scholarly journals Effect of carbon nanotubes loading and pressure on the performance of a polyethersulfone (PES)/carbon nanotubes (CNT) membrane

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mlungisi Martin Ngoma ◽  
Machodi Mathaba ◽  
Kapil Moothi

AbstractThis paper focuses on modifying a PES membrane with acid-functionalised carbon nanotubes (CNT) for industrial wastewater treatment. Embedding acid functionalised carbon nanotubes (CNTs) within the membrane matrix would increase the membrane flux by increasing the membrane pore size and surface area, rejection and thermal stability. Pure PES membranes were prepared by phase inversion method and infused with CNTs at 2.5, 5, 7.5 and 10 wt% loading to fabricate PES/2.5 wt% CNT, PES/5 wt% CNT, PES/7.5 wt% CNT and PES/10 wt% CNT membranes respectively. Characterisation was performed using Transmission Electron Microscopy (TEM) to determine CNT morphology, X-ray Diffraction (XRD) to determine the functional groups attached to CNTs, Thermogravimetric Analysis (TGA) to determine the thermal stability of the membranes, Scanning Electron Microscope (SEM) to determine membrane morphology, Bunauer-Emmett-Teller (BET) method to obtain pore size information and Contact Angle (CA) to determine the membrane hydrophilicity. Membrane performance was then evaluated with a dead-end stirred cell using industrial wastewater containing traces of Cu, Fe, Ni, Zn and Cl. Permeate flux results showed a direct proportion relationship with increasing CNT loading and increasing pressure (100 kPa, 300 kPa, 500 kPa, 700 kPa, 900 kPa and 1100 kPa). PES/5 wt% CNT membrane showed the most enhanced performance compared to the other membranes, achieving reasonably high flux of 43.7 L/m2h and rejection of 89.6% Cu, 100% Fe, 90.5% Ni, 68.8% Zn and 99.99% Cl at 300 kPa. The results obtained showed that the PES membrane embedded with functionalised CNTs could be used for the treatment of industrial wastewater.

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
W. Youravong ◽  
M. Phukdeekhong ◽  
P. Taksinpatanapong

The experiment was carried out to investigate the influence of membrane pore size and hydrophobicity on the quality of clarified pineapple wine and fouling characteristics, using stirred cell dead–end microfiltration. The test membranes were mixed cellulose acetate (MCE, pore size 0.45 and 0.22 μm), modified polyvinylidene fluoride (MPVDF, 0.22 μm) and polyethersulfone (PESF, 0.22 μm). It was found that all types of membrane successfully clarified the pineapple wine. The membrane pore size and hydrophobicity played an importance role in membrane fouling, both reversible and irreversible. Regarding the permeate flux and fouling, 0.45 μm MCE was the most suitable for pineapple wine clarification. However, intensive organoleptic test with pilot scale would be needed.


Membranes ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
Sri Mulyati ◽  
Syawaliah Muchtar ◽  
Mukramah Yusuf ◽  
Nasrul Arahman ◽  
Sofyana Sofyana ◽  
...  

This paper reports the application of silica derived from natural biomasses of rice husk and bagasse ashes as membrane modifying agents. The modification was conducted on poly(ether sulfone) (PES) membrane by blending the silica into the dope solution. The modification was aimed to improve the structure and hydraulic performance of the resulting PES membrane. The effects of silica addition to the membrane system were evaluated through the analysis of change in chemical structure using ATR-FTIR, surface morphological change using AFM, and surface hydrophilicity using water contact angle measurement. SEM and AFM images show the silica loading significantly affects the membranes morphologies. Silica loading also promotes hydrophilic property as shown by the decrease in water contact angles from 82° to 52–60° due to the presence of polar groups in some residual silica in the membrane matrix. Silica blending also leads to the formation of membranes with higher permeability of up to three folds but lower humic acid rejection (78–62%). The findings indicate the role of silica to enhance the membrane pore size. The ability of membrane to reject humic acid (of 0.8 nm minimum diameter) indicating that the resulting membranes were in between tight ultrafiltration and nanofiltration type. Nonetheless, applying too-high silica concentration decreased the humic acid rejection most likely due to over enlargement of the membrane pore size.


2012 ◽  
pp. 217-224 ◽  
Author(s):  
Vesna Vasic ◽  
Marina Sciban ◽  
Aleksandar Jokic ◽  
Jelena Prodanovic ◽  
Dragana Kukic

Stillage is one of the most polluted waste products of the food industry. Beside large volume, the stillage contains high amount of suspended solids, high values of chemical oxygen demand and biological oxygen demand, so it should not be discharged in the nature before previous purification. In this work, three ceramic membranes for microfiltration with different pore sizes were tested for stillage purification in order to find the most suitable membrane for the filtration process. Ceramic membranes with a nominal pore size of 200 nm, 450 nm and 800 nm were used for filtration. The influence of pore size on permeate flux and removal efficiency was investigated. A membrane with the pore size of 200 nm showed the best filtration performance so it was chosen for the microfiltration process.


Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 146 ◽  
Author(s):  
Mora ◽  
Pérez ◽  
Quezada ◽  
Herrera ◽  
Cassano ◽  
...  

