scholarly journals New insights into the organic fouling mechanism of an in situ Ca2+ modified thin film composite forward osmosis membrane

RSC Advances ◽  
2019 ◽  
Vol 9 (65) ◽  
pp. 38227-38234 ◽  
Author(s):  
Xiujuan Hao ◽  
Shanshan Gao ◽  
Jiayu Tian ◽  
Songxue Wang ◽  
Huizhong Zhang ◽  
...  

In this study, the effect of organic substances on the fouling behavior of a thin film composite (TFC) membrane with in situ Ca2+ addition (TFC-Ca membrane) was evaluated.

2013 ◽  
Vol 47 (21) ◽  
pp. 12219-12228 ◽  
Author(s):  
Xinglin Lu ◽  
Santiago Romero-Vargas Castrillón ◽  
Devin L. Shaffer ◽  
Jun Ma ◽  
Menachem Elimelech

Membranes ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 115
Author(s):  
Youngpil Chun ◽  
Kwanho Jeong ◽  
Kyung Hwa Cho

This study investigated the influence of combined organic fouling and inorganic scaling on the flux and fouling behaviors of thin-film composite (TFC) forward osmosis (FO) membranes. Two organic macromolecules, namely, bovine serum albumin (BSA) and sodium alginate (SA), and gypsum (GS), as an inorganic scaling agent, were selected as model foulants. It was found that GS scaling alone caused the most severe flux decline. When a mixture of organic and inorganic foulants was employed, the flux decline was retarded, compared with when the filtration was performed with only the inorganic scaling agent (GS). The early onset of the conditioning layer formation, which was due to the organics, was probably the underlying mechanism for this inhibitory phenomenon, which had suppressed the deposition and growth of the GS crystals. Although the combined fouling resulted in less flux decline, compared with GS scaling alone, the concoction of SA and GS resulted in more fouling and flux decline, compared with the mixture of BSA and GS. This was because of the carboxyl acidity of the alginate, which attracted calcium ions and formed an intermolecular bridge.


Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 70 ◽  
Author(s):  
Ralph Gonzales ◽  
Myoung Park ◽  
Leonard Tijing ◽  
Dong Han ◽  
Sherub Phuntsho ◽  
...  

Electrospun nanofiber-supported thin film composite membranes are among the most promising membranes for seawater desalination via forward osmosis. In this study, a high-performance electrospun polyvinylidenefluoride (PVDF) nanofiber-supported thin film composite (TFC) membrane was successfully fabricated after molecular layer-by-layer polyelectrolyte deposition. Negatively-charged electrospun polyacrylic acid (PAA) nanofibers were deposited on electrospun PVDF nanofibers to form a support layer consisted of PVDF and PAA nanofibers. This resulted to a more hydrophilic support compared to the plain PVDF nanofiber support. The PVDF-PAA nanofiber support then underwent a layer-by-layer deposition of polyethylenimine (PEI) and PAA to form a polyelectrolyte layer on the nanofiber surface prior to interfacial polymerization, which forms the selective polyamide layer of TFC membranes. The resultant PVDF-LbL TFC membrane exhibited enhanced hydrophilicity and porosity, without sacrificing mechanical strength. As a result, it showed high pure water permeability and low structural parameter values of 4.12 L m−2 h−1 bar−1 and 221 µm, respectively, significantly better compared to commercial FO membrane. Layer-by-layer deposition of polyelectrolyte is therefore a useful and practical modification method for fabrication of high performance nanofiber-supported TFC membrane.


2015 ◽  
Vol 49 (3) ◽  
pp. 1436-1444 ◽  
Author(s):  
Xinglin Lu ◽  
Laura H. Arias Chavez ◽  
Santiago Romero-Vargas Castrillón ◽  
Jun Ma ◽  
Menachem Elimelech

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 260 ◽  
Author(s):  
Yuanyuan Tang ◽  
Shan Li ◽  
Jia Xu ◽  
Congjie Gao

This study reported a series of thin film composite (TFC) membranes with single-walled nanotubes (SWCNTs) interlayers for the forward osmosis (FO) application. Pure SWCNTs with ultrahigh length-to-diameter ratio and without any functional group were applied to form an interconnect network interlayer via strong π-π interactions. Compared to the TFC membrane without SWCNTs interlayer, our TFC membrane with optimal SWCNTs interlayer exhibited more than three times the water permeability (A) of 3.3 L m−2h−1bar−1 in RO mode with 500 mg L−1 NaCl as feed solution and nearly three-fold higher FO water flux of 62.8 L m−2 h−1 in FO mode with the deionized water as feed solution and 1 M NaCl as draw solution. Meanwhile, the TFC membrane with SWCNTs interlayer exhibited significantly reduced membrane structure parameters (S) to immensely mitigate the effect of internal concentration polarization (ICP) in support layer with micro-sized pores in favor of higher water flux. It showed that the pure SWCNTs interlayer could be an effective strategy to apply in FO membranes.


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