scholarly journals Preparation of cellulose nanofiltration membranes and their removal of typical pollutants from drinking water

Author(s):  
Rengui Weng ◽  
Feng Tian ◽  
Xin Huang ◽  
Liufang Ni ◽  
Beidou Xi

Abstract Cellulose membranes have the advantages of good hydrophilicity, excellent mechanical properties, and biodegradability. Therefore, they are the first choice to replace petroleum polymer membranes. In this study, cellulose (BC) and chitosan (CS) were used as raw materials, and N-methylmorpholine-N-oxide (NMMO) was used as solvent. A new kind of cellulose nanofiltration membrane (BC-NFM), cellulose/chitosan nanofiltration membrane (BC/CS-NFM), and interfacial polymerized cellulose/chitosan composite nanofiltration membrane (IP-BC/CS-NFM) were successfully prepared by NaOH hydrolysis and chloroacetic acid carboxymethylation modification, piperazine (PIP), and 1,3,5-trimellitic chloride (TMC) interfacial polymerization, respectively. These two methods were used for the preparation of cellulose nanofiltration membranes for the first time.We also studied their structure, separation performance and their capacity to remove typical pollutants. The results showed that obvious holes appeared on the surface of the nanofiltration membrane obtained by alkali hydrolysis and chloroacetic acid carboxymethylation modification, and the cross-section showed a spongelike structure. The surface of the nanofiltration membrane obtained by interfacial polymerization formed a rough and dense separation layer. The rejection rates of the three kinds of nanofiltration membranes were all over 30% for monovalent salt ions, over 60% for divalent salt ions, over 92% for methyl orange, and over 98% for methyl blue. They had good removal effects for typical pollutants in drinking water.

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 269 ◽  
Author(s):  
Yu-Hsuan Chiao ◽  
Tanmoy Patra ◽  
Micah Belle Marie Yap Ang ◽  
Shu-Ting Chen ◽  
Jorge Almodovar ◽  
...  

Nanofiltration membranes have evolved as a promising solution to tackle the clean water scarcity and wastewater treatment processes with their low energy requirement and environment friendly operating conditions. Thin film composite nanofiltration membranes with high permeability, and excellent antifouling and antibacterial properties are important component for wastewater treatment and clean drinking water production units. In the scope of this study, thin film composite nanofiltration membranes were fabricated using polyacrylonitrile (PAN) support and fast second interfacial polymerization modification methods by grafting polyethylene amine and zwitterionic sulfobutane methacrylate moieties. Chemical and physical alteration in structure of the membranes were characterized using methods like ATR-FTIR spectroscopy, XPS analysis, FESEM and AFM imaging. The effects of second interfacial polymerization to incorporate polyamide layer and ‘ion pair’ characteristics, in terms of water contact angle and surface charge analysis was investigated in correlation with nanofiltration performance. Furthermore, the membrane characteristics in terms of antifouling properties were evaluated using model protein foulants like bovine serum albumin and lysozyme. Antibacterial properties of the modified membranes were investigated using E. coli as model biofoulant. Overall, the effect of second interfacial polymerization without affecting the selectivity layer of nanofiltration membrane for their potential large-scale application was investigated in detail.


Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 2
Author(s):  
Qiang Xue ◽  
Kaisong Zhang

Nanomaterials embedded in nanofiltration membranes have become a promising modification technology to improve separation performance. As a novel representation of two-dimensional (2D) nanomaterials, MXene has nice features with a strong negative charge and excellent hydrophilicity. Our previous research showed that MXene nanosheets were added in the aqueous phase, which enhanced the permeselectivity of the membrane and achieved persistent desalination performance. Embedding the nanomaterials into the polyamide layer through the organic phase can locate the nanomaterials on the upper surface of the polyamide layer, and also prevent the water layer around the hydrophilic nanomaterials from hindering the interfacial polymerization reaction. We supposed that if MXene nanosheets were added in the organic phase, MXene nanosheets would have more negative contact sites on the membrane surface and the crosslinking degree would increase. In this study, MXene were dispersed in the organic phase with the help of ultrasound, then MXene nanocomposite nanofiltration membranes were achieved. The prepared MXene membranes obtained enhanced negative charge and lower effective pore size. In the 28-day persistent desalination test, the Na2SO4 rejection of MXene membrane could reach 98.6%, which showed higher rejection compared with MXene embedded in aqueous phase. The results of a long-time water immersion test showed that MXene membrane could still maintain a high salt rejection after being soaked in water for up to 105 days, which indicated MXene on the membrane surface was stable. Besides MXene membrane showed high rejection for high-concentration brine and good mono/divalent salt separation performance in mono/divalent mixed salt solutions. As a part of the study of MXene in nanofiltration membranes, we hoped this research could provide a theoretical guidance for future research in screening different addition methods and different properties.