The influence of membrane pore size on the permeate flux, fouling mechanism, and rejection of soluble and suspended solids, as well as of phenolics and anthocyanins, in the clarification of grape marc extract by microfiltration (MF) was studied. MF was operated by using three monotubular ceramic membranes with a pore size of 0.14, 0.2, and 0.8 µm, respectively, according to a batch concentration configuration in selected operating conditions (2.25 bar as operating pressure, 4.93 L/min as feed flow rate, and 25 °C as operating temperature). No significant differences in the permeate flux values were appreciated despite the difference in pore size. The mathematical analyses of the flux behavior revealed that intermediate pore blocking is the predominant mechanism for 0.14 and 0.2 µm membranes, whereas complete pore blocking prevails for the 0.8 µm membrane. Differences in the fouling mechanism were associated with differences in the total phenols rejection: the highest rejection was observed for the 0.8 µm membrane followed by 0.2 and 0.14 µm membranes. All selected membranes showed low rejection of sugars, with values lower than 10%, and no retention towards anthocyanins. All the clarified extracts showed a turbidity lower than 4.87 NTU. Based on the experimental results, the 0.14 µm membrane appeared as the best option for the clarification of grape marc extract.


2016 ◽  
Vol 99 (8) ◽  
pp. 6164-6179 ◽  
Author(s):  
Camilla Elise Jørgensen ◽  
Roger K. Abrahamsen ◽  
Elling-Olav Rukke ◽  
Anne-Grethe Johansen ◽  
Reidar B. Schüller ◽  
...  

2001 ◽  
Vol 34 (12) ◽  
pp. 1524-1531 ◽  
Author(s):  
TAKAAKI TANAKA ◽  
YOSHINOBU YAMAGIWA ◽  
TETSUYA NAGANO ◽  
MASAYUKI TANIGUCHI ◽  
KAZUHIRO NAKANISHI

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
A. Laorko ◽  
Z. Li ◽  
W. Youravong ◽  
S. Tongjitpakdee ◽  
S. Chantachum

Coconut water has been considered as a nutritional, refreshing and highly isotonic beverage with delicate aroma and flavor. In food sterilization technique, thermal processing, however tends to reduce these beneficial properties especially estrogen hormone and flavor. To overcome this limitation, this study therefore aimed to clarified and sterilized coconut water using non–thermal processing, membrane filtration. Hollow fiber microfiltration (MF) membrane with pore size of 0.1 and 0.2 μm and ultrafiltration (UF) membrane with molecular weight cut–off (MWCO) of 100 and 30 kDa were used. The effect of membrane pore size and MWCO on quality of clarified juice, permeate flux and fouling were studied. It was found that fresh coconut water and clarified coconut water obtained from MF and UF did not show difference in pH, total soluble solid, reducing sugar, estrogen hormone and minerals including calcium, magnesium, phosphorus, potassium and sodium. The results from microbiological analysis of the clarified coconut water showed that sterilized of coconut water was obtained using either MF or UF membranes. This microbiological quality of clarified coconut water was met the Thai legislation for juice and drinks. The permeate flux of MF was much higher than those of UF while the fouling resistance of UF membrane was much higher than those of MF membrane. The permeate flux of membrane with pore size of 0.1 £gm was slightly lower than that of membrane with pore size of 0.2 μm. The results also indicated that the major fouling of both MF and UF membranes was reversible. The irreversible fouling resistance of 0.1 μm membrane was the lowest and most of this irreversible fouling was external irreversible fouling, formed on the membrane surface. According to these results, it could be concluded that 0.1 μm membrane was the most suitable membrane for clarification and sterilization of coconut water. In addition, the effects of TMP, cross flow velocity (CFV) and the % recovery on permeate flux in batch concentration mode were also studied. It was found that the permeate flux of 0.1 μm membrane was significantly increased with increasing CFV and decreased as % recovery increased. These results suggested that permeate flux during MF of coconut water was dependent on reversible fouling and could be improved by using hydrodynamic modification techniques.


Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 150
Author(s):  
Bushra Khan ◽  
Sajjad Haider ◽  
Rooha Khurram ◽  
Zhan Wang ◽  
Xi Wang

The UF membrane with a narrow and uniform pore size distribution and a low tendency to foul has significant applications in wastewater treatment. A major hindrance in the preparation of the UF membrane with these features is the lack of a scalable and economical membrane fabrication method. Herein, we devise a new strategy to prepare a high-quality polyvinylidene fluoride/polymethyl acrylate/cellulose acetate (PVDF/PMMA/CA) blend UF membrane via a combination of the etching mechanism with the traditional Loeb–Sourirajan (L-S) phase inversion method. Different concentrations of silicon dioxide (SiO2) nanoparticles (NP) in the membrane matrix were etched by using a 0.2 M hydrofluoric acid (HF) solution in a coagulation bath. This strategy provided the membrane with unique features along with a narrow and uniform pore size distribution (0.030 ± 0.005 μm). The etched membrane exhibits an increase of 2.3 times in pure water flux (PWF) and of 6.5 times in permeate flux(PF), with a slight decrease in rejection ratio (93.2% vs. 97%) when compared to than that of the un-etched membrane. Moreover, this membrane displayed outstanding antifouling ability, i.e., a flux recovery ratio (FRR) of 97% for 1000 mg/L bovine serum albumin (BSA) solution, a low irreversible fouling ratio of 0.5%, and highly enhanced hydrophilicity due to the formation of pores/voids throughout the membrane structure. The aforementioned features of the etched membrane indicate that the proposed method of etching SiO2 NP in membrane matrix has a great potential to improve the structure and separation efficiency of a PVDF/PMMA/CA blend membrane.


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