Enhancement in permeability of piperazine‐based thin‐film composite membrane via surface roughening using a highly organic‐soluble additive

Abstract

The water permeability of a piperazine-based thin-film composite membrane was enhanced via roughening its smooth surface by adding a highly organic-soluble additive to a piperazine-aqueous solution. The additive could rapidly diffuse into organic solvent drawing piperazine during interfacial polymerization, and consequent, rapid diffusion of piperazine led to an increase in the size and number of ridges on the surface of the prepared membrane. Polyethylene glycol (PEG) was the most effective among the tested additives, and PEG with lower molecular weight exhibited a better effect. Mw 2000 PEG scarcely affected the surface roughness, whereas Mw 200 PEG raised the surface roughness by seven times. As a result, the membranes prepared with Mw 2000 PEG and Mw 200 PEG exhibited 9 and 41% enhanced water permeability compared to the control membrane, respectively, despite their similar hydrophilicity. This difference could be attributed to their different surface roughness.

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

“…Introducing a water-soluble polymer into the aqueous solution of the interfacial polymerization reaction is an effective method to prepare a membrane with a crumpled structure. Chae and Kim 48 added polyethylene glycol (PEG) with a molecular weight of 200 Da and piperazine to water to prepare a PA membrane. Compared with PIP, small-sized PEG molecules have better solubility in the oil phase and are easier to diffuse from aqueous solution to organic solution.…”

“…Comparison in surface roughness of the original membranes and crumpled membranes based on the literatures 45,48,[60][61][62]66,[69][70][71][72][73]78,79,[81][82][83][84]86,88,90,91,[93][94][95]97,[99][100][101]111,[114][115][116]118,121 [Color figure can be viewed at wileyonlinelibrary.com]…”

Development and Investigation of Hierarchically Structured Thin-Film Nanocomposite Membranes from Polyamide/Chitosan Succinate Embedded with a Metal-Organic Framework (Fe-BTC) for Pervaporation

“…One of the most common approaches to tackling this challenge is the use of additives during the synthesis of a selective layer by IP. For this purpose, surfactants, nanoparticles and nanomaterials, hydrophilic polymers, and multifunctional additives are added to either an aqueous or organic phase during IP [ 73 , 74 , 75 , 76 ]. More often than not, nanomaterials are used as modifying agents that can improve the characteristics of the polyamide layer: increasing hydrophilicity, anti-fouling, catalytic ability, narrow dispersed nanochannels, and so on.…”

Optimization of water flux and salt rejection properties of polyamide thin film composite membranes

“…Therefore, numerous research studies have been devoted to explore the underlying correlations between the synthesis parameters for the PA and desalination properties of the final TFCs. The most important parameters include the type and concentration of monomers and additives, organic solvents, reaction time, curing time and temperature, posttreatment strategies, and fabrication method of the PA layer …”