Thin film composite membranes containing intrinsic CD cavities in the selective layer

Second interfacial polymerization of thin‐film composite hollow fibers with amine‐cyclodextrins for pervaporation dehydration

“…As shown in Figure 1a, compared to the spectrum of β ‐CD, the new characteristic peaks observed in the spectra of amine‐CDs at 1463 and 2833 cm −1 belong to CH bending and stretching vibrations of the methylene groups in ECH, EDA, and TAEA, respectively, 43 validating the successful modification of β ‐CD as expected. In addition, the presence of NH 2 + /NH 3 + (primary/secondary amine salts) groups in amine‐CDs is indicated by the appearance of the strong absorption peak in the range of 3000–2600 cm −1 43 . This result shows the existence of some amine groups in amine‐CDs in the form of the amine salt, by adjusting the pH of amine‐CDs solution with sulfuric acid.…”

“…48, 49 Figure 2 shows that peaks of amide III band of selective layers with SIP modification by amine‐CDs are distinctly stronger than those in PA‐control and PA‐ β ‐CD selective layers, suggesting that amine‐CDs react successfully with acyl chloride groups to form more amide groups. Since the hydroxyl groups in β ‐CD and amine‐CDs can also react with chloride groups during SIP process, the characteristic peak of CO stretching of the formed ester groups in SIP‐modified selective layer should exist at around 1720 cm −1 theoretically, 43 which is however invisible in Figure 2, probably because the ester characteristic peak with the weak intensity is overlapped by strong peak of amide I band, implying the much lower reaction degree between hydroxyl and acyl chloride groups than that between amide and acyl chloride groups.…”

“…Amine‐CDs were synthesized in simple and mild conditions, according to our previous work 43 . Firstly, 8.1 g β ‐CD (0.007 mol) and 6.7 g KOH (0.12 mol) were dissolved in an aqueous solution and stirred continuously at 50°C.…”

“…TFC membrane prepared by β ‐CD as IP monomer was also investigated as a loose NF membrane to precisely discriminate solvents and dyes with different 3D sizes 41 . In our previous works, amine‐functionalized cyclodextrin (amine‐CDs) with better reactivity were further synthesized and employed them as IP monomers to fabricate the novel TFC FO and NF membranes, 42,43 which enable the fast permeation of water molecules through nanocavities of β ‐CD but restrict the transport of larger ions or molecules.…”

Dopamine incorporating forward osmosis membranes with enhanced selectivity and antifouling properties

“…[19][20][21][22][23] However, the low water ux and membrane fouling are still two key problems in FO. 18,[24][25][26][27][28] Water molecules have to pass through the active layer, thus the thickness and hydrophilicity changes in membranes can make water transport faster by reducing the mass transfer resistance. It has been reported that the thinner and more hydrophilic polyamide layer improves the water permeability and anti-fouling property of the TFC membrane.…”