RSC Advances ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 2042-2054 ◽  
Author(s):  
Hao Wang ◽  
Zhong Wei ◽  
Heyun Wang ◽  
Haoji Jiang ◽  
Yinchun Li ◽  
...  

Here, an acid stable PSA membrane with positively charge was prepared through the IP between macromolecular PAH and BDSC on PES substrate. In addition, the PSA membrane exhibited excellent separation performance to divalent metal ions.


2021 ◽  
Author(s):  
Lu Bai ◽  
Min Wang ◽  
Hongjun Yang ◽  
Jun Zheng Peng ◽  
Youjing Zhao ◽  
...  

An acid resistance nanofiltration (NF) membrane with higher permeability and rejection is of great significance. NF membrane was prepared by interfacial polymerization under the assistance of surfactants, three different common...


RSC Advances ◽  
2020 ◽  
Vol 10 (27) ◽  
pp. 16168-16178
Author(s):  
Bo Lin ◽  
Huifen Tan ◽  
Wenchao Liu ◽  
Congjie Gao ◽  
Qiaoming Pan

Thin-film composite (TFC) nanofiltration (NF) membranes with zwitterionic striped surface were fabricated via the co-deposition and interfacial polymerization.


2013 ◽  
Vol 427 ◽  
pp. 92-100 ◽  
Author(s):  
Jinming Peng ◽  
Yanlei Su ◽  
Wenjuan Chen ◽  
Xueting Zhao ◽  
Zhongyi Jiang ◽  
...  

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 592
Author(s):  
Yi-Li Lin ◽  
Nai-Yun Zheng ◽  
Yu-Shen Chen

Through interfacial polymerization (IP), a polyamide (PA) layer was synthesized on the top of a commercialized polysulfone substrate to form a thin-film composite (TFC) nanofiltration membrane. Graphene oxide (GO) was dosed during the IP process to modify the NF membrane, termed TFC-GO, to enhance oxidant resistance and membrane performance. TFC-GO exhibited increased surface hydrophilicity, water permeability, salt rejection, removal efficiency of pharmaceutical and personal care products (PPCPs), and H2O2 resistance compared with TFC. When H2O2 exposure was 0–96000 ppm-h, the surfaces of the TFC and TFC-GO membranes were damaged, and swelling was observed using scanning electron microscopy. However, the permeate flux of TFC-GO remained stable, with significantly higher NaCl, MgSO4, and PPCP rejection with increasing H2O2 exposure intensity than TFC, which exhibited a 3.5-fold flux increase with an approximate 50% decrease in salt and PPCP rejection. GO incorporated into a PA layer could react with oxidants to mitigate membrane surface damage and increase the negative charge on the membrane surface, resulting in the enhancement of the electrostatic repulsion of negatively charged PPCPs. This hypothesis was confirmed by the significant decrease in PPCP adsorption onto the surface of TFC-GO compared with TFC. Therefore, TFC-GO membranes exhibited superior water permeability, salt rejection, and PPCP rejection and satisfactory resistance to H2O2, indicating its great potential for practical applications.


Author(s):  
Ming Yan ◽  
Yilin Wu ◽  
Rongxin Lin ◽  
Faguang Ma ◽  
Zhongyi Jiang

Although many researchers have done lots of studies on improving the selective separation performance of membrane materials, conceptions and applications of membrane-based molecular imprinting separation&recognition with both high permselectivity and...


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