New RO TFC Membranes by Interfacial Polymerization in n-Dodecane with Various co-Solvents

Abstract

The objective of this research is to prepare and characterize a new and highly efficient polyamide TFC RO membrane by interfacial polymerization in dodecane solvent mixed with co-solvents. Three co-solvents were tested namely; acetone, ethyl acetate, and diethyl ether of concentration of 0.5, 1, 2, 3, and 5 wt %. The modified membranes were characterized by SEM, EDX, AFM and contact angle techniques. The results showed that addition of co-solvent results in a decrease in the roughness, pore size and thickness of the produced membranes. However, as the concentration of the co-solvent increases the pore size of the membranes gets larger. Among the three co-solvents tested, acetone was found to result in membranes with the largest pore size and contact angle followed by diethyl ether then ethyl acetate. Measured contact angle increases as the concentration of the co-solvent increases reaching a constant value except for ethyl acetate where it was found to drop. Investigating flux and salt rejection by the formulated membranes showed that higher flux was attained when acetone was used as a co-solvent followed by diethyl ether then ethyl acetate. However, the highest salt rejection was achieved with diethyl ether.

Polyimide thin film composite (TFC) membranes via interfacial polymerization on hydrolyzed polyacrylonitrile support for solvent resistant nanofiltration

“…7E and F. The addition of acetone as co-solvent could adjust the morphology of the composite membranes, 42 leading to the appearance of larger ridge-valley structure and the increase of the pore size on the outermost layer. 43 However, the membrane could still maintain a high dye rejection with a slight increase of permeance, as shown in Fig. 5, revealing that the pores were not through-holes and there was a dense separation layer inside the skin porous layer.…”

“…However, when the acetone concentration increased higher than 0.25 wt%, the skin layer formed in the IP reaction zone would become loose gradually due to the extension of the narrow miscible zone, causing the formation of larger pores on the membrane surface and the decrease of the densication of the skin layer. [41][42][43] Thus it resulted in the decrease of both Na 2 SO 4 and CBBG250 rejections. As depicted in Fig.…”

Constructing highly rough skin layer of thin film (nano)composite polyamide membranes to enhance separation performance: A review

“…The reactive monomers polymerize in the microdomain, which widens the reaction site and forms a wider PA film. Commonly used organic solvents added to the organic phase are acetone (AC), 26,[49][50][51][52][53] propanone, butanone, 54 ethyl acetate, 53 diethyl ether, toluene, isopropyl alcohol (IPA), and N,N 0 -dimethyl formamide (DMF) 26 in hexane, AC, ethyl acetate, and diethyl ether in dodecane, 55 and diethyl ether or ethyl acetate in heptane. 56 And some so-solvents including DMSO, 47,57 methanol, 50 alcohols 58 and dimethyl sulfoxide 47,59 were added into aqueous phase.…”

Circulating-infiltrating preparation of hydrophilic nylon 6 membrane to hydrophobic MWCNT@nylon composite membrane

“…Some multilayered TFN membranes are often cast from nanocomposite onto a polymeric substrate, while others can be coated in a polymerization reaction. In both methods, nanosized materials can be easily dispersed in coating layers to enhance the original features or adapt new abilities for TFNs such as hydrophilicity, electrostatic interaction, adsorption capacity, specific surface area, etc [3,6,[9][10][11][12][13][14][15][16][17][18][19][20]. Therefore, multi-layered TFN membranes have many applications in separation processes with longer lifetime than normal polymeric of TFC membranes.…”