (Zonyl® BA) was used as the coating material. From FESEM, the modified PEI-Zonyl membrane showed an open structure with large finger-like cavities. The modified membrane displayed a narrow pore size distribution with mean pore size of 0.028 μm. The outer surface contact angle of the PEI-Zonly membrane increased from 81.3° to 100.4° due to the formation of an ultra-thin coated layer. The pure water flux of the PEI-Zonyl membrane was slightly reduced compared to the pristine PEI membrane. The permeate flux of 6.5 kg/m2 h and MB rejection of 98% was found for the PEI-Zonyl membrane during 76 h of the AGMD operation. Adsorption of MB on the membrane surface was confirmed based on the Langmuir isotherm evaluation, AFM and FESM analysis. The modified PEI-Zonyl membrane can be a favorable alternative for AGMD of dyeing wastewaters.

Oily wastewater treatment by blend polyether imide‐sulfonated poly (ether ether keton) hollow fibre membrane through a side‐stream MBR process

“…Generally, for fabrication of hollow fibre membranes, using a weak nonsolvent bore fluid results in a delay phase‐inversion from the bore side and produces inner skinless layer. A similar inner surface structure was also reported for the PEI hollow fibre membranes prepared by a mixture of NMP/H 2 O 70/30 as the bore fluid (Mousavi et al, 2021b). This structure is favourable for minimizing the membrane resistance and improving the water flux.…”

Hydrophobic Modification of Polyetherimide Hollow Fiber Membrane Contactor by 2-(Perfluoroalkyl) Ethanol Coating for Carbon Dioxide Absorption

“…In order to prepare a highly porous PEI hollow fiber membrane, composition of the polymer dope was adjusted as PEI/glycerol/NMP 14/4/82 wt% according to our previous study [14]. The homogeneous PEI dope was prepared under a continuous stirring at 60 °C for 12 h. Prior to spinning hollow fiber membranes, the polymer dope was de-bubbled by an ultrasonic bath (15 min) at temperature of 60 °C.…”

“…The homogeneous PEI dope was prepared under a continuous stirring at 60 °C for 12 h. Prior to spinning hollow fiber membranes, the polymer dope was de-bubbled by an ultrasonic bath (15 min) at temperature of 60 °C. The hollow fiber membranes were fabricated by a dry-wet spinning process using constant spinning conditions [14] and then they were immersed in distilled water for 3 days to remove residual NMP and glycerol. The membranes were immersed in pure ethanol for 15 min to minimize shrinkage and pores collapse during drying at room temperature.…”

“…A dip-coating process was applied for surface modification of the dry hollow fiber membranes. The coating solution was prepared by dissolution of 2 wt% Zonyl in acetone according to our previous study [14]. Then, the dead ends hollow fibers were immersed in the coating solution for 30 min to form an ultra-thin layer on the outer surface.…”

State-of-the-Art Organic- and Inorganic-Based Hollow Fiber Membranes in Liquid and Gas Applications: Looking Back and Beyond

“…A surge of interest in developing polymeric hollow fiber membranes has been witnessed in the past few decades. Examples of polymers reported include polysulfone (PSF) [ 80 , 81 , 82 , 83 ], polyethersulfone (PES) [ 84 , 85 , 86 , 87 ], cellulose acetate [ 88 , 89 , 90 ], polyimide [ 91 , 92 , 93 , 94 ], polyetherimide [ 95 , 96 , 97 , 98 ], polycarbonate (PC) [ 99 , 100 ], polyvinylidene fluoride (PVDF) [ 83 , 86 , 101 , 102 , 103 , 104 , 105 , 106 , 107 ], and polybenzimidazole (PBI) [ 108 , 109 ]. The fabrication of polymeric hollow fiber membranes follows the common practice mentioned previously, which often includes a post-treatment such as silicon rubber coating to seal the defects on hollow fiber membranes for superior separation performance [ 110 ].…”