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1. Hollow fiber gas membrane-based removal and recovery of ammonia from water in three different scales and types of modules

   https://doi.org/https://doi.org/10.1016/j.seppur.2019.04.074  

   Philip A. Aligwe, Kamalesh K. ( April 2019 , Separation and purification technology)

   Ammonia present in many industrial process streams and effluent streams is beginning to be recovered by means of microporous hydrophobic hollow fiber-based membrane contactor devices with gas-filled pores; the process is often characterized as supported gas membrane (SGM) process. Ammonium sulfate is usually obtained in a sulfuric acid stream on the other side of the membrane. It is useful to develop a quantitative basis for the extent of ammonia removal in such devices. Unlike deoxygenation of aqueous streams in such devices, membrane resistance is quite important for ammonia transport. Ammonia transport modeling in such devices is hampered by the complexity of feed liquid flow in the shell side of commercially used devices and lack of information on membrane resistance where membrane tortuosity introduces considerable uncertainty. The approach adopted here involves studying ammonia transport with the feed solution flowing through the hollow fiber bore where the fluid mechanics is simpler than shell-side flows. Comparison of model-based predictions of overall mass transfer coefficient (ko) with experimentally observed values allows estimation of the membrane mass transfer coefficient (km). One can use such estimates of km to model the observed ammonia transport in small crossflow devices and develop an empirical guidance of the dependences of the shell side mass transfer correlations. Guided by such information and deoxygenation SGM literature, a model was developed for large modules used for ammonia recovery via SGM. Model predictions of performances of the large modules are likely to be useful for various process considerations including the effect of temperature and feed flow rate variations on ammonia removal. 

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2. Hollow fiber membrane supported metal organic framework-based packed bed for gas/vapor adsorption

   https://doi.org/10.1016/j.cej.2022.140228  

   Song, Yufeng ; Sirkar, Kamalesh K. ( February 2023 , Chemical Engineering Journal)
3. Biofilms Benefiting Plants Exposed to ZnO and CuO Nanoparticles Studied with a Root-Mimetic Hollow Fiber Membrane

   https://doi.org/10.1021/acs.jafc.7b02524  

   Bonebrake, Michelle ; Anderson, Kaitlyn ; Valiente, Jonathan ; Jacobson, Astrid ; McLean, Joan E. ; Anderson, Anne ; Britt, David W. ( May 2017 , Journal of Agricultural and Food Chemistry)
4. Performance Comparison between Polyvinylidene Fluoride and Polytetrafluoroethylene Hollow Fiber Membranes for Direct Contact Membrane Distillation

   https://doi.org/10.3390/membranes9040052  

   Huang, Frank Y. ; Arning, Allie ( April 2019 , Membranes)

   Increasing water demand coupled with projected climate change puts the Southwestern United States at the highest risk of water sustainability by 2050. Membrane distillation offers a unique opportunity to utilize the substantial, but largely untapped geothermal brackish groundwater for desalination to lessen the stress. Two types of hydrophobic, microporous hollow fiber membranes (HFMs), including polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), were evaluated for their effectiveness in direct contact membrane distillation (DCMD). Water flux and salt rejection were measured as a function of module packing density and length in lab-scale systems. The PVDF HFMs generally exhibited higher water flux than the PTFE HFMs possibly due to thinner membrane wall and higher porosity. As the packing density or module length increased, water flux declined. The water production rate per module, however, increased due to the larger membrane surface area. A pilot-scale DCMD system was deployed to the 2nd largest geothermally-heated greenhouse in the United States for field testing over a duration of about 22 days. The results demonstrated the robustness of the DCMD system in the face of environmental fluctuation at the facility. 

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5. Antifouling UV-treated GO/PES hollow fiber membranes in a membrane bioreactor (MBR)

   https://doi.org/10.1039/c9ew00217k  

   Fathizadeh, Mahdi ; Xu, Weiwei L. ; Shen, Margaret ; Jeng, Emily ; Zhou, Fanglei ; Dong, Qiaobei ; Behera, Dinesh ; Song, Zhuonan ; Wang, Lei ; Shakouri, Abolfazl ; et al ( June 2019 , Environmental Science: Water Research & Technology)

   Single layer graphene oxide (SLGO) was studied as a novel coating material to drastically improve the antifouling performance of polyether sulfone (PES) hollow fiber (HF) membranes in membrane bioreactor (MBR) application. By selectively modifying the membrane surface, only a small amount of SLGO coating (6.2 mg m −2 ) was needed to achieve acceptable membrane performance. The UV treatment of the SLGO coating further assisted in improving the antifouling properties of the as-prepared PES HF membranes. By comparing the transmembrane pressure of pristine PES HF and PES_GO 6.20_ UV X (X = 0–1.5 h) membranes in a MBR for wastewater treatment at a fixed water flux, the PES_GO 6.20_ UV 1.0 membrane coated with 1 h UV-treated SLGO was demonstrated to substantially relieve the bio-fouling problem. To understand the influence of SLGO modification on membrane performance, FESEM, ATR-FTIR, and AFM analyses were conducted to characterize the as-prepared membranes, and the SLGO deposition mechanism was also proposed in this study. 

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