scholarly journals Chemical Enhanced Backwashing for Controlling Organic Fouling in Drinking Water Treatment Using a Novel Hollow-Fiber Polyacrylonitrile Nanofiltration Membrane

2021 ◽  
Vol 11 (15) ◽  
pp. 6764
Author(s):  
Heejin Kim ◽  
Intae Shim ◽  
Min Zhan

A novel polyacrylonitrile (PAN)-based ultrafiltration (UF) hollow-fiber membrane was newly synthesized for nanofiltration (NF) applications. This semi-fully NF hollow-fiber membrane was characterized using a variety of analysis techniques. The membrane exhibited higher negative charge and hydrophilicity and lower surface roughness compared to the pristine UF hollow-fiber membrane. Experiments to study the performance and fouling were simulated under laboratory conditions in a cross-flow system and in–out mode using organic compounds, namely, humic acid and sodium alginate. The removal efficiencies of humic acid and sodium alginate were 65% and 73%, respectively, in the pristine hollow-fiber membrane and 93% and 95%, respectively, in the proposed membrane. The flux decline by natural organic matter was less in the case of the proposed membrane compared to that in the pristine membrane. To mitigate organic fouling on the proposed membrane, sodium hypochlorite (NaClO) was used as a chemical enhanced backwashing agent. At a NaClO concentration of 1 mg/L with a backwashing time of 30 s, an optimal flux recovery of 92.1% of the initial permeability of the PAN-NF hollow-fiber membrane was achieved with less membrane degradation. The results of this study will provide practical insight and act as a technical guide for NF-based plant engineers/operators.

AIChE Journal ◽  
2010 ◽  
Vol 57 (7) ◽  
pp. 1780-1795 ◽  
Author(s):  
Hanyong Lee ◽  
Fei He ◽  
Liming Song ◽  
Jack Gilron ◽  
Kamalesh K. Sirkar

2018 ◽  
Vol 96 (12) ◽  
pp. 1272-1287 ◽  
Author(s):  
Mustafa Usta ◽  
Michael Morabito ◽  
Mohammed Alrehili ◽  
Alaa Hakim ◽  
Alparslan Oztekin

Hollow fiber membrane (HFM) modules are among the most common separation devices employed in membrane separation applications. Three-dimensional steady-state computational fluid dynamics (CFD) simulations are carried out to study flow past hollow fiber membrane banks (HFMB). The current study investigates the effects of flow behavior on membrane performance during binary mixture separations. Carbon dioxide (CO2) removal from methane (CH4) is examined for various arrangements of HFMs in staggered and inline configurations. The common HFM module arrangement is the axial flow configuration. However, this work focuses on the radial cross-flow configuration. The HFM surface is a functional boundary where the suction rate and concentration of each species are coupled and are functions of the local partial pressures, the permeability, and the selectivity of the HFM. CFD simulations employed the turbulent k–ω shear stress transport (SST) model to study HFM performance for Reynolds numbers, 200 ≤ Re ≤ 1000. The efficiency of the inline and staggered arrangements in the separation module is evaluated by the coefficient of performance and the rate of mass flow per unit area of CO2 passing across the membrane surface. This work demonstrates that the module with staggered arrangement outperforms the module with the inline arrangement.


Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1207 ◽  
Author(s):  
Nasrul Arahman ◽  
Suffriandy Satria ◽  
Fachrul Razi ◽  
M. Bilad

The efforts to improve the stability of membrane filtration in applications for wastewater treatment or the purification of drinking water still dominate the research in the field of membrane technology. Various factors that cause membrane fouling have been explored to find the solution for improving the stability of the filtration and prolong membrane lifetime. The present work explains the filtration performance of a hollow fiber membrane that is fabricated from polyethersulfone-2-(methacryloyloxy) ethyl phosphorylchloline while using a sodium alginate (SA) feed solution. The filtration process is designed in a pressure driven cross-flow module using a single piece hollow fiber membrane in a flow of outside-inside We investigate the effect of Ca and Mg ions in SA solution on the relative permeability, membrane resistance, cake resistance, and cake formation on the membrane surface. Furthermore, the performance of membrane filtration is predicted while using mathematical models that were developed based on Darcy’s law. Results show that the presence of Ca ions in SA solution has the most prominent effect on the formation of a cake layer. The formed cake layer has a significant effect in lowering relative permeability. The developed models have a good fit with the experimental data for pure water filtration with R2 values between 0.9200 and 0.9999. When treating SA solutions, the developed models fit well with experimental with the best model (Model I) shows R2 of 0.9998, 0.9999, and 0.9994 for SA, SA + Ca, and SA + Mg feeds, respectively.


2007 ◽  
Vol 7 (4) ◽  
pp. 95-101
Author(s):  
Hyun-je Oh ◽  
June-Seok Choi ◽  
Byong-Bo Choi ◽  
Sangho Lee ◽  
Tae-Mun Hwang

Understanding the fouling phenomena in submerged membrane systems is challenging because the efficiency of hollow fiber membrane highly depends on the dimensions of the fibers as well as filtration conditions. Thus, modeling filtration behavior of hollow fibers is important for improving the performance of hollow fiber system. In this work, a theoretical model based on critical flux concept was developed to simulate filtration resistance and axial pressure drop along the fiber in drinking water treatment. The application of a model for experimental data indicated that the model matches the experiments quite well. Thus, simulation of membrane system was carried out under various conditions using the parameters from the model fit. The axial distribution of pressure and flux affect the filtration characteristics of hollow fiber membranes. The effect of model parameters (specific cake resistance and critical flux) and module geometry were theoretically also investigated using the model.


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