Preparation of supported carbon molecular sieve membrane from novolac phenol–formaldehyde resin

Wei, Wei; Qin, Guotong; Hu, Haoquan; You, Longbo; Chen, Guohua

doi:10.1016/j.memsci.2007.06.055

Cited by 77 publications

(33 citation statements)

References 26 publications

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“…Subsequently, a variety of precursor materials were used to prepare carbon membranes, including derivatives of polyimides [12,13], polyfurfuryl alcohol (PFFA) [14], phenolic resins [15][16][17][18], polyacylonitrile [19], and polymers of intrinsic microporosity (PIM) [20]. Carbon membranes have been extensively developed for gas separation, though also investigated for liquid separation including oil/water [21], desalination [22], de-colorization of coke furnace wastewater [23], pervaporation of azeotropic benzene-cyclohexane mixtures [24], oil and water separation [25] and separation of chromium (VI) in ultrafiltration of water solutions [26] as representative examples.…”

Section: Introductionmentioning

confidence: 99%

Vacuum-assisted tailoring of pore structures of phenolic resin derived carbon membranes

Jalil

Wang²,

Yacou

et al. 2017

Journal of Membrane Science

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This work shows the preparation and separation performance assessment of carbon membranes derived from phenolic resin by a vacuum-assisted method and carbonisation in an inert atmosphere.The vacuum time played an important role in tailoring the structure of the membranes. For instance, pore volumes and surface areas increased from 0.81 and 834 to 2.2 cm 3 g -1 and 1910 m 2 g -1 , respectively, as the vacuum time exposure increased from 0 to 1200 s. The significant structural changes correlated very well with water permeation, as fluxes increased by 91% as the vacuum time increased from 0 to 1200s, reaching up to 169 kg m -2 h -1 at 5 bar. Molecular weight cut-off tests showed no rejection for the smaller glucose and sucrose molecules, though this increased to ~ 80% and full rejection for 36kD and 400kD polyvinyl pyrrolidine. Interestingly, FTIR spectra showed that the peaks of C-H stretching vibration (2800-3200 cm -1 ) and C-O stretching (1030 cm -1 ) became more pronounced as a function of increasing vacuum time, strongly suggesting that the use of vacuum further assisted in the polycondensation of phenolic oligomers. Based on these outcomes, a cluster to cluster model is proposed, whereby vacuum application promoted crosslinking reactions of the phenolic resin, creating microporous regions within the clusters, and mesoporous regions between the clusters. 2 Graphical AbstractKeywords: carbon membranes; vacuum-assisted method; water; molecular weight cut-off.

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Section: Introductionmentioning

confidence: 99%

Vacuum-assisted tailoring of pore structures of phenolic resin derived carbon membranes

Jalil

Wang²,

Yacou

et al. 2017

Journal of Membrane Science

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“…Therefore, the characteristics of polymer precursor and carbonisation process affect the structure and performance of CMS membranes. There is an array of polymers that have been employed for the preparation of CMS membranes including phenolic resin [1][2][3][4][5][6][7], polyimide (PI) [8][9][10][11][12][13][14][15][16][17], polyfurfuryl alcohol [18,19], poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) [20] and poly (phthalazinone ether sulfone ketone) (PPESK) [21]. In addition, carbon templates such as triblock copolymers [22] and surfactant hexyltriethylammonium bromide (C6) [23] have been embedded and carbonised in silica films as molecular sieve structures for desalination and gas separation.…”

Section: Introductionmentioning

confidence: 99%

Fine ultra-micropore control using the intrinsic viscosity of precursors for high performance carbon molecular sieve membranes

Qin

Cao

Wen

et al. 2017

Separation and Purification Technology

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Please cite this article as: G. Qin, X. Cao, H. Wen, WeiWei, J.C. Diniz da Costa, Fine ultra-micropore control using the intrinsic viscosity of precursors for high performance carbon molecular sieve membranes, Separation and Purification Technology (2016), doi: http://dx.doi.org/10.1016/j.seppur. 2016.12.047 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Fine ultra-micropore control using the intrinsic viscosity of precursors for high performance carbon molecular sieve membranes AbstractHere we report the permeability and separation performance of self-standing carbon molecular sieve (CMS) membranes formed by pyrolysis of polyimide (PI) precursors derived from poly(amic acid) (PAA) with varying intrinsic viscosity. CMS resulted in ultra-microporous membranes showing a classical molecular sieving structure as gas permeation was high for smaller molecular gas (H 2 ), which then decreased sequentially as the molecular sizes increased in the order of CO 2 , O 2 and N 2 . An important relationship was found when the intrinsic viscosity of the PAA precursor decreased from 1.66 to 0.65 dl g -1 , the ideal gas selectivity jumped to higher values such as from 101.8 to 163.1 for H 2 /N 2 , from 21.5 to 34.6 for CO 2 /N 2 and from 6.7 to 10.7 for O 2 /N 2 while the permeability decreased such as from 1816 to 1487 Barrer for H 2 , from 383.4 to 314.8 Barrer for CO 2 , from 119.0 to 97.7 Barrer for O 2 , from 17.8 to 9.1 Barrer for N 2 . The low intrinsic viscosity conferred a superior pore size control of the CMS structure, with an average ultramicropore size around 3Å. The O 2 /N 2 and H 2 /N 2 ideal selectivity versus permeability results were all above the Robeson's upper bound line, thus demonstrating the effect of low intrinsic viscosity precursors in  Corresponding author. E-mail: qingt@buaa.edu.cn (Guotong Qin); Tel +86-10 82338556 the synthesis of high performance CMS membranes.

