Jianqiang Meng

The membrane aerated biofilm reactor (MABR) is a novel wastewater treatment technology that combines biofilm technology and gas separation membrane technology. The hollow fiber (HF) composite membrane combines the benefits of a porous membrane with those of a dense membrane, which shows promise in the development of robust aerators. Polydimethylsiloxane (PDMS) emerges as an ideal membrane material for MABR processes. However, a few papers have reported the continuous fabrication of PDMS HF composite membrane. In this work, the continuous fabrication of the PDMS/polysulfone (PSF) HF composite membrane for MABR was first presented by thermal curing process. A series of curing parameters for the PDMS were determined by fabricating PDMS/PSF flat sheet composite membranes. The coatability of the PDMS coating solution stored at low temperatures was also investigated. In the continuous fabrication of PDMS/PSF HF composite membranes, it was found that glycerol, used as a pre‐wetting agent, caused defects, which were related to the special structure of the HF membrane. Consequently, the strategy of filling the membrane pores with a glycerol aqueous solution and then removing the water prevents the PDMS coating solution from intruding the membrane pores in the support layer, thus continuously preparing the defect‐free PDMS/PSF HF composite membrane. Furthermore, the interfacial adhesion between the PDMS layer and the PSF support was improved by optimizing the extraction time to control the depth of pore intrusion. In this paper, a PDMS/PSF HF composite membrane with a burst pressure of more than 200 kPa, an O ₂ permeance of about 20–40 GPU, an O ₂ /N ₂ selectivity of about 2.1 and an oxygen transfer rate (OTR) of 5.6 g/m ² d was successfully prepared. The PDMS/PSF HF composite membrane demonstrated considerable potential for OTR (oxygen transfer rate) and great potential for the application of MABR.

Directionally solidified eutectic ceramic (DSEC) Al ₂ O ₃ /YAG is fabricated with the high frequency induction heated vertical Bridgman method. The evolutions of the microstructure and the mechanical properties are investigated during a long term heat treatment at 1500°C for 100–300 h for the DSEC samples grown at different growth rates (10–30 mm/h). The results show that the eutectic maintains the two‐phase Al ₂ O ₃ and YAG microstructure after the heat treatment. The eutectic spacing increases significantly with the heat treatment time for all the DSECs, and the higher the growth rate at which the sample is grown, the more pronounced the microstructure coarsening. The eutectic spacing of DSEC Al ₂ O ₃ /YAG grown at 30 mm/h HAY(30) increases by 33.4%, much higher than 7.55% by which HAY(10) grown at 10 mm/h. The hardness and fracture toughness of HAY(10) decrease by only 3.6% and 12.7%, respectively, whereas those of HAY(30) decrease by 9.05% and 21.5%, respectively. The samples grown at lower rates exhibit a better thermal stability. Furthermore, the coarsening‐kinetics analysis indicates that the coarsening of Al ₂ O ₃ /YAG DSEC follows a diffusion‐controlled Ostwald ripening mechanism, governed primarily by the interfacial diffusion at the early stage, transitioning to the volume diffusion at the later stage.

Hydrophobic charge‐induced chromatography (HCIC) membrane adsorbers are cost‐effective for IgG separation but have limited adsorption capacity. Based on the nanofiber membrane, an HCIC nanofiber membrane adsorber with a high specific surface area was prepared by gel modification of the fiber surface. The regenerated cellulose (RC) nanofiber membrane obtained by electrospinning, thermal crosslinking, and deacetylation reaction was modified via cationic ring‐opening polymerization (CROP) of polyethylene glycol diglycidyl ether (PEGDE), followed by epoxy ring‐opening with 2‐mercaptobenzimidazole (MBI) to prepare the HCIC nanofiber membrane adsorber (HCIC‐g‐MBI). Successful preparation of the HCIC membrane adsorber was confirmed by SEM, FTIR, and XPS analyses. The HCIC membrane adsorber had a static adsorption capacity of 252 mg/g for human immunoglobulin G (IgG) under pH 7 and 0.8 mol/L Na ₂ SO ₄ conditions in PBS buffer. At pH 3, the recovery of IgG reached 91%, which showed a high recovery efficiency. These results indicated that the HCIC nanofiber membrane adsorber could be used in antibody purification.