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“…Hence, the Resole resin was no longer considered and this thesis focused entirely on the Novolac resin. The Novolac resin is a linear chain condensation product (Wei, Qin et al 2007). As shown in Figure 4.1, the phenol units are mainly linked by methylene groups and contain 10-20 phenol units, with a molecular weight in the low thousands.…”

Section: Materials and Characterisationmentioning

confidence: 99%

“…CMSs have been derived from different precursors, including the pyrolysis of polymeric materials such as polyfurfuryl alcohol (PFA) , polyvinylidene chloride (PVDC) , polyimides , and phenolic resin Wei, Hu et al 2002;Zhang, Hu et al 2006;Wei, Qin et al 2007;Zhang, Hu et al 2007;Gun'ko, Kozynchenko et al 2008;Teixeira, Campo et al 2011). The organic precursor and the pyrolisation process deliver carbon with different structures and functionalities.…”

Section: Introductionmentioning

confidence: 99%

Carbon molecular sieve membranes for desalination

Song¹

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i This work reports on the development of novel carbon molecular sieve (CMS) membranes for desalination. The membranes were prepared by vacuum impregnation of precursor solutions containing phenolic resin into porous alumina tubes. Subsequently, the membrane tubes were calcined in an inert atmosphere, leading to the carbonisation of the resin impregnated into the porous alumina substrate. A systematic and parametric study was undertaken to investigate the effect of: (i) substrate porosity, (ii) precursor solution, (iii) vacuum impregnation time and (iv) carbonisation temperature on the performance of the resultant membranes. AbstractHigh quality CMS membranes were successfully prepared. High water fluxes were achieved using a pervaporation setup with values of 27 kg m -2 h -1 observed at 75 °C whilst delivering salt rejection in excess of 96% for a synthetic aqueous solution of 0.3 wt% NaCl chosen to represent brackish water. Increasing the salt concentration resulted in the water flux reducing, which was most likely due to salt concentration polarisation. However, the CMS membranes continued to perform well for processing sea water (3.5 wt% NaCl) at room temperature delivering water fluxes in the region of 9.4 kg m -2 h -1 with a salt rejection close to 100%. The high performance given by the CMS membranes in terms of water fluxes are at least one order of magnitude higher than those reported for other inorganic membranes derived from silica or zeolites.One important finding of this work is that the water flux increased by a factor of 70 as the concentration of the phenolic resin precursor solution decreased from 40 to 1 wt%. This result indicates that high resin concentration led to a higher amount of carbonised resin in the porous substrate and a higher resistance to water diffusion. The precursor solutions with a low resin concentration allowed for the formation of ideal CMS structures, which polymerised into the interparticle pore domains of the porous alumina substrate. As such a molecular sieving structure was formed as it preferentially allowed for the diffusion of the smaller molecule water with a kinetic diameter of 2.6 Å, and to a higher degree rejected the passage of hydrated ions with sizes in excess of 7 Å.A second important finding is that the functionality of the carbonised resin plays a role in delivering CMS membranes with high performance. CMS materials carbonised at 500 °C still retained some functional aromatic groups which were hydrophilic and impacted on membrane performance.However, increasing the carbonisation temperature to 700 °C lead to optimal microporosity, enhanced surface area and reduced hydrophilicity as the functional groups were almost completely ii removed. Further increases of carbonisation temperature to 800 °C resulted in the formation of larger, mesoporous structures and the unfavourable reduction of salt rejection.A third important finding is that best CMS membranes were prepared by longer vacuum times of 300 to 600 s, instead of short times of 30 or 60 s. This result wa...

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Preparation of supported carbon molecular sieve membrane from novolac phenol–formaldehyde resin

Cited by 77 publications

References 26 publications

Vacuum-assisted tailoring of pore structures of phenolic resin derived carbon membranes

Vacuum-assisted tailoring of pore structures of phenolic resin derived carbon membranes

Fine ultra-micropore control using the intrinsic viscosity of precursors for high performance carbon molecular sieve membranes

Carbon molecular sieve membranes for desalination